Search

As formigas cortadeiras, cujo nome deriva do habito de cortar folhas e outras partes de plantas, sao herbivoros dominantes nas Americas, atacando diferentes culturas para manter o fungo simbiotico (principal fonte de alimento) na colonia. Habitam o solo, ambiente rico em microorganismos, muitos dos quais sao considerados entomopatogenicos. Para descrever um tipo de controle biologico microbiano nessas formigas, atraves de tecnicas histologicas, utilizou-se o fungo Beauveria bassiana (Bals.-Criv.) Vuill., aplicado em larvas e trabalhadores adultos de Atta sexdens (Linnaeus, 1758), que foram expostos a uma suspensao de fungos com a concentracao de 106/conidios/mL. Foram adequadamente preparados para descrever o comportamento do fungo no tegumento as 24, 48 e 72 horas apos a exposicao inicial. Alguns individuos foram utilizados para representar esses periodos, sendo processados adequadamente para realizar a tecnica do microscopio eletronico de varredura para documentar o desenvolvimento do fungo na superficie do tegumento do inseto. Para entender melhor a dinâmica da infeccao fungica, desde a adesao dos conidios ate a potencial colonizacao no interior do inseto, foi aplicada a tecnica histologica com coloracao com HE. Os resultados mostraram que, em individuos imaturos, a penetracao das hifas de B. bassiana no tegumento do inseto ocorreu em 48 h.

Made available in DSpace on 2022-04-29T08:35:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Claustral foundation of nests by Atta sexdens Forel (Hymenoptera: Formicidae) involves great effort by its queens, solely responsible for the cultivation of the fungus and care for her offspring at this stage. The minimum workers, after 4 months, open access to the external environment to foraging plants to cultivate the symbiotic fungus, which decomposes the plant fragments and produces gongilidea nodules as food for the individuals in the colony. Colony gas exchange and decomposition of organic matter in underground ant nests generate carbon dioxide (CO2) emitted into the atmosphere. We described the carbon dioxide concentration in colonies in the field. The objective was to evaluate the carbon dioxide concentration in initial A. sexdens colonies, in the field, and their development. The CO2 level was also measured in 4-month-old colonies in the field, using an open respirometric system fitted with an atmospheric air inlet. The CO2 level of the respirometric container was read by introducing a tube into the nest inlet hole and the air sucked by a peristaltic pump into the CO2 meter box. The CO2 concentration in the initial colony was also measured after 4 months of age, when the offspring production (number of eggs, larvae, pupae and adult workers) stabilized. Ten perforations (15 cm deep) was carried out in the adjacent soil, without a nest of ants nearby, to determine the concentration of CO2. The composition of the nests in the field was evaluated after excavating them using a gardening shovel and they were stored in 250 ml pots with 1 cm of moistened plaster at the bottom. The CO2 concentration was higher in field nest than in adjacent soil. The concentration of carbon dioxide in A. sexdens nests in the field is higher than in those in the soil, due to the production of CO2 by the fungus garden and colony. Departamento de Proteção Vegetal Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agronômicas Campus Experimental de Itapeva Universidade Estadual Paulista Departamento de Entomologia/BIOAGRO Universidade Federal de Viçosa Laboratório de Fitossanidade (FitLab) Instituto Federal de Mato Grosso Departamento de Proteção Vegetal Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agronômicas Campus Experimental de Itapeva Universidade Estadual Paulista

Chemical control using toxic baits containing the active ingredient sulfluramid at 0.3% (w/w) is the main method for controlling leaf-cutting ants of the genera Atta and Acromyrmex. However, since 2009, when sulfluramid was included in Annex B of the Stockholm Convention on Persistent Organic Pollutants, there has been an intense search for new methods that are efficient in controlling these insects. Among said new methods, biological control using pathogenic fungi has shown promising results in laboratory conditions. The objective of this study, given the context presented, was to assess the potential of the fungi Beauveria bassiana and Trichoderma harzianum in controlling Atta sexdens. Colonies of A. sexdens were exposed to the fungi by means of formulated baits provided in a foraging chamber, or of suspensions sprayed on the fungus garden, and had their behavioral changes recorded for 21 days. For both formulations, concentrations of 10 and 20% (w/w) of the fungi being studied were used. The results allowed concluding that baits containing 10 and 20% (w/w) of the fungi B. bassiana and T. harzianum were not efficient in controlling colonies of A sexdens. On the other hand, spraying suspensions of 20% (w/w) of B. bassiana and 10% and 20% (w/w) of T. harzianum was efficient and resulted in 100% mortality of the colonies 11, 9 and 7 days after application, respectively. These findings indicate that the fungi B. bassiana and T. harzianum are promising as agents for the control of A. sexdens colonies, when sprayed on the fungus garden, although there are still some challenges as to their use related to the development of technologies for the application of the pathogen. RESUMO O controle químico com iscas tóxicas contendo o ingrediente ativo sulfluramida a 0,3% (p/p) é o principal método de controle de formigas cortadeiras dos gêneros Atta e Acromyrmex. No entanto, desde 2009, quando a sulfluramida foi incluída no Anexo B da Convenção de Estocolmo sobre Poluentes Orgânicos Persistentes, há uma intensa busca por novos métodos que sejam eficientes no controle desses insetos. Dentre os novos métodos, o controle biológico por fungos patogênicos tem mostrado resultados promissores em condições de laboratório. O objetivo deste estudo, dado o contexto apresentado, foi avaliar o potencial dos fungos Beauveria bassiana e Trichoderma harzianum no controle de Atta sexdens. Colônias de A. sexdens foram expostas aos fungos por meio de iscas formuladas fornecidas em câmara de forrageamento, ou de suspensões pulverizadas no jardim de fungos, e tiveram suas alterações comportamentais registradas durante 21 dias. Para ambas as formulações, foram utilizadas concentrações de 10 e 20% (p/p) dos fungos em estudo. Os resultados permitiram concluir que iscas contendo 10 e 20% (p/p) dos fungos B. bassiana e T. harzianum não foram eficientes no controle de colônias de A. sexdens. Por outro lado, a pulverização de suspensões de 20% (p/p) de B. bassiana e 10% e 20% (p/p) de T. harzianum foi eficiente e resultou em 100% de mortalidade das colônias aos 11, 9 e 7 dias após a aplicação, respectivamente. Esses achados indicam que os fungos B. bassiana e T. harzianum são promissores como agentes de controle de colônias de A. sexdens, quando pulverizados sobre o jardim de fungos, embora ainda existam alguns desafios quanto ao seu uso relacionados ao desenvolvimento de tecnologias para a aplicação do patógeno.

Made available in DSpace on 2021-06-25T11:00:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 BACKGROUND: Leaf-cutting ants (LCAs) of the genera Atta and Acromyrmex (Hymenoptera: Formicidae) are important pests of forest plantations, agriculture and livestock. Toxic baits containing the active ingredients fipronil or sulfluramid are the main method used to control LCAs. Insecticide dispersion among members of an LCA colony during control with toxic bait is not well understood. The objective of the study was to determine whether self-grooming, allogrooming or touching behavior among Atta sexdens (Hymenoptera: Formicidae) workers disperses the insecticides fipronil and sulfluramid among members of the colony. The insecticides were topically applied on groups of A. sexdens workers and social interactions between ants with and without insecticide, and group mortality were evaluated. RESULTS: Behavioral analysis showed an increase in interaction among LCA workers as the numbers of individuals increased, with touches between workers being the most frequent behavior. The frequency of observed behaviors was higher in groups treated with sulfluramid compared with fipronil. The mortality of groups treated with fipronil was almost twice as high compared with ants treated with sulfluramid. The insecticides are probably dispersed by excessive touching among workers and subsequent self-grooming and allogrooming. CONCLUSION: These behaviors were responsible for the rapid dispersion of insecticides among members of the colony. Corroboration of the hypothesis that social interactions contaminate nestmates is a model for future studies on contamination of ant workers with active insecticide ingredients. Laboratory of Social Insects Pests Department of Plant Protection Faculty of Agronomic Sciences State University of São Paulo (UNESP) Department of Entomology/BIOAGRO Federal University of Viçosa (UFV) Itapeva Experimental Campus State University of São Paulo (UNESP) Laboratory of Social Insects Pests Department of Plant Protection Faculty of Agronomic Sciences State University of São Paulo (UNESP) Itapeva Experimental Campus State University of São Paulo (UNESP)

Made available in DSpace on 2022-04-29T08:36:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-01 Toxic baits, containing the active ingredients sulfluramid or fipronil, are the main methods to control leaf-cutting ants of the genera Atta Fabricius, 1805, and Acromyrmex Mayr, 1865 (Hymenoptera: Formicidae). However, the insecticide dispersion among members of the colony during the control needs further studies. We studied whether the behaviors of allogrooming, self-grooming, and contact among individuals spread the insecticides among those of the colony. The insecticides sulfluramid and fipronil (0.1% and 1.0% (w/w)) were applied topically in groups of workers of Atta sexdens (Linnaeus, 1758), and the social interactions among them with or without insecticide were studied. In addition, toxic baits (sulfluramid or fipronil) were provided to colonies and their behavioral acts were observed. At the end of the experiment, colony mortality, number and mass of dead workers, and mass of wet waste were compared between ant nests receiving baits and ants with topical application. In the topical application, behavioral analysis showed higher interaction between ants in the colonies and touch and allogrooming behaviors as the most frequent in those that received the concentrations of sulfluramid. In the baits, the behavior of licking the pellet and allogrooming was more frequent. Colony mortality was faster for those that received topical application, especially with the insecticide fipronil (0.1%). However, the number and mass of dead workers was similar between topical application and toxic baits. In the toxic baits, the licking behavior of the bait pellets and subsequent allogrooming probably dispersed the insecticides. In the topical application, the route of the insecticide occurred by excessive touches among workers, with subsequent allogrooming. Thus, allogrooming, self-grooming, and touching among workers increased the dispersion of insecticides among members of the ant colonies. Depto de Produção Vegetal Faculdade de Ciências Agronômicas Univ Estadual Paulista - FCA/UNESP, São Paulo Depto de Entomologia/BIOAGRO Univ Federal de Viçosa - UFV, Minas Gerais Lab de Fitossanidade (FitLab) Instituto Federal de Mato Grosso - IFMT, Mato Grosso Campus Experimental de Itapeva Univ Estadual Paulista - UNESP, São Paulo Depto de Produção Vegetal Faculdade de Ciências Agronômicas Univ Estadual Paulista - FCA/UNESP, São Paulo Campus Experimental de Itapeva Univ Estadual Paulista - UNESP, São Paulo

Simple Summary The used active ingredient sulfluramid for toxic baits for the control of leaf-cutting ants has been included in Annex B of the Stockholm Convention on Persistent Organic Pollutants. The use of entomopathogenic fungi to control these insects has shown promising results, Trichoderma harzianum showed high pathogenicity against A. sexdens rubropilosa larvae and pupae, leading to a faster mortality and a decrease in survival rates. Beauveria bassiana was responsible for causing faster worker mortality and lower survival rates. An individual contaminated with B. bassiana or T. harzianum in a group decreases its survival rate, supporting the hypothesis that entomopathogenic fungi are efficient in controlling leaf-cutting ants when contaminated workers are allocated to groups of healthy workers. Abstract In 2009, sulfluramid, the main ingredient in toxic baits for leaf-cutting ant control, was included in Annex B of the Stockholm Convention on Persistent Organic Pollutants. This resulted in interest in the use of entomopathogenic fungi such as Beauveria bassiana and Trichoderma harzianum for leaf-cutting ant control. The efficiency of these fungi in controlling these insects and the way that ants react individually or in group to the biological risks posed by these fungi is poorly understood. For this reason, we assessed the effects of B. bassiana and T. harzianum on Atta sexdens rubropilosa larvae, pupae and workers. Moreover, we investigated whether the number of contaminated individuals within a group has an influence in controlling the spread of fungi among workers. We found that the fungus T. harzianum showed high pathogenicity against A. sexdens rubropilosa larvae and pupae, leading to faster mortality and a survival rates. On the other hand, the fungus B. bassiana was responsible for causing faster worker mortality and lower survival rates. In addition, we observed that an increase in individuals contaminated with B. bassiana or T. harzianum in the group decreases its survival rate. The results support the hypothesis that entomopathogenic fungi are efficient in controlling leaf-cutting ants when contaminated workers are allocated to groups of healthy workers.

Made available in DSpace on 2021-06-25T12:30:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Leaf-cutting ants are widely distributed in Brazil, particularly species of the genus Atta. We therefore described the occurrence of leaf-cutting and grass-cutting ant species of the genus Atta. Five routes comprising some of the main highways in the South, Southeast, Midwest, and North of Brazil were sampled, in addition to ants received from other 82 municipalities, composing 300 municipalities sampled. This is the first comprehensive study of Atta in Brazil. The following species and subespecies were found: A. laevigata, A. capiguara, A. sexdens rubropilosa, A. sexdens piriventris, A. sexdens sexdens, and A. cephalotes. Atta laevigata and A. capiguara were the species present in the largest number of the Brazilian municipalities sampled. Atta sexdens piriventris was only recorded in the southern region of Brazil. Atta bisphaerica presented lower expansion than A. capiguara. Atta cephalotes and Atta opaciceps are species of very restricted occurrence. Southeastern region was characterized by the occurrence of A. capiguara and A. laevigata. Atta laevigata exhibited a generalized pattern of occurrence in the Midwest and North. Our study contributes to a better understanding of the so far unknown occurrence of leaf-cutting and grass-cutting ants within Brazil. State Univ Sao Paulo, Sch Agr Sci, Vegetal Protect Dept, Lab Social Insects Pests, Botucatu, SP, Brazil State Univ Northern Parana, Vegetal Prod Dept, Campus Luiz Meneghel, Bandeirantes, Brazil State Univ Southwestern Bahia, Dept Crop Sci & Anim Sci, Vitoria Da Conquista, Brazil State Univ Sao Paulo, Sch Agr Sci, Vegetal Protect Dept, Lab Social Insects Pests, Botucatu, SP, Brazil CNPq: 301718/2013-0

Made available in DSpace on 2021-06-25T12:28:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Asclepias curassavica L. plant is toxic for vertebrates, and little is known about its effects on invertebrates, as well as whether its secondary metabolites have an influence on food preference and survival of insects. Thus, a study was conducted to verify the action of A. curassavica on Spodoptera frugiperda J.E.Smith. The plants were collected, dried and ground to compose a crude ethanolic extract. Food tests were carried out with and without opportunity of choice, using corn leaf discs immersed in the extract at concentrations of 1%, 2% and 4%, for assessment of food consumption (g) and preference index. Later, the extract was topically applied on secondand fifth-instar caterpillars, at concentrations of 1%, 2%, 4% and 6%, in order to observe its effect on survival. In parallel, analysis was conducted to verify the presence and measure the amount of total polyphenols and flavonoids in the extract. There was contact action between the extract and second-instar caterpillars at all concentrations, with treatment 6% causing 100% of mortality 72 hours after application. None of the treatments promoted contact action on fifth-instar caterpillars. In food tests with and without opportunity of choice, all treatments caused reductions in consumption, which classified all as phagodeterrent, with treatment 4% standing out as the least favorite. The presence of total polyphenols and flavonoids was found in the extract, presenting 58.75 ug/mL and 150.1 ug/mL, respectively. The A. curassavica extract proved promising in S. frugiperda control. Univ Oeste Paulista, Univ Western Sao Paulo, UNOESTE, Coll Agr Sci,Agron Dept,Lab Agr Entomol, Presidente Prudente, SP, Brazil Univ Oeste Paulista, Univ Western Sao Paulo, UNOESTE, Coll Agr Sci,Agron Dept, Presidente Prudente, SP, Brazil Univ Estadual Paulista, Sao Paulo State Univ, Vegetal Protect Dept, Lab Social Insects Pests, Botucatu, SP, Brazil Univ Estadual Paulista, Sao Paulo State Univ, Vegetal Protect Dept, Lab Social Insects Pests, Botucatu, SP, Brazil CNPq: 301718/2013-0

Made available in DSpace on 2020-12-10T17:33:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-22 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Colonies of leaf-cutting ants of the genus Atta need to collect large quantities of vegetal substrate in their environment to ensure their growth. They do so by building and extending over time a foraging network that consists of several underground tunnels extending above ground by physical trails. This paper presents a longitudinal study of the foraging network of two mature colonies of the grass-cutting ant Atta capiguara (Goncalves) located in a pasture in central Brazil. Specifically, we investigated whether the extension of the foraging area of the colonies required to reach new resources occurs by building new and longer underground tunnels or by building new and longer physical trails. Each nest was surveyed at intervals of approximately 15 days during 1 year. At each survey we mapped the position of the tunnel entrances and foraging trails at which activity was observed. In addition, we assessed the excavation effort of the colonies since the last survey by the number and distance to the nest of new tunnel entrances, and the physical trail construction effort by the number and length of newly built physical trails. Our study reveals that in A. capiguara the collection of new resources around the nest required to ensure the continuous growth of the colonies is achieved mainly through the excavation of new underground tunnels, opening at greater distance from the nest, not through the building of longer aboveground physical trails. Univ Estadual Paulista, Sao Paulo, Brazil Univ Fed Juiz de Fora, Juiz De Fora, Brazil Univ Toulouse, CNRS, Toulouse, France Univ Estadual Paulista, Sao Paulo, Brazil FAPESP: 2011/003699 CAPES: 633/08

Made available in DSpace on 2018-12-11T17:20:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Social information exchange through physical contacts and chemical trail deposition forms the basis of food recruitment in leaf-cutting ants. The scout initiates the process and passes the information to nestmates that recruit more foragers, thus amplifying the stimulus and ensuring the success of foraging. An interruption of the contact between workers and a reduction in trail laying can diminish the effectiveness of mass recruitment and alter scouting activity and forager flow. This study verified an increase in scout trips as a consequence of inbound workers (with or without a plant load) removal during Atta sexdens foraging, sustaining the outbound flow of foragers, and consequently foraging activity, either through direct contact or chemical trail deposition. Data indicate as one of the roles of unladen workers along the foraging trail must be to stimulate other workers to go out and so speed up the recruitment process The remarkable ability to organize themselves without central control is a major strength of social insects and the increase in scouting activity observed here is an example of this behavioral flexibility in leaf-cutting ants. Although foraging performance is enhanced through communication between workers, the simple adjustment in scouting activity can maintain the outbound flow of foragers which is an essential activity of the colony. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal – Setor Defesa Fitossanitária FCA/UNESP, P.O. Box 237 PPGCB: Comportamento e Biologia Animal PPG: Ecologia Instituto de Ciências Biológicas – ICB Universidade Federal de Juiz de Fora – UFJF, Campus Universitário Martelos Laboratory of Agricultural Entomology Agronomy Department College of Agricultural Sciences University of Western São Paulo [Universidade do Oeste Paulista] (UNOESTE), São Paulo Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal – Setor Defesa Fitossanitária FCA/UNESP, P.O. Box 237 CNPq: 143495/2011-9 CNPq: 301917/2009-4

Made available in DSpace on 2018-12-11T17:34:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Atta bisphaerica is a species of grass-cutting ants commonly found in the Cerrado biome. The Brazilian Cerrado (savanna) biome covers 2 million km representing 23% of the area of the country. It is an ancient biome with rich biodiversity, estimated at 160,000 species of plants, fungi and animals. However, little is known about their nest architecture development. This study investigated the architecture of fourteen A. bisphaerica nests from Botucatu, São Paulo, Brazil. Molds were made of the nests by filling them with cement to allow better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. As expected, there was a lateral development in the nests and increase in the number of chambers over time. Results showed that in nests with an estimated age of 14 months, the average depth was 1.6 ± 0.4 m; for those with 18 months it was 2.2 ± 0.7 m and at 28 months it was 2.5 ± 0.7 m. The number of chambers varied from 4 to 7 in 28-month nests, 2 to 4 in 18-month nests, and from 2 to 3 in 14-month nests. With respect to the dimensions of the internal tunnels, there were variations in their average width, increasing with time. The fungus chambers were located beneath the largest mound of loose soil. This study contributes to a better understanding of the so far unknown nest architecture development of A. bisphaerica grass-cutting ants. Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agronômicas Universidade Estadual do Sudoeste da Bahia (UESB) Departamento de Fitotecnia e Zootecnia Laboratório s de Entomologia Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agronômicas CNPq: 301718/2013-0

Made available in DSpace on 2018-11-26T17:42:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 The bean weevil Acanthoscelides obtectus (Say, 1831) (Coleoptera: Bruchidae) is one of the most serious pests of stored beans worldwide because of the damage it causes to grains within warehouses. The use of resistant genotypes may offer a control strategy for this pest. In the current study, we screened common bean genotypes of Andean American and Mesoamerican origin in laboratory and greenhouse bioassays to select the most promising beans for resistance to the bean weevil. In the laboratory, we evaluated number of eggs, period of development (egg-adult), number of emerged adults, dry weight of adults, and weight of consumed grains. In the greenhouse, number of pods per plant and number of grains per pod were evaluated. We also assessed the percentages of damaged pods per plant and damaged grains per pod. Combining the results obtained in the laboratory and greenhouse assays, the common bean genotypes Arc.1, Arc.2, Arc.1S, Arc.5S, and Arc.3S were identified as resistance expressing antibiosis against A. obtectus. The lowest percentages of damaged pods were found in the Arc.1 and Arc.1S genotypes, and their resistance to damage was apparently morphological (antixenotic) because they possessed structures that prevented contact between larvae and grains. The use of resistant genotypes in combination with other techniques may improve management of the weevil. Additionally, the resistant genotypes identified here can be used in breeding programs to develop common bean lines with resistance to A. obtectus. Sao Paulo State Univ, Dept Crop Protect, Coll Agron Sci, BR-18610307 Botucatu, SP, Brazil Sao Paulo State Univ, Dept Plant Protect, Coll Agron & Vet Sci, BR-14884900 Jaboticabal, SP, Brazil Sao Paulo State Univ, Dept Crop Protect, Coll Agron Sci, BR-18610307 Botucatu, SP, Brazil Sao Paulo State Univ, Dept Plant Protect, Coll Agron & Vet Sci, BR-14884900 Jaboticabal, SP, Brazil

Made available in DSpace on 2021-06-25T12:20:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01. Added 1 bitstream(s) on 2021-07-15T14:36:13Z : No. of bitstreams: 1 S0085-56262020000300206.pdf: 1039700 bytes, checksum: b072abef0afea0c5f47e704564172bcc (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Atta capiguara grass-cutting ants are commonly found in the Cerrado biome, in open fields. Although grass-cutting ants build giant nests, little has been elucidated about this building pattern and when chambers and tunnels emerge. The present study describes the nest architecture development of A. capiguara grass-cutting ants from data on 31 cement-molded nests. A. capiguara nests grow with increases in the number of fungus chambers and emergence and increase of waste chambers and foraging tunnels. The structural growth of A. capiguara nests in the first year and a half of age (18 months) is vertical, with the building of the first chambers in the soil profile. After 18 months, the nests grow sideways with the addition of chambers and tunnels, and the first waste chambers appear. Between 18 and 54 months, the number of fungus chambers increases from 1-3 to 21-32, and the chambers are concentrated at the soil surface, although they can be found more than 3 in deep. In addition, the total volume of the waste chambers increases with the increment in the fungus chambers volume. Thus, this study contributes to understanding the nest architecture development of A. capiguara grass-cutting ants and demonstrates that the total volume of waste chambers is proportional to the total volume of fungus chambers suitable for the colony. Univ Estadual Paulista, Fac Ciencias Agronom, Dept Protecao Vegetal, Botucatu, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agronom, Dept Protecao Vegetal, Botucatu, SP, Brazil CAPES: 001 CNPq: 301-938/2017-2

Chemical control of leaf-cutting ants is widely used, but alternative control with toxic plant extracts is promising. Substances with insecticidal potential extracted from plants have numerous ecological advantages. This study evaluated the insecticidal and/or fungicidal potential of the plants Asclepias curassavica (tropical milkweed), Rosmarinus officinalis L. (Lamiaceae) (rosemary) and Equisetum spp. (horsetail) for control of the leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 (Hymenoptera: Formicidae). Forty laboratory-reared colonies of Atta sexdens rubropilosa were used. The plants were collected, dried out in a circulating air oven for 48 hours, ground, and macerated in 96 o ethanol until exhaustion. After filtration, the products were evaporated under reduced pressure to obtain the ethanolic extracts. Acceptance of the reagent, topical application of the extracts, and application of baits containing 4% of the plant extracts were tested. The results showed that all plant extracts tested negatively influenced the development of the fungus garden. Baits produced with Asclepias curassavica caused the highest mortality of the colonies within 7 days. In conclusion, the ethanolic extracts of Asclepias curassavica , Rosmarinus officinalis and Equisetum spp. exhibit insecticidal (contact and ingestion) and fungicidal activity in colonies of the leaf-cutting ant Atta sexdens rubropilosa .

Made available in DSpace on 2019-10-06T16:30:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-04-03 The success of incipient colonies of leaf-cutter ants depends on multiple factors such as temperature, humidity, soil type, the queen’s fertility and vigor, frequency of harmful microfungi, among others. Based on this observation, three factors related to Atta sexdens were characterized: (1) initial nest morphology (depth and volume); (2) queen oviposition rate; and (3) prevalence of Escovopsis (parasitic fungus) and other fungi in incipient colonies. Our observation showed a variation in chamber dimensions and volume, indicating differences in colony development rates. The oviposition rate of queens from nests of the same age showed a difference among queens. About microfungi prevalence, it was found that many are potentially deleterious. In particular, the parasite Escovopsis was present in 16.7% of the colonies. Our study shows positive correlations between queen condition and nest size/fungus garden size. These correlations collectively suggest that ecological factors such as plant availability can generate substantial variation between nests and thus shape the success of incipient colonies. Laboratory of Entomology Department of Phytotechny and Zootechny State University of Southwestern Bahia [Universidade Estadual do Sudoeste da Bahia] (UESB) Laboratory of Social Insects-Pests Department of Vegetal Protection School of Agricultural Sciences São Paulo State University [Universidade Estadual Paulista] (UNESP), Postal Code 237 Laboratory of Agricultural Entomology Agronomy Department College of Agricultural Sciences University of Western São Paulo [Universidade do Oeste Paulista] (UNOESTE) Laboratory of Social Insects-Pests Department of Vegetal Protection School of Agricultural Sciences São Paulo State University [Universidade Estadual Paulista] (UNESP), Postal Code 237

Made available in DSpace on 2020-12-10T19:50:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Toxic baits are the most efficient method to control leaf-cutter ants in eucalyptus forests for paper and cellulose production. For the proper use of these baits, insecticide compounds must reach workers and contaminate them. Thus, understanding how these baits are processed inside the nests is vital for a successful control, especially when it comes to genus Acromyrmex. Lack of information on toxic baits and on contamination of Acromyrmex workers raises the question: do workers from subspecies Acromyrmex subterraneus (Forel) prepare leaves and toxic baits in similar ways for their fungus garden? To answer it, this study described and analyzed the behavioral repertoire executed by A. subterraneus workers during the preparation of leaf disks and baits and their incorporation into the fungus garden. Results show that the act of licking the substrate was the most frequently executed behavior, regardless of subspecies or size categories. Moreover, additional behaviors have been observed when workers processed the baits, such as licking and scraping their jaws on the surface of the bait pellet, as well as licking and biting fragments of bait pellets, moistening them. Thus, it is concluded that the preparation of baits is different from that of leaves; baits are more processed and can therefore contribute to contaminating workers via insecticides. Sao Paulo State Univ, Sch Agr Sciences,Vegetal Protect Dept, Lab Social Insects,Pests, Botucatu, SP, Brazil Sao Paulo State Univ, Expt Campus Itapeva, Sao Paulo, SP, Brazil Univ w Sao Paulo, Coll Agr Sciences, Agron Dept, Lab Agr Entomol, Presidente Prudente, SP, Brazil Sao Paulo State Univ, Sch Agr Sciences,Vegetal Protect Dept, Lab Social Insects,Pests, Botucatu, SP, Brazil Sao Paulo State Univ, Expt Campus Itapeva, Sao Paulo, SP, Brazil CNPq: . 301167/2003-6 CAPES: Finance Code 001

Made available in DSpace on 2020-12-10T19:40:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-07 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Leaf-cutter ants perform a series of specialized behaviors in preparing plant substrates for their symbiotic fungus. This process may be related to contamination of workers by substances such as insecticides, leading us to hypothesize that substances are spread among workers through behaviors they perform to grow the fungus. To test this hypothesis, we analyzed the behavioral acts of workers during the processing of the pellets by using a fat-soluble tracing dye, since the active ingredient that composes toxic baits, used for control of leaf-cutter ants, is fat-soluble. The frequencies of performed behaviors were recorded and the number of dyed workers was assessed after fungus cultivation. The most frequent behavior is allogrooming and corresponds to 45.87% of the contamination process in workers, followed by holding, licking, and cutting pellets, which account for 40.22% of the process. After pellet processing, the workers had their external and internal morphological structures marked by the tracing dye-93.75% and 79.25%, respectively. These results confirm that behaviors performed during fungus cultivation contribute to dispersing substances such as insecticides, causing the contamination of workers. Univ Estadual Paulista, Fac Ciencias Agron, Dept Protecao Vegetal, Botucatu, SP, Brazil Univ Fed Piaui, Campus Univ Ministro Petronio Portella, Teresina, PI, Brazil Univ Estadual Paulista, Fac Ciencias Agron, Dept Protecao Vegetal, Botucatu, SP, Brazil CAPES: 001 CNPq: 301-938/2017-2

Made available in DSpace on 2019-10-06T16:16:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-25 Research related to the comparative biology of phylogenetically close ant species has received little attention, although it is the basis for understanding the systematics of some sibling groups. The objective was to study the polygyny, oviposition, life cycle and longevity of the three subspecies of leaf-cutting ants. For that, we studied: oviposition rate – queens from three colonies were individually placed in plastic containers, and at 24-hour intervals, the laid eggs were quantified over a period of 96 hours; the workers’ life cycle – the development of immature ants was observed every 24 hours and, as a result, the duration of each stage of development was determined; the workers’ longevity – newly emerged adults were tagged and returned to the fungus chamber of their respective nests, and daily observations were made in each of the nest’s chamber. Laying rates were variable in the three queens studied, with a mean of total eggs laid of 271 for Acromyrmex subterraneus brunneus, 113 for Acromyrmex subterraneus subterraneus and 119 for Acromyrmex subterraneus molestans.The incubation period was 21.2 days in A. s. brunneus, 22.8 days in A. s. subterraneus and 20.4 days in A. s. molestans. The larval phase and pupal phase lasted on average 22.5 and 21.2 days in A. s. brunneus, 22.8 and 15.8 days in A. s. subterraneus and 17.2 and 14.2 days in A. s. molestans, respectively. Life cycle was different in the studied taxa, from 62 to 77 days in A. s. brunneus, from 59–68 days in A. s. subterraneus and from 51 to 55 days in A. s. molestans. The workers’ longevity varied between subspecies A. s. brunneus, A. s. subterraneus and A. s. molestans. Laboratory of Social Insects-Pests Vegetal Protection Department College of Agricultural Sciences São Paulo State University (Universidade Estadual Paulista) UNESP Laboratory of Agricultural Entomology Agronomy Department College of Agricultural Sciences University of Western São Paulo (Universidade do Oeste Paulista) (UNOESTE) College of Biological Sciences Student Federal University of Piauí Laboratory of Social Insects-Pests Vegetal Protection Department College of Agricultural Sciences São Paulo State University (Universidade Estadual Paulista) UNESP

Cyphoderus innominatus Mills, 1938 (Collembola: Paronellidae) was first observed in early colonies of Atta sexdens leaf-cutting ants (Hymenoptera: Formicidae). The colonies were collected on February 6, 2019, from a transition area between the Atlantic Forest and the Cerrado, located in the municipality of Botucatu, São Paulo, Brazil. A total of four colonies collected had an average population density of 227 ± 212 C. innominatus individuals, and most of the latter were found in peripheral areas inside the fungus-garden-growing chamber of the colony. In addition, we observed a possible defensive behavior on the part of workers when C. innominatus individuals were present in the fungus garden chamber. Thus, this is the first record of C. innominatus living in association with early colonies of A. sexdens. Cyphoderus innominatus Mills, 1938 (Collembola: Paronellidae) foi observado pela primeira vez nas primeiras colônias de formigas cortadeiras Atta sexdens rubropilosa , Forel, 1908 (Hymenoptera: Formicidae). Essas colônias foram coletadas em 6 de fevereiro de 2019, em uma área de transição entre a Mata Atlântica e o Cerrado, localizada no município de Botucatu, São Paulo, Brasil. Um total de quatro colônias coletadas teve uma densidade populacional média de 227, de C. innominatus , ea maioria dos últimos foram encontrados em áreas periféricas dentro da câmara de cultivo do jardim de fungo da colônia. Além disso, observamos um possível comportamento defensivo por parte dos trabalhadores quandoC. innominatus estava presente presentes na câmara do jardim de fungos. Assim, este é o primeiro registro de C. innominatus vivendo em associação com colônias iniciais de A. sexdens rubropilosa .

Made available in DSpace on 2018-12-11T17:00:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Dynamics of the restoration of physical trails in the grass-cutting ant Atta capiguara. Leaf-cutting ants of the genus Atta build long physical trails by cutting the vegetation growing on the soil surface and removing the small objects they find across their path. Little is known on the dynamics of trail construction in these ants. How much time do they need to build a trail? To answer this question we selected six trails belonging to two different nests of A. capiguara and removed on each trail a block of soil of 20 cm × 15 cm that included a portion of the physical trail. This block was then replaced by a new block of the same size that was removed in the pasture near the trail and that was uniformly covered by the same type of vegetation as that found on the block of soil that was removed. The time required to restore the trail was then evaluated by the length of the grass blades found along the former location of the trail. The results show that ants rapidly restore the portion of the physical trail that was interrupted, which suggests that they could also do the same after their trails have been recolonized by the vegetation. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas Universidade Estadual Paulista (UNESP) MirmecoLab Programa de Pós-graduação em Ciências Biológicas Comportamento e Biologia Animal Universidade Federal de Juiz de Fora Université Fédérale de Toulouse Midi-Pyrénées UPS Centre de Recherches sur la Cognition Animale CNRS Centre de Recherches sur la Cognition Animale Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas Universidade Estadual Paulista (UNESP)

Made available in DSpace on 2021-06-25T21:08:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Simple Summary Atta bisphaerica grass-cutting ants build giant nests with hundreds or thousands of large chambers. Here, we assessed whether the total volume of fungus chambers and other nest parameters grow at close or similar proportions to worker numbers in the A. bisphaerica colony. The fungus garden biomass, external area, and total fungus chamber volume increased at rates similar to that of worker numbers. The total volume of chambers, and external area increased at a similar proportion to that of the number of workers, probably due to the fungus garden allocation needs of the colony. On the other hand, the number of fungus chambers, number of entrance holes, and nest depth increased more slowly than the number of workers. Thus, this study demonstrates that A. bisphaerica nest development regarding the total volume of chambers is similar to the increase in the number of colony workers. Atta grass-cutting ants (Formicidae: Myrmicinae: Attini) are found in the Cerrado biome and build giant nests with hundreds or thousands of large chambers. We assessed for Atta bisphaerica grass-cutting ants whether the total volume of fungus chambers and other nest parameters grow at close or similar proportions to worker numbers in the colony. Data on fungus garden biomass, population, external area, number of entrance holes, number of fungus chambers, total fungus chambers volume, and nest depth were obtained during colony growth/nest development. Our results reveal that the fungus garden biomass, external area, and total fungus chamber volume increased at rates similar to the increase in the number of workers. The total volume of chambers, and external area increased at a similar proportion to the increase in number of workers, probably due to the fungus garden allocation needs of the colony. The number of fungus chambers, number of entrance holes, and nest depth increased less than 4-fold for every 10-fold increase in the worker number. In addition, the height of the fungus chambers increased as the width increased, a pattern not observed for tunnel height and length, and the chamber volume increased according to worker number. Thus, this study demonstrates for A. bisphaerica that nest development in terms of chamber volume is similar to the increase in number of colony workers, and this contributes to a better understanding of Atta nest architecture. Sao Paulo State Univ, Sch Agron Sci, Dept Vegetal Protect, BR-18603970 Botucatu, SP, Brazil Sao Paulo State Univ, Sch Agron Sci, Dept Vegetal Protect, BR-18603970 Botucatu, SP, Brazil CAPES: 001 CNPq: 301718/2013-0

Made available in DSpace on 2018-12-11T17:22:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-01 During foraging, thousands of leaf-cutting ant workers travel along high traffic foraging trails which, when narrow, reduce the leaf delivery rate due to the reduction in workers’ travel-speed. On the other hand, high worker traffic promotes head-on encounters which are supposed to mediate worker task allocation and so could constitute a cue which induces traffic reduction. Very small workers along trails, for example, could change their task between marking the trail chemically to hitchhiking. Since they assume the hitchhiker function even in the absence of phorid parasitoids, one can suppose that hitchhiker behavior could be a strategy mediated by head-on encounters to avoid the high density of workers. Thus, we studied how the variation of worker density on the trail influences the hitchhiker frequency, testing the hypothesis that very small workers climb on the transported leaves to reduce trail traffic. Therefore, five Acromyrmex subterraneus colonies were linked to a foraging area by trails of different width (1.5 or 3 cm). We counted the number of hitchhikers and the outbound worker flow. The frequency of hitchhikers increased along narrow trails, and also due to outbound workers in both trail widths. Regardless of outbound foraging flow being comparable in both trail widths, the narrower ones had high density of workers leading to a presumed increase in head-on encounters. Head-on encounter rates cause a reduction in travel speed and, furthermore, are regulatory factors of task-allocation. Thus, high density trails lead to an increase in the rate of head-on encounters which could constitute as a stimulus to task-allocation of very small workers to the function of hitchhiker to avoid traffic jams. Programa de Pós-Graduação em Ecologia Universidade Federal de Juiz de For a, Rua José Lourenço Kelmer, s/n. Campus Universitário, Bairro São Pedro Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Setor Defesa Fitossanitária FCA/UNESP, PO Box 237 Programa de Pós-Graduação em Ciências Biológicas Comportamento e Biologia Animal Universidade Federal de Juiz de Fora, Rua José Lourenço Kelmer, s/n. Campus Universitário, Bairro São Pedro Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Setor Defesa Fitossanitária FCA/UNESP, PO Box 237

Made available in DSpace on 2018-12-11T17:20:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-07-01 Leaf-cutting ants live symbiotically with a fungus that they cultivate on the plant leaves that they cut. The innumerous studies on the plant selection mechanism used by leaf-cutting ants show the researchers’ interest in this issue. Many classical studies propose that plants are selected according to the fungus garden nutritional needs and the absence of potentially harmful substances. This hypothesis is corroborated by behavioral experiments using cycloheximide (fungicide) with citric pulp or forage plants greatly accepted by leaf-cutting ants. According to this hypothesis, under the action of a fungicide, the fungus emits an allomone that informs worker ants that some food is inadequate to its growth. Although some authors state that the cycloheximide “fungicide” used is specific and non toxic to ants, our findings are distinct. In our study, various concentrations of cycloheximide were administered orally to leaf-cutting worker ants in a citric pulp paste diet. After the ingestion period, the ants were isolated and offered the symbiotic fungus for 21 days and the mortality rate was evaluated. As expected, the treatment with 0.01% cycloheximide showed a low mortality rate (8.86%). At 0.1%, the mortality rate was mild (27.85%), and treatment with 1% cycloheximide resulted in moderate mortality (45.57%). In contrast, the positive control with 0.1% sulfluramid showed a high mortality rate (91.14%). Therefore, we concluded that the ingestion of high concentrations of cycloheximide results in a moderate mortality rate in leaf-cutting worker ants. Universidade Estadual Paulista – UNESP Faculdade de Ciências Agronômicas Departamento de Produção Vegetal Laboratório de Insetos Sociais-Praga Universidade Estadual Paulista – UNESP Faculdade de Ciências Agronômicas Departamento de Produção Vegetal Laboratório de Insetos Sociais-Praga

Our study seeks to discover contamination routes of leaf-cutting worker ants during chemical control by formicide baits. To do so, toxic baits containing fat-soluble tracer dye were provided to colonies of three subspecies of Acromyrmex under laboratory conditions, in order to assess the proportion of dyed workers by size category, as well as dyed internal morphological structures. Results showed that nearly 50% of the workers come into contact with the active ingredient, since the internal structures of their bodies are dyed by the fat-soluble tracer dye within the first 24 h from contact with the toxic bait. In addition, the three subspecies of leaf-cutting ants present a similarity as to the contamination of their workers, probably due to their specialized behavior performed during the growth of the fungus garden with the baits. We conclude that the workers’ pattern of behavior during fungus garden growth was the main means for dispersion of a fat-soluble substance among approximately half of the nest mates in our experiments, serving as a model for further studies on contamination of worker ants with insecticides.

Made available in DSpace on 2018-11-26T17:48:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 During foraging, worker ants are known for making use of many information sources to guide themselves in external environments, especially individual (memory) and social (trail pheromone) information. Both kinds of information act in a synergic way, keeping the foraging process efficient and organized. However, when social and individual information is conflicting face a trail bifurcation, it is necessary to establish a hierarchical order so prioritizing one of them. This study aims to verify which information (social or individual) is prioritized by Acromyrmex subterraneus workers when facing a bifurcation in a Y-trail system. Only one branch of the Y-trail leads to food resource and it had a section covered by filter paper where trail pheromone was deposited by workers. Pheromone deposition was here estimated by worker flow. After an individually marked forager (target-worker) made 1, 3 or 5 trips to the food resource, the filter paper was transferred to the branch which did not lead to the food. The time spent by target workers on branch selection and their right choice (branch with food) frequency were registered. Regardless of the target worker's previous trips to the resource, right choice frequency stood over 70%. In addition, the number of previous trips did not influence the time spent on decision making. However, the higher the flow of workers, the longer the time spent on decision making. By simulating a situation with conflicting information, it was possible to verify that a hierarchical order is established by A. subterraneus, which prioritized individual information (memory). (C) 2017 Sociedade Brasileira de Entomologia. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license. Univ Fed Juiz de Fora UFJF, Inst Ciencias Biol, MirmecoLab, Juiz De Fora, MG, Brazil Univ Estatal Paulista UNESP, Colegio Ciencias Agr, Dept Prod Vegetal, Botucatu, SP, Brazil Univ Fed Juiz de Fora UFJF, Inst Ciencias Biol, PPG Ecol, Juiz De Fora, MG, Brazil Univ Estatal Paulista UNESP, Colegio Ciencias Agr, Dept Prod Vegetal, Botucatu, SP, Brazil

Made available in DSpace on 2018-12-11T17:17:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Leaf-cutting ants are insects that use plant material to grow fungus from which they feed. These fungus-growing ants perform various behavioral activities to establish an environment conducive to the fungus. Among these behaviors are activities that can serve to detect materials harmful to the colony, such as licking, scraping, chopping, etc. However, there are substances that may not be detected as harmful to the fungus on first contact. Cycloheximide (CHX) is one such substance, described as a fungicide that inhibits the synthesis of proteins in eukaryotes, although its mechanism of action remains unclear. The present study aimed at evaluating the behavioral changes of worker ants, time carrying orange pellets, waste deposition and mortality, when subjected to seven days of CHX-incorporated pellets and another seven days of CHX-free pellets. The fungicide adversely and structurally affected the leaf-cutter ant colonies. Their behavior went through changes, such as an increase in pellet-licking frequencies and cleaning among the ants from the third day onward. Moreover, there was an increase in time carrying orange pellets, as well as in the mortality of workers during CHX incorporation. Laboratório de Insetos Sociais-Praga Departamento de Proteção Vegetal Faculdade de Ciências Agronômicas UNESP, Caixa Postal 237 Laboratório de Insetos Sociais-Praga Departamento de Proteção Vegetal Faculdade de Ciências Agronômicas UNESP, Caixa Postal 237 CNPq: 301718/2013-0

Made available in DSpace on 2018-12-11T17:13:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Studies related to the demography of individual members from ant colonies have received little attention, although they are the basis to understanding the population dynamics of colonies. Thus, the objective of this work was to study the queen oviposition rate and the duration of the life cycle and longevity of Acromyrmex rugosus rugosus workers. To determine the oviposition rate, queens from three colonies were individually placed in plastic containers, and the eggs laid were quantified over a 96 h period. The development of the immature forms was observed every 24 h, with which the duration of each stage of development was determined. To verify the longevity of workers, the newly emerged adults were marked and daily observations were made. According to the results, there is variation in the development time of immature forms within the colony itself and between colonies. In addition, the number of eggs deposited was also inconstant in the three colonies, ranging from 5 to 119 eggs per day, while the longevity of workers varied from 3 to 7 months. Occasionally, it was found that the workers feed on the eggs produced by the queen; besides, there was a disappearance of larvae and pupae during the research, indicating a possibility of the practice of cannibalism in this species. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal-Defesa Fitossanitária Faculdade de Ciências Agronômicas UNESP-São Paulo State University Fazenda Experimental Lageado, Rua José Barbosa de Barros Faculdade de Ciências Biológicas e Ambientais Universidade Federal da Grande Dourados UFGD Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal-Defesa Fitossanitária Faculdade de Ciências Agronômicas UNESP-São Paulo State University Fazenda Experimental Lageado, Rua José Barbosa de Barros CNPq: 301167/2003-6

Made available in DSpace on 2018-12-11T17:12:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-06-09 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The aim of this study was to determine whether worker self-grooming, allogrooming, and direct contact promotes the dispersal of substances among members of the colony. For this purpose, a tracer (Sudan III dye) was applied topically to a worker ant and the social interactions between the worker with the tracer and workers without the tracer were studied. Additionally, the worker heads were dissected to visualize whether or not the post-pharyngeal gland was stained. The post-pharyngeal glands from 50% to 70% of workers were stained depending on the size of the group. With the increase in the experimental group size, the frequency of interactions between workers increased, with touching being the most frequent behavior. The tracer dye was probably passed on by direct contact between workers, followed by self-grooming and allogrooming. These behaviors are responsible for the rapid dispersal of substances among colony members as observed in our experiment. The results therefore support the hypothesis that contact with substances promotes the contamination of nestmates, even in the absence of feeding, serving as a model for further studies on the contamination of workers with the active ingredients of insecticides. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas UNESP, Caixa Postal 237 Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas UNESP, Caixa Postal 237 CNPq: 301718/2013-0

Made available in DSpace on 2018-12-11T17:11:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-06-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from a fragment of Cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found distant from the mound of loose soil and were spaced apart and distributed laterally at the soil profile. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers were separated and distant. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas/UNESP, Caixa Postal 237 Laboratório de Entomologia Departamento de Fitotecnia e Zootecnia Universidade Estadual do Sudoeste da Bahia (UESB), Caixa Postal 95 Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas/UNESP, Caixa Postal 237 FAPESP: 03/00082-5 FAPESP: 03/06935-0 CNPq: 301718/2013-0

Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from the fragment of cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the typical shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found outside the apparent main part of the nest and were spaced apart and distributed laterally at ground level. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers exhibited a sectoral distribution. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara.

Ascia monuste orseis (Godart) (Lepidoptera: Pieridae) is a production limiting pest in collard greens, Brassica oleracea (L.) var. acephala, cultivation. Because of the overuse and harmful effects of synthetic insecticides on nontarget species, the use of insect-resistant cultivars can be a valuable strategy in pest control. In this study, newly hatched A. monuste orseis larvae were confined to the leaves of 29 collard greens cultivars under a controlled environment to investigate plant resistance. We evaluated the incubation period, duration of instars, total duration of the immature and pupal phases, the egg to adult life cycle duration, mortality per instar, total weight of fifth instar larvae and pupae (age = 24 h) and larval and pupal sur- vival and eclosion. Antibiosis and/or antixenosis were observed in selected cultivars. The results show that Gig- ante I-915 (E) exhibited high larval mortality and that the Pires 1 de Campinas cultivar (P) prevented all pupae from proceeding to the adult stage. The Introducoes do mu- nicipio de Arthur Nogueira Z (Y), Cabocla (AA), Japonesa (R) and Manteiga de Mococa (M) cultivars prolonged the larval stage. Japonesa (R) and Introducoes do municipio de Arthur Nogueira Z (Y) increased the egg to adult devel- opmental period, and the Japonesa (R) cultivar also prolonged the pupal stage. The Verde-escura (O), Crespa de Capao Bonito (I), Couve de folhas Manteiga 900 Legitima PeAlto (AB), Gigante I-915 (E) and Manteiga Ribeirao Pires I-2446 (H) cultivars reduced the larval weight of A. monuste orseis.

This study investigated the stimulus for the exca- vation of fungus chamber by leaf-cutting ants (Atta sexdens rubropilosa) during nest building. Thus, it was hypothesized that the fungus garden or the brood is a stimulus for excavat- ing the chamber. Therefore, four treatments were designed: treatment 1, fixed number of workers (30), without the fungus garden and brood; treatment 2, fixed number of workers (30), with fungus garden (average weight 1.5 g) and without brood; treatment 3, fixed number of workers (30), without the fungus garden and with brood (30 larvae or pupae); and treatment 4, fixed number of workers (30), with fungus garden (average weight 1.5 g) and brood items (30 larvae or pupae). The variables studied were (a) morphological structure parameters (size and thickness of tunnels and the chamber formed (in centimeters)), (b) workers' excavation flow, and (c) soil vol- umeexcavatedevery24h.Asexpected,theresultssupportthe hypothesis that the fungus garden and brood are a stimulus for excavating the chamber. The hypothesis is confirmed by the absence of a functional structure, such as a chamber, when the symbiotic fungus and brood are absent. We can then conclude that the presence of the fungus garden and brood stimulate the workerstoa greater excavationactivity,resulting infunctional structures such as tunnels and chamber.

Made available in DSpace on 2014-10-01T13:08:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-12-01Bitstream added on 2014-10-01T14:04:07Z : No. of bitstreams: 1 S0085-56262013000400009.pdf: 141619 bytes, checksum: 8cca099e553cfaaa1176041d25192393 (MD5) Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius). During nest excavation, leaf-cutting ant workers undergo reduction in their body reserve, particularly carbohydrates. In order to estimate the energetic cost of digging, groups of 30 workers of the leaf-cutting ant Atta sexdens were sealed in a hermetic chamber for 24, 48 and 72 hours, with and without soil for digging, and had the CO2 concentration measured using respirometric chambers as well as volume of soil excavated (g). As expected, the worker groups that carried out soil excavation expelled more carbon dioxide than the groups that did not excavate. Therefore, a worker with body mass of 9.65 ± 1.50 mg dug in average 0.85 ± 0.27 g of soil for 24 hours, consuming ca. 0.58 ± 0.23 J. In this study, we calculate that the energetic cost of excavation per worker per day in the experimental set-up was ca. 0.58 J. Universidade Federal de Juiz de Fora Instituto de Ciências Biológicas UNESP Faculdade de Ciências Agronômicas Departamento de Produção Vegetal UNESP Faculdade de Ciências Agronômicas Departamento de Produção Vegetal

Anualmente, as colônias maduras de Atta spp. produzem formigas aladas, machos e fêmeas, que abandonam a colônia na qual foram produzidas para formarem novas colônias e, dessa forma, continuarem a perpetuação da espécie. A fundação de colônias de Atta spp. sempre envolve grande esforço da rainha, única responsável pelo cultivo do fungo e pelos cuidados consigo mesma e com sua prole. Nesse período de fundação ocorre o consumo de grande parte de suas reservas. O presente estudo investigou como o ambiente influencia o desenvolvimento das colônias recém-fundadas de Atta sexdens rubropilosa. Para tanto, foram comparadas colônias de campo coletadas cinco meses após a revoada e colônias mantidas em laboratório desde o voo nupcial. Foram analisados o peso e o tamanho da população (número de operárias, de larvas, de pupas e de ovos), o tamanho das operárias, o volume e peso do jardim de fungo e o esforço para a fundação dos ninhos (teor de lipídeos e peso das rainhas). Comparadas às colônias de campo, as colônias de laboratório apresentaram maiores valores no tamanho e no peso da população, no volume e no peso do jardim de fungo. As medidas das operárias, por classe de tamanho, não variaram entre as colônias de campo e de laboratório. O esforço da fundação dos ninhos foi maior nas colônias de campo, cujas rainhas apresentaram menor porcentagem de lipídeos e menor peso em relação às colônias de laboratório. Esses resultados demonstram que o ambiente exerce forte influência no desenvolvimento das colônias durante a fase de fundação, bem como sobre o status fisiológico das rainhas, sendo, portanto, a sobrevivência, o desenvolvimento e o sucesso da colônia reflexos das condições do ambiente e do esforço da rainha. Annually, mature colonies of Atta ants produce winged males and females, where leave the colony in which they were produced to form new colonies and thus continue the species perpetuation. The foundation of Atta spp. colonies always involves high queen effort, solely responsible for growing the fungus and the care with itself and its offspring. During the foundation there is consumption of body reserves. This study investigated how the environment influences the development of newly founded colonies of leaf cutting ant, Atta sexdens rubropilosa. Therefore, it was compared field colonies collected five months after the nuptial flight and colonies maintained in the laboratory since the nuptial flight. It was analyzed the weight and size of the population (number of workers, larvae, pupae and eggs), the workers size, the volume and weight of the fungus garden and queen effort for the nest foundation (lipid content and weight of queens). In comparison to the field colonies, the laboratory colonies showed higher values in the weight and size of population, the volume and weight of the fungus garden. Measures of workers by class size did not vary between colonies from field and laboratory. The queen effort for nest foundation was higher in field colonies, which showed a lower percentage of fat and lower weight compared to laboratory colonies. These results show that the environment has a strong influence on the colonies development during the foundation, as well as on the physiological status of the queens, and therefore the survival, development and success of the colony, it is a reflection of the queen efforts and of the environment conditions.

As formigas cortadeiras, importantes pragas agrícolas, anualmente realizam a fundação de novas colônias. Para o início de novas colônias, é preciso a escavação de túneis e de câmaras no solo, sendo que, para isso, as rainhas recém fecundadas gastam muita energia, no entanto a quantificação dessa energia gasta é desconhecida. Nossa hipótese é que a reserva lipídica, armazenada no corpo da rainha, seja utilizada durante a escavação do ninho. Testamos essa hipótese comparando o aumento do esforço de escavação das rainhas, as quais foram experimentalmente estimuladas a escavar uma, duas ou três vezes consecutivas, em relação ao controle, ou seja, em relação às rainhas que não escavaram. Foram quantificados a massa corporal e o teor de lipídios das rainhas. Os resultados mostraram que, ao contrário de nossas expectativas iniciais, massa e teor de lípideos não foram afetadas pelo aumento do esforço de escavação do ninho. Conclui-se que a escavação pelas rainhas não afetou os percentuais de lipídios em seu corpo, consequentemente, o conteúdo de energia. Provavelmente, os recursos energéticos para a escavação não se originam de fontes lipídicas, mas de outros, provavelmente carboidratos. Nest digging spends a lot of energy existing a question about how much energy is required to dig the tunnel and initial chamber. It was hypothesized that the lipid content is used during nest digging. This hypothesis was tested by comparing the consequences of increasing digging effort in queens that were experimentally stimulated to excavate a complete founding nest either once, twice or three times consecutively, compared to control queens that didn't dig. Weight and lipid content of queens were quantified. Results showed that, in contrast with the initial expectations, weight and lipid content were not affected by the increased digging effort in the experimentally-induced successive excavations. It was conclude that the excavation by the queens did not affect the percentages of lipids and consequently the energy content, in their bodies. Probably, energy resources for the excavation wasn't originated from lipid reserves, but from other energy sources, perhaps carbohydrates.

Made available in DSpace on 2018-11-26T17:21:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01 This study investigated the stimuli that trigger digging behavior inAcromyrmex subterraneus during nest building. The hypothesis was that the presence of the fungus garden and/or brood triggers the excavation of tunnels and chambers. For the experiment, the excavation rate of individually marked workers kept in plastic cylinders filled with soil was recorded. Four treatments were applied: (1) 30 medium-sized workers, 5 g fungus garden and 30 brood items (larvae and pupae); (2) 30 medium-sized workers and 5g fungus garden; (3) 30 medium-sized workers and 30 brood items; (4) 30 medium-sized workers without fungus and brood. After 24 h, morphological parameters of nest structure (length and width of the chambers and tunnels in cm) and the volume of excavated soil were recorded. In contrast to the expected findings, no change in morphological structure, rate of excavation by workers, or volume of excavated soil was observed between treatments, except for tunnel width, which was greater, when no brood or fungus garden was present. Thus, the results do not support the hypothesis that the fungus garden and/or brood are local stimuli for nest excavation or that they mold the internal architecture of the nest. Although this hypothesis was confirmed for Acromyrmex lundii and Atta sexdens rubropilosa, the same does not apply to A. subterraneus. The digging behavior of workers is probably the result of adaptation during nest building in different habitats. (C) 2016 Sociedade Brasileira de Entomologia. Published by Elsevier Editora Ltda. Univ Fed Juiz de Fora, Inst Ciencias Biol, Programa Posgrad Comportamento & Biol Anim, Juiz De Fora, MG, Brazil Univ Estadual Paulista, Fac Ciencias Agron, Dept Prod Vegetal, Botucatu, SP, Brazil Univ Fed Juiz de Fora, Inst Ciencias Biol, Programa Posgrad Ecol, Juiz De Fora, MG, Brazil Univ Estadual Paulista, Fac Ciencias Agron, Dept Prod Vegetal, Botucatu, SP, Brazil

Made available in DSpace on 2018-12-11T17:07:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-09-01 Feeding adaptaton is crucial for the ecological success of animals, which explore specific or varied resources according to the suitability of the selected morphological feature. We hypothesized that the mandibles of leaf-cutng ants exhibit a specializaton because of the specific food preference of some species. The objectve of this study was to highlight possible morphological differences between the mandibles of leaf-cutng ant species of the genus Ata related to food preference, i.e., to investgate the morphofunctonality. A detailed descripton of the mandibles of workers of the grass-cutng ant Ata bisphaerica and of the leaf-cutng ant Ata sexdens rubropilosa was provided. For morphometric analysis, 50 individuals of four size classes were dissected for removal of the right mandible and one sample of each caste was processed for scanning electron microscopy. It was observed differences between species and among castes, demonstratng the clear specializaton of workers. Although the results of mandibular morphometry accept the hypothesis of morphofunctonality, further investgaton is needed taking into consideraton the body size of foragers, robustness and factors that confer greater resistance to the mandibles such as zinc content, the force employed during cutng, and mandibular biomechanics. Faculdade de Ciências Agronômicas UNESP Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal, Rua Dr. José Barbosa de Barros, 1780 Universidade Federal de Juiz de Fora Faculdade de Ciências Agronômicas UNESP Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal, Rua Dr. José Barbosa de Barros, 1780

Made available in DSpace on 2018-12-11T17:02:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-07-10 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ABSTRACT: Acromyrmex balzani is a grass-cutting ant species frequently found in Cerrado areas. However, little is known about the architecture of the polydomous nests of this ant. Fifteen A. balzani nests located in a cerrado region in Botucatu, São Paulo, Brazil, were studied. The polydomous nests were studied in three ways. First, we investigated the architecture in nests moulded with cement and without moulding. Second, we performed an aggressiveness test among workers in different subnests and nests. Third, we excavated the nest and collected the colony to measure the population, verifying the existence or not of a queen in all nests. A cement mould was made of seven nests to permit better visualization of internal structures such as chambers and tunnels. Eight nests were excavated without moulding and white neutral talc was used to highlight the parts of the nests. After excavation, the depth and dimensions (length, width and height) of the chambers were measured. The results showed that the nests had a single entrance hole whose structure consisted of straw and other plant residues in winter. Mounds of loose soil, if present, were found 6–48 cm from the hole. The number of chambers containing fungus ranged from one to five, with the first being found a few centimetres beneath the ground surface (4 cm) and the last up to a maximum depth of 160 cm. The length of the tunnels ranged from 12 to 28 cm. These tunnels were built in a vertical or inclined position, leading to the chambers. No waste chambers were found, with the waste being deposited externally. Additionally, the polydomous nests contained one to eight subnests. In the aggressiveness test, when concolonial workers were confronted, no aggressiveness was observed. In contrast, when allocolonial workers were confronted, there was a high incidence of aggression among them. Excavation of polydomous nests showed only one queen for each polydomous nest, i.e. subnests with a single queen. Our study contributes to a better understanding of the so far unknown nest architecture of the polydomous grass-cutting ant A. balzani. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas/UNESP Mirmecolab Instituto de Ciências Biologicas Universidade Federal de Juiz de Fora Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas/UNESP FAPESP: 07/04010-0 FAPESP: 07/07091-0

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:26:27Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:47:40Z : No. of bitstreams: 1 2-s2.0-84859727256.pdf: 5126920 bytes, checksum: af5898ee0221483de644477b66f68a1e (MD5) Made available in DSpace on 2014-05-27T11:26:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-04-18 We present a detailed description of the predatory behavior of the beetle Canthon virens Mannerheim, 1829, on the leafcutter ant Atta sp. We observed 51 acts of predation, which were also recorded on film and subjected to behavioral analysis. Canthon virens exhibited 28 behaviors while predating upon Atta sp. queens. Adult beetles search for queens while flying in a zigzag pattern, 15 to 20cm above the ground. After catching a queen, the predator stands on its back and starts cutting the queen cervix. Once the prey is decapitated, the predator rolls it until an insurmountable obstacle is reached. The distance from the site of predation to the obstacle can vary widely and is unpredictable. The beetle rolling the queen also buries it in a very peculiar way: first, it digs a small hole and pulls the queen inside, while another beetle is attached to the prey. The burial process takes many hours (up to 12) and may depend on the hardness of the soil and the presence of obstacles. In general, one or two beetles are found in a chamber with the queen after it is buried. They make the brood balls, which serve as food for the offspring. This study contributes to the knowledge of the predatory behavior of Canthon virens, a predator poorly studied in Brazil and widespread in the country. Copyright © 2012 Luiz Carlos Forti et al. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas, P.O. Box 237, 18603-970 Botucatu, SP Departamento de Zoologia Instituto de Biociências UNESP, 18618-970 Botucatu, SP Departamento de Zoologia Instituto de Biociências UNESP, 18618-970 Botucatu, SP

Made available in DSpace on 2013-08-12T18:58:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-01 Made available in DSpace on 2013-09-30T17:45:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:20:16Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T13:20:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-01 Leaf-cutting ant workers dig underground chambers, for housing their symbiotic fungus, interconnected by a vast quantity of tunnels whose function is to permit the entrance of food (leaves), gaseous exchanges, andmovement of workers, offspring, and the queen. Digging is a task executed by a group of workers, but little is known about the group effect and group-constructed functional structures. Thus, we analyzed the structures formed by worker groups (5, 10, 20, and 40 individuals) of the leaf-cutting ant, Atta sexdens rubropilosa, for 2 days of excavation. The digging arena was the same for the 4 groups, with each group corresponding to a different density. Our results verified a pattern of tunneling by the workers, but no chamber was constructed. The group effect is well known, since the 40-worker group dug significantly more than the groups of 5, 10, and 20. These groups did not differ statistically from each other. Analysis of load/worker verified that workers of the smallest group carried the greatest load. Our paper demonstrates the group effect on the digging of nests, namely, that excavation is proportional to group size, but without emergence of a functional structure such as a chamber. Laboratorio de Insetos Sociais-Praga, Departamento de Producao Vegetal, Faculdade de Ciencias Agronomicas, UNESP, P.O. Box 237, 18603-970 Botucatu, SP, Brazil Laboratorio de Insetos Sociais-Praga, Departamento de Producao Vegetal, Faculdade de Ciencias Agronomicas, UNESP, P.O. Box 237, 18603-970 Botucatu, SP, Brazil

Nest foundation in the leaf-cutting ant Atta sexdens is claustral, and the single queen completely relies on its body reserves throughout, approximately, 9 weeks until the first workers emerge and initiate foraging. Nest digging is much time- and energy-consuming, and it is an open question how queens decide on the length of the tunnel they dig and therefore the depth of the initial chamber. Shallow founding nests may be energetically cheaper to dig, but queens may be more exposed to changing environmental variables. Deeper nests, on the other hand, may be climatically more stable and suitable, but more expensive to dig. We hypothesized that the maximal nest depth excavated by Atta founding queens may represent the outcome of an evolutionary trade-off between maximizing nest depth and minimizing energy expenditure during digging, so as to save energy for the long claustral phase. We tested this hypothesis by comparing the fitness consequences of increased digging effort in queens that were experimentally stimulated to excavate a complete founding nest either once, twice or three times consecutively compared to control queens that did not dig. Fitness was quantified as mortality rates, rates of egg-laying and offspring production, and size of the fungus garden until the emergence of the first workers. Results showed that, in contrast with the initial expectations, fungus growth, egg-laying rates and offspring production were not affected by the increased digging effort in the experimentally induced successive excavations. However, a significant higher mortality was observed in queens with increased digging effort, i.e., those that dug two or three nests consecutively. It is argued that in queens a behavioral mechanism for the control of nest depth has evolutionary been selected for as a trade-off between maximizing nest depth, to favor protection of the queen against unsuitable environmental variables, and minimizing energy expenditure during digging, which significantly affects survival.

Made available in DSpace on 2018-11-26T16:19:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-11 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Foraging networks are a key element for ant colonies because they facilitate the flow of resources from the environment to the nest and they allow the sharing of information among individuals. Here we report the results of an 8-month survey, extending from November 2009 to June 2010, of the foraging networks of four mature colonies of Atta bisphaerica, a species of grass-cutting ant which is considered as a pest in Brazil. We found that the distribution of foraging effort was strongly influenced by the landscape features around the nests, in particular by the permanently wet parts of the pasture in which the nests were located. The foraging networks consisted of underground tunnels which opened on average at 21.5m from the nests and of above-ground physical trails that reached on average 4.70m in length. The use of the foraging networks was highly dynamic, with few sections of the networks used for long periods of time. Three different phases, which could be linked to the seasonal change in the local rainfall regime, could be identified in the construction and use of the foraging networks. The first phase corresponded to the beginning of the rainy season and was characterized by a low foraging activity, as well as a low excavation and physical trail construction effort. The second phase, which began in February and extended up to the end of the humid season at the end of March, was characterized by an intense excavation and trail construction effort, resulting in an expansion of the foraging networks. Finally, in the third phase, which corresponded to the beginning of the dry season, the excavation and trail construction effort leveled off or decreased while foraging activity kept increasing. Our hypothesis is that ants could benefit from the underground tunnels and physical trails built during the humid season to maintain their foraging activity at a high level. Univ Fed Juiz de Fora, Programa Pos Grad Ciencias Biol Comportamento & B, Juiz De Fora, MG, Brazil Univ Fed Juiz de Fora, Programa Pos Grad Ecol, Juiz De Fora, MG, Brazil Univ Estadual Paulista, Dept Prod Vegetal, Fac Ciencias Agron, Botucatu, SP, Brazil Univ Fed Toulouse Midipyrenees, Univ Toulouse 3, Ctr Rech Cognit Anim, Toulouse 9, France CNRS, Ctr Rech Cognit Anim, UMR 5169, Toulouse 9, France Univ Estadual Paulista, Dept Prod Vegetal, Fac Ciencias Agron, Botucatu, SP, Brazil CAPES: 633/09

UNESP, Dept Prod Vegetal, Lab Insetos Sociais Praga, Setor Defesa Fitossanitaria,FCA, BR-18603970 Botucatu, SP, Brazil

The aim of this paper is to investigate the influence of physical and chemical factors on transport and use of substrate for Atta sexdens rubropilosa workers. Three types of rectangular fragments were used to study the physical influence factors: filter paper with paraffin, filter paper without paraffin and polyester film. To study the chemical factors, some fragments were impregnated with organic extract of orange albedo, others were soaked with soybean oil and for the remaining ones nothing was applied. The following parameters were evaluated: (i) attractiveness of substrate for transport and number of loading workers per treatment; (ii) foraged material incorporation; (iii) rejection by numbers of fragments deposited in the garbage or beside the fungus garden. All the polyester film fragments carried out to the fungus garden were subsequently rejected. We verified that chemical factors of the substrate were more quickly detected by the workers, whereas physical factors were used as a criterion in the decision-making to reject or accept the substrate collected.

This study describes and quantifies the behavioural acts of two laboratory colonies of Acromyrmex subterraneus brunneus by investigating worker age polyethism. Twenty-nine behavioural acts were recorded during the 19-week observation period. Young individuals performed tasks inside the nest related to brood care and care for the fungus garden, whereas older individuals performed activities outside the nest such as foraging and activities in the waste chamber. The average longevity (±SD) was 108.21 ± 3.30, 109.15 ± 1.92 and 122.71 ± 1.55 days for large, medium and small workers, respectively. The small-sized workers presented a higher probability of reaching older age than large- and medium-sized workers. This study describes task switching according to age polyethism and the relationship of physical and temporal subcastes.

Made available in DSpace on 2018-12-11T17:00:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-01 Leaf-cutting ants rely on the obligate symbiosis with a fungus, Leucoagaricus gongylophorus, on which they feed. This fungus garden is maintained preferentially with green leaves in combination with other tissues of plant origin. The nutritional composition of this symbiotic relationship is extremely beneficial for the colony, representing the main food source for larvae and an important food component of adult workers. The objective of this study was to observe the behavioral repertoire of Atta sexdens rubropilosa during the preparation and incorporation of two different substrates, leaves and bait pellets, as well as the participation of each caste in these processes this process. The first substrate offered to the colonies were Citrus sp. leaves cut into disks and the second were pellets of citrus pulp bait formulated without the active ingredient. The observations were made under a stereomicroscope and were started when the first portion of the substrate offered was carried to the fungus garden. The behaviors executed during preparation and incorporation of the leaf disks, and subsequently of the bait pellets, were recorded using three colonies, with six repetitions of 5 and 7 hours per colony, respectively. Eight behavioral acts were recorded for the three castes found, irrespective of the substrate processed by the workers. Licking was the most frequently executed behavioral act, which occurred throughout the observation period, regardless of the substrate offered. Gardeners and generalists were the castes most engaged in the execution of this behavior. Considering the large number of individuals involved in the execution of this task, it can be concluded that this behavior is important for dispersion of the active ingredient and contamination of workers inside the colony. Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas UNESP, Caixa Postal 237 Campus Experimental de Itapeva UNESP Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas UNESP, Caixa Postal 237 Campus Experimental de Itapeva UNESP

Made available in DSpace on 2018-12-11T16:59:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-01 Foraging behavior of leaf cutting ants: How do workers search for their food? Forager ants search for adequate food sources in nature and, after their discovery, they decide whether the source is suitable or not for the colony. However, we asked How do workers seek out the substrate for cultivation of the symbiontic fungus on which they feed? To answer this question, we evaluated the distance traveled by individual workers in the search of food and the distance traveled to return to the nest, as well as the time and velocity necessary for these activities. The results showed that the distance traveled by the leaf cutting ant, Atta sexdens rubropilosa (Linneus, 1758), in the search of food was greater than the distance traveled to return with the substrate to the colony. On the other hand, the mean time and velocity were similar for food search and return to the colony. These results support the hypothesis of information transfer, according to which the worker needs to return to the nest at the beginning of foraging to transfer information to other workers and thus to establish the process of worker ant foraging. It can be concluded that workers travel large distances in a random manner until finding their substrate, but the return to the nest is efficient considering the shorter distance traveled. Universidade Estadual Paulista-UNESP Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas, Caixa Postal 237 Universidade Estadual Paulista-UNESP Laboratório de Insetos Sociais-Praga Departamento de Produção Vegetal Faculdade de Ciências Agronômicas, Caixa Postal 237

Leaf-cutting ant workers care for larvae with an elaborate behavioural repertoire to satisfy the needs of the offspring. In order to investigate worker discrimination ability in the leaf-cutting ant Acromyrmex subterraneus brunneus, we compared the behavioural responses of workers towards worker-produced male larvae and queen- produced worker larvae, including the following behavioural acts: licking the larval body, transporting larvae, feeding larvae with hyphae, scraping larval mouth parts, ingesting faecal fluid excreted by the larva, and inserting hyphae of the symbiontic fungus on the larval body. We verified that workers behaved differently depending on larval origin, i.e. licking the larval body, transporting larvae and inserting hyphae of the symbiontic fungus on the larval body. Observed differences denote the ability of workers in discriminating among larvae, probably because of their different individual needs.

The larvae of leaf-cutting ants are maintained within the fungus gardens of their colonies and are fed pieces of fungus by the adult workers. However, little else is known about the nature of the worker-larva interaction in these ecologically important ants. To examine whether workers can gauge the needs of individual larvae, we isolated larvae without adult workers for different lengths of time. We then placed workers with the larvae and recorded the type and frequency of the subsequent behaviours of the workers. Workers scraped the mouthparts of larvae, ingested their faecal fluid, fed them with fungal hyphae, transported them around the fungus garden and, most frequently, licked their bodies. The workers were also observed to ‘plant’ fungal hyphae on the bodies of larvae. Workers interacted more frequently with larvae that had been isolated without workers than with those that had not, but there was no effect of the length of isolation. The results suggest that the interactions are complex, involving a number of behaviours that probably serve different functions, and that workers are to some extent able to assess the individual needs of larvae.