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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 2018-11-26T16:19:11Z (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