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Ants use chemical cues known as cuticular hydrocarbons (CHCs) for both intraspecific and interspecific recognition. These compounds serve ants in distinguishing between nestmates and non-nestmates, enabling them to coexist in polydomous colonies characterized by socially connected yet spatially separated nests. Hence, the aim of this study was to investigate the intraspecific aggression level between nestmates and non-nestmates of the bullet ant Paraponera clavata (Fabricius, 1775), analyze and compare their CHCs, and evaluate the occurrence of polydomy in this species. We conducted aggression tests between foragers, both in laboratory and field settings. To identify the chemical profiles, we utilized gas chromatography coupled with mass spectrometry (GC-MS). We marked the foragers found at nest entrances and subsequently recaptured these marked ants to validate workers exchange among nests. Across all nests, a low intraspecific aggression level was observed within the same area. However, a significant difference in aggression correlated to distance between nests. Analysis of the cuticular chemical profile of P. clavata unveiled colony-specific CHCs, both qualitatively and quantitatively. Notably, we observed instances of ants from certain nests entering or exiting different nests. This behavior, in conjunction with the observed low intraspecific aggression despite differences in CHCs suggests polydomy for this species. Polydomy can offer several benefits, including risk spreading, efficient exploitation of resources, potential for colony size increasing and reduced costs associated with foraging and competition., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

When an insect walks, it leaves chemical cues that derive from the arolium, a tarsal structure. These cues may contain important information about other species that occur in their community and can then mediate interactions of competition, predation, and information about resources with ants from their own colony. The compounds of these cues are released into the substrate in the form of chemical footprints. There are still few species studied, and little is known about the behavior of ants regarding these signals and how they use them in their interactions. Therefore, the aim of this study was to assess the behavioral strategy of different ant species when confronted with chemical footprints left by other ants, as well as identify their compounds and their relationship with the cuticular hydrocarbon profile. The experiments were performed using a Y-maze, where in one of the arms, there were chemical footprints of their own species or of other species, and the other Y arm was footprint-free. The chemical compounds of footprints and cuticle were analyzed by gas chromatography-mass spectrometry. The results show that foragers of all species detect and respond to the presence of chemical cues in the form of footprints left by other ants. Foragers of all species followed footprints of individuals of the same species both nestmates and non-nestmates; however, Neoponera villosa avoided the footprints of Cephalotes borgmeieri, and C. borgmeieri avoided the footprints of the other two species. The chemical compositions of the cuticle and footprints are related to each other and are specific to each species., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Several studies have investigated the consequences of exposure to neonicotinoids in honeybees. Given the lack of studies concerning the consequences of exposure of social wasps to neonicotinoids, as well as the ecological importance of these insects, the objective of this study was to test the hypothesis that chronic exposure to sublethal concentrations of thiamethoxam decreases survival and mobility by causing damage to the brain and midgut of the social wasp Polybia paulista. The wasps were exposed to different concentrations of thiamethoxam, in order to obtain the mean lethal concentration (LC 50 ), which was used as a reference for calculation of two sublethal concentrations (LC 50/100 and LC 50/10 ) employed in subsequent experiments. To calculate survival, groups of exposed (EW) and unexposed (UW) wasps were monitored until death, allowing calculation of the average lethal time. The EW and UW groups were evaluated after 12, 24, 48, and 72 h of exposure, considering their mobility and histopathological parameters of the midgut and brain. A lesion index based on semiquantitative analyses was used for comparison of histopathological damage. The results demonstrated that exposure to the LC 50/10 led to a significantly shorter survival time of the P. paulista workers, compared to unexposed wasps. In addition, both sublethal concentrations decreased mobility and caused damage to the intestine (loss of brush border, presence of spherocrystals, loss of cytoplasmic material, and pyknosis) and the brain (loss of cell contact and pyknosis), regardless of the exposure time. The findings showed that, like bees, social wasps are nontarget insects susceptible to the detrimental consequences of neonicotinoid use, with exposure leading to impaired survival, locomotion, and physiology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Agricultural production and the indiscriminate use of insecticides such as thiamethoxam have put at risk the biodiversity and ecosystem services provided by bees, including native stingless species. Since most of the native species do not present economic importance, they may suffer "silent extinction", due to lack of monitoring of their colonies. Therefore, this study aimed to determine the lethal and sublethal concentrations of the insecticide thiamethoxam, with evaluation of its sublethal effects on mobility, in the stingless bee Plebeia catamarcensis (Holmberg, 1903). Foraging bees were collected and exposed to thiamethoxam to determine lethal (LC 50 ) and sublethal concentrations. The 24 h LC 50 was 0.408 ng a.i./μL, a value demonstrating that this species may be as sensitive as other stingless bees already studied. Sublethal concentrations influenced the locomotion abilities of the bees, making them hyperactive when exposed to LC 50/10 and lethargic when exposed to LC 50/100 . The effects of sublethal concentrations on individuals may have collective consequences, especially in colonies with few individuals, as is the case of P. catamarcensis. The findings reinforce the hypothesis that thiamethoxam may contribute to the decline of native stingless bees, which can be significantly impacted when chronically exposed to agricultural production systems that use this insecticide, consequently affecting the ecosystem services provided by these bees., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In the last few years, with the increase in agricultural productivity, there has also been an increase in the use of insecticides to combat insects considered pests. However, these chemical compounds end up affecting nontarget insects that also interact with the crops. Studies have shown that social bees are among the insects that are suffering most from the effects of these compounds, resulting in negative ecological and economic impacts, considering that these insects provide pollination services in ecosystems. At the same time, social wasps also interact with plants, including cultivated ones, and perform ecological services similar to those of social bees, so it can be hypothesized that insecticides are also affecting social wasp colonies. Therefore, the purpose of this study was to evaluate contamination and sublethal effects of neonicotinoids on the mobility of the social wasp Protopolybia exigua (Saussure). In the first step, oral exposure experiments were performed to determine lethal and sublethal concentrations. In a second step, the wasps were exposed to sublethal concentrations, in order to evaluate the effects on their mobility. The results demonstrated that this species is more susceptible to exposure to neonicotinoids, compared to several bee species that have so far been studied, but lower than others. Exposure to sublethal concentrations can significantly reduce wasp mobility, which can have short-term consequences both for worker wasps and for the maintenance of their colonies., (© 2023. Sociedade Entomológica do Brasil.)

Neonicotinoids are among the chemicals most widely used against insects considered agricultural pests, although they may also affect nontarget species, as has been reported for social bees. Social wasps are recognized as efficient predators of larvae of other insects, including pest species, so they may have contact with insecticides, at least indirectly. However, to date, there have been no studies investigating the consequences for social wasps of the use of neonicotinoids. Therefore, the aim of this study was to obtain the topical and oral acute lethal mean doses of the neonicotinoid thiamethoxam, as well as to evaluate the effects of sublethal contamination, for the social wasp Polybia paulista. Foraging wasps were exposed orally and topically, with monitoring of their mortality after 24 and 48 h, in order to calculate the LD 50 values. Other wasps were then exposed with sublethal doses, in order to evaluate the effects of contamination on their mobility. The results indicated that P. paulista workers are as sensitive to thiamethoxam contamination as several nontarget species studied previously. Exposure to a sublethal dose (LD 10 ) negatively affected their mobility. It could be concluded that social wasp colonies may be as much affected by exposure to neonicotinoids as social bees. Further toxicological studies should be conducted, evaluating other parameters and different species, in order to understand the extent of the problems faced by these insects due to the use of neonicotinoids., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Cuticular hydrocarbons perform multiple functions in insects such as protecting against desiccation and pathogenic infection, and signaling interactions. Evaluation of cuticular hydrocarbon (CHC) profiles of insects is commonly performed by extraction using a nonpolar solvent such as hexane. Specimens intended for CHC analysis are ideally handled by avoiding contact with solvents such as ethanol. However, insects are frequently stored in ethanol after collection, especially if intended for molecular analysis. To determine if it is possible that chemical compounds in the cuticles of specimens can withstand previous exposure to ethanol, we evaluated the efficiency of CHC extraction from specimens preserved in 95% ethanol. We extracted cuticular compounds from specimens of the social wasp Polybia paulista (Ihering) with no contact with ethanol solvents and compared them with those from specimens stored in 95% ethanol. We analyzed chemical composition from wasps and the 95% ethanol in which they had been stored by a gas chromatograph coupled to a mass spectrometer. In total, 56 compounds were detected: 50 that were classified as hydrocarbons which were mostly branched alkanes, followed by linear alkanes and alkenes. Three compounds were identified as fatty acids, and three compounds were unidentifiable. The ethanol-preserved specimens showed similar chemical profiles to those of specimens that had no contact with ethanol. Thus, we suggest that it is possible to study the chemical profiles of ethanol-preserved specimens., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Insects can provide clues in a variety of ways to assist in criminal investigations. The FTIR-PAS technique has been successfully used to assess the cuticular chemical profiles of insect samples from different groups and for several goals. However, until now, it has never been used to evaluate samples of forensic interest, despite providing faster results, compared to the methods currently used. In this study, mid-infrared photoacoustic spectroscopy was employed to assess the cuticular chemical profiles of different stages of development of the blow fly Chrysomya megacephala sampled from two distinct populations. The results showed that this technique enabled detection of significant differences between the main vibrational modes of the chemical bonds present in the cuticles of the two populations and the different stages of development of the fly. The method enables identification of the age of individuals collected at the crime scene, as well as the distinction of different populations. Therefore, this methodology could assist in forensic investigations, in both estimating the Postmortem Interval and determining the location where the crime occurred, or whether the body had suffered some type of translocation. The technique provides high reproducibility and fast analysis, so its application for analysis of C. megacephala is a viable option in forensic crime investigations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Chemical compounds present on the cuticle of social insects are important in communication, as they are used in recognition of nestmates and sexual partners as well as in caste distinction, varying according to several factors, such as genetic and environmental. In this context, some studies have explored the cuticular chemical profile as a tool for assessing intra- and interspecific differences in social insects, although few studies have investigated this in social wasps. This study aimed to assess the differences in cuticular chemical profiles among different geographic samples of the wasp Mischocyttarus consimilis Zikán. Our hypothesis was that environmental factors are decisive to compose the cuticular chemical profiles of colonies of these social wasps and that there are differences regarding the geographic distribution among colonies. We used Fourier Transform Infrared-Photoacoustic Spectroscopy (FTIR-PAS) to assess the chemical profiles of samples. Our results show that despite there are differences between the cuticular chemical composition of the wasps' samples from different populations, there is no significant correlation compared to the spatial distribution of the colonies nor with the environment. Thus, our hypothesis was refuted, and we can infer that in this species neither exogenous nor genetic factors stand out to differentiate the chemical signature of their colonies, but a combination of both.

Social insects such as ants can use geomagnetic field information in orientation and navigation tasks. However, few studies have assessed the effect of magnetic fields on aspects such as orientation and decision making during foraging of ants. Therefore, the present study aims to test the hypothesis that foragers of different species of ants with different foraging strategies when under effect of applied magnetic field change the patterns of search for resources and recruitment of ants. We used two species with solitary foraging strategy, Ectatomma brunneum and Neoponera inversa, and another with mass recruitment, Pheidole sp. The experiments were performed in field and laboratory conditions. We used some parameters for comparison such as speed, distance and time during foraging in the field and laboratory experiments, under normal and applied magnetic field with the coils on and off. We also performed SQUID magnetometry analysis for all species. The results demonstrate that changes in normal values of magnetic field affect workers behaviour of the three species. Thus, we can conclude that ants under the effect of applied magnetic fields can suffer significant changes in their foraging activities decreasing the flow of workers, increasing the travelled distance from the nest to the resource and back to the nest, in addition to time and distance to fetch the resource and decision-making, in both types of species, those which have mass recruitment, or forage individually, and that the three species are magnetosensitive, being affected by changes of low intensity in the local magnetic field., Competing Interests: The authors have declared that no competing interests exist.

One of the most important contributions of forensic entomology is to assist criminal expertise to determine the postmortem interval, which depends on the duration of the immature stages of insects of forensic interest. On the other hand, the time of development of the different stages varies according to the species; therefore, its identification is essential. Currently, few studies have investigated the use of cuticular hydrocarbons, and none regarding fatty acids, as complementary taxonomic tools to expedite species identification. Therefore, we evaluated whether cuticular hydrocarbons together with fatty acids of eggs of flies of the family Calliphoridae, main group of forensic interest, can be used to distinguish species. The analyses were performed by chromatographic techniques. The results show that there are significant differences between the composition of cuticular hydrocarbons and fatty acids between species and, therefore, they can be used to provide a complementary taxonomic tool to expedite the forensic expertise., (© 2019 American Academy of Forensic Sciences.)

Social insects depend on their nests for protection against predation and abiotic threats. Accordingly, the chemical compounds present in the material wasps use to build their nests can both facilitate communication and repel predators. It is herein hypothesized that different wasp species build their nests with different structure and substrate materials and that such materials consist of chemical compounds related to unique wasp behavior and outside temperature variation. To test this hypothesis, nests were collected from three species of social wasps, the samples of which were subjected to temperature variation under laboratory conditions. The compounds present in the substrate were analyzed by gas chromatography coupled to mass spectrometry. Chemical compounds identified in the nest material of the three species responded differently to temperature variation. Chemical compounds from Polybia nests were altered significantly when subjected to temperature variation, whereas the nests of Polistes versicolor did not significantly change in relation to the control. The differences found between Polistes and Polybia nests may be related to genetic factors, but also to the type of nest they construct. It is possible that divergent evolutionary strategies for maintaining colony temperature, as a function of the chemical composition of the nests, may have appeared between wasps that have open and closed nests. In relatively small colonies, nest substrate is more resistant to temperature variation because it is composed of a greater diversity of elements and thus capable of holding heavier, longer carbon chains. Our results suggest that chemical compounds in the nest material of the three wasp species analysed responded differently to fluctuating ambient temperatures and that such variation could result from the biochemical differences of unique wasp species or from thermoregulation strategies of colonies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Climatic factors, such as temperature variation, interfere with the survival of insects. To respond to these variations, insects have some specific characteristics. These include water content of the body, thickness of the lipid layer, as well as the qualitative and quantitative characteristics of cuticular chemical components. This study hypothesizes that different ant species respond to temperature changes in different ways and that such differences may be associated with cuticle hydrocarbons (CHCs) and fatty acids. As model ant species, Atta sexdens, Odontomachus bauri and Ectatomma brunneum were used for experimental analyses. Ants were submitted to a water bath for 5 h at different temperatures, and their CHCs and fatty acids were identified and quantified, followed by correlating these chemical compounds with temperature variations and the survival. Temperatures below 30 °C did not affect the survival of the three species. E. brunneum had a higher percentage of survival at temperatures above 30 °C. O. bauri was the most sensitive species with 100% mortality at 40 °C. Survival was found to be unrelated to any of the identified fatty acids. However, CHCs underwent significant quantitative and qualitative variation, as shown by an increased percentage of CHCs with longer chain length of linear alkanes at temperatures above 30 °C. These increase enables these ants to maintain the integrity of their cuticle and survive at temperatures above 30 °C. It can be concluded that the forager ants studied respond differently to temperature variation and that changes in the conformation of CHCs are in line with the ecological characteristics of the different studied species because, they vary in terms of diurnal/nocturnal foraging and types of environments foraged. Among the three species, E. brunneum foragers were found to be more active under adverse conditions and more tolerant to temperature variation with the correspondingly appropriate changes in CHCs composition., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Most flies of forensic importance are in two superfamilies, the Muscoidea and the Oestroidea, with similar life stages including the puparium. Upon completion of metamorphosis the adult fly emerges from the puparium, leaving behind an exuvia that is of potential significance in forensic investigation. The empty puparium is a durable piece of entomological evidence lasting several years. Through the study of chemical compounds, specifically the hydrocarbons of these puparia, it is possible to identify the species, in addition to how long they have been exposed to weathering and for this reason, these parameters can assist forensic entomologists in estimating long-term postmortem interval (minPMI). In corpses that take a relatively longer time to decompose, insects may use the same corpses for several oviposition cycles. Therefore, the aim of this study was to develop a new method to determine the PMI based on chemical compounds of the puparia from different oviposition cycles of the fly Chrysomya megacephala. The chemical composition of 50 puparia from different cycles of oviposition were evaluated by Gas Chromatography-Mass Spectrometry (GC-MS). In total, 60 compounds were identified ranging from C18 to C34, 38 of those were common to all generations. Our results demonstrate that chemical profiles can be used to differentiate puparia collected from successive cycles, and therefore valuable in the estimation of minPMI., Competing Interests: The authors have declared that no competing interests exist.

The cuticle of social insects is a barrier against desiccation and a channel for chemical communication, two characteristics fundamental to the success of this group. The compounds present in the cuticle interact dynamically in order to achieve a balance between these two functions. Thus, viscosity correlates with waterproofing, whereas fluidity correlates with effective communication. Temperature variation can cause the cuticular hydrocarbon (CHC) layer of the cuticle to change in order to maintain body homeostasis. Thus, in this study, we tested the hypothesis that wasps with different body sizes and nest types will differ in their tolerance to temperature variation and ability to respond by changing cuticular chemical composition. To test this hypothesis, workers of three species of social wasps with different body sizes and nests, both with or without envelope, were subjected to different temperatures under controlled conditions. Cuticular compounds were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Results show that tolerance to temperature variation is not directly related to either wasp size or nesting type. An increase in the percentage of linear alkanes and a decrease in the percentage of branched alkanes were correlated with increased temperature. Thus, instead of either body size or nest type, tolerance to temperature variation seems to be mediated by the changing chemical composition of the cuticle., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The aim of this study was to explore whether the nest chemical profile (NCP) can be used to determine intra- and interspecific differences in social wasps of the subfamily Polistinae. For this purpose, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to directly analyze small pieces of nest as well as the gasters of females. An advantage of the methodology was that no sample preparation was required. FTIR-PAS combined with multivariate discriminant analyzes was used, to the best of our knowledge for the first time, to evaluate the NCPs of six species of polistine wasps, observing the influence of the nesting environment and investigating the relationships among the nest and female cuticular chemical profiles. The results revealed significant inter-species differences among the NCPs, as well as strong correlations with the environments in which the nests were located. The Mischocyttarus and Polistes species belong to the same tribe (Polistini) and therefore exhibited similar NCPs. These species were separated from the Polybia species in the NCP dendrogram, mainly because the Polybia belong to another tribe (Epiponini). Correlation was observed between the NCPs and the cuticular chemical profiles of females. The findings of the study demonstrated the importance of the NCP for differentiation of species and environments, and the utility of FTIR-PAS for identification of correlations between individuals and nests. The results confirmed the hypothesis that the NCP can be used as an additional tool for intra- and interspecific differentiation in social wasps of the subfamily Polistinae., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Studies of venomous animals have shown that environmental and genetic factors contribute to determining the chemical composition of venom. It is well known that external effects cause differences in the toxicity, concentration, and prey specificity of venom. However, the influence of different factors on the chemical profile of Hymenoptera venom remains little explored. In view of this, the aim of this study was to evaluate intraspecific differences and the influence of diet on the chemical profile of Ectatomma brunneum venom using Fourier transform infrared photoacoustic spectroscopy. For the study of intraspecific variation of the venom, foragers were collected at locations with different environmental conditions, such as urban, intermediate, woodland and monoculture sites. To investigate the influence of diet on the venom, two colonies were sampled in the same area and were maintained in the laboratory under controlled diet conditions and at room temperature. The mid-infrared absorption spectra obtained were interpreted using discriminant function analysis. The results showed significant differences among the chemical profiles of the venoms of individuals from different environments and individuals exposed to a controlled diet in the laboratory, suggesting that venom composition was determined not only by genetic traits inherent to the species, but also by exogenous factors., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Wasps are able to synthesize toxic compounds known as venoms, which form a part of a mechanism to overcome prey and also to defend their colonies. Study of the compounds that constitute these substances is essential in order to understand how this defense mechanism evolved, since there is evidence that the venoms can vary both intra- and interspecifically. Some studies have used liquid and gas chromatography as a reliable technique to analyze these compounds. However, the use of Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) to analyze the variations in venom's chemical profile has been proposed recently. This study evaluated whether the FTIR-PAS technique is effective for assessing the role of environmental factors on intra- and interspecific differences in the venom of the wasps Polybia paulista Von Ihering and Polybia occidentalis Olivier by FTIR-PAS. The colonies were collected in three municipalities of Mato Grosso do Sul, Brazil, in different types of environments. The results showed that the venoms of P. paulista and P. occidentalis differed significantly in profile. In addition, the intraspecific differences in the venom's chemical profile of P. paulista are related to the type of environment where they nested, regardless of the geographical distance between the nests. The FTIR-PAS technique proved to be reliable and effective to evaluate the variations in the venom's chemical profile in social wasps.

Necrophagous insects such as blow flies (Diptera: Calliphoridae) are considered crucial in forensic entomology. Identification at species level and determination of larval stage are the basis for estimation of postmortem interval (PMI). Insect evidence can also be used in the determination of crime scenes, since body displacement is common. The aim of this study was to determine the chemotaxonomic profile and intraspecific variability of the forensically important blow fly Chrysomya megacephala (F. 1794). Adults were collected in the municipalities of Dourados-MS (Brazil) and Rio Claro-SP (Brazil), and then transferred to the laboratory for oviposition and development of the immature stages. Chemical analysis of cuticular compounds was performed by gas chromatography. Cuticular chemical profiles varied significantly between the two populations, as well as between developmental stages, supporting the use of these compounds as a complementary tool to help identify the species and its stages, along with geographical variability. This could greatly accelerate forensic investigations, eliminating the need to allow the fly larvae to develop until adult stage in order to confirm the species identity and sample origin., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Social wasps can face many challenges during their colony cycle, including the presence of parasites. The order Strepsiptera is among the main parasites of the wasp genus Polistes. The aim of this study was to evaluate the effect of an endoparasite species on the host Polistes ferreri, with the hypothesis that females of this social wasp would undergo morphophysiological alterations as well as changes in their cuticular chemical profile caused by the obligate endoparasite. On average, parasitism was found in 10% of the colonies studied. All the parasitized females showed filamentous ovarioles without developing oocytes, which indicates a physiological castration. Moreover, the endoparasites present in the gaster of females caused its volume to increase, and the presence of endoparasites changed the cuticular chemical profiles of females, confirming our hypothesis. It is likely that this parasitism effect could hamper the maintenance of wasp colonies.

Forensic entomology is a science that uses insect fauna as a tool to assist in criminal investigations and civil proceedings. Although the most researched insects are the Diptera and Coleoptera, ants may be present in all stages of decomposition. The aim of this study was to evaluate the role of ants and their action on blow flies during the decomposition process. Experiments were performed in which four pig carcasses were exposed in the cold and dry season (November/2012 and March/2013) and four in the hot and wet season (May/2013 and August/2013). Flies were the first insects to detect and interact with the carcasses, and six species of the Calliphoridae family were identified. Ants (Hymenoptera: Formicidae) were the second group, with six subfamilies identified. Myrmycinae represented 42% of the species, followed by Formicinae (28%), Ectatominae and Ponerinae (both 10%), and Ecitoninae and Dolichoderinae (both 5%). The ants acted on the carcasses as predators of visiting species, omnivores, and necrophagous, in all cases significantly affecting the decomposition time, slowing it down when the ants preyed on adult and immature insects consuming the carcass, or accelerating it by consuming the carcass and creating holes that could serve as gateways for the action of other organisms. The ants also generated artifacts that could lead to forensic misinterpretation., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Studies related to communication on spiders show that, as in other invertebrates, the interactions between conspecifics are also made through chemical signals. Therefore, in order to assess whether the composition of cuticular compounds might be involved in interactions that occur during the days after the emergence of juveniles in Latrodectus geometricus, we conducted behavioral and cuticular chemical profiles analysis of females and juveniles of different ages. The results show that females, regardless of their reproductive state, tolerate juveniles of other females with up to 40 days post-emergence and attack juveniles of 80 days post-emergence. Cuticlar chemical analysis shows that while the profile of juveniles is similar to adult's profile, they can remain in the web without being confused with threat or prey. Also, cuticular chemical profiles vary between different populations probably due to genetic and environmental differences or similarities between them. Finally, females in incubation period are able to detect the presence of eggs within any egg sac, but cannot distinguish egg sacs produced by conspecifics from the ones they had produced., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The chemical signature of social insects is very important for communication, and specific signs of each colony and its individuals are acquired throughout their development. This chemical signature can also be related to the composition of the materials employed during nest construction. Furthermore, the venom also contains important chemicals required for the maintenance of wasp colonies. Therefore, the objective of this study was to evaluate the chemical composition of the wasp Protopolybia exigua along its different development stages, including the nest substrate and the venom of adult worker at different ages. To achieve this, gas chromatography coupled to mass spectrometry was used. The results show that the chemical cuticular compounds present in different stages of development, and in the nest of P. exigua, are qualitatively similar, but quantitatively different, demonstrating that these compounds can be used as signals for the identification of co-specific individuals within the colonies. However, there was no significant variation in these compounds between different colonies, which may be related to the parental level between the colonies and due to them sharing the same resources. The non-polar compounds of the venom vary significantly according to the age of the workers, probably due to their different roles within the colony, and there was a clear increase in the complexity of the compounds as the wasps aged. Older wasps perform higher-risk activities, such as foraging, and therefore need to make more use of venom.

Apiculture in Brazil is quite profitable and has great potential for expansion because of the favorable climate and abundancy of plant diversity. However, the occurrence of pests, diseases, and parasites hinders the growth and profitability of beekeeping. In the interior of the state of São Paulo, apiaries are attacked by ants, especially the species Camponotus atriceps (Smith) (Hymenoptera: Formicidae), which use the substances produced by Apis mellifera scutellata (Lepeletier) (Hymenoptera: Apidae), like honey, wax, pollen, and offspring as a source of nourishment for the adult and immature ants, and kill or expel the adult bees during the invasion. This study aimed to understand the invasion of C. atriceps in hives of A. m. scutellata. The individuals were classified into castes and subcastes according to morphometric analyses, and their cuticular chemical compounds were identified using Photoacoustic Fourier transform infrared spectroscopy (FTIR-PAS). The morphometric analyses were able to classify the individuals into reproductive castes (queen and gynes), workers (minor and small ants), and the soldier subcaste (medium and major ants). Identification of cuticular hydrocarbons of these individuals revealed that the eight beehives were invaded by only three colonies of C. atriceps; one of the colonies invaded only one beehive, and the other two colonies underwent a process called sociotomy and were responsible for the invasion of the other seven beehives. The lack of preventive measures and the nocturnal behavior of the ants favored the invasion and attack on the bees.

Wasps belong to societies that are highly complex and diverse, especially considering social organization and parental care. They use chemicals in their daily communication, and act incisively in recognition of mates and non-nest mates, and can even identify individuals of different castes. In this study, cuticle composition was examined during the development of Polistes versicolor from the egg stage to adulthood, with the aim to assess changes in the chemical signature of the species, using gas chromatography. Linear alkanes and branched alkanes were identified that were important to distinguish the various developmental stages of P. versicolor. The variation in the linear alkanes and branched alkanes was quantitative, since most of them are present in all stages, with the exception of some linear alkanes that uniquely characterized the egg stage. At the egg stage, differences were predominant for linear alkanes C8, C24, C27, and C29. For the larval instars, there was a predominance of linear alkanes C8, C22 and C24 to C30. In the pre-pupae, pupae and adult stages, C8, C22, C24, and C26 to C30 showed a higher abundance during later developmental stages. The addition to branched alkanes increased their abundance from the egg (13.52%) to adult (22.96%) stages.

In the subfamily Polistinae, caste dimorphism is not pronounced and differences among females are primarily physiological and behavioral. We investigated factors that indicate the reproductive status in females of Polistes ferreri Saussure. We analyzed females from nine colonies and evaluated morphometric parameters, ovarian development, occurrence of insemination, relative age, and cuticular chemical profile. The colony females showed three kinds of ovarian development: type A, filamentous ovarioles; type B, ovarioles containing partially developed oocytes; and type C, long and well-developed ovarioles containing two or more mature oocytes. The stepwise discriminant analysis of the cuticular chemical profile showed that it was possible to distinguish the three groups of females: workers 1, workers 2, and queens. However, the stepwise discriminant analysis of the morphological differences did not show significant differences among these groups. The queens were among the older females in the colony and were always inseminated, while the age of the workers varied according to the stage of colony development.

The cuticular chemical composition plays a significant role in the recognition of nest mates in social insects, thus functioning as a chemical signature of the colony. The structure of cuticular chemicals is subject to interference from genetic and exogenous factors, including diet. In this study, various colonies of the Ectatomma brunneum ant were removed from their natural environment and housed in a laboratory to monitor the response of the cuticular chemical composition to dietary changes. Analyses were performed using gas chromatography and Fourier transform infrared photoacoustic spectroscopy, which has not been previously used for this type of analysis. The results indicate that this method is useful for analyzing biological and natural systems. We observed changes in the chemical signature with food traces in the first 30 days under feed control. Therefore, genetic information may not be the only criterion that can be used to describe the chemical signature of a species; environmental variations also influence recognition signals. Furthermore, these results reinforce the reliability of the Fourier transform infrared photoacoustic spectroscopy method.

Tropical ants commonly exhibit a hyper-dispersed pattern of spatial distribution of nests. In polydomous species, nests may be satellites, that is, secondary structures of the main nest, where the queen is found. In order to evaluate whether the ant Ectatomma opaciventre Roger (Formicidae: Ectatomminae) uses the strategy of building polydomous nests, the spatial distribution pattern of 33 nests in a 1,800 m(2) degraded area located in Rio Claro, SP, Brazil, were investigated using the nearest neighbor method. To complement the results of this investigation, the cuticular chemical profile of eight colonies was analyzed using Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). The nests of E. opaciventre presented a hyper-dispersed or regular distribution, which is the most common in ants. The analysis of the cuticular hydrocarbons apparently con-firmed the hypothesis that this species is polydomous, since the chemical profiles of all studied colonies with nests at different sites were very similar to the chemical signature of the single found queen and were also different from those of colonies used as control., (This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.)

Insects use pheromones as a means of chemical communication. Pheromones act on individual receptors and produce specific behavioral or physiological responses that are fundamental to intra- and interspecific recognition. The objective of this study was to evaluate the interspecific differences among the linear hydrocarbon profiles of the cuticles of 3 wasp species of the genus Mischocyttarus. The chemical strategy that permits an interaction among 2 of these species was also examined about their hydrocarbon profiles. The cuticular hydrocarbons present on the abdomen of each individual were extracted with hexane in an ultrasonic bath and analyzed using gas chromatography with a flame ionization detector. The results suggested that the wasp species have distinct chemical signatures as the linear hydrocarbons of their cuticles. However, these signatures are more alike in those with similar morphological and behavioral aspects. These similarities facilitate an interaction of facultative parasitism observed among these species, in which the invaders acquire parts of the chemical signature of the host colony, possibly as a chemical strategy to increase the likelihood that an invader will be accepted by the females of a host colony. Both invader and host have their own chemical signature changed by the first contact between the species.

One of the most important attributes that allowed the evolution and maintenance of sociality in insects is their ability to distinguish members of their own colonies. The capacity for individual recognition in social insects is mediated by chemical signals that are acquired soon after the adult emerges, and vary according to the tasks performed by individuals in their colonies. We determined the time when adults of the wasp Mischocyttarus consimilis acquire the chemical signature of their colonies, as well as the variation in the cuticular hydrocarbon profiles of the exoskeleton of individuals, according to their functions in the colony. The method used was Fourier transform infrared photoacoustic spectroscopy directly on the gaster of each individual. Young wasps take three to four days to acquire the colony's chemical signature, with a small change on the fifth day, when the cuticular hydrocarbon profile of the workers is more similar to that of the queens than that of the males, probably because they are of the same sex, but primarily because of the similarity of tasks executed by these two groups of females in the colonies.

The division of labor between castes and the division of labor in workers according to age (temporal polyethism) in social wasps are crucial for maintaining social organization. This study evaluated the division of labor between castes, and the temporal polyethism in workers of Mischocyttarus consimilis Zikán (Hymenoptera: Vespidae). To describe the behavioral repertory of this species, observations were made of 21 colonies, with 100 hours of observations. In order to observe temporal polyethism, each newly emerged wasp was marked with colored dots on the upper area of the thorax. This allowed the observation of behavioral acts performed by each worker from the time of emergence to its death. Through hybrid multidimensional scaling, a clear division between queens and workers could be identified, in which the behaviors of physical dominance and food solicitation characterized the queen caste; while behaviors such as adult-adult trophallaxis, destruction of cells, alarm, foraging for prey, foraging for nectar, and unsuccessful foraging characterized the worker caste. Hybrid multidimensional scaling characterized two groups, with intra-nest activities preferentially accomplished by younger workers, while extra-nest activities such as foraging were executed more frequently by older workers.

Tis study examined the nest architecture, colony productivity, and duration of the immature stages of the social wasp Mischocyttarus consimilis Zikán (Hymenoptera: Vespidae). The study was carried out under field conditions. Nests of M. consimilis consist of a single uncovered comb, which is attached to the substratum by a single petiole. The data for the nest architecture showed a positive and significant correlation between the size of the comb and the diameter of the petiole, and also between the height and diameter of the cells. The nests were constructed on horizontal, vertical, and sloping substrata with no apparent preference for a specific orientation. The colonies produced 72.9 cells and 40.7 adults on average. The mean frequency of productive cells was 33.3%, and 19.4% of the cells were reused. The mean duration of the immature stages combined was 69.7 days and the egg, larval, and pupal stages had mean durations of 14.9, 36.0, and 18.8 days, respectively. The duration of each immature stage was significantly shorter in the warm-humid season, and the larval and pupal stages were shorter during the colony pre-emergence stage.