Polydomy in the ant Ectatomma opaciventre.

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.

Bait and habitat preferences, and temporal variability of social wasps (Hymenoptera: Vespidae) attracted to vertebrate carrion.

In addition to feeding on carrion tissues and fluids, social wasps can also prey on immature and adult carrion flies, thereby reducing their populations and retarding the decomposition process of carcasses. In this study, we report on the occurrence and behavior of social wasps attracted to vertebrate carrion. The collections were made monthly from September 2006 to October 2007 in three environments (rural, urban, and forest) in six municipalities of southeast Brazil, using baited bottle traps. We collected Agelaia pallipes (Olivier, 1791) (n = 143), Agelaia vicina (Saussure, 1854) (n = 106), Agelaia multipicta (Haliday, 1836) (n = 18), and Polybia paulista Ihering, 1896 (n = 3). The wasps were observed feeding directly on the baits and preying on adult insects collected in the traps. Bait and habitat associations, temporal variability of social wasps, and possible forensic implications of their actions are discussed.

Colony defense behavior of the primitively eusocial wasp, Mischocyttarus cerberus is related to age.

The colony defense behavior of the wasp Mischocyttarus cerberus Richards (Hymenoptera, Vespidae) was studied to verify whether there were different reactions of wasps of different ages and hierarchical positions during attacks of ants. Detailed nest mapping was first performed, then the wasps were marked and were divided in four distinct categories: queens, older workers, younger workers and males. Tests were made simulating attacks of ants in the nests. The main results showed that the M. cerberus behaviors against ant attacks is more related to the age of the wasps than to their hierarchical position. The oldest wasps (queens and older workers) defend the nest more than the younger workers and males, representing a form of temporal polyethism.

Divisão de trabalho em colônias da vespa social neotropical Polistes canadensis canadensis Linnaeus (Hymenoptera, Vespidae) / Division of labor in colonies of the neotropical social wasp Polistes canadensis canadensis Linnaeus (Hymenoptera, Vespidae)

Foram realizadas 100 horas de observação usando o método "scanning sample" para a qualificação e quantificação dos atos comportamentais de rainhas e operárias de quinze colônias de Polistes canadensis canadensis. Foi descrito um repertório comportamental com 28 atos, no qual rainhas executam 19 atos na colônia, enquanto operárias 26, ocorrendo 17 atos em comum entre as duas castas. Dentre esses atos, dois foram exclusivos do repertório de rainhas e nove de operárias. O resultado do teste do qui-quadrado apontou diferenças significativas entre os repertórios das duas castas, sendo que rainhas permanecem mais tempo no ninho e executam com maior freqüência atividades intra-nidais, ligadas à reprodução, enquanto que as operárias executam mais freqüentemente atividades relacionadas à manutenção das colônias, como a atividade de forrageamento que demanda um maior risco e alto custo energético.

Using "scanning sample" methods for qualifying and quantifying behavioral acts of queens and workers belonging to fifteen colonies of Polistes canadensis canadensis, one hundred hours of observation were performed. A behavioral repertoire with twenty-eight acts was described, in which queens perform nineteen acts in the colony, while workers perform twenty-six, and seventeen common acts between the two castes occur. Among those acts, two were exclusive to queen's repertoire and nine to worker's. Chi-square test pointed significant differences between the repertoires of the two castes, where the queens remain longer in the nest and perform the intra-nidal tasks, related to the reproduction, while the workers perform more frequently tasks related to the maintenance of the colonies, such as the foraging, which demands higher risks and high energetic costs.

Morphological caste studies in the neotropical swarm-founding Polistinae wasp Angiopolybia pallens (Lepeletier) (Hymenoptera: Vespidae) / Estudos morfológicos das castas da vespa Polistinae enxameadora neotropical, Angiopolybia pallens (Lepeletier) (Hymenoptera: Vespidae)

Neotropical swarm-founding wasps present polygynic colonies and a great variation in relation to caste differentiation, ranging from species in which queens and workers are similar in shape and size to those where variation in shape and size is conspicuous. Canonical discriminant analysis and Bonferroni t-test analysis on morphometric data collected from eight body parts of specimens from nine colonies of Angiopolybia pallens (Lepeletier) were undertaken as a step towards to a better understanding on caste differenciation in Epiponini. All specimens were dissected to verify the ovary developmental stage, and the spermatheca was removed to check for the mating status. Females were then grouped as queens (mated with developed ovaries), intermediates (virgin with developed ovaries) and workers (virgin with undeveloped ovaries). Even though differences were found for some measurements in seven out of the nine colonies evaluated, multivariate analysis (Wilks' lambda values) indicated castes could not be reliably distinguished only by morphology. We conclude that morphological differences among A. pallens castes are low or absent, reflecting a possible groundplan for the Epiponini, i.e. a post-imaginal pattern of caste differentiation.

As vespas neotropicais enxameadoras possuem colônias poligínicas e uma variação muito grande em relação à diferenciação das castas, desde espécies em que rainhas e operárias possuem formas e tamanhos semelhantes até aquelas em que grande diferença na forma e no tamanho são observados. Estudos morfométricos utilizando oito medidas corporais em nove colônias de Angiopolybia pallens (Lepeletier) foram realizados a fim de aumentar o conhecimento sobre diferenciação de castas em Epiponini, empregando-se análise canônica discriminante e teste t de Bonferroni. Os indivíduos foram dissecados para determinar o nível de desenvolvimento ovariano e as espermatecas foram removidas para verificar a ocorrência de inseminação e assim definir os três grupos de fêmeas: rainhas (ovários desenvolvidos e espermateca fecundada), intermediárias (ovários desenvolvidos e espermateca não-fecundada) e operárias (ovários não-desenvolvidos). Apesar de serem encontradas diferenças significativas para algumas medidas em sete das nove colônias, a análise multivariada (lambda de Wilks) mostrou que as castas são de difícil distinção apenas pela morfologia. É possível concluir que diferenças morfológicas entre castas de A. pallens são pequenas ou ausentes, o que reflete o plano basal para os Epiponini, i.e. padrão pós-imaginal de diferenciação castas.

Morphological caste studies in the neotropical swarm-founding Polistinae wasp Angiopolybia pallens (Lepeletier) (Hymenoptera: Vespidae).

Neotropical swarm-founding wasps present polygynic colonies and a great variation in relation to caste differentiation, ranging from species in which queens and workers are similar in shape and size to those where variation in shape and size is conspicuous. Canonical discriminant analysis and Bonferroni t-test analysis on morphometric data collected from eight body parts of specimens from nine colonies of Angiopolybia pallens (Lepeletier) were undertaken as a step towards to a better understanding on caste differenciation in Epiponini. All specimens were dissected to verify the ovary developmental stage, and the spermatheca was removed to check for the mating status. Females were then grouped as queens (mated with developed ovaries), intermediates (virgin with developed ovaries) and workers (virgin with undeveloped ovaries). Even though differences were found for some measurements in seven out of the nine colonies evaluated, multivariate analysis (Wilks' lambda values) indicated castes could not be reliably distinguished only by morphology. We conclude that morphological differences among A. pallens castes are low or absent, reflecting a possible groundplan for the Epiponini, i.e. a post-imaginal pattern of caste differentiation.

Occurrence of Hymenoptera on Sus scrofa carcasses during summer and winter seasons in southeastern Brazil

Considerable importance has been given to nest construction and larval food transport to the nest as a precondition for the eusociality of insects. Most adult hymenopterans feed on liquids, although bees and a few wasps may also feed on pollen. Carrion represents an additional source of protein for some species and they will scavenge for dead animals in the wild. This paper aims at analyzing Hymenoptera visitors on a pig carcass during the process of decomposition, in the summer of 2005 and the winter of 2006 in Brazil, and comparing the results with other studies in the Neotropical region. To our knowledge, this is the first study which described the occurence of Agelaia pallipes, Polybia paulista and Scaptotrigona depilis on decomposing carcasses in southeastern Brazil. It also raises the hypothesis of possible applications of Hymenoptera to achieve more precise PMI estimations, apart from other insects already known as having great importance in such estimates.

Considerável importância tem sido dada às construções de ninhos e transporte de alimento larval para o ninho como uma pré-condição para a eusociabilidade dos insetos. Muitos adultos de himenópteros alimentam-se em líquidos, embora as abelhas e poucas vespas podem também se alimentarem de pólen. Carcaças representam uma fonte adicional de proteína para algumas espécies e elas foram uma vez observadas se alimentando de animais mortos na natureza. Este trabalho tem por objetivo analisar Hymenoptera visitantes em carcaças de porcos durante o verão de 2005 e inverno de 2006 no Brasil, ao longo dos estágios de decomposição, comparando com resultados de outros estudos na região Neotropical. Pelo nosso conhecimento, esse é o primeiro estudo que descreveu a ocorrência de Agelaia pallipes, Polybia paulista e Scaptotrigona depilis em carcaças em decomposição no sudeste do Brasil. Isso também aumenta a hipótese na possibilidade de aplicação de Hymenoptera em auxiliar a estimar o IPM de maneira mais precisa, sem levar em conta insetos que já possuem grande importância forense.