Castes and asynchronous colony cycle in Polybia bistriata (Fabricius) (Hymenoptera: Vespidae)
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Data
2007-12-01
Autores
Oliveira, Otavio A. L. de [UNESP]
Noll, Fernando Barbosa [UNESP]
Mateus, Sidnei
Gomes, Bruno
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Entomológica do Brasil
Resumo
Os Epiponini, vespas sociais neotropicais, são um grupo de insetos sociais com sociedades poligínicas, construtoras de ninhos complexos. O dimorfismo das castas varia de incipiente até altamente distinto. Análises morfométricas de nove partes corporais, estágio de desenvolvimento ovariano, idade relativa e desenvolvimento da glândula do quinto esternito do gáster (glândula de Richards) de Polybia bistriata (Fabricius) foram utilizados para calcular o nível de diferenciação das castas de nove colônias. Dados morfológicos e fisiológicos foram usados em análises multivariadas para avaliar o nível de discriminação entre fêmeas inseminadas e não-inseminadas. Foram encontradas diferenças fisiológicas claras: rainhas tinham ovários altamente desenvolvidos e inseminados, e as operárias não estavam inseminadas e tinham ovários não desenvolvidos ou uns poucos oócitos desenvolvidos (em duas colônias). ANOVA e análise da função discriminante detectaram diferenças significantes entre as castas. Considerou-se, pelos dados obtidos, que as colônias estavam nas seguintes fases em relação ao ciclo colonial: uma em pré-emergência, quatro em produção de operárias ;.e quatro em produção de sexuados. Análises das glândulas de Richards indicaram o seu menor desenvolvimento em rainhas de colônias pequenas (< 100 fêmeas) do que aquelas de colônias médias (100-200 fêmeas), e grandes (> 200 fêmeas). Considerando-se todos os dados, é possível concluir que as diferenças entre as castas são pequenas, mas evidentes em algumas fases do ciclo colonial, um fenômeno previamente descrito para outros epiponíneos.
Neotropical swarm-founding wasps, the Epiponini, are an outstanding group of social insects whose societies are polygynic and complex nest builders. Caste dimorphism in these wasps ranges from incipient to highly distinct. Morphometric analyses of nine body parts, ovarian status, relative age and development of the 5th gastral sternite gland (Richards´ gland) of Polybia bistriata Fabricius were undertaken in order to estimate caste differentiation in nine colonies. Morphological and physiological data were used in multivariate analyses in order to evaluate the level of discrimination between inseminated and non-inseminated females. Clear physiological differences were found: queens had highly developed ovaries and they were inseminated, and workers had totally undeveloped ovaries or they had few developed oocytes (only in two colonies), but in both cases insemination was not detected. ANOVA and discriminant function analysis detected slight, but significant differences between castes. In relation to colony cycle, colonies were considered to be in the following stages: one in pre-emergence, four in worker production and four in sexuals production. Richards´ gland analyses indicated that in small colonies (<100 females) queens had a less developed gland than in medium (100-200 females), and large colonies (>200 females). Taking the whole data, it was possible to conclude that caste differences were slight, but more evident in some phases of the colony cycle, a phenomenon previously described for other epiponines.
Neotropical swarm-founding wasps, the Epiponini, are an outstanding group of social insects whose societies are polygynic and complex nest builders. Caste dimorphism in these wasps ranges from incipient to highly distinct. Morphometric analyses of nine body parts, ovarian status, relative age and development of the 5th gastral sternite gland (Richards´ gland) of Polybia bistriata Fabricius were undertaken in order to estimate caste differentiation in nine colonies. Morphological and physiological data were used in multivariate analyses in order to evaluate the level of discrimination between inseminated and non-inseminated females. Clear physiological differences were found: queens had highly developed ovaries and they were inseminated, and workers had totally undeveloped ovaries or they had few developed oocytes (only in two colonies), but in both cases insemination was not detected. ANOVA and discriminant function analysis detected slight, but significant differences between castes. In relation to colony cycle, colonies were considered to be in the following stages: one in pre-emergence, four in worker production and four in sexuals production. Richards´ gland analyses indicated that in small colonies (<100 females) queens had a less developed gland than in medium (100-200 females), and large colonies (>200 females). Taking the whole data, it was possible to conclude that caste differences were slight, but more evident in some phases of the colony cycle, a phenomenon previously described for other epiponines.
Descrição
Palavras-chave
Social insects, Caste difference, Social wasp, morphometric analysis, Inseto social, Diferenciação de castas, Vespa social, Morfometria
Como citar
Neotropical Entomology. Sociedade Entomológica do Brasil, v. 36, n. 6, p. 817-827, 2007.