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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Body size variation in males of Eulaema nigrita Lepeletier (Hymenoptera, Apidae, Euglossini). Maternal response to resource fluctuation?

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Rui Carlos Peruquetti
Total Authors: 1
Document type: Journal article
Source: Revista Brasileira de Zoologia; v. 20, n. 2, p. 207-212, Jun. 2003.

It was compared body size (measured as intertegular span) variance of trapped-males of Eulaema nigrita Lepeletier, 1841 sampled in dry (July, August and September) and wet (December, January and February) seasons of the years 1988/89 and 1994/95 in Viçosa (Minas Gerais, Brazil). It was also compared the body size variance between males and females sampled in three nests found in São Carlos (São Paulo, Brazil) and between these males and trapped ones. The smaller male (6.4 mm) was sampled in June and the bigger (8.9 mm) in July 1994, but the majority (32.3%) showed an intertegular span ranging from 7.8 to 8.0mm. The observed variance in body size was similar between males sampled in nests and trapped-males and the variance found inside a nest was similar between the sexes. However, males sampled in 1988/89 were bigger than 1994/95 males and males sampled in nests were smaller than trapped-males. The variance of the body size of males did differ between 1988/89 and 1994/95. In the first period differences between males sampled in dry or wet season was not observed, but in 1994/95 period the males sampled in dry season showed significantly greater variance in body size than males sampled in wet season. The body size variance did not differ between the wet seasons of 1988/89 and 1994/95. The body size variation, measured as the coefficient of variation in intertegular span, did not differ between males of E. nigrita (CV = 4.3%) and ground-nesting bees. These results show that the variation in body size of males of E. nigrita reflects that one found inside the nests of this bee, being similar among males and females. This variation is expected as result of ecological factors influences the nesting females. El Niño climatic events alone or in association with the lack of local food resources due to deforestation and presence of monocultures might play a role in observed body size variation. However this hypothesis is not sufficient to explain the observed body size variation inside a single nest. The absence of pressures of selection related to the females' advantages of produce large offspring perhaps contributes to the maintenance of the observed size variation. Studies regarding maternal allocation in E. nigrita may be useful to explain either the variation in body size or sex ratio found in this Neotropical bee. (AU)