Atividades relacionadas à construção e aprovisionamento de ninhos de Xylocopa subcyanea (Hymenoptera, Apidae) em uma área de restinga na Bahia, Brasil

Abstract

ABSTRACT. Activities related to construction and provioning of nests of Xylocopa subcyanea (Hymenoptera, Apidae) in an area of sandbank in Bahia, Brazil. Bees of the genus Xylocopa Latreille, 1802 are frequent in sandbank ecosystems under accelerated degradation. They nest especially in dead or rotted wood. The nest construction and nest structure of Xylocopa (Schoenherria) subcyanea Perez, 1901 were studied in a sandbank from Bahia's north littoral, Brazil. We observed 43 active nests, under different stages of development, in two dead logs. The main activities were excavation of the logs, entering and leaving nest, permanence in the nest entrance, entering with pollen, and nectar dehydration. Preferential times along the day were observed for entering and leaving nest, showing influence of sunrise and sunset times. Abandoned nests were reused by X. subcyanea and Centris tarsata Smith, 1874. Active nests were occupied by four different adult bees. An individual frequently stayed at nest entrance, adopting a defensive behavior. The nest structure was described.KEYWORDS. Apoidea, Xylocopa subcyanea, nest construction, sandbank. RESUMO.As abelhas do gênero Xylocopa Latreille, 1802 são comuns em ecossistemas de restingas em acelerada fase de degradação e são importantes polinizadores deste ecossistema. Elas nidificam especialmente em madeira morta ou apodrecida. As atividades relacionadas à construção e estrutura dos ninhos de Xylocopa (Schoenherria) subcyanea Perez, 1901 na restinga do litoral norte da Bahia, Brasil, foram observadas em 43 ninhos ativos de X. subcyanea, em diferentes fases de desenvolvimento, em dois troncos apodrecidos. A fase de fundação ou reuso no primeiro tronco foi em agosto e a fase de provisionamento das células nos ninhos, em ambos troncos, em janeiro. As principais atividades foram escavações no tronco, entrada e saída dos ninhos, permanência na entrada do ninho, entrada com pólen e desidratação de néctar. Foi observado horário preferencial ao longo do dia para as atividades de entrada e saída dos ninhos, sendo estas influenciadas pelos horários do nascer e pôr do sol. Ninhos abandonados foram reusados por X. subcyanea e Centris tarsata Smith, 1874. Os ninhos ativos eram ocupados por quatro diferentes abelhas adultas. Geralmente, uma abelha ficava na entrada do ninho. A estrutura do ninho foi descrita.

Comparisons in nesting biology of two sympatric carpenter bee species (Apidae: Xylocopini)

“…According to this hypothesis, the reuse of abandoned nests is also more profitable because females do not have to dig channels. The reuse of abandoned nests observed for both species was also reported for other neotropical Brazilian Xylocopa bees (Camillo and Garófalo 1989;Silveira 2002;Gimenes et al 2006).…”

“…The duration of pollen and nectar gathering flights was highly variable, similar to that observed for other Xylocopa species (Hogendoorn and Velthuis 1993;Gimenes et al 2006), and was neither influenced by the temperature nor by the relative humidity. Therefore, the variability of the duration of these flights is likely to be influenced by other factors, such as: abundance and distance to the resource (Schaffer et al 1979;Costa et al 2002;Gathmann and Tscharntke 2002), quality of pollen and nectar sources (Willmer 1988;Gerling et al 1989) and time spent on the manipulation of flowers.…”

“…This behaviour seems to be conspicuous among Xylocopa species, being reported by several authors (e.g. Gerling et al 1989;Gimenes et al 2006). Though the sequence of events of this behaviour seems to prevail in different species, the time invested in nectar dehydration presents intra-specific and inter-specific variations, which are likely to be influenced by microclimate and initial concentration and volume of nectar.…”

“…Pollen collecting flights were restricted to the morning period in the dry season, but pollen and nectar gathering flights did not show any peak in relation to the time of the day in the wet season, differing from the observations for other Xylocopa species (Gerling and Hermann 1978;Camillo and Garófalo 1982;Camillo et al 1986;Gimenes et al 2006;Neves et al 2006).…”

“…Besides that, the majority of the studies consider the substrate characteristics only in a descriptive approach (e.g. Camillo and Garófalo 1982;Camillo et al 1986;Gimenes et al 2006;Neves et al 2006). The analyses presented here revealed that the substrate circumference positively influences the number of channels in X. ordinaria nests but not in the nests of X. frontalis.…”