Phenological Patterns and Preferences for Aromatic Compounds by Male Euglossine Bees (Hymenoptera, Apidae) in Two Coastal Ecosystems of the Brazilian Atlantic Forest.

In order to investigate phenological patterns and seasonal and geographic variations in the preference for fragrances of Euglossini males, monthly sampling was carried out from August 2007 to July 2009 in two coastal areas of Atlantic Forest in Ubatuba, northern coast of the state of São Paulo. Fourteen aromatic baits were used, 3 of them in the first year (August 2007 to July 2008) and the other 11 in the second year (August 2008 to July 2009). A total of 1,475 individuals from 22 species were collected. The highest frequency of the individuals of the majority of the sampled species occurred in the hot/super-humid season. However, Eulaema cingulata (Fabricius) showed peaks of abundance in the cold/less-humid season on Anchieta Island. Seasonal variation in fragrance choice by males was not registered. Males of El. cingulata showed preference for ß-ionone on Anchieta Island and for benzyl acetate in the Picinguaba region, characterizing the single example of geographic variation in preference for scent baits we recorded.

Bionomics and sociological aspects of Euglossa fimbriata (Apidae, Euglossini).

The nesting biology and the social structure of Euglossa fimbriata were studied based on two original nests found on the campus of the University of São Paulo, Ribeirão Preto, Brazil. Nest 1 contained two inseminated females, 39 sealed cells, one cell being provisioned, and six old and empty cells. Nest 2 contained three inseminated females, 45 sealed cells, one cell being provisioned, and 27 old and empty cells. The cells of nest 1 were distributed into three clusters from which three new nests were set up in the laboratory and maintained in observation boxes from August 1993 to March 1994 in order to study the behaviors performed by the bees. The males left the nest immediately after emergence and did not return. Some females left the nest within a few days of eclosing, and others stayed in their original nests and began to reactivate them. The E. fimbriata colonies were small, with semi-social and eusocial organization. In these colonies one female becomes the dominant female, usually the oldest female, and the others behave as subordinate females. The subordinate females build their cells, provision and oviposit in them, while the dominant female becomes the major guard bee, and oviposits in cells oviposited in by subordinate females. Oviposition by the dominant female is always preceded by oophagy. Irrespective of the behavior displayed, all the females that we dissected had been inseminated. The behavior displayed by the dominant female is characteristic of brood parasitism and fits the parental parasitism hypothesis developed as an alternative pathway by which insect sociality could have arisen.

Trap-nesting bees (Hymenoptera: Apoidea) in forest fragments of the State of São Paulo, Brazil.

We studied the community ecology of trap-nesting bees in two forest fragments of the state of São Paulo, Brazil, during two years, utilizing bamboo canes and tubes made of black cardboard as trap nests. The traps were inspected once a month with an otoscope. One hundred and fifteen nests were obtained at Estação Ecológica de Paulo de Faria, Paulo de Faria (EEPF). These included nine species belonging to five genera and two families. At Santa Cecília Farm (SCF), 12 species belonging to seven genera and three families built 392 nests. Natural enemies reared from nests of both areas included Hymenoptera, Diptera and Coleoptera. Species richness was similar between the areas but the communities differed considerably in species composition. The higher diversity found at EEPF was due to more even distribution of the species. No difference was observed between the numbers of nests built in each year in each area. Although the species richness was lower in the cool/dry season of both years at SCF, and in the first year at EEPF, the nesting frequencies did not differ between seasons for both the overall community but for each of the most abundant species. No annual fluctuation in the frequencies of nesting was observed. As temperature and precipitation were not found to be significantly different between the two years of study in each area, we concluded that climatic stability resulted in population stability.

Worker life tables, survivorship, and longevity in colonies of Bombus (Fervidobombus) atratus (Hymenoptera: Apidae).

Survivorship curves and longevity of workers were studied in two queenright and two queenless colonies of Bombus (Fervidobombus) atratus. Survivorship curves for workers of all colonies were, in general, convex, indicating an increasing mortality rate with increasing age. The mean longevity for the workers from queenright colonies, 24.3 days and 17.6 days, was not significantly different from that in queenless colonies, 21.2 days and 20.2 days. In all colonies workers started foraging activities when aged 0-5 days, and the potential forager rates rose progressively with increasing age. Mortality rates within each age interval were significantly correlated with the foraging worker rates in all colonies. Only in two of the colonies (one queenright and one queenless) longevity was significantly correlated with worker size. The duration of brood development period seems to be one of the most important factors influencing adult worker longevity in bumble bee species.