Carlos A. Garófalo

Comunidades de machos de Euglossini (Hymenoptera: Apidae) em matas semidecíduas do Nordeste do estado de São Paulo

A composicao, abundância e mudancas sazonais da fauna de Euglossini foram determinadas pela atracao de machos por iscas de cineol, eugenol e vanilina. O estudo foi realizado em duas Reservas do Estado de Sao Paulo: Estacao Experimental de Zootecnia (EEZ), municipio de Sertaozinho, e Fazenda Santa Carlota, Seccao Itaoca (SI), municipio de Cajuru. As coletas foram realizadas a cada 15 dias, das 08:00 as 17:00h, durante um ano, em cada localidade. Machos de 10 e 14 especies foram atraidos na EEZ e SI, respectivamente. Todas as especies amostradas na EEZ ocorreram tambem na SI proporcionando um coeficiente de similaridade entre as areas de 0,83. Eulaema nigrita Lepeletier, Euglossa pleosticta Dressler e Euglossa fimbriata Rebelo & Moure foram as especies mais abundantes em ambas as areas, correspondendo a 80.3% da amostra total na SI e 90,6% na EEZ. Em ambas as areas os machos foram mais abundantes no outono (53.8% da amostragem da EEZ e 46.3% da SI) e menos no inverno (0.7% da EEZ e 4.8% da SI). A abundância de machos e o numero de especies amostradas por estacao nao foram significantemente correlacionados. Cineol foi a isca mais atrativa tanto na EEZ (58,7% do total de machos coletados e 9 especies) como na SI (71,5% dos machos e 13 especies) seguido por eugenol e vanilina.

Nesting biology of Centris (Hemisiella) tarsata Smith (Hymenoptera, Apidae, Centridini)

Ninhos de Centris tarsata Smith, 1874 foram obtidos atraves da utilizacao de ninhos-armadilha, em areas de floresta estacional semi-decidua (Baixa Grande) e de caatinga (Ipira), no Estado da Bahia. A nidificacao ocorreu em gomos de bambus e em tubos de cartolina preta, estes com comprimentos de 5,8 cm (= tubos pequenos) e 10,5 cm (= tubos grandes), e diâmetro de 0,6 e 0,8 cm, respectivamente. Em ambas as areas C. tarsata nidificou durante a estacao umida, produzindo quatro geracoes anuais em Baixa Grande e tres em Ipira. Os imaturos de uma das geracoes passaram por diapausa em ambos os locais. As abelhas construiram seus ninhos com uma mistura de areia e oleo. Em geral, as celulas foram alongadas e arranjadas em serie linear, com sua abertura dirigida para a entrada do ninho. Os ninhos completados tinham de duas a tres celulas nos tubos pequenos, de uma a sete celulas nos tubos grandes e de duas a 13 nos gomos de bambu. A parede de fechamento do ninho lembrava uma celula incompleta e era coberta externamente com oleo. As celulas foram aprovisionadas com polen, oleo e nectar. Os ninhos foram parasitados por Mesocheira bicolor (Fabricius, 1804) (Hymenoptera, Apidae) e por outra especie de abelha nao identificada.

Age-Survival Curves for Workers of Two Eusocial Bees (Apis Mellifera and Plebeia Droryana) in a Subtropical Climate, with Notes on Worker Polyethism in P. Droryana

SummaryUnder the subtropical climate of Ribeirao Preto, Brazil, the relationships between age and survival in worker bees were studied with Apis mellifera and a stingless bee (Plebeia droryana), using 3 colonies of each. In contrast to colonies in the temperate region, winter workers of A. mellifera did not show a prolongation of life span. A marked prolongation was observed in workers of two broodless colonies of P. droryana, one queenless and the other not, compared with a normal brood-rearing colony. In the normal colony, workers changed activities in relation to age as they do in A. mellifera, but their mean life span was much longer.

Trap-nesting bees (Hymenoptera, Apoidea) in areas of dry semideciduous forest and caatinga, Bahia, Brazil

In this study were examined the species richness and seasonal abundance of cavity-nesting bees in areas of dry semi-deciduous forest and caatinga in the State of Bahia, Brazil. Sampling was done employing two types of trap-nests: bamboo canes and tubes made of black cardboard with dimensions of either 58 x 6 mm or 105 x 8 mm. The traps were inspected once a month. One hundred and forty-six nests of 11 bee species were collected in the forest, and 121 nests of seven species were collected in the caatinga. Five species of cleptoparasitic bees were also reared from these nests. The highest nesting frequencies occurred in the wet season in both areas. Nests parasitism was important only for Centris tarsata Smith, 1874, and was higher at the caatinga site than in the forest. The mortality of pre-emergent adults was high, especially in C. tarsata,Tetrapedia diversipes Klug, 1810 and Euglossa cordata (Linnaeus, 1758). Information on the number of cells per nest, the size, shape, and arrangement of brood cells in the nests, as well as the number of adults produced and the number of generations per year are also presented. Species richness, temporal patterns of nesting, and percentage of parasitism were compared with other habitats.

Nest structure and communal nesting in Euglossa (Glossura) annectans Dressler (Hymenoptera, Apidae, Euglossini)

Three nests of Euglossa (Glossura) annectans Dressier, 1982 were obtained from trap nests at Serra do Japi, Jundiai, Sao Paulo State, Brazil. The bees nested in bamboo cane (one nest) and in wooden-boxes (two nests). Solitary (two cases) and pleometrotic (one case) foundations were observed. Two nests were re-used once by two females working in each of them. Re-using females that shared the nests were of the same generation and each built, provisioned and oviposited in her own cells, characterizing a communal association. The brood development period was related to climatic conditions. Natural enemies included Anthrax oedipus oedipus Fabricius, 1805 (Bombyliidae), Coelioxys sp. (Megachilidae) and Melittobia sp. (Eulophidae).

Sex determination in bees. I. Balance between femaleness and maleness genes inBombus atratus franklin (Hymenoptera,Apidae)

Mating between a diploid male and a diploid female ofBombus atratus produced fertile triploid F1 females. The F2 descendents of these virgin females were composed of haploid males (10), diploid males (4), aneuploid males (3) and intersexes (2). These data indicate that sex is produced by a balance between male determining and female determining genes: they, also, suggest that the number of sex genes are not large.

Analysis of the niche of two sympatric species of Bombus (Hymenoptera, Apidae) in southeastern Brazil

The sources of food and the width and overlap of the food niches of Bombus atratus and Bombus morio were determined by field observations and analysis of the pollen loads carried to the colonies by worker bees. The two species together utilized 50 flower species of which 26 were used by both. Solatium paniculatum (Solanaceae) and Psidium guajava (Myrtaceae) were the most frequently visited plants. The food niche width and niche evenness for both species were similar. The correlation between niche width and niche evenness was non-significant showing that evenness does not depend on niche width. In addition, there was no correlation between niche width and overlap, i.e. overlap varied independently of niche width. A high overlap of food sources utilized by the two species was observed in September, October and November. This may be explained in one of two ways: (a) if B. atratus and B. morio compete for resources, competition would be more intense during those three months; (b) the convergency of both species to the same plant species ( Solatium paniculatum and Psidium guajava ) would only result in more intensive competition if resources were limiting. However, at that period of the year resources are abundant, therefore although the values of overlap were high, competition need not have occurred.

Occurrence of Aglae caerulea Lepeletier & Serville (Hymenoptera: Apidae: Euglossini) in the Parque Nacional da Chapada dos Guimarães, Mato Grosso State, Brazil

In a study conducted in the gallery forest of the Vale doVeu de Noiva in the Parque Nacional da Chapada dos Guimarães, Mato Grosso state, chemical baits were used to attract and sample male orchid bees. From September 2003 to July 2005, male euglossine bees were captured monthly, from 8:00 a.m. to 4:00 p.m. as they arrived at the baits. Of the 264 males captured, eight males belonged to Aglae caerulea Lepeletier & Serville, a cleptoparasitic euglossine species that presumably occurred only in the Amazon basin. Therefore, the occurrence of A. caerulea in this study area extends its geographical distribution range by approximately 2,400 km southwards in South America, as it is now recorded in both the Amazon and Platina basins.

Small-scale elevational variation in the abundance of Eufriesea violacea (Blanchard) (Hymenoptera: Apidae)

Eufriesea violacea (Blanchard) males were sampled in a small-scale elevational gradient in Southeastern Brazil and showed sequential peaks of abundance from lowest (700 m) to highest (1,100 m) altitudes during the sampling period. The influence of the temperature on the length of the egg-to-adult period and flowering dates of plants producing food (nectar) suggests that it may be one of the factors determining the distribution of male abundance along the altitudinal gradient. The results emphasize the importance of obtaining altitudinal stratified samples when studying Euglossini populations, especially when the studies are done at sites with marked topographical variation.

Biologia de Monobia angulosa Saussure em ninhos armadilhas (Hymenoptera: Vespidae: Eumeninae)

Nests of Monobia angulosa Saussure were obtained at Santa Cariota Farm, Cajuru, Sao Paulo (n=10), and at the Ecological Station of Jatai, Luis Antonio, Sao Paulo (n=3). The wasps nested in segments of bamboo canes, 158 to 194 mm in length and 9.5 to 15 mm in internal diameter. Nests consisted of a linear series of 1 to 6 cells, separated by mud partitions followed or not by a vestibular cell and final-closure mud plug, generally inside of the tube entrance. Intercalary cells were observed in 33.3% of nests. Brood cells were provisioned with caterpiliars and eggs were attached to the ceiling of the cells by a thin filament. More females than males were produced with females being reared of cells from the interior end of the nest. Females were larger than males, as well as the lengths of their respective cells. Natural enemies were: Chrysis intrincata Dahibom (Chrysididae), Anthrax sp. (Bombyliidae), and a Tachinidae fly. M. angulosa presented at least two generations/year, during both the hot and wet seasons.