-The community structure of cavities-nesting solitary bees species was systematically investigated over two years, from May/97 to April/99, in a fragment of tropical sand dune, Salvador, Bahia (12º56'S; 38º21'W), Northeast of Brazil. Trap nests were placed randomly in the area, in blocks with 16 nests, with variable diameter at a height of 1.5 m. Traps were inspected each 15 days. Seven bee species established 62 nests. Two species were predominant in the area, Centris (Hemisiella) tarsata Smith (58% of the total of established nests) followed by Euplusia musitans Fabricius (31%). In general, bees' abundance showed seasonal fluctuations. The total frequencies of nesting varied between the two years of sampling. The two predominant species presented different seasonal patterns. There were always trap nests available in the field for the bees. Just 14% of the available nests were occupied.

This study describes how the foraging activity of Melipona rufiventris is influenced by the environment and/or by the state of a colony. Two colonies were studied in Ubatuba, SP (44° 48' W and 23° 22' S) from July/2000 to June/2001. These colonies were classified as strong (Colony 1) and intermediate (Colony 2) according to their general conditions: population and brood comb size and number of food pots. The bees were active from dawn to dusk. The number of pollen loads presented a positive correlation with relative humidity (r s = 0.401; p <0.01) and was highest between 70 and 90%. However, it was negatively correlated with temperature (r s = -0.228; p <0.01) showing a peak between 18 and 23 °C. The number of nectar loads presented a positive correlation with temperature (r s = 0.244; p <0.01) and light intensity (r s = 0.414; p <0.01); it was greater between 50 and 90% of relative humidity and 20 and 30 °C of temperature. They collected more nectar than pollen throughout the day, and were more active between 6 and 9 hours. Workers from Colony 1 (strong) collected nectar in greater amounts and earlier than those from Colony 2 (intermediate). The number of pollen, nectar and resin loads varied considerably between the study days. Peaks of pollen collection occurred earlier in months with longer days and in a hotter and more humid climate. The foraging behavior of M. rufiventris is probably affected by the state of the colony and by environmental conditions, notably temperature, relative humidity, light intensity and length of the day.Keywords: Melipona rufiventris, Apinae, Meliponini, foraging behavior, nectar, pollen. Comportamento de forrageamento de Melipona rufiventrisLepeletier (Apinae; Meliponini) em Ubatuba, SP, Brasil ResumoEste estudo descreve como a atividade de forrageamento de Melipona rufiventris é influenciada pelo ambiente e/ou pelo estado da colônia. Duas colônias foram estudadas em Ubatuba, SP (44° 48' W and 23° 22' S), de julho de 2000 a junho de 2001. Estas colônias foram classificadas como forte (Colônia 1) e intermediária (Colônia 2), de acordo com as condições gerais das mesmas: tamanho da população e dos favos de cria e número de potes de alimento. As abelhas foram ativas do amanhecer ao anoitecer. O número de cargas de pólen apresentou correlação positiva com a umidade relativa (r s = 0,401; p <0,01) e foi maior entre 70 e 90%. Entretanto, foi negativamente relacionado com a temperatura (r s = -0,228; p <0,01), com pico entre 18 e 23 °C. O número de cargas de néctar apresentou correlação positiva com a temperatura (r s = 0,224; p <0,01) e com a intensidade luminosa (r s = 0,414; p <0,01); sendo maior entre 50 e 90% de umidade relativa e entre 20 e 30 °C de temperatura. Elas coletaram mais néctar do que pólen ao longo do dia, sendo mais ativas entre 6 e 9 hours. A Colônia 1 (forte) coletou néctar em maiores quantidades e mais cedo que a colônia 2 (intermediária). O número de cargas de pólen, néctar e resina coletadas variou consideravelmente entre os dias de estudo. Os picos de col...

ECOLOGY OF XYLOCOPA (NEOXYLOCOPA) CEARENSIS (HYMENOPTERA, ANTHOPHORIDAE) IN ABAETÉ SAND DUNES, SALVADOR, BAHIA. The study was carried out in a 8.2 ha area in an environmental protection area of tropical sea coastal sand dune with "restinga" vegetation in Salvador, Bahia, northeastern Brazil. A total of 1760 bees of Xylocopa (Neoxylocopa) cearensis Ducke, 1910 were netted during the whole year on flowers of 43 plant species belonging to 26 botanic families. The majority of the individuals (79%) concentrated their foraging activity in five plant species. Individuals foraged all day long being the greatest activity between 8 h and 14 h. Similar proportions of young and old bees were sampled over the year. The density of substrates used for nesting was 4.56/ha. In total, 94% of the nests were found in branches of Agaristha revoluta (Spr.) DC. (Ericaceae). The great occurrence (68.7%) of old perforations indicates that the nests were used twice or more times by bees.

ABSTRACT. Community of Euglossini (Hymenoptera, Apidae) from the coastal sand dunes of Abaeté, Salvador, Bahia, Brazil. The Euglossini community structure was analyzed by attracting males with the scents eucalyptol, eugenol, vanillin, benzyl benzoate and methyl salicylate, and by netting bees on flowers. The samplings took place three times a month along one year from 6:00 a.m. to 6:00 p.m. The scent baits attracted 670 individuals belonging to seven species of three genus. The predominant species were Euglossa cordata (Linnaeus, 1758) (76.6%) and Eulaema nigrita Lepeletier, 1841 (21.8%). Euglossini males visited the scents along the whole year, being more abundant in May and in August. The most efficient fragrance was eucalyptol, attracting 624 individuals of five species. The males abundance fluctuated along the day, being the highest frequency observed between 8:00 a.m. to 10:00 a.m. Forty eigth Euglossini females of four species were netted visiting flowers of 14 plant species belonging to 13 families. Solanaceae and Caesalpiniaceae were the most visited. The species catched on flowers were Euglossa cordata, Eulaema nigrita, Euplusia mussitans (Fabricius, 1787) and Eulaema meriana flavescens Friese 1899. Euglossa cordata was the predominant species on flowers (64.6%), being collected during almost the whole year. Euplusia mussitans was the only species netted on flowers which males were not sampled on the scents.