The floral phenology and reproductive biology of six sympatric arboreal Myrtaceae species were studied in the coastal plain forest (Ubatuba, Brazil, 44°48′W 23°22′S), from September 1999 to April 2002. Flowering started in the transition from the driest to the most humid season (Sep/Oct) and lasted until March. The sequence with which the species flowered each year was consistently the same. However, the timing of flowering onset, peak, end, and overlap differed from one year to another. Myrtaceae species were classified as xenogamic according to the pollen:ovule ratios, but two of them seem to present some degree of self-compatibility. Flowers of all species opened at sunrise and lasted for 1 day. Bombus morio (Apidae: Bombini) was the most common visitor followed by Melipona rufiventris (Apidae: Meliponini). Buzz pollination in Myrtaceae was common at the study area and seems to be related to bees' behaviour and to some aspects of flowers' morphology.

Potential conflict between the queen and workers over the production of males is expected in stingless bees as a result of the higher relatedness of workers with their sons than with their brothers. This conflict was studied in Melipona subnitida by observing how the queen and the workers share in male production. The oviposition of individual cells was observed in two colonies with individually marked workers for a period of 51 and 40 days respectively. The gender that developed from these cells was then determined. The results revealed that most male production was concentrated in a 2 -3-week period, during which laying workers were present. During these weeks, the queens produced twice as many males as all laying workers together. Outside this distinct period, the queens produced an occasional male. A reproductive worker either oviposited before the queen did, in which case she immediately proceeded to close the cell and thus prevented the queen from oviposition, or oviposited and sealed the cell after the queen had laid an egg. When cell construction and oviposition occured on several combs simultaneously, the workers preferentially laid male eggs on the newest combs. We discuss the proximate mechanism and ultimate cause of the way in which queenworker male production occurred. In conclusion, we argue that overt behavioural conflict, occasionally displayed by reproductive workers of this species, can be of great cost to the colony.

-We describe the environment effects on the amount and quality of resources collected by Melipona rufi ventris Lepeletier in the Atlantic Forest at Ubatuba city, São Paulo state, Brazil (44 o 48 'W, 23 o 22'S). Bees carrying pollen and/or nectar were captured at nest entrances during 5 min every hour, from sunrise to sunset, once a month. Pollen loads were counted and saved for acetolysis. Nectar was collected, the volume was determined and the total dissolved solids were determined by refractometer. Air temperature, relative humidity and light intensity were also registered. The number of pollen loads reached its maximum value between 70% and 90% of relative humidity and 18 o C and 23 o C; for nectar loads this range was broader, 50-90% and 20-30ºC. The number of pollen loads increased as relative humidity rose (rs = 0.401; P < 0.01) and high temperatures had a strong negative infl uence on the number of pollen loads collected (rs = -0.228; P < 0.01). The number of nectar loads positively correlated with temperature (rs = 0.244; P < 0.01) and light intensity (rs = 0.414; P < 0.01). The percentage of total dissolved solids (TDS) on nectar loads positively correlated with temperature and light intensity (rs = 0.361; P < 0.01 and rs = 0.245; P < 0.01), negatively correlated with relative humidity (rs = -0.629; P < 0.01), and it increased along the day. Most nectar loads had TDS between 11% and 30%, with an average of 24.7%. The volume measures did not show any pattern. Important pollen sources were Sapindaceae, Anacardiaceae, Rubiaceae, Arecaceae, Solanaceae and Myrtaceae; nectar sources were Sapindaceae, Fabaceae, Rubiaceae, Arecaceae and Solanaceae.KEY WORDS: Apidae, Atlantic Forest, environment infl uence, food resource, fl oral origin Foraging behavior of bee species is related to resources abundance and to their local distribution, to species susceptibility to abiotic factors, their communication ability and to colony size (Sommeijer et al 1983, Ramalho et al 1985, 1989, Roubik 1989.Stingless bees are generalists using resources of varied fl oral origin, which is essential for survival of their perennial colonies (Ramalho et al 1989, White et al 2001. Their foragers, however, exhibit fl oral constancy, and individuals usually restrict their visits to a type of fl ower during a certain foraging fl ight (Ramalho et al 1994, White et al 2001. This behavior makes these bees important potential pollinators in natural habitats and in agro-ecosystems (Roubik 1989).Following this pattern, foragers of the genus Melipona usually carry pollen loads of a single fl oral origin and the species most visited by them belong to the plant families Myrtaceae, Melastomataceae and Solanaceae (Ramalho et al 1989, 1990, 1994, 2007, Wilms & Wiechers 1997. Myrtaceae is the most important plant family in tropical forests, both in number of individuals and in number of species (Mori et al 1983, Cesar & Monteiro 1995, Assis 1999. In the plain coast at State Park of the Serra do Mar, in Ubatuba, the most common plant f...

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This work evaluated the effect of pollination on the quality of seeds and plantlets of Eugenia uniflora L., as well as on the regenerative capacity of the seeds. Twelve individuals were monitored for their phenology and their floral visitors. Recently-opened flowers were subjected to self-pollination (SP), cross-pollination (CP) and natural pollination/control (C) treatments. The seeds obtained were evaluated for their germination and the resulting seedlings were transferred to a greenhouse and evaluated for their height, stem diameter, number of leaves, leaf area and fresh and dry mass of root, stem, and leaves. SP, CP and C seeds were fractionated into two and four parts and evaluated for their ability to germinate and produce normal seedlings. Seeds and seedlings from manual cross-pollination were the most vigorous. The worst performance of the natural pollination (C) evidenced the pollen limitation caused by the scarcity of efficient pollinators in the study area.