Production of sexuals in the stingless bee Trigona (Lepidotrigona) ventralis flavibasis Cockerell (Apidae, Meliponini) in northern Vietnam

In a two-year study on the stingless bee Trigona ventralis under field conditions in Vietnam, production of males and gynes was investigated in ten colonies. Male production in this species was found to be periodic. Typically, colonies produced a batch of males in a period of several weeks. At the population level, however, males were found throughout the year, since male production was not synchronized between colonies. Male production varied significantly among various months and between the rainy and the dry season. The number of males produced was positively correlated with numbers of brood cells, of food storage pots, and of emerging workers. Unlike the clumped male production in a certain colony, gynes were continuously produced in all colonies at low numbers, but seasonal effects on their numbers were found similar to effects on the numbers of males. In a previous study, the same periodical production of males in individual colonies without synchronization between colonies was found in a new world-species, Melipona favosa. This suggests that the mechanisms underlying allocation of resources between sexes may be general for a number of stingless bees