The response of the stingless bee Melipona beecheii to experimental pollen stress, worker loss and different levels of information input

In honey bees, both the allocation of foragers to pollen collecting and the behaviour of the pollen foragers depends on the colony's need for pollen, the mortality rate of foragers and the input of information regarding pollen availability in the field. The response of stingless bees to these factors is not known. Therefore, we studied the response of Melipona beecheii to experimental pollen deprivation, worker loss and controlled information input. Following pollen stress M. beecheii did not increase its forager force, but allocated more foragers to pollen foraging. There was an indication that individual foraging was intensified. During the first 10 days after the reduction of the pollen reserve, pollen availability in the field was low and pollen foraging almost stopped. The increase in pollen foraging occurred after these 10 days. M. beecheii did not respond to daily variation in worker mortality or experimentally induced 50% worker loss. Behaviour of pollen foragers was related to previous day foraging experience and not to colony foraging parameters such as the total number of pollen loads and the size of the work force. More foragers were allocated to pollen foraging when more information on pollen availability (returning successful foragers) came into the hive. This study indicates that in M. beecheii the allocation of foragers to pollen collecting depends both on the availability of pollen sources and on colony needs. Their response to pollen stress was similar to that reported for Apis mellifera, except for the more conservative response to low pollen availability in the environment. This conservative reaction may be typical for stingless bees, that due to the mass provisioning of brood cells, do not suffer immediate brood loss when pollen is lacking.