Individual foraging, activity level and longevity in the stingless bee Melipona beecheii in Costa Rica (Hymenoptera, Apidae, Meliponinae)

Abstract

Foraging behaviour of individually marked workers of Melipona beecheii (Meliponinae) was monitored in Costa Rica to investigate individual specialisation for different materials and how this influences foraging longevity. The majority of the individuals harvested one commodity (pollen, nectar or resin) during a single day. Half of the age-marked foragers specialised on nectar or pollen during their complete foraging career, the other half collected two or three commodities. Most members of the latter group switched daily from early morning pollen (or resin) collecting to nectar collecting. Life-long foraging of one-material collectors was not more efficient than that of two-material collectors. The groups of foragers differed significantly in activity patterns and longevity: activity was traded off with longevity. Nectar foragers were active all day and died after an average of 3 foraging days. Pollen foragers were active for 1-3 hours per day, but lived for 12 days on average. However, pollen foragers and nectar foragers performed a similar number of flights in their career. How bees become pollen, nectar or mixed foragers is not clear. Age and performance of pre-foraging hive tasks did not influence forager specialisation in M. beecheii.