Native bees as alternative crop pollinators: Reproductive behaviour of Tetragonula carbonaria

Abstract

Bee pollination benefits the productivity of a wide variety of fruit crops worldwide. Although the western honey bee Apis mellifera is the dominant pollinator of most crops, global instability in honey bee populations has led to calls to diversify the world’s pollination services by enlisting other bee species as alternative pollinators. The stingless bees (Meliponini) are top candidates for this role. They have a large native distribution covering the tropics and subtropics of the world and are already known to be effective pollinators of many fruits. Knowledge of how to maintain stingless bees in agricultural landscapes will also have substantial benefits for their conservation in the wild, where they provide key ecosystem services. An important step towards better utilising these bees as crop pollinators is to advance our understanding of their reproductive and foraging biology. In this thesis, I review the plants visited by stingless bees around the world, to uncover broad patterns in their floral visitation (Chapter 2). I then investigate the reproductive biology of the Australian endemic stingless bee Tetragonula carbonaria to: determine the distance males travel between their natal nest and mating aggregations, and assess the viability of using male dispersal behaviour to estimate the colony density of a region (Chapter 3); describe the reproductive anatomy of queens and workers, and confirm that workers are irreversibly sterile as adults (Chapter 4); document the early phase of a queen’s life, and rear and mate queens under controlled conditions (Chapter 5); describe the volatiles produced by virgin queens, males and queenless colonies, and assess their effect on the attraction of rival colonies (Chapter 6). Together, these new insights improve our understanding of the biology of T. carbonaria and other stingless bees, and bring us closer to the goal of utilizing stingless bees as alternative crop pollinators in Australia.