Assessing pathogen risks to Australian stingless bees

Abstract

The greatest challenges faced by honeybees and beekeeping are pests and diseases. To safeguard against the risks posed by these threats, various native bee species are being used or at least considered as potentially substituting for the role of honeybees as pollinators of various crops. In Australia, stingless bee species maybe especially useful as in this capacity because they are comprised of colonies of thousands of foragers and can be managed in manmade hives and transported in large numbers to farms during crop flowering. However, a concern with this approach is that diseases that infect honeybees "" especially viruses "" may also infect stingless bee species and vice versa. If so, then the hope of using stingless bees as a backup in times where honeybee stocks have been impacted by disease may be misguided because stingless bees may be impacted just as much under such circumstances. While researchers have focused a great deal on the diseases of honeybees, we know comparatively little about the diseases of stingless bees, despite their growing importance in commercial pollination. Thus, this thesis aimed to expand our knowledge of the diseases of stingless bees and their dynamics. What little is known about stingless bee diseases relates to those affecting the developing brood (brood disease). Brood disease among stingless bees was first detected at the University of Western Sydney, Richmond, Australia. Hive losses were reported in Tetragonula carbonaria and Austroplebeia australis, and the causative organism was identified as Lysinibacillus sphaericus. What remains unknown, however, are the geographical and host ranges of this disease. There is also insufficient evidence for us to yet adjudicate whether this is a true pathogen or merely an opportunistic one, i.e., causing disease given certain suitable conditions, such as hosts with compromised immune systems. In this thesis, I explore the incidence of L. sphaericus in samples of foragers and larvae collected from asymptomatic and symptomatic hives using both commercial and hobby hives.

Date of Award	2020
Original language	English