Jody Gerdts: Who’s your Mummy: Investigating the host-pathogen relationship between Apis mellifera and Ascosphaera apis in Australia

Three years and over 800 colonies later, we conclude that Australian honey bees are incredibly hygienic and even without intended selection, Australian queen bee breeders produce very hygienic bees. “But how can that be?” asked one beekeeper “Chalkbrood is such a huge problem”. To answer this question, we conducted a nation-wide chalkbrood genotyping survey and found multiple strains of chalkbrood in Australia. We then collected volatiles from infected larvae and discovered a reason why hygienic bees can be infected with chalkbrood disease. Finally, we challenged individual larvae and entire colonies with chalkbrood spores and recorded how they responded giving us insight into individual and colony immunity and virulence of different chalkbrood strains. Each of these steps has informed our understanding of chalkbrood disease in Australia.

Bronwen Roy: Molecular screening reveals a wider geographic and host range for a novel stingless bee disease.

Our limited knowledge of stingless bee diseases is disconcerting in light of their growing importance in commercial pollination. The first description of a brood disease in stingless bees was only reported in 2017. This implicated Lysinibacillus sphaericus a common soil bacterium as the casual pathogen in Western Sydney in T. carbonaria and A. australis hives. However, the geographic and host ranges of the disease have yet to be investigated. In this study 50 healthy hives and 10 “sick” hives were tested for the bacterium using a species-specific qPCR. Key findings were that 1) L. sphaericus was only detected in “sick” hives (i.e. those exhibiting a sudden dumping of discoloured larvae, and with reduced foraging activity) and 2) sick hives were not restricted to Western Sydney, but also found in other sites in NSW and in Queensland. Additionally, the host range included an additional bee species, T. hockingsi. Analyses of L. sphaericus DNA sequences from infected larvae from all 10 sick hives suggest that the pathogen is a specific non-toxigenic strain of L. sphaericus. While the mechanism of transmission remains elusive, it appears that the bacterium does not form part of the normal commensal flora of stingless bees, and that the spread of the disease is probably introduced from external environmental sources.

Tim Heard: Conservation of Stingless bees

Keeping stingless bees is gaining popularity. Can we ensure that this movement has a positive impact on their conservation? Is it possible to utilize stingless bees sustainably? I first explore how stingless bees have recently travelled from obscurity to become ambassadors for nature. I show how popular they are becoming for recreation and education. I review the explosion of resources that have recently become available. This phenomenon is not confined to Australia but to many tropical parts of the world. I examine the conservation of stingless bees in the context of this increasing utilisation and disturbance. I address the following threats: 1) Harvesting of wild populations. 2) Destruction of colonies by land clearing. 3) Anthropogenic movements cause adverse genetic consequences for wild populations. 4) Spread of disease. 5) Competitive impacts on other species and 6) Loss of cryptic species. I conclude that there are areas that need to be better managed and monitored.

Tim Heard: Research developments in support of Stingless beekeeping

I review research activities that have supported the utilization of stingless bees. I review the research on taxonomy and systematics, which allows Australian researchers and beekeepers to identify their species. I introduce the extensive research in the effect of plant diversity on colony success. I also review natural enemies and our knowledge of their biology and impact. I discuss how stingless bee defend themselves against those enemies. The relationship between stingless bees and the cadaghi tree is now well understood and we now believe the resin of this plant is not a threat to the bees. Queenlessness can be a problem for keeping stingless bees, but our improved understanding of colony re-queening helps us to manage this issue. Fighting swarms which is the result of aggressive interactions between colonies of stingless bees, is now much better understood, and our ability to manage them is improved. We have measured the flight range which is crucial information for managing hives. The composition, microbiology and antimicrobial properties of the honey of stingless bees has been the target of a few studies which allows us to develop this product.

Adrian Dyer: See like a bee: think like a bee

With growing interest in how to best study plant-pollinator interactions it is of high value to understand how important pollinators like bees see their world, and how flowers have evolved signals to promote optimal forager visits. We will discuss how recent advances in photography enable the recording of flower UV, Blue and Green reflectances to map both the spatial and colour variability of signals. We will also show how innovative photographic techniques can be used to map the spatial resolution of flower shapes, and explain why foraging choices for flower visual signals are extremely difficult at distances greater than about half a metre. To solve the complexities of the limited resolution of the compound eye, we will finally discuss recent behavioural evidence that bees use cognitive-like solutions like counting to enable survival in a complex, changing environments.