Miss Holly Farnan1, Dr Peter Yeeles1, Dr John Roberts2, Dr Lori Lach1

1College of Science and Engineering, Centre for Tropical Biosecurity, James Cook University, Cairns, Australia, 2Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia

Biography:

Holly Farnan is a PhD candidate at James Cook University researching interactions affecting bee nesting and survival in bee hotels. After completing a Bachelor of Science majoring in Zoology & Ecology in 2020, she undertook an Honours research project investigating the effects of insecticide exposure and heat stress on stingless bees. Since graduating with a First Class Honours in 2021, she has worked on several entomology projects including investigating how insects manage microplastic contamination in waste at CSIRO, cacao pollination at the Department of Agriculture and Fisheries, non-target species monitoring as part of the Yellow Crazy Ant eradication program at James Cook University and canegrub and other pests of sugar cane management at Sugar Research Australia. Holly loves science communication and hopes to continue to inspire the next generation to foster a love for insects and the important roles that they play.

Abstract:

Public concern for bee populations has spurred the popularisation of bee hotels to provide nesting sites for solitary bees. While touted as beneficial for bee conservation, evidence supporting these claims is lacking, and there are concerns that bee hotels may have adverse effects on bee nesting and survival. We investigated the impact of nesting space density in bee hotels on the presence of competitors, predators, parasites and pathogens by placing two designs of bee hotels, including an aggregated design with twelve nesting blocks bound together, and a dispersed design with twelve nesting blocks dispersed 1 m apart (totaling 360 bee hotels) across fifteen sites. Results from the first five months of our field experiment revealed that bees occupied a small fraction of nesting spaces in both aggregated (1.63%, 7 nests) and dispersed (0.9%, 7 nests) bee hotels, with high competition observed from other invertebrates in both aggregated (98.4%, totaling 378 nests), and dispersed (99.1%, totaling 352 nests) bee hotels. Ants predominated among the occupants, particularly in aggregated hotels where there was a total of 287 nests (74.5% of total occupancy). Dispersed hotels hosted fewer ants with a total of 175 nests (48.7% of total occupancy) than aggregated hotels. Parasitism rates of trap-nesting Hymenoptera (bees and wasps) occurred in 23.7% of nests in aggregated hotels, and 17% of nests in dispersed hotels. These findings suggest that bees experience increased competition when nests are artificially aggregated, with the caveat that our study had low bee occupation.