Bee-microbe symbioses are influenced by fungicides and heat

Authors: Steffan, Shawn; DHARAMPAL, PRARTHANA - University Of Wisconsin

Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/18/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Pervasive microbivory among animal species underscores the importance of animal-microbe symbioses. Bees, for example, are widely thought to derive all protein directly from floral resources, but recent findings suggest this is largely untrue. It appears that larval bees feed extensively on pollen-borne microbes, as well as the pollen, itself. These microbial prey are suffused throughout a fermenting pollen-provision. Because the microbes are actively consuming the pollen, these herbivorous organisms represent ‘microbial meat’ within the aging provision. Here, we provide empirical evidence of trophic omnivory across six of the seven extant bee families, revealing the prevalence of microbivory among the major bee fauna. We also looked at the roles of anthropogenic stressors on bee-microbial symbioses—specifically, fungicides and heat exposure. The risk of exposure to fungicide residues is likely to be high if the spray occurs on, or near, host plants while the bees are collecting pollen to provision their nests. We examined species of Bombus and Osmia, focusing on the roles of pollen-borne microbes in bee nutrition and fitness. We quantified the impacts of fungicide residues on individual- and colony-level metrics. Fungicide residues and heat spikes were shown to be profoundly negative for both Bombus and Osmia larvae. These findings suggest that bee-microbe symbioses will require further scrutiny in future bee conservation studies.