Data from: Nutrition, pesticide exposure, and virus infection interactions in honey bees

Declines in pollinator health are frequently hypothesized to be the
combined result of multiple interacting biotic and abiotic stressors;
namely, nutritional limitations, pesticide exposure, and pathogen
infection. Despite this, most studies examining stressor interactions have
been constrained to two concurrent factors, limiting our understanding of
multi-stressor dynamics. Using honey bees as a model, we addressed this
gap by studying how variable quality diet, field-realistic levels of
multiple pesticides, and virus infection interact to affect survival,
infection intensity, and immune and detoxification gene expression.
Although we found evidence that agrochemical exposure (a field-derived
mixture of chlorpyrifos and two fungicides) can exacerbate infection and
increase virus-induced mortality, this result was nutritionally-dependent,
only occurring when bees were provided artificial pollen. Provisioning
with naturally-collected polyfloral pollen inverted the effect, reducing
virus-induced mortality and suggesting a hormetic response. To test if the
response was pesticide specific, we repeated our experiment with a
pyrethroid (lambda-cyhalothrin) and a neonicotinoid (thiamethoxam),
finding variable results. Finally, to understand the underpinnings of
these effects, we measured viral load and expression of important immune
and detoxification genes. Together, our results show that multi-stressor
interactions are complex and highly context-dependent, but have great
potential to affect bee health and physiology.