Data from: Individual and combined impacts of sulfoxaflor and Nosema bombi on bumblebee (Bombus terrestris) larval growth

Sulfoxaflor is a globally important novel insecticide that can have
negative impacts on the reproductive output of bumblebee (Bombus
terrestris) colonies. However, it remains unclear as to which life-history
stage is critically affected by exposure. One hypothesis is that
sulfoxaflor exposure early in the colony’s life cycle can impair larval
development, reducing the number of workers produced, and ultimately
lowering colony reproductive output. Here we assess the influence of
sulfoxaflor exposure on bumblebee larval mortality and growth both when
tested in insolation and when in combination with the common fungal
parasite Nosema bombi, following a pre-registered design. We found no
impact of sulfoxaflor (5ppb) or N. bombi exposure (50,000 spores) on
larval mortality when tested in isolation but found an additive, negative
effect when larvae received both stressors in combination. Furthermore, we
found that sulfoxaflor and N. bombi exposure individually impaired larval
growth but also found possible antagonistic effects when used in
combination. Ultimately, our results suggest that colony-level
consequences of sulfoxaflor exposure for bumblebees may be mediated
through direct effects on larvae. As sulfoxaflor is licenced for use
globally, our findings highlight the need to understand how novel
insecticides impact non-target insects at various stages of their
development.