Meeting Abstract
To defend against herbivory, plants and fungi produce a variety of secondary metabolites. While understanding the biological effects of these host secondary metabolites on plant-insect interactions remains an active area of research, many studies focus on a single metabolite or a subset of the compounds. However, the potent bioactivity of some compounds is due to their synergistic/antagonistic interactions with other metabolites in their natural matrix. Thus, there is a need to characterize plant-insect interactions using complex mixtures that more closely resemble the chemical matrix found in the host. In this study, we examine this question by assessing how the survival of mushroom-feeding Drosophila in the immigrans-tripunctata radiation is impacted by the natural suite of toxins found in a small proportion of their hosts. Previous work examining toxin tolerance in these flies focused only on the effect of α-amanitin; however, the toxic mushrooms contain over 14 known toxins. To assess the impact of a natural toxin mix on survival, we reared the larvae of three tolerant and six susceptible species from the radiation and the distantly related D. melanogaster on diets containing differing concentrations of a toxin mix extracted from the host Amantia phalloides. To quantify the effect of the natural toxin mix, we measured several fitness phenotypes, including survival to adult and thorax length. Our results demonstrated that tolerant species exhibit similar patterns of survival to a diet containing a single toxin. We also found that the susceptible species could develop on low levels of the natural toxin mix that are lethal to most other Eukaryotes, including D. melanogaster. Thus, this study provides context for future research examining the evolution of toxin tolerance.
