Data from: Transcriptional profile and differential fitness in a specialist milkweed insect across host plants varying in toxicity
Birnbaum, Stephanie S.L. et al. (2017), Data from: Transcriptional profile and differential fitness in a specialist milkweed insect across host plants varying in toxicity, Dryad, Dataset, https://doi.org/10.5061/dryad.fc1m8
Interactions between plants and herbivorous insects have been models for theories of specialization and coevolution for over a century. Phytochemicals govern many aspects of these interactions and have fostered the evolution of adaptations by insects to tolerate or even specialize on plant defensive chemistry. While genomic approaches are providing new insights into the genes and mechanisms insect specialists employ to tolerate plant secondary metabolites, open questions remain about the evolution and conservation of insect counter-defenses, how insects respond to the diversity defenses mounted by their host plants, and the costs and benefits of resistance and tolerance to plant defenses in natural ecological communities. Using a milkweed-specialist aphid (Aphis nerii) model, we test the effects of host plant species with increased toxicity, likely driven primarily by increased secondary metabolites, on aphid life history traits and whole body gene expression. We show that more toxic plant species have a negative effect on aphid development and lifetime fecundity. When feeding on more toxic host plants with higher levels of secondary metabolites, aphids regulate a narrow, targeted set of genes, including those involved in canonical detoxification processes (e.g., cytochrome P450s, hydrolases, UDP-glucuronosyltransferases, and ABC transporters). These results indicate that A. nerii marshal a variety of metabolic detoxification mechanisms to circumvent milkweed toxicity and facilitate host plant specialization, yet, despite these detoxification mechanisms, aphids experience reduced fitness when feeding on more toxic host plants. Disentangling how specialist insects respond to challenging host plants is a pivotal step in understanding the evolution of specialized diet breadths.
National Science Foundation, Award: DGE-1445197