Dopamine mediates the pea aphid wing plasticity

<p><span>Many organisms exhibit phenotypic plasticity, in which developmental processes result in different phenotypes depending on their environmental context. We focus on the molecular mechanisms underlying that environmental response. Pea aphids (<em>Acyrthosiphon</em> <em>pisum</em>) show a wing dimorphism, in which pea aphid mothers produce winged or wingless daughters when exposed to a crowded or low-density environment, respectively. We investigated the role of dopamine in mediating this wing plasticity, motivated by a previous study that found higher dopamine titers in wingless- versus winged-producing aphid mothers. In this study, we found that manipulating dopamine levels in aphid mothers affected the number of winged offspring they produced. Specifically, asexual female adults injected with a dopamine agonist produced a lower percentage of winged offspring, while asexual females injected with a dopamine antagonist produced a higher percentage of winged offspring, matching expectations based on the titer difference. We also found that genes involved in dopamine synthesis, degradation, and signaling were not differentially expressed between wingless- and winged-producing aphids. This result indicates that titer regulation happens in a non-transcriptional manner or that we sampled non-relevant timepoints or tissue. Overall, our work emphasizes that dopamine is an important component of how organisms process information about their environments.</span></p>