Meeting Abstract
Oxidative stress mediates sexual selection in many animals by linking cellular stress to condition-dependent sexual signals. While the relationship between oxidative stress and ornamental carotenoid pigments is well established, carotenoids and related pigments play a lesser role in cellular redox status than endogenous antioxidants. Previous work has shown that environmental treatments boosting the enzyme activity of superoxide dismutase (SOD) are also associated with greater sexual competitiveness in the Caribbean fruit fly, Anastrepha suspensa, a lek mating species with intense male-male competition and sexual selection. Here, we test the link between antioxidants and sexual selection by transgenic overexpression of SOD in A. suspensa. Using piggyBac-mediated germline transformation, we generated several lines that overexpress either the cytosolic or mitochondrial isoform of SOD. Our transgene contains a single copy of the native SOD driven by a heat shock promoter, all contained within loxP sites to allow recombinase-mediated cassette exchange. Transgene expression varied across genotypes, with our best lines exhibiting 4-fold increases in SOD mRNA levels and a doubling of enzyme activity. There was strong correlation between mRNA levels and SOD activity across lines, allowing for precise control of SOD activity levels. We are now conducting experiments to test whether elevated SOD activity attenuates ROS-mediated oxidative damage and improves mating competitiveness of males. These lines also provide a valuable genetic resource for testing the roles of ROS and antioxidants in aging and stress and may inform strategies for enhancing the quality of males released for Sterile Insect Technique.
