Is secondary sexual trait size an indicator of ability to resist oxidative stress?

Indicator models of sexual selection have been widely studied and are accepted as viable, but support for them remains inconsistent. Indicator models propose that by mating with relatively highly ornamented males, females accrue indirect benefits as genes transmitted to offspring that enhance general health and vigor. One increasingly prominent hypothesis suggests that indirect benefits may be in the form of ability to mitigate oxidative stress (OS). Reactive oxygen species in low quantities are used as molecular messengers, but in larger quantities are highly damaging to DNA and other molecules in the form of OS, and have been suggested to be an important factor in reducing sexual ornamentation and sperm quality. I studied the relationship between the size of the male sex comb in Drosophila bipectinata (Diptera, Drosophilidae) on adult life-history and reproductive traits under variable oxidative stress administered by feeding males paraquat, a chemical agent know to induce the generation of ROS. The male sex comb in this species is a secondary sexual trait known to be both heritable and condition dependent. Males from genetic lines expressing higher comb counts did not induce females to have greater fecundity, produce more viable eggs, nor have a higher fertilization rate in a competitive setting under increasing levels of OS. However, males from these high lines expressed greater survivorship under increasing levels of OS relative to small-combed genetic line males.  These results suggest that relative sex comb size in D.bipectinata reveals the ability to cope with OS in terms of longevity.