Impact of the nematode, Paraiotonchium autumnale (Nickle), on the longevity of Musca autumnalis DeGeer

Paraiotonchium autumnale (Nickle) (TYLENCHIDA: SPHAERULARIIDAE), causes parasitic sterilization in female Musca autumnalis DeGeer (DIPTERA: MUSCIDAE). Evaluating the impact of P. autumnale on M. autumnalis longevity may reveal physiological costs of being parasitized in addition to sterilization. No record of reduced host lifespan in this system is known. We hypothesize that parasitized M. autumnalis of both sexes will have a shorter lifespan than non-parasitized flies. Studies were conducted with wild M. autumnalis collected as larvae in cow dung pats from Browns Valley, CA. Field-collected larvae were reared to adulthood and flies of the same emergence dates were caged together, regardless of whether or not they were parasitized. The study was replicated at least 9 times. Caged flies were kept at 25°C with a photoperiod of 16L:8D and given water, sugar cubes, powdered milk, and beef liver ad libitum. Fresh cow dung was provided every 2 days for oviposition. Dead flies were collected daily, and infection status was confirmed by dissection. Kaplan-Meier survival analysis was used to determine the effect of nematode parasitism on M. autumnalis lifespan. Our results suggest that parasitized male and female M. autumnalis have significantly reduced lifespans compared to non-parasitized individuals.