49. Effects of food deprivation on parasitism in the wasp, Copidosoma floridanum (Hymenoptera)

Food deprivation is a general concern for any species because a lack of nutrients can have major effects on an organism, such as causing changes in behavior, life span, and reproductive rates. In insects, there are well documented trade-offs between reproduction and longevity mediated by food availability. The purpose of this study is to examine the effects of food on reproduction in an endoparasitic wasp, Copidosoma floridanum. This wasp lays its eggs in the eggs of Trichoplusia ni, its moth host. To understand how food influences the reproduction of C. floridanum, 180 wasps were evenly divided into six groups, half of which were fed sugar water while the other half were fed distilled water. Because it is experimentally tractable, 20 host eggs were placed into individual compartments with 30 wasps. There was not a statistically significant difference (t=2.0, p=0.23) between fed and unfed groups. However, fed females on average laid approximately twice as many eggs as unfed females. Our lack of statistical difference may be due to low overall rates of parasitism and high mortality. On day one of the experiment, only 40% of T. ni eggs were parasitized by fed C. floridanum females while only 29% of eggs were parasitized by unfed females. There was 100% wasp mortality by the end of day 2. The high proportion of non-parasitized eggs additionally indicates competition was likely not a major factor. Overall it appears that food availability may affect reproductive rate, but additional studies are needed to explore this relationship