EFFECTS OF TEMPERATURE AND DIET IN STABLE FLY (DIPTERA: MUSCIDAE) DEVELOPMENT

Stable flies are among the most important blood feeding ectoparasites of cattle worldwide. The livestock industry is losing more than $2 billion dollar annually in the United States alone. Moist decaying vegetative material with bacteria supports larval development. Temperature and diet quality are important factors for stable fly development, affecting development rates, adult survival, and size, but how temperature affects adult size and interacts with nutrition is unknown. This study characterizes the relationship of temperature and diet quality in the development of stable flies. Two statistical models were used to analyze the effect of temperature alone (Lysyk, 1998) and temperature-diet interactions (Boetel, et al. 2003). Temperature drives larval development, at higher temperatures stable flies develop faster. Interaction of the two factors affects when larvae pupate, larvae exposed to good nutrition and low temperatures take 90% more time than those at bad nutrition under high temperatures. Diet controls adult size, bigger flies grew on the standard diet at low temperatures, but also temperature influences size when flies are starving, and grew larger at higher temperatures. Results from this experiment show that temperature and diet interact in complex manners to affect stable fly development. At higher temperatures, development is fast but size is reduced. At low temperatures, development is slow, and although flies are exposed longer to predation, size increases, which may increase reproductive success. However, the interaction changes when food is limited, it is better to grow at small size for an opportunity to reproduce.Understanding of stable flies biology helps to discern population dynamics. Stable flies exhibit an evolutionary plasticity allowing successful development in a variety of conditions. This plasticity may account for their global colonization and prevalence in a variety of habitats. Trade-offs between fast growth and small size, and slow growth and larger size on stable flies, needs further study. Studies that compare stable flies size from the field are required to understand their phenology and how these conclusions could be apply. Advisers: David B. Taylor and Gary Brewe