Rachel Mohr
Major Professor: Dr. Jeff Tomberlin
Ph.D. Candidate
"Patterns of adult Cochliomyia macellaria and Chrysomya rufifacies attraction to carrion"
Forensic entomology's most frequent use is calculating the length of time that insects have been active on a body. Most commonly, what is actually calculated is the duration of immature insect inhabitation of the cadaver. Little attention has been paid to the time between exposure of a body to insect activity and the onset of oviposition, termed the pre-colonization interval (pre-CI). Experiments were performed in summer and winter evaluating the attractiveness of carrion to early-arriving blowflies. Pigs were killed and placed in a field within one hour of death. At hourly daylight intervals, temperature observations were made and adult flies were collected. Flies were identified to species, sexed, and weighed. Female flies were dissected, and their ovarian developmental status measured. The post-CI and behavior patterns were evaluated for each species and sex. Male flies showed no particular behavioral trends. Summer-active females showed a distinct behavior pattern, with fully developed flies showing a tendency to arrive at the corpse earlier than immature flies. Winter-active females showed a much weaker correlation between arrival time and ovarian development. There was also substantial variation in female arrival time between individual carcasses. The results of this study are useful in improving the characterization of the pre-CI of these four necrophilous species, and for demonstrating the importance of considering the pre-CI when making PIA estimations. They also illustrate the significance of individual variation on fly activity and the importance of collecting adult insects as well as immatures from a body recovery site.