Effect of Water on Blow Fly (Diptera: Calliphoridae) Colonization of Pigs in Northwest Indiana
Forensic entomology is the use of insects in the criminal justice system. Blow flies (Diptera: Calliphoridae) are early colonizers of carrion and any information on factors that influence their oviposition (egg laying) is of vital importance to forensic entomologists. This study examined the effect that being placed in a water environment had on blow fly oviposition. Six pigs were used in this study: three were in water and three were on land (control). Pigs were checked daily to document the arrival time of adult flies, fly eggs, fly larvae, the start of larval migration, and the end of larval migration. Data were analyzed using t-tests to determine if significant differences existed in the timing of blow fly life events between control pigs and pigs in water. Significant differences were seen in the timing of adult flies, fly eggs, fly larva, start of larval migration, and the end of larval migration. Pigs in the water environment initially sank but floated on the water’s surface after four days. Colonization by blow flies occurred five days after field placement on the pigs in water. There was an average of a five day difference in postmortem interval (PMI) estimations between control pigs and pigs in water. The results from this study will be valuable to forensic entomologists because it provides important information about blow fly oviposition, growth and development on pigs in a water environment.