Effects of parasitism and soil compaction on pupation behavior of the green bottle fly Lucilia sericata (Meigen) (Diptera: Calliphoridae)

Although the pupation behavior of blow flies has been widely studied, my work is the first to examine the effects of parasitoids and soil compaction on pupation behavior. The objectives of my research were to provide insight into a host-parasitoid system involving Lucilia sericata (Meigen) (Diptera: Calliphoridae) and Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) and to develop a predictive model of pupation depth for L. sericata, with respect to soil compaction. Two experiments were conducted examining the effects of parasitoids and soil compaction on the pupation behavior of L. sericata. In all experiments, larvae of L. sericata were introduced to containers with soil of different compaction levels. Development time, depth of pupation, pupal orientation, and spatial distribution of puparia were recorded after emergence of adult flies. Although females of N. vitripennis did not significantly affect the burrowing depth of L. sericata, they increased the rate of pupal development by 15.0--23.7 hours at 28.4°C +/-1.20 and increased the clumping of puparia. Burrowing depth of L. sericata is negatively related to soil compaction. Mean depth of pupation was 4.4 cm in low-compaction soil and 0.5 cm in high-compaction soil. In high-compaction soil, rate of pupal development decreased by 10.5--18.8 hours at 25.2°C +/-0.30 and puparia were clumped. Based on these results, I suggest that forensic entomologists should add a pocket penetrometer, ruler, and garden trowel to their evidence collection kit, allowing efficient location of blow fly puparia at a body-recovery scene. Future research should address the influence of parasitoids and other properties of soil on the development of additional forensically important insects.