Biology and Immature Stages of Three Species of Otitidae (Diptera) Which Have Saprophagous Larvae1

In northeastern Ohio, adults of Delphinia picta (F.) were found from mid-May until late summer. The premating period averaged less than 2 days; the preoviposition period after mating was 3–7 days. Field-collected females each deposited 400–500 eggs in decaying herbaceous vegetation. Eggs hatched in 4–7 days, and larvae given rotting vegetation completed their development in 20–31 days. Larvae of the first generation pupated, with adults emerging 12–15 days later, but increasing percentages of the larvae of the second and subsequent generations entered diapause. Overwintering took place as diapausing mature larvae in the soil. The life history of Seioptera vibrans (L.) was generally similar to that of D. picta, but the larvae seemed to prefer dung or vegetation mixed with dung, and this species was univoltine. The latest seasonal record for adults was made on July 14. The life cycle of Physiphora demandata (F.) also resembled that of D. picta, but larvae could be reared only on dung or vegetation mixed with dung. The eggs, the 3 larval instars, and the puparia of the 3 species are described and illustrated. Possible trends in the exploitation of food sources are suggested. Most species of Otitidae apparently have saprophagous larvae, but a few show tendencies toward phytophagy, and 2 species are known to have larvae which are primary invaders of bulbs and roots of living plants.