Lifetime ovipositional patterns of mated and virgin onion flies, Delia antiqua (Diptera: Anthomyiidae)

Over their 47.2+/-1.9 (mean+/-SEM) day lifespan, mated onion flies, Delia antiqua, oviposited more uniformly than did virgins. Mated females began ovipositing at 6.4+/-0.2 days old and regularly deposited 14.2+/-0.6 eggs/day for 3-4 weeks. Thereafter, oviposition slowed and stopped at about 1 week before death. Virgin flies began ovipositing 24.7+/-1.5 days into their 59.0+/-3.8 day lifespan, and deposited eggs at an increasing rate for 3-4 weeks, generating a mean overall ovipositional rate of 5.8+/-0.5 eggs/day. The later onset of virgin oviposition (ovipositional activation) and not a shorter ovipositional period largely accounted for the disparity between virgin and mated female lifespans. Mean lifetime egg production of mated females was 475+/-27 eggs versus 179+/-30 eggs for virgins. Ovipositional and post-ovipositional periods (34.4+/-1.8 and 7.2+/-1.0 days) for mated females were not significantly different from those of virgin females (30.9+/-3.6 and 6.7+/-1.2 days). Over 90% of virgin females laid eggs. The distinction between mated and virgin ovipositional patterns may be specifically attributed to differences in: (1) egg maturation, (2) age at ovipositional activation, and (3) egg-laying rate.