Biology of Apanteles dignus (Hymenoptera: Braconidae), a Primary Parasite of the Tomato Pinworm2

Apanteles dignus Muesebeck, a solitary, primary, larval endoparasite of Keiferia lycopersicella (Walsingham), was studied under insectary conditions of 26.6±1◦C and 50±2% RH. The elongated, translucent-white egg, averaging 0.350×0.063 mm (newly deposited), is randomly deposited in the body cavity of the host larva where the parasite larvae develop. There are 3 instars, the first being mandibulate and the other two hymenopteriform. Mature parasite larvae emerged from the mature host larvae, killing it, and then spun a silver-white cylindrical cocoon. The total developmental time from egg to adult was about 18 days; egg 1 day; 1st instar 4 days; 2nd instar 1 day; 3rd or last instar 1–2 days; prepupa 1 day; and pupa 8–10 days. Adult emergence was stimulated by light, and copulation took place soon after emergence. Males mated several times, females only once. Unmated females produced males only, mated females both males and females. There is essentially no preoviposition period. Without food and water, adults died within 1.2 days; with both honey and water, females lived an average of 10.2 days and males lived 13.6 days. Ten mated females had an average ovipositional period of 6.7 days (maximum 10) and produced an average of 152.1 adult progeny (maximum 182). Longevity of the ovipositing females averaged 7.0 days (maximum 10) and the sex ratio (♂ : ♀) of their progeny averaged 1.5. Average production of progeny remained above 19 per day through the 1st 5 days of the female's life, reaching a peak of 35.9 progeny per day on the 3rd day. Virgin females lived an average of 3.2 days longer than mated females, but produced an average of 32 fewer progeny. Parasitization occurred when tomato fruit infested with tomato pinworm larvae were exposed to parasite females.