Biological Studies of Zeteticontus utilis (Hymenoptera: Encyrtidae), a Parasite of Carpophilus spp. (Coleoptera: Nitidulidae)

Author： BLUMBERG D. DEMETER MICHAL KEHAT M. WILLIAMS R. N.

Publisher： Entomological Society of America

ISSN： 1938-2901

Source： Annals of the Entomological Society of America, Vol.77, Iss.2, 1984-03, pp. : 130-133

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Abstract

Data are presented on the development, fecundity, survival, and host preference of Zeteticontus utilis Noyes, a solitary internal parasite of Carpophilus spp. larvae. In the laboratory, successful parasite development occurred in Carpophilus hemipterus (L.) and in C. mutilatus Erichson, but not in two other nitidulids, C. humeralis (F.) and Haptoncus luteolus (Erichson). The male parasite developed significantly faster than the female. The values for the developmental threshold and the thermal constant were 10.4°C and 345 day-degrees for the male and 10.2°C and 370 day-degrees for the female. The mean number of progeny per female was 78.6. Oviposition lasted for an average of 9.5 days, whereas the life span was 12.6 days. Survival of adults was maximal (9.2 days) when fed on 10% honey solution, and minimal when only water, date extract, or no food was supplied (3.2–3.8 days). Even at moderate temperatures (20–32°C), adult survival was greatly reduced by low RH; this was particularly pronounced at extremely high temperatures. The female parasite showed no ovipositional preference for either C. hemipterus or C. mutilatus, and parasite development in both species was the same (19.0 days). Although development was somewhat faster in large (6–7 mm) than in small (2–3 mm) larvae, both sizes were suitable for parasite development. Percent parasitism was similar in all group sizes of larvae. The parasite female was capable of locating its host even when completely hidden inside the food.