Low temperature storage of larvae and synchronization of adult emergence in the predatory midge Aphidoletes aphidimyza.
Diapause larvae of Aphidoletes aphidimyza were stored at a temperature of 3 degrees C under continuous darkness for up to 7 months with survival rates above 50%; after storage for 1 year the survival rate dropped to 12%. Diapause was terminated in the majority of individuals within 120 days of chilling under storage conditions. Brief exposure (10-60 s) to the vapor of n-hexane appeared to be a useful alternative to chilling for the termination of diapause. The larvae with terminated diapause required, on average, an additional 31 days at 22 degrees C and long-day conditions in order to reach the adult stage. The 10-90% adult emergence spanned a period of 21.1 days. When the larvae with terminated diapause were exposed to 30 degrees C for 1 week after the end of low temperature storage, the survival rate was not affected, the average "time-to-adult" shortened moderately to 28 days, and the synchrony of adult emergence improved considerably to 10 days. Low temperature storage of nondiapause larvae resulted in a decrease in survival from 98 to 31% during the first 60 days of storage. Nondiapause larvae did not enter diapause during low temperature storage and, as a consequence, the adults emerged relatively rapidly (after 14-15 days) and synchronously (within 2-3 days) after the end of storage. Directions for future research, which might bring further improvement in low temperature storability and synchrony of adult emergence in A. aphidimyza, are proposed.
Kostal
V
V
Institute of Entomology, Ceske Budejovice, Czech Republic.
Havelka
J
J
D000818:Animals; D001042:Aphids / Q000469:parasitology; D015925:Cryopreservation / Q000379:methods*; D003890:Desiccation; D004175:Diptera / Q000254:growth & development / Q000472:pathogenicity; D006586:Hexanes / Q000494:pharmacology; D007814:Larva / Q000254:growth & development; D010572:Pest Control, Biological; D011235:Predatory Behavior; D013696:Temperature; D013997:Time Factors
D006586:Hexanes; C026385:n-hexane