A NEW CONCEPT IN ARTIFICIAL DIETS FOR CHRYSOPERLA-RUFILABRIS - THE EFFICACY OF SOLID DIETS

A semisolid artificial diet is described for rearing larvae of a green lacewing, Chrysoperla rufilabris Burmeister (Neuroptera: Chrysopidae) . Fifteen successive generations have been produced using this diet fo r larval development and a yeast, sucrose, and water mixture as the ad ult diet. The biological parameters of survival to the adult stage, me an egg production/female/ day (= fecundity), duration of larval and pu pal stages, and pupal weight measured 1 day after pupation were evalua ted in generations 6-10. Survival from egg to pupa was about 87% on th e larval diet and 89% on eggs from Ephestia kuehniella (Zeller) (Lepid optera: Phycitidae). Fecundity was nearly identical in diet-produced C . rufilabris and those produced on eggs from E. kuehniella. Mean pupal weight for C. rufilabris fed diet was 9.40 (+/-0.19 SE) mg, and for t hose fed E. kuehniella eggs, it was 8.61 (+/-0.16) mg. Development tim e for larvae reared from newly emerged first instar larvae to onset of pupation was 10.85 (+/-0.15) days on the diet and 8.05 (+/-0.08) days on E. kuehniella eggs. Pupal duration was 9.41 (+/-0.07) days for die t-reared individuals and 10.08 (+/-0.11) for E. kuehniella-related ind ividuals. Diet-reared adults laid 21.5 eggs per female per day over a 5-day period compared to 19 eggs per C. rufilabris reared on E. kuehni ella eggs. Larvae from the diet culture readily attacked and consumed cotton aphids, Aphis gossipyi Glover (Homoptera: Aphididae). The diet is a solid, stringy paste presented in stretched Parafilm membrane. Th e diet costs about $6.00 (U.S.) per kilogram, including packaging, com pared with about $50 per kilogram for diets with protein hydrolysates and about $500 per kilogram for E. kuehniella eggs. We explain how sol id diets accommodate, better than liquids, the feeding mechanisms of l arval chrysopids and other predaceous arthropods that use extraoral di gestion. (C) 1998 Academic Press.