A New Concept in Artificial Diets forChrysoperla rufilabris: The Efficacy of Solid Diets1

Abstract

Abstract 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 for larval development and a yeast, sucrose, and water mixture as the adult diet. The biological parameters of survival to the adult stage, mean egg production/female/day (= fecundity), duration of larval and pupal stages, and pupal weight measured 1 day after pupation were evaluated in generations 6–10. Survival from egg to pupa was about 87% on the larval diet and 89% on eggs from Ephestia kuehniella (Zeller) (Lepidoptera: 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 those fed E. kuehniella eggs, it was 8.61 (±0.16) mg. Development time 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 diet-reared individuals and 10.08 (±0.11) for E. kuehniella -reared individuals. 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. kuehniella 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. The diet costs about $6.00 (U.S.) per kilogram, including packaging, compared with about $50 per kilogram for diets with protein hydrolysates and about $500 per kilogram for E. kuehniella eggs. We explain how solid diets accommodate, better than liquids, the feeding mechanisms of larval chrysopids and other predaceous arthropods that use extraoral digestion.