Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2015
Publication Date: 9/28/2015
Citation: Riddick, E.W., Wu, Z. 2015. Does a change from whole to powdered food (Artemia franciscana eggs) increase oviposition in the ladybird Coleomegilla maculata. Insects. 6:815-826.
Interpretive Summary: A hindrance to the widespread adoption of augmentative biological control is the high cost of mass producing natural enemies, e.g., predators. Discovery of more cost-effective, nutritious food for predators (ladybird beetles) could help to ameliorate this problem. In this study, we discovered that a simple transformation of food from a whole to a powdered form, increased oviposition in the pink-spotted ladybird beetle, Coleomegilla maculata. Also, supplementing powdered food with a low concentration of palmitic acid (a fatty acid) seemed to hasten the onset of oviposition of some females. This research is useful because it provides some clues on how to reduce costs and increase production of ladybirds destined for release onto crop plants to control plant pests, such as aphids.
Technical Abstract: The limited availability of alternative foods to replace natural prey hinders cost-effective mass production of ladybird beetles for augmentative biological control. We compared the effects of powdered versus whole Artemia franciscana (brine shrimp) eggs with or without a dietary supplement on development and reproduction of Coleomegilla maculata (Coleoptera: Coccinellidae). We tested the hypotheses that (1) powdered eggs are more suitable than whole eggs, and (2) palmitic acid is an effective dietary supplement. Development time, pre-imaginal survival, sex ratio, and body weight of adults did not diffe significantly amongst individuals fed powdered vs whole eggs, with or without 5% palmitic acid. Significantly more eggs were laid by females fed powdered eggs only. A functional relationship was found between pre-oviposition time and total eggs laid by females fed powdered eggs with 5% palmitic acid; pre-oviposition time decreased as oviposition increased. Food treatments had no significant differential effect on egg hatch rate. In conclusion, a simple change in A. franciscana egg texture and particle size (i.e., blending whole eggs into a dust-like powder) increases ovipositoin in C. maculata. Supplementing powdered eggs with 5% palmitic acid might accelerate egg maturation (oogenesis) in some females.