Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/23/2011
Publication Date: 6/30/2011
Citation: Weber, D.C., Lundgren, J.G. 2011. Effect of prior diet on consumption and digestion of prey and non-prey food by adults of the generalist predator Coleomegilla maculata (Coleoptera: Coccinellidae. Entomologia Experimentalis et Applicata. 140:146-152. Interpretive Summary: The native lady beetle, Coleomegilla maculata, is an omnivore, eating both prey such as aphids and insect eggs, and non-prey such as nectar and corn pollen, as part of its diet. Its effectiveness as a beneficial natural enemy, helping in biological control of crop pests, is dependent on the mix of foods available in crop and surrounding habitats. More knowledge is required on how the predator functions as a biological control, after feeding on different diets such as corn pollen, in the field or in the lab. This study establishes that male and female beetles may differ in their dietary preferences, with females consuming more corn pollen when offered. They are equally efficient at digestion of both prey (Colorado potato beetle eggs in this experiment) and non-prey (corn pollen in this experiment), with the exception that adults feeding only on prey beforehand, when then offered pollen, digested pollen more slowly, presumably gaining less nutrition. This research indicates that non-prey foods such as pollen may be important in diets used for rearing lady beetles for biological control releases, and that the availability of pollen in the field may also be important for optimal development and reproduction of this important predator species. These results will benefit biological control researchers, providers and practitioners, as well asa growers using biological control for management of insect pests of agricultural crops.
Technical Abstract: Coleomegilla maculata adults fed on prey (Colorado potato beetle eggs) or non-prey (corn pollen) food following 7 days of feeding on a mixed diet, showed differences in ingestion, with females consuming greater quantities of pollen, and males consuming greater quantities of eggs, under no-choice conditions. Digestion rates, as measured by decline of quantitative PCR marker in predator gut over 8 hours, were not significantly different by sex. When newly-eclosed females were fed with only prey or non-prey diet for 7 days, then starved for 24 hours and either fed their previous diet, or fed the alternative (crossover) diet, the ingestion amounts, and the digestion rates, did not differ, with the exception that prey-fed females then digested non-prey (pollen) at a significantly slower rate than did all other diet treatments. Results suggest that males and females of this omnivorous predator may have differing food preferences, consuming different quantities of food when offered under no-choice conditions. Furthermore, for females, a pollen diet facilitates digestion of prey foods, relative to the reverse situation in which a prey diet precedes pollen ingestion.