title: Does a Change from Whole to Powdered Food (Artemia franciscana eggs) Increase Oviposition in the Ladybird Coleomegilla maculata?
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 vs. whole Artemia franciscana (A. franciscana) (brine shrimp) eggs with or without a dietary supplement on development and reproduction of Coleomegilla maculata (C. maculata) (Coleoptera: Coccinellidae). We tested the hypotheses that (1) powdered A. franciscana eggs are more suitable than whole eggs; and (2) palmitic acid, a common fatty acid in natural prey, i.e., aphids, is an effective dietary supplement. Development time, pre-imaginal survival, sex ratio, and body weight of adults did not differ significantly amongst individuals fed powdered vs. whole eggs, with or without 5% palmitic acid. Significantly more oviposition occurred when females were fed powdered eggs than whole eggs and powdered eggs with 5% palmitic acid than whole eggs with or without 5% palmitic acid. A weak functional relationship was found between pre-oviposition time and total oviposition by females fed powdered eggs with 5% palmitic acid; pre-oviposition time decreased as oviposition increased. Food treatments had no significant differential effect on progeny (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 oviposition in C. maculata. Supplementing powdered eggs with 5% palmitic acid might accelerate oogenesis (egg maturation) in some females.
authors.affiliation: National Biological Control Laboratory, Jamie Whitten Delta States Research Center, ARS-USDA, Stoneville, MS 38776, USA. eric.riddick@ars.usda.gov.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Riddick
authors.affiliation: National Biological Control Laboratory, Jamie Whitten Delta States Research Center, ARS-USDA, Stoneville, MS 38776, USA. zhixin.wu@ars.usda.gov.
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Wu
keywords: Artemiidae; Coccinellidae; biological control; lady beetle; lipids; predator