Yellow mutant of the Neotropical green lacewing Chrysoperla externa: trait inheritance and predator performance

Abstract

The Neotropical green lacewing Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) is a key predator of various small soft-bodied pest species. Chrysopidae species are known as ‘green lacewings’ due to their overall green body coloration. However, yellow mutant individuals were observed emerging from our lacewing rearing colony. Thus, the mode of inheritance of the yellow trait was studied and the hypothesis of an autosomal recessive allele for yellow color was tested using hybridization and backcrossing techniques. Furthermore, the possible implications of this color variation on specific life-history characteristics of C. externa and the predation rates of each morph were evaluated. In both yellow and green morphs, basic life-history characteristics were monitored, including time to hatching and viability of eggs, duration, and viability of larval and pupal stages, emergence rate and survivorship of adults, and fecundity and longevity of females. The yellow and green morphs were indistinguishable with respect to all life-history traits evaluated and the predation rate of their larvae. Crossing experiments revealed the yellow color to be caused by a homozygous recessive allele, without sex-linked expression. We conclude that the allele for yellow color is occurring at high frequency in the laboratory colony, supporting the existence of a genetic polymorphism for body ground color.