Effect of Herbivore Insect Pest Age on Fecundity and Attractiveness to Egg Parasitoids in Maize and Its Wild Relative, Teosinte

Abstract

Little is known about insect pest ontogeny, with respect to fecundity, on domesticated plants and their wild relatives, and the effect of fecundity on parasitoids. The aim was to determine fecundity in young (2 wk old) and mature (8 wk old) females of the pest Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae) on maize, Zea mays ssp. mays , and its wild relative, teosinte. The effect of fecundity on parasitoid attraction was also evaluated. First, the fecundity of young D. maidis females and their attractiveness to parasitoids was evaluated in the native maize race “maiz ancho” and in the teosinte Zea perennis . Next, the fecundity of mature females and their attractiveness to parasitoids was evaluated in the native maize race “maiz ancho” at two juvenile stages, and in the teosintes Zea mays ssp. parviglumis and Z. perennis . Whereas young females laid more eggs on maize than on Z. perennis , mature females laid similar numbers of eggs on all plants studied. Anagrus incarnatus Haliday (Hymenoptera: Mymaridae) was the most abundant egg parasitoid. Eggs from young versus mature D. maidis females attracted more parasitoids. Furthermore, more parasitoid adults emerged from eggs produced by young D. maidis females on maize than on Z. perennis , whereas no difference was seen in the number of parasitoid adults emerging from eggs produced by mature D. maidis females from any of the four plant treatments. These results indicate that fecundity changes with herbivore pest age and egg parasitoid attraction depends on herbivore density; in this case, attraction was higher for young D. maidis females.