POPULATION-STRUCTURE OF A PREDATORY BEETLE - THE IMPORTANCE OF GENE FLOW FOR INTERTROPHIC LEVEL INTERACTIONS

Migration and gene flow of natural enemies play an important role in t he stability of predator-prey interactions and community organization in both natural and managed systems. Yet, relative to that of their he rbivorous insect prey, the genetic structure of natural enemy populati ons has been little studied. We present evidence that populations of t he predatory coccinellid beetle Coleomegilla maculata (Coleoptera: Coc cinellidae), are not genetically subdivided and that levels of gene fl ow among these populations are extremely high. Furthermore, in the sam e geographical area, gene flow of C. maculata was significantly (one o rder of magnitude) greater than that of an abundant prey species, the Colorado potato beetle Leptinotarsa decemlineata (Coleoptera: Chrysome lidae). The high mobility of this natural enemy relative to the insect herbivores on which it feeds may contribute to its effectiveness as a biological control agent in agricultural systems.