Attraction of fall armyworm males (Lepidoptera: Noctuidae) to host strain females

Attraction of wild male fall armyworm, Spodoptera frugiperda (J. E. Smith), was compared in trapping experiments during 2005-2009 in Florida. Traps were baited either with a commercial sex pheromone lure or corn and rice strain females obtained from laboratory colonies. Over 6,900 male moths were collected, and a large subset (>1,500) of these moths was analyzed for their host strain identity. The pheromone lure attracted over four times more males than virgin corn or rice strain females. Almost 60% of males attracted to the pheromone lure were identified as corn strain. However, both corn and rice strain females attracted a higher percentage of rice strain males, providing evidence that the commercial lure used in our study is biased to attract corn strain males and underestimates rice strain population numbers relative to corn strain numbers. Corn and rice strain males were attracted more to corn strain females than rice strain females, although there was variation in response according to location and season. Our results suggest that attraction of males to corresponding-strain females does not appear to be a premating mechanism that results in assortative mating between corn and rice host strains. Clearly other premating or perhaps even postmating mechanisms are important for the maintenance of host strains in S. frugiperda.