Mating Behavior and Species Status of Host-Associated Populations of the Polyphagous Thrips, Frankliniella schultzei

Abstract

The thrips taxon, Frankliniella schultzei Trybom, could possibly comprise a complex of unrecognised cryptic species. We therefore made a range of reproductive behavioral observations on F. schultzei individuals from different host-associated populations to investigate their species status. We first described the mating behavior of F. schultzei taken from flowers of a primary host species, Malvaviscus arboreus. The pattern of male-female interaction was complex and protracted, with several behavioral steps being performed. These steps were similar for all mating pairs. Most females responded to male presence before physical contact, suggesting that male pheromones may be involved. We then compared mating behaviors, brood sizes and sex ratios of F. schultzei pairs derived from different host plant species. All pairs in crosses regardless of their original host plant species produced female offspring, indicating successful mating. Frequencies of behaviors were similar for all pairs. Only those crosses involving F. schultzei individuals from Erythrina crista-galli flowers differed from the general pattern in pre-copulation and copulation times. The females from E. crista-galli also produced significantly fewer offspring than females from other crosses. Finally we used traps baited with males from two populations, but set among flowers of one host plant species, to test for differential attraction of females. We found no evidence that the different host-associated populations investigated differ from one another functionally in their sex pheromone system. However, these results do not yet discount the possibility of cryptic species within the taxon F. schultzei. Populations of F. schultzei on many other host species need to be investigated from this perspective.