title: Pheromonal divergence between two strains of Spodoptera frugiperda.
abstract: Spodoptera frugiperda consists of two genetically and behaviorally different strains, the corn- and the rice-strain, which seem to be in the process of sympatric speciation. We investigated the role of strain-specific sexual communication as a prezygotic mating barrier between both strains by analyzing strain-specific variation in female pheromone composition of laboratory and field strains, and also male attraction in wind tunnel and field experiments. Laboratory-reared and field-collected females from Florida exhibited strain-specific differences in their relative amount of (Z)-7-dodecenyl acetate (Z7-12:OAc) and (Z)-9-dodecenyl acetate (Z9-12:OAc). In wind tunnel assays, we did not find strain-specific attraction of males to females. However, in field experiments in Florida, we observed some differential attraction to synthetic pheromone blends. In a corn field, the corn-strain blend attracted more males of both strains than the rice-strain blend, but both blends were equally attractive in a grass field. Thus, habitat-specific volatiles seemed to influence male attraction to pheromones. In dose-response experiments, corn-strain males were more attracted to 2 % Z7-12:OAc than other doses tested, while rice-strain males were attracted to a broader range of Z7-12:OAc (2-10 %). The attraction of corn-strain males to the lowest dose of Z7-12:OAc corresponds to the production of this compound by females; corn-strain females produced significantly smaller amounts of Z7-12:OAc than rice-strain females. Although corn-strain individuals are more restricted in their production of and response to pheromones than rice-strain individuals, it seems that differences in sexual communication between corn- and rice-strain individuals are not strong enough to cause assortative mating.
authors: Department of Entomology, MPICE, Hans-Knoell-Str. 8, 07745, Jena, Germany. munbehend@ice.mpg.de
authors: Melanie
authors: M
authors: Unbehend
authors: Sabine
authors: S
authors: Hänniger
authors: Robert L
authors: RL
authors: Meagher
authors: David G
authors: DG
authors: Heckel
authors: Astrid T
authors: AT
authors: Groot
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D012275:Oryza; D012724:Sex Attractants / Q000096:biosynthesis / Q000378:metabolism* / Q000494:pharmacology*; D012726:Sexual Behavior, Animal / Q000187:drug effects; D013045:Species Specificity; D018411:Spodoptera / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays
chemical_list: D012724:Sex Attractants