Pheromonal divergence between two strains of Spodoptera frugiperda

J Chem Ecol. 2013 Mar;39(3):364-76. doi: 10.1007/s10886-013-0263-6. Epub 2013 Mar 1.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Female
  • Male
  • Oryza
  • Sex Attractants / biosynthesis
  • Sex Attractants / metabolism*
  • Sex Attractants / pharmacology*
  • Sexual Behavior, Animal / drug effects
  • Species Specificity
  • Spodoptera / classification
  • Spodoptera / drug effects*
  • Spodoptera / genetics
  • Spodoptera / metabolism*
  • Zea mays

Substances

  • Sex Attractants