A Novel Method for Estimating the Pre-Reproductive Period of Female African Armyworm Moths, Spodoptera Exempta

  • Kenneth Wilson
Research Article


In the majority of insects, migration occurs exclusively or predominantly during the pre-reproductive period (PRP) and therefore, the duration of the PRP provides a useful index of migratory potential. The present study describes a novel method for estimating the PRP of Spodoptera exempta (Walker) (Lepidoptera: Noctuidae). It relies on the fact that as the female approaches sexual maturity, there is a substantial change in the shape of her gonopore-patch (an area of black scales at the posterior of the abdomen). Gonopore-patch shape (GPS) is strongly correlated with PRP (as determined by “calling” behaviour) and may prove to be the best method for estimating migratory potential in some circumstances. A number of other species of moths also have gonopore-patches which may aid the study of their migration.

Key Words

African armyworm gonopore-patch size pre-reproductive period calling behaviour moth migration 


Chez la plupart des insectes, la migration se produit exclusivement ou abondament pendant la période précédant la reproduction. Par conséquent, la durée de cette période peut journir un indice utile du potential migrateur de ces insectes. L’étude dont il est question dans cet article décrit une méthode nouvelle pour l’estimation du PRP de la femelle de Spodoptera exempta (Walker) (Lepidoptera: Noctuidae). La méthode vient du fait que, chez la femelle, juste avant la maturité sexuelle, il y a un changement substantial de la forme de son rustine (l’aggloromeration d’écailles noires à la partie postérieure de l’abdomen). Il existe une grande corrélation entre la forme du rustine (“GPS”) et la PRP (comme indiqué par le comportement et le cri d’appel de la femelle). Dans certaines circonstances, le GPS peut être la meilleure méthode pour estimer le potentiel migrateur. Chez d’autres espéces de papillons de nuit, il existe également des GPS qui pourraient servir, éventuellement, dans l’étude de leur migration.


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Copyright information

© ICIPE 1993

Authors and Affiliations

  • Kenneth Wilson
    • 1
  1. 1.School of Biological SciencesUniversity of WalesBangor, GwyneddUK

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