Intra-sexual dimorphism in male mandibles and male aggressive behavior in the broad-horned flour beetle Gnatocerus cornutus (Coleoptera: Tenebrionidae)

Kensuke Okada, Akihiro Miyanoshita, Takahisa Miyatake

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

In the stored-product beetle, the broad-horned flour beetle, Gnatocerus cornutus (Fabricius), all males possess enlarged mandibles, widened gena, and a pair of small horns on the vertex, but females lack these completely. Observations of male-male interactions of G. cornutus showed that larger individuals won male-male fights, and that the mandibles were used as weapons. Morphological analysis based on the non-linearity test of Eberhard and Gutierrez's model (1991) showed that intra-sexual dimorphism in males was only found in the mandibles used in male-male combat, but not in the gena and horns. This beetle can be an ideal model for evolutionary studies of exaggerated weapons for male combat, because rearing successive generations and observing male fighting are easy.

Original languageEnglish
Pages (from-to)457-467
Number of pages11
JournalJournal of Insect Behavior
Volume19
Issue number4
DOIs
Publication statusPublished - Jul 1 2006

Keywords

  • Alternative phenotype
  • Male-competition
  • Sexual selection
  • Weapon

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Insect Science

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