Allometry and fighting behaviour of a dimorphic stag beetle Cyclommatus mniszechi (Coleoptera: Lucanidae)

Zhen Yi Chen, Yuying Hsu, Chung Ping Lin

Research output: Contribution to journalArticle

Abstract

Male stag beetles (Coleoptera: Lucanidae) use their mandibles as weapons to compete for resources and reproduction. Mandible size in stag beetles can be associated with different behaviours and the outcome of male contests. We investigated the allometric relationship between mandible and body size in males of the stag beetle Cyclommatus mniszechi to uncover distinct morphs. The results divided male C. mniszechi into majors and minors with the switch point of mandible length at 14.01 mm. The allometric slope of mandibles was positive for both morphs but was steeper for the minors. We also characterised the fighting behaviour of the different morphs in size-matched contests using sequential analyses. Males matched each other’s behaviour in contests with many physical contacts, no injury and a progression from low towards high aggression and rare de-escalation. Major and minor males employed the same behavioural elements in contests, but major males were more likely to escalate directly into more aggressive phases and minor males tended to stay within phases. This finding suggests that major males may compete more aggressively than minor males in contests.

Original languageEnglish
Article number81
JournalInsects
Volume11
Issue number2
DOIs
Publication statusPublished - 2020 Feb 1

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Keywords

  • Body size
  • Male-male competition
  • Mandible
  • Sequential analysis
  • Sexual selection
  • Weapon

ASJC Scopus subject areas

  • Insect Science

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