Fitness advantages of the biased use of paired laterally symmetrical penises in an insect

Yoshitaka Kamimura, Chin Cheng Scotty Yang, Chow Yang Lee

Research output: Contribution to journalArticle

Abstract

The evolution of laterality, that is the biased use of laterally paired, morphologically symmetrical organs, has attracted the interest of researchers from a variety of disciplines. It is, however, difficult to quantify the fitness benefits of laterality because many organs, such as human hands, possess multimodal functions. Males of the earwig Labidura riparia (Insecta: Dermaptera: Labiduridae) have morphologically similar laterally paired penises, only one of which is used for inseminating the female during a single copulation bout, and thus provide a rare opportunity to address how selection pressure may shape the evolution of population-level laterality. Our population studies revealed that in 10 populations, located at 2.23–43.3° north, the right penis is predominantly used for copulating (88.6%). A damaged penis was found in 23% of rare left-handers, suggesting that the left penis can function as a spare when the right one is damaged. By pairing L. riparia females with surgically manipulated males, we found that males forced to use the right penis outperformed left-handed males in copulation (the probability of establishing genital coupling during the 1-hr observation period: odds ratio [OR] of 3.50) and insemination (probability of transferring a detectable amount of sperm: OR of 2.94). This right-handed advantage may be due to the coiled morphology of the sperm storage organ with a right-facing opening. Thus, female genital morphology may play a significant role in the evolution of handedness and may have acted as a driving force to reduce penis number in related taxa.

Original languageEnglish
Pages (from-to)844-855
Number of pages12
JournalJournal of Evolutionary Biology
Volume32
Issue number8
DOIs
Publication statusPublished - 2019 Jan 1

Fingerprint

penis
fitness
insect
insects
copulation
sperm
handedness
odds ratio
Labiduridae
Labidura riparia
spermatozoa
Dermaptera
Riparia
storage organs
female genitalia
Insecta
insemination
genitalia
hands
researchers

Keywords

  • evolution of laterality
  • genital coevolution
  • morphological asymmetry
  • sexual conflicts
  • sexual selection

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

Fitness advantages of the biased use of paired laterally symmetrical penises in an insect. / Kamimura, Yoshitaka; Yang, Chin Cheng Scotty; Lee, Chow Yang.

In: Journal of Evolutionary Biology, Vol. 32, No. 8, 01.01.2019, p. 844-855.

Research output: Contribution to journalArticle

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