Sperm precedence in Callosobruchus chinensis estimated using the sterile male technique

Tomohiro Harano, Yutaka Nakamoto, Takahisa Miyatake

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


P2, the proportion of offspring sired by the second male to mate, is an indicator of the outcome of postcopulatory sexual selection, which occurs through sperm competition and/or cryptic female choice. We determined the appropriate dose of gamma radiation for sterilization of adult males and, using the sterile male technique, measured P2 in the adzuki bean beetle, Callosobruchus chinensis. Adult males of C. chinensis were almost completely sterilized when irradiated at 80 Gy. Thus, we obtained sterile males through irradiation at this dose. Neither the probability of female first mating nor the probability of female remating was affected by whether females were paired with normal or sterile males. The P2 calculated from the hatching success of eggs laid by females that mated both with normal and sterile males did not differ between reciprocal mating sequences, indicating that the sterilization has no effect on sperm fertilizing ability. The P2 was estimated at 0.25. This study shows that female remating in C. chinensis means the coexistence of sperm from two males and thus the occurrence of postcopulatory sexual selection within the female reproductive tract, resulting in first-male sperm precedence.

Original languageEnglish
Pages (from-to)201-206
Number of pages6
JournalJournal of Ethology
Issue number1
Publication statusPublished - Jan 2008


  • Bean beetle
  • Callosobruchus chinensis
  • Cryptic female choice
  • Irradiation
  • Postcopulatory sexual selection
  • Sperm competition
  • Sterilization

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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