Spermatophore expulsion in the carrion beetle Silpha perforata (Coleoptera: Silphidae)
Article first published online: 6 JAN 2011
© 2011 The Entomological Society of Japan
Volume 14, Issue 1, pages 37–42, January 2011
How to Cite
SUMITOMO, H., SHIRAISHI, K. and HIROTA, T. (2011), Spermatophore expulsion in the carrion beetle Silpha perforata (Coleoptera: Silphidae). Entomological Science, 14: 37–42. doi: 10.1111/j.1479-8298.2010.00418.x
- Issue published online: 6 JAN 2011
- Article first published online: 6 JAN 2011
- Received 11 April 2010; accepted 22 August 2010.
- male strategy;
- physical replacement;
- reproductive behavior
Silphinae (Coleoptera: Silphidae) is an abundant decomposer that plays important roles in the ecosystem. However, there is little information about the life history of this taxon. We found sperm displacement behavior in carrion beetle Silpha perforata. Copulating males bit the female's antenna strongly and inserted the penis into the partner's genital organ more than once. We found a white substance on the tip of penis during copulation. We examined whether this white substance is a previous male's spermatophore, which was removed from the mating partner. When females were dissected just after mating, the same substance that often presents on the penis of mating males was found in the bursa copulatrix of females, although the bursa copulatrix of virgin females was empty. Male behavior during copulation with females of different mating history was also observed to confirm that the removal of spermatophores was observed only in copulation with females that have the spermatophores of previous males. Consequently, we estimated that S. perforata males removed spermatophores of previous males from mating partners. In addition, we dissected the males frozen during copulation, and inspected the penis morphology. This observation revealed that the apical part of the penis was usually hidden in the basal part of penis, but expanded and appeared during insertion. This apical part had many spines, which play an important role in sperm displacement and sexual conflict in some species. These results indicate that there is the sperm competition in S. perforata. This is the first report on sperm competition in Silphinae.