Present address: Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan.
Sexual difference in the photoperiodic induction of pupal diapause in the flesh fly Sarcophaga similis
Article first published online: 26 SEP 2010
© 2010 The Entomological Society of Japan
Volume 13, Issue 3, pages 311–319, September 2010
How to Cite
TAGAYA, J., NUMATA, H. and GOTO, S. G. (2010), Sexual difference in the photoperiodic induction of pupal diapause in the flesh fly Sarcophaga similis. Entomological Science, 13: 311–319. doi: 10.1111/j.1479-8298.2010.00394.x
- Issue published online: 26 SEP 2010
- Article first published online: 26 SEP 2010
- Received 1 March 2010; accepted 28 March 2010.
- diapause titer;
- external coincidence model;
- photoinducible phase;
- qualitative time measurement;
- quantitative time measurement;
The flesh fly Sarcophaga similis enters pupal diapause in response to short days, but averts diapause under long days. This species shows a sexual difference in the photoperiodic induction of diapause, with females having shorter critical daylength than males. Here, we proposed two hypotheses to explain this sexual difference. First, we proposed a sexual difference in the qualitative evaluation of photoperiods. This hypothesis assumes under the external coincidence model that although the photoinducible phase of both sexes locates at late scotophase, in males, it locates at a slightly earlier phase. However, the results of night interruption experiments clearly ruled out this hypothesis. Because we verified that S. similis evaluated photoperiods quantitatively, we next proposed a sexual difference in the quantitative evaluation of photoperiods. This hypothesis incorporates concepts of a hypothetical substance accumulation that shows a diapause-inducing effect and an internal threshold that serves as a reference to determine the diapause/nondiapause developmental program. In long-day exposure experiments and night interruption experiments, females consistently showed a lower incidence of diapause than males. Thus, the present study data satisfactorily meet the second hypothesis, that is a sexual difference in the quantitative evaluation of photoperiods exists in S. similis.