Does DNA methylation play a role in photoperiodic diapause of moths

The present study pharmacologically investigated the involvement of DNA methylation in photoperiodic diapause of the domestic silkworm Bombyx mori (Lepidoptera: Bombycidae) and the Chinese giant silkmoth Antheraea pernyi (Lepidoptera: Saturniidae). The DNA methyltransferase inhibitor 5-azacytidine was dietarily given to larvae of B. mori under short days or long days. However, regardless of the drug administration, most resultant moths that had been exposed to short days during the larval stage laid diapause eggs and those to long days laid nondiapause eggs. 5-azacytidine did not significantly affect the diapause status of eggs. In addition, 5-azacytidine was intraperitoneally injected into diapause pupae of A. pernyi. The drug treatment caused no significant effect on diapause maintenance during short days or adult emergence under long days. We could not find evidence that DNA methylation plays a role in photoperiodic diapause of moths.