Figure 9. Schematic illustration of 5HTRs role on diapause induction/maintenance in pupal diapause of A. pernyi.

The moth has two 5HTR subtypes, 5HTR_A and 5HTR_B.The former subtype shows no transcription rhythm [24] and did not respond to photoperiodic activation by long day, while the latter showed rhythmic expression and responded to photoperiodic activation. Therefore, it may be regulated by circadian system. Via one type of arylalkylamine N-acetyltransferase, aaNAT. This engyme is encoded by nat is that a circadian-controlled gene (ccg) since dsRNA^CYC, and dsRNA^CLK suppressed nat transcription and dsRNA^NAT dysfunctioned photoperiodism. Transcription of 5HTR_A was not rhythmic. MT-binding closes the endocrine switch to PTTH release that finally terminates diapause, while 5HTR_B cuts this circuit to enforce or initiate diapause. Diapause of A.penyi is therefore under binary regulation and circadian system regulates at least two points in this system, nat transcription and 5HTR_B expression. aaNAT, arylalkylamine N-acetyltransferase. PER, Period protein, a negative regulator of transcription translation feedback. CYC/CLK, heterodimeric circadian transcription regulator. Mel, melatonin. MT, melatonin receptor. LD, long day. SD, short day. PTTH, prothoracicotropic hormone. PTG, prothoracic gland. E, ecdysone. 20E, 20 hydroxyecdysone.