Photoperiodic clock of diapause termination in Pseudopidorus fasciata (Lepidoptera: Zygaenidae)

Abstract

Abstract. Photoperiodic control of diapause termination was systematically investigated in Pseudopidorus fasciata. In 24 h lightdark cycles, the rate of diapause termination in this species depended on photoperiod. The critical night length (CNL) for diapause termination was 10 h, 0.5 h shorter than that for diapause induction. Night-interruption experiments with T = 24 showed that dia pause was effectively terminated when the scotophases separated by light pulse were shorter than the critical night length (10 h); no developing individuals were found if the duration of the pre-interruption scotophase or the post-interruption scotophase exceeded the CNL. A 15-min light pulse was sufficient to reverse the effect of long night when it was placed 8 h after lights-off. Resonance experiments with a constant photophase of 12 h or 16 h and various scotophases of 4-80 h showed an hourglass-type photoperiodic response, where no rhythmicity was found. In another resonance experiment with constant scotophase of 8 h and various photo phases of 4-72 h, all individuals developed into cocoons. In the Bunsow experiment, the response curve showed two apparent peaks for diapause termination, one being 8 h after lights-off, and another 8 h before lights-on. However, there was no periodic rhythmicity, which again indicates an hourglass principle. The results lead to the conclusion that the same photoperiodic clock mechanism (a long-night measuring hourglass) is involved in both diapause induction and termination.

Diapause Regulation in Newly Invaded Environments: Termination Timing Allows Matching Novel Climatic Constraints in the Box Tree Moth, Cydalima perspectalis (Lepidoptera: Crambidae)

“…For instance, photoperiod was identified as the main factor triggering diapause termination in multiple insect species, such as Sesamia nomagrioides (Lepidoptera: Noctuidae) [41], Pseudopidorus fasciata (Lepidoptera: Zygaenidae) [42], and Pieris brassicae (Lepidoptera: Pieridae) [43]. Yet, we found no clear effect in the box tree moth, with only a slight and unstructured influence on the general dynamics of returns to activity, while T 50% was not significantly impacted.…”

Clock-talk: have we forgotten about geographic variation?

“…4) Pieris brassicae 1p 24, 30, 12 Mid Bünning ( 1973 , Fig. 126) Pseudopidorus fasciasta 1p 24, 60, 9 (3) Li et al ( 2003 , Fig. 2) Pseudopidorus fasciasta 1p 24, 60, 9 (3) Wei et al ( 2001 , Fig.…”

“…11) Plodia interpunctata 1p 72, 120, 12 (7) Kikukawa et al ( 2009 , Fig. 3) Pseudopidorus fasciasta 1p 72, 60, 12 NC Mtn Li et al ( 2003 , Fig. 7C) Pseudopidorus fasciasta 1p 72, 60, 12 (14) Wei et al ( 2001 , Fig.…”

Diapause regulation in newly invaded environments: termination timing allows matching novel climatic constraints in the box tree moth, Cydalima perspectalis (Lepidoptera: Crambidae)

“…For instance, photoperiod was identified as the main factor triggering diapause termination in multiple insect species, such as Sesamia nomagrioides (Lepidoptera: Noctuidae) [40], Pseudopidorus fasciata (Lepidoptera: Zygaenidae) [41], and Pieris brassicae (Lepidoptera: Pieridae) [42]. Yet, we found no clear effect in the box tree moth, with only a slight and unstructured influence on the general dynamics of returns to activity while T 50% was not significantly impacted.…”