Phase Responses in the Circannual Rhythm of the Varied Carpet Beetle, Anthrenus verbasci, Under Naturally Changing Day Length
In the varied carpet beetle, Anthrenus verbasci, we examined the effects on the circannual pupation rhythm of a short-day or long-day pulse under naturally changing day length at a constant 20°C. A short-day pulse for 4 weeks caused a prominent phase delay or advance under constant long days, but had little or no effect on the phase under naturally changing day length between 4 August and 24 November. A long-day pulse for 4 weeks given under naturally changing day length caused a phase shift in the first pupation group, as under constant short days. A long-day pulse given on 4 August, 1 September, or 29 September caused a phase delay, and a pulse given on 27 October or 24 November caused a phase advance. Pupation was least synchronous just before the transition from delaying to advancing. However, the magnitude of phase delays was much smaller under natural day length than under short days. In the second pupation group, larvae pupated at the same time as in the control experiment without a long-day pulse, and this result can be attributed to entrainment to the geophysical year by long days in spring and summer.
- Zoological science
Zoological science 23(11), 1031-1037, 2006-11-25