Some effects of low temperature on the photoperiodic clock in Drosophila triauraria |
| |
Authors: | TAKAO YOSHIDA MASAHITO T. KIMURA |
| |
Affiliation: | Department of Biology, Faculty of Science, Hokkaido University;*Division of Ecological Science, Graduate School of Environmental Earth Science, Hokkaido University, Japan |
| |
Abstract: | Abstract. Prior studies revealed that the photoperiodic clock in Drosophila triauraria operates during the scotophase and the processes measuring scotophase are composed of two phases: the A phase which lasts 6–7 h from the onset of the scotophase and the B phase which follows the A phase. In this study the photoperiodic clock in this species was analysed by low-temperature pulses. Low temperature (5C) or a low-temperature (2C) pulse of 3 or 4 h decreased the induction of diapause when applied during the scotophase, but not when applied within the photophase. The low-temperature pulse showed two maxima of the effect, 0–4 h and 8–10 h after the onset of the scotophase, approximately corresponding to the A and B phases, respectively. It is considered that low temperature retards the time measurement processes operating during these phases. In the period which was rather insensitive to the diapause-preventing action of low temperature, i.e. 5-7h after the onset of the scotophase, substances or stimuli accumulated during the A phase may be converted to information required for operation of the machinery in the B phase. Experiments using a combination of low-temperature and light pulses suggested that low-temperature decreases the sensitivity to light, especially in the B phase. |
| |
Keywords: | Drosophila triauraria reproductive diapause photoperiodic clock low temperature |
|
|