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Adult eclosion rhythm of the I ndian meal moth Plodia interpunctella : response to various thermocycles with different means and amplitudes
Author(s) -
KIKUKAWA SHIGERU,
HASHIZUME RYOU,
HONDA MIHO,
INOUE YUKA,
MAEKAWA TATSUYA,
SAKATA RISA,
TAKAHASHI NANAKO,
TANAKA KUNIAKI,
UCHIDA YU
Publication year - 2013
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/phen.12031
Subject(s) - pyralidae , biology , photoperiodism , zeitgeber , circadian rhythm , lepidoptera genitalia , rhythm , zoology , diapause , larva , medicine , endocrinology , circadian clock , botany
In addition to photoperiod, thermoperiod (or thermocycle) might be an important Zeitgeber for entraining the circadian oscillator controlling adult eclosion rhythm in the Indian meal moth Plodia interpunctella Hübner (Lepidoptera: Pyralidae). This is confirmed by exposing larvae receiving diapause‐preventing treatments to various thermocycles with different means and amplitudes of temperature. The thermocycles investigated in the present study are TC 8 : 16 h, TC 12 : 12 h, TC 16 : 8 h and TC 20 : 4 h, where T and C represent thermophase (30 °C) and cryophase (20 °C), respectively. For all thermocycles, the peak of adult eclosion rhythm occurs at around the mid‐thermophase. This indicates that the larvae use both ‘temperature‐rise’ and ‘temperature‐fall’ signals to adjust the eclosion phase in each thermocycle. The absence ( DD ) or presence ( LL ) of light affects this time‐keeping system slightly under the given thermocycle. The rhythmic adult eclosion noted after exposure of larvae to 30 °C DD for 14 days is recorded in the thermocycles ( TC 12 : 12 h, DD ; mean temperature = 25 °C) with different amplitudes of 27.5/22.5 °C, 26.5/23.5 °C and 25.5/24.5 °C. The peak in adult eclosion advances in time as the amplitude of the temperature cycle decreases. In the temperature cycle of 25.5/24.5 °C, a peak occurs at the end of the cryophase, 2 h before the temperature‐rise. The adult eclosion rhythm is also observed under various thermocycles ( TC 12 : 12 h, DD ) consisting of different temperature levels (30 to 20 °C) with different amplitudes. It is found that the temporal position of the peak advances significantly when the amplitude of the thermocycle becomes lower.