A. Veerman, Photoperiodic time measurement in insects and mites: a critical evaluationof the oscillator-clock hypothesis, J INSECT PH, 47(10), 2001, pp. 1097-1109
The validity of the oscillator-clock hypothesis for photoperiodic time meas
urement in insects and mites is questioned on the basis of a re-interpretat
ion of available experimental evidence. The possible role of the circadian
system in photoperiodism in arthropods is critically reviewed. Apart from t
he outcome of kinetic experiments, based on diel and non-diel light/dark cy
cles. evidence from various genetic and physiological experiments is discus
sed in relation to the oscillator-clock hypothesis. The conclusion is that
photoperiodic time measurement in insects and mites is performed by a non-c
ircadian 'hourglass' clock. Experimental evidence suggests a non-clock role
for the circadian system in the photoperiodic mechanism of insects and mit
es. (C) 2001 Published by Elsevier Science Ltd.