Timing regulation in insect reproduction.
Resource
Invertebrate Reproduction & Development, 48, 185-196
Journal
Invertebrate Reproduction & Development
Pages
185-196
Date Issued
2005
Date
2005
Author(s)
Abstract
Summary The interaction of planets, the earth, the moon, and the sun, causes rhythmic changes in the environment. Many aspects of the lives of insects have to coincide with these changes in order for them to survive and prosper. For insects to anticipate the rhythmic changes of the environment, an endogenous clock (or clocks) is employed in almost all known species. The canonical circadian clock is the best known system used in temporal regulation of insect daily life processes. It is employed in the regulation of reproductive physiology and behavior of insects, providing a timing mechanism that ensures sexual receptivity, mate finding, sperm release, and ovulation, for instance, occurring at appropriate times, thereby maximizing fitness. Several insect species exhibit life cycles longer than 1 year, such as the 17-year cicada or the two-year life cycle of some mayflies. However, it is more common in insects to have reproductive cycles shorter than 1 year. The requirement for a circannual clock, therefore, is less common in insects compared to the circadian clock. To outline the underlying mechanism and the role of the circadian clock in an overt rhythm which is much longer than 24 h is a challenging subject. However, a photoperiodic system with the ability to respond to the duration of periods of light and dark can certainly drive a seasonal rhythm in temperate regions where the photoperiodic change is significant. It is possible that insects use a photoperiod to gate the reproductive season, but they may also depend on the circadian clock to control the time of mate-pairing within the breeding season. Several species have been investigated to reveal the driving force behind the timing of reproduction, including our own research on the German cockroach. Although molecular expression of the circadian clock has been advancing rapidly, the functional elements of the putative circannual clock remain unexplored. The linkage between overt behavioral rhythms with internal physiological conditions and the molecular mechanism of clock expression certainly can unveil the mystery of timing regulation in insect reproduction. Key words: Circadian rhythmbiological clockphotoperiodseasonality
SDGs
Type
journal article