Circadian rhythms and endocrine functions in adult insects

Guy Bloch*, Esther Hazan, Ada Rafaeli

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

72 Scopus citations


Many behavioral and physiological processes in adult insects are influenced by both the endocrine and circadian systems, suggesting that these two key physiological systems interact. We reviewed the literature and found that experiments explicitly testing these interactions in adult insects have only been conducted for a few species. There is a shortage of measurements of hormone titers throughout the day under constant conditions even for the juvenile hormones (JHs) and ecdysteroids, the best studied insect hormones. Nevertheless, the available measurements of hormone titers coupled with indirect evidence for circadian modulation of hormone biosynthesis rate, and the expression of genes encoding proteins involved in hormone biosynthesis, binding or degradation are consistent with the hypothesis that the circulating levels of many insect hormones are influenced by the circadian system. Whole genome microarray studies suggest that the modulation of farnesol oxidase levels is important for the circadian regulation of JH biosynthesis in honey bees, mosquitoes, and fruit flies. Several studies have begun to address the functional significance of circadian oscillations in endocrine signaling. The best understood system is the circadian regulation of Pheromone Biosynthesis Activating Neuropeptide (PBAN) titers which is important for the temporal organization of sexual behavior in female moths. The evidence that the circadian and endocrine systems interact has important implications for studies of insect physiology and behavior. Additional studies on diverse species and physiological processes are needed for identifying basic principles underlying the interactions between the circadian and endocrine systems in insects.

Original languageAmerican English
Pages (from-to)56-69
Number of pages14
JournalJournal of Insect Physiology
Issue number1
StatePublished - Jan 2013

Bibliographical note

Funding Information:
Research in the Bloch laboratory was supported by grants from the Israeli Science Foundation (ISF), US - Israel Binational Foundation (BSF), German –Israeli Foundation (GIF), The National Institute for Psychobiology in Israel (NIPI), the US-Israel Binational Agricultural Research and Development Fund (BARD). The authors thank three anonymous reviewers for their comments on an earlier version of this article.


  • Biological clock
  • Circadian rhythms
  • Hormone
  • Insect
  • Physiology
  • Reproduction


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