Researchers Reveal a Hidden Biological Clock in Insects

Humidity governs the daily rhythms of some insects, raising the question of whether it affects humans too.

Inside a tightly controlled chamber, kissing bugs, fruit flies, mosquitoes, and spider beetles adjusted their behavior to repeating changes in humidity. Even after researchers removed the humidity cycle, the insects continued following the established rhythm of moist and dry conditions.

“They take humidity cues as a biological clock,” UC Professor Joshua Benoit said.

Researchers at the University of Cincinnati conducted the experiment in an environment where both climate and light could be controlled. The study, supported by grants from the National Institute of Allergy and Infectious Diseases, was published in the Nature journal Biological Timing and Sleep.

Humidity can reset insects’ clocks

Circadian rhythms are internal cycles that help regulate processes ranging from body temperature to hormone activity. Light and temperature are known to synchronize these biological clocks, but humidity has received far less attention, said lead author Shyh-Chi Chen, formerly a researcher in Benoit’s laboratory.

“Light and temperature are well-known environmental factors that can entrain the circadian clocks,” said Chen, now an assistant professor at Georgia College & State University. “Humidity, like light and temperature, fluctuates daily.”

Extreme humidity may be uncomfortable for people, but insects can face much higher stakes because their survival depends on maintaining enough water without becoming dehydrated, Chen said.

“This could be critical for terrestrial organisms, as their survival depends on staying hydrated or avoiding dehydration,” Chen said.

Anticipating daily humidity changes could therefore help insects choose safer times to search for food or perform other activities that require energy, he said.

The signal is weaker than light

Although the results were statistically significant, humidity influenced the insects less strongly than daylight or temperature. Mosquitoes showed the weakest behavioral response to changing moisture levels.

Animals commonly use predictable environmental cycles to organize their behavior. Lunar cycles correspond with tides, while solar cycles determine changing hours of daylight. Previous UC research found that monarch butterflies use sunlight as a compass during their long continental migrations.

Humans may sense it subtly

Could recurring humidity patterns also influence biological timing in mammals, including humans?

The researchers said that the possibility cannot be excluded, although any effect would probably be too small for people to notice.

“While our current study focuses on animal models, it opens a fascinating door to human biology,” Chen said. “Although mammalian circadian biology is heavily dominated by the light-dark cycle, the potential for subtle, multisensory integration — including humidity — cannot be ruled out.”

Reference: “Humidity as a potential zeitgeber for circadian entrainment of insect systems” by Shyh-Chi Chen, Grace Goodhart, Daniel Eaton, Nathan Catlett, Tabitha Cady, Hannah Tran, Luke E. Lutz, Lyn Wang, Ella Girard, Jaida Savino, Jodi Perry, Libby Coen, Leo Walker, Amena Bidiwala, Emma Tarter, Joshua Tompkin, Nina Greene, Aiden Yang and Joshua B. Benoit, 22 June 2026, npj Biological Timing and Sleep.
DOI: 10.1038/s44323-026-00082-4

Supported by grants from the National Institute of Allergy and Infectious Diseases

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