Heat waves may cause humans to slow down. But it gets crickets chirping
By Elizabeth Rembert , Food, Energy and Agriculture Reporter Nebraska Public Media, Harvest Public Media
July 21, 2023, 2 p.m. ·
A chorus of cricket chirps isn’t just summer background music – it can also be a temperature gauge.
Crickets chirp faster when it’s hotter outside, according to a scientific article published in 1897. In “Cricket as Thermometer,” Amos Dolbear wrote that counting the number of chirps in 15 seconds and adding 40 gets you the temperature in Fahrenheit.
Crickets are cold-blooded animals. Kyle Koch, an entomologist at the University of Nebraska-Lincoln, said heat helps their muscles warm up to scrape their wings together and produce the chirps.
“Crickets’ bodies are affected by the ambient temperature,” he said. “As the temperature rises, they can have those muscle contracts occurring more rapidly which allows them to have a higher frequency. And as temperatures fall, that chirp rate also starts to decrease.”
Koch said it’s similar to how, for humans, it’s easier to go on a run in June than it is in January.
Crickets could be chirping faster than ever this year. Many experts predict 2023 could be the hottest in modern history.
It’s already been a scorchingly hot summer in parts of the world, like El Paso, Texas. Daily highs there have broken records set more than 40 years ago, as residents experienced at least 36 straight days of heat above 100 degrees.
El Paso’s National Weather Service office has a cricket chirp converter, which calculates the temperature based on how many chirps people hear in 15 seconds. But Jason Laney, the office’s warning coordination meteorologist, joked counting chirps may not be very useful amid an intense heat wave.
“Unfortunately, down here we've lost track of the temperature because now we have fried crickets,” he said. “The crickets don’t have a chance. They’re going to rub their poor little wings off.”
Extreme temperatures impact humans, too. Laney said this long stretch of high temperatures is dangerous to human health.
“We could all be resilient to one or two days of excessive heat,” he said. “But what makes this stand out is the duration of the high temperatures.”
El Niño – a weather pattern that brings warm water to the Pacific Ocean near the equator and tends to raise global temperatures – is contributing to the record-breaking conditions in El Paso and elsewhere.
Climate change and insects
The pattern is exacerbating an already-hotter planet. Earth has warmed roughly 2 degrees Fahrenheit since the 19th century.
Heat and other impacts of climate change pose serious implications for insects beyond noisier crickets, according to May Berenbaum, an entomologist at the University of Illinois Urbana-Champaign.
Higher temperatures have caused some species to increase reproduction rates, or migrate north in search of cooler conditions.
Insects might also find themselves out of sync with the plants and other organisms they rely on, Berenbaum said.
“Pollinators might respond to climate change differently than the flowers they depend on,” she said. “If you’re an insect that only has one host plant and you emerge when the leaves are no longer edible, then you’re out of luck.”
Impacts will vary across the millions of species, with some winning and others losing when their environments change. But, Berenbaum said, the chance that some populations could decline shouldn’t seem like a silver lining to climate change.
“They’re all a part of global biodiversity and we don’t know how they interact. What seems to us to be a species that will be missed by no one, could turn out to have an important ecological role,” she said. “We only see a tiny sliver of how insects interact with the rest of the world.”
This story was produced in partnership with Harvest Public Media, a collaboration of public media newsrooms in the Midwest. It reports on food systems, agriculture and rural issues.