From Watts Up With That?

Essay by Eric Worrall

What a disaster that would be – not.

MARCH 4, 2026

Climate change pushes tropical insects to their heat limit

by Julius Maximilian University of Würzburg
edited by Gaby Clark, reviewed by Robert Egan

Up to half of the insects in the Amazon region could be exposed to life-threatening heat levels due to progressive, anthropogenic global warming. This is shown by a recent study by the universities of Würzburg and Bremen.

“Current evaluations of the heat tolerance of insects such as moths, flies, and beetles paint a differentiated—and at the same time alarming—picture,” explains study author Dr. Kim Holzmann, researcher at the Chair of Animal Ecology and Tropical Biology of the Julius-Maximilians-Universität Würzburg (JMU). According to the study, insects’ ability to tolerate high temperatures does not simply adapt to their respective environment. “While species at higher altitudes can increase their heat tolerance, at least in the short term, many lowland species largely lack this ability,” says Holzmann.

Threatening consequences for entire ecosystems

The study, published in Nature, makes it clear that tropical insects have only a very limited ability to adapt to climate change. Dr. Marcell Peters, animal ecologist at the University of Bremen and study author, says, “Rising temperatures could have a massive impact on insect populations, especially in regions with the world’s highest biodiversity. Since insects fulfill central functions in ecosystems as pollinators, decomposers, and predators, there is a threat of far-reaching consequences for entire ecosystems.”

…Read more: https://phys.org/news/2026-03-climate-tropical-insects-limit.html

The abstract of the study;

• Article
• Open access
• Published: 04 March 2026

Limited thermal tolerance in tropical insects and its genomic signature

Kim L. Holzmann, Thomas Schmitzer, Antonia Abels, Marko Čorkalo, Oliver Mitesser, Mareike Kortmann, Pedro Alonso-Alonso, Yenny Correa-Carmona, Andrea Pinos, Felipe Yon, Mabel Alvarado, Adrian Forsyth, Alejandro Lopera-Toro, Gunnar Brehm, Alexander Keller, Mark Otieno, Ingolf Steffan-Dewenter & Marcell K. Peters 

Nature (2026)Cite this article

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Abstract

Insects make up the majority of all animal species, with 70% occurring in the tropics¹, yet the impacts of warming on tropical insects remain highly uncertain². This stems from sparse, taxonomically biased data on thermal tolerance of tropical insects and an incomplete understanding of the underlying physiological mechanisms³. Here we compared environmental temperatures with field-measured upper and lower thermal tolerance limits of around 2,300 insect species along Afrotropical and Neotropical elevational gradients and identified genomic signatures of thermal tolerance across the insect tree of life. We show that thermal tolerances do not proportionally track environmental temperatures but approach an asymptote in tropical lowlands. Insects at high elevations utilize plasticity to cope with rising temperatures, whereas lowland species have limited plastic abilities. Heat tolerance showed strong differences among insect orders and families, reflected in the thermal stability of proteins, suggesting that variation in thermal tolerance is founded in the fundamental protein architecture. Up to 52% of future surface temperatures and 38% of air temperatures in the Amazonian lowlands can cause heat mortality in half of the studied community. Our data suggest a limited capacity of insects in the Earth’s most biodiverse regions to buffer future warming.Read more: https://www.nature.com/articles/s41586-026-10155-w

Frankly this study doesn’t pass the smell test.

Would some insect species suffer significant changes in distribution if conditions changed? Absolutely. 10s of thousands of insect species in intense competition with each other, even slight advantages matter. Any change which shifts the balance in favour of a different species causes changes in distribution and population.

Would such changes threaten critical insect activities such as pollination? Absolutely not. The Palaeocene-Eocene Thermal Maximum, 5-8C hotter than today, was the age of monkeys. Our mostly fruit eating monkey ancestors thrived on the abundance of the hothouse PETM, and colonised much of the world. Since those monkey ancestors mostly ate fruit, there must have been an abundance of pollinators, even in the hottest parts of the hothouse PETM world.

Regardless of whether the author’s claim of plasticity limits applies to the species they studied, the abundance of insects and pollinators in past periods of extreme warmth unequivocally demonstrates there is no risk of a pollinator apocalypse, even if the species fulfilling that role changes with temperature.