Two researchers from Stellenbosch University (SU) were part of the team, led by researchers from the University of Pretoria (UP) and Adelaide University, that have overturned a long-held theory that gigantic dragonfly-like insects could only have existed 300 million years ago because atmospheric oxygen levels were about 45% higher than they are today.

Over the past five years, Prof. Susana Clusella-Trullas from SU’s Department of Botany and Zoology, and Prof. John Terblanche from the Department of Conservation Ecology and Entomology, have been working with Dr Edward (Ned) Snelling and Dr Antoinette Lensink from UP’s Faculty of Veterinary Science, and Dr Roger Seymour from Adelaide University.

Clusella-Trullas says it is thanks to the remarkable insect diversity of Southern Africa that they were able to measure the investment of tracheoles (fine respiratory tubes in the tracheal system of insects) in the muscle of more than 40 species: “These varied in size by more than four orders of magnitude, hence facilitating the test of this long-held hypothesis.” 

According to Terblanche, studying the form and function of insects remains an active research field: “The systematic, comparative physiological approaches using relatively simple techniques such as microscopy, can yield fundamental insights into how animals work.”

Moreover, understanding insect body size and their functional limits has broad implications for understanding biodiversity responses to human-made pressure in an era of rapid change, they conclude.

Read the media release from University of Pretoria here.

Read the original paper published in Nature, titled “Oxygen supply through the tracheolar–muscle system does not constrain insect gigantism”.

DOI 10.1038/s41586-026-10291-3

URL https://www.nature.com/articles/s41586-026-10291-3