Researchers have discovered that pond frogs can consume highly venomous hornets without apparent harm, even after multiple stings. This resilience, observed in controlled experiments, highlights the frogs' tolerance to potent insect toxins. The findings could aid studies on venom resistance in animals.
In a series of laboratory experiments conducted by ecologist Shinji Sugiura at Kobe University, adult pond frogs demonstrated remarkable ability to prey on hornet workers. The study, published in the journal Ecosphere, tested frogs against three hornet species: Vespa simillima, V. analis, and the Asian giant hornet V. mandarinia. Each frog was paired with a hornet matching its size, and larger frogs faced the giant hornets.
The results were striking. Of the frogs tested, 93% successfully ate V. simillima workers, 87% consumed V. analis, and 79% managed V. mandarinia, despite stings occurring inside their mouths or even on their eyes. Sugiura noted, "Although stomach-content studies had shown that pond frogs sometimes eat hornets, no experimental work had ever examined how this occurs."
Unlike mice, which can die from a single sting of similar potency, the frogs exhibited no noticeable damage from repeated stings. Sugiura emphasized, "While a mouse of similar size can die from a single sting, the frogs showed no noticeable harm even after being stung repeatedly. This extraordinary level of resistance to powerful venom makes the discovery both unique and exciting."
Hornet venom typically causes intense pain, tissue damage, red blood cell destruction, and cardiac issues, which can be fatal. The frogs' success suggests they have evolved mechanisms to neutralize both the painful and toxic effects. Prior research indicates that pain from stings does not always correlate with lethality, supporting the idea of dual resistance in these amphibians.
This discovery opens avenues for further investigation into physiological traits like barriers or proteins that mitigate venom effects. The research, funded by the Japan Society for the Promotion of Science KAKENHI grants JP23K18027 and JP24K02099, positions pond frogs as potential model organisms for studying vertebrate tolerance to venoms and pain.