Rosa Rubicondior: Unintelliget Designer News - How Frogs Have Evolved To Resist Hornet Stings.

Fearless frogs feast on deadly hornets | Kobe University News site

The venomous stinger of an Asian giant hornet (Vespa mandarinia). The venom injected by this stinger can cause sharp, intense pain as well as local tissue damage and systemic effects such as destruction of red blood cells and cardiac dysfunction, which may even be fatal.

Does anything eat wasps?

Yes. As I’ve observed myself, the common pond frog eats wasps apparently with impunity. I once watched a frog in our garden pond consume three wasps within a few minutes as they came down to drink. These frogs have, of course, evolved in the presence of wasps.

Now, according to research by Shinji Sugiura at Kobe University, Japan, published today, open access, in the journal Ecosphere, frogs that have evolved alongside an even more dangerous member of the wasp family – the Asian giant hornet – have also evolved resistance to venom that is toxic, even lethal, to many other creatures.

Creationists, however, insist that evolution does not happen and that wasps, frogs, and hornets were all intelligently designed by a supernatural deity synonymous with the god of the Bible and Qur’an. This leaves us wondering why an allegedly omnipotent, omniscient, supremely intelligent designer would equip wasps and hornets with a sting to defend themselves against predators, only then to design predators with resistance to that sting.

Creationists normally ignore this question, of course. Even their stock excuse – 'The Fall' – cannot be applied here. Neither frog nor hornet is parasitic on the other, except in the trivial sense that any predator is a “parasite” on its prey. But in this case, the frog appears to be the beneficiary: it gains a meal at no cost, while the wasp or hornet loses its life. And it is difficult to imagine that the genes conferring this immunity do *not

fall within William A. Dembski’s definition of “complex, specified information”. If they do not, then nothing producing a beneficial outcome can be so classified, and his argument for the existence of an intelligent designer collapses.

As the outcome of an evolutionary arms race, both the sting and the resistance in frogs make perfect sense—no need to invoke some forgetful designer who cannot recall what it supposedly created yesterday and treats it as a problem to be solved today.

In the case of these frogs, there may even be two distinct forms of immunity: resistance to pain and resistance to toxicity. It is already known that some hymenopterans deliver an excruciating sting with low toxicity, while others deliver a highly toxic sting with little or no pain.

The venom of the Asian giant hornet (Vespa mandarinia) is one of the most studied hymenopteran venoms because of its potency, its medical significance, and its role in predator–prey interactions. Its effects come from a *combination
of toxins, enzymes, peptides, and small molecules rather than a single active component.

Key Components of Asian Giant Hornet Venom.

Mastoparans (e.g., Mastoparan-M)

Small amphipathic peptides common in vespine wasps.
Cause intense pain, inflammation, and immune activation.
Disrupt cell membranes, contributing to tissue damage.
Can trigger histamine release, worsening swelling and shock‐like symptoms.

Mandaratoxin (a neurotoxic protein)

A large neurotoxic enzyme unique to V. mandarinia.
Causes:

Neuromuscular damage
Severe local tissue necrosis
Systemic effects when delivered in large amounts (multiple stings)

This toxin is thought to be partially responsible for the unusual severity of giant hornet stings compared with typical wasps.

Phospholipases (PLA₁ and PLA₂)

Enzymes that degrade cell membranes (phospholipids).
Contribute to:

Pain
Tissue destruction
Spreading the venom through tissues

PLA₂ can also trigger allergic and anaphylactic responses.

Hyaluronidase

“Spreading factor” enzyme.
Breaks down connective tissue, allowing venom to diffuse more easily.
Often allergenic.

Serotonin and other biogenic amines

Present at relatively high levels.
Intensify pain and cause vasodilation, increasing toxin spread.

Antimicrobial and cytolytic peptides

Hornet venom also contains peptides that destroy bacteria, fungi, and cells.
These may have evolved partly for colony defence and partly to disable prey.

Non-protein components

Free amino acids, small peptides, and trace elements that modulate activity.

Why the Venom Is So Dangerous

Asian giant hornets inject a large volume of venom, and colonies can attack en masse. The venom's danger comes from:

Potent cell membrane–disrupting peptides
High concentrations of neurotoxic proteins
Rapid diffusion enzymes
Large volumes injected by multiple large workers
Deaths in humans typically involve renal failure, rhabdomyolysis, or anaphylaxis, not just pain.

Evolutionary Notes

The venom shows classic hallmarks of an evolutionary arms race:

Honeybees in Japan have evolved heat-ball defence behaviour.
Certain frogs (in this article) show partial toxicity resistance.
Hornets evolved peptides aimed at both prey and vertebrate deterrence.

Shinji Sugiura's work at Kobe University is summarised in the university's press release.

Fearless frogs feast on deadly hornets
A remarkable resistance to venom has been discovered in a frog that feasts on hornets despite their deadly stingers. This frog could potentially serve as a model organism for studies on mechanisms underlying venom tolerance.
While just the sight of a hornet’s stinger is enough to fill many of us with dread, some animals, such as some birds, spiders and frogs, are known to prey on adult hornets. The venom injected by their stingers can cause sharp, intense pain as well as local tissue damage and systemic effects such as destruction of red blood cells and cardiac dysfunction, which may even be fatal. But whether the animals that hunt hornets are able to tolerate the venomous stings, or just manage to avoid them, has remained unclear.

Although stomach-content studies had shown that pond frogs sometimes eat hornets, no experimental work had ever examined how this occurs.

SUGIURA Shinji, author
Graduate School of Agricultural Science
Kobe University
Kobe, Japan.

To test whether frogs avoid or tolerate these potentially deadly hornet stings, Sugiura presented individual adult pond frogs with workers of three hornet species, Vespa simillima, V. analis, and V. mandarinia, under laboratory conditions. Each frog was used only once, and was matched to fit the size of their prospective hornet prey, with larger frogs preferentially matched with Asian giant hornet (V. mandarinia) prey.

The black-spotted pond frog shows remarkable tolerance to venomous stings from an Asian giant hornet. The stings caused no visible harm and the frog behaved normally after predation. Close-up views of the hornet’s stinger embedded in the frog’s mouth are shown in the circular insets in (C) and (D).

© Shinji Sugiura, Ecosphere 2025 (DOI 10.1002/ecs2.70457) (CC BY)

In the journal Ecosphere, Sugiura submits striking evidence that adult pond frogs actively attacked workers of the three hornet species. What’s more, he also reports that 93%, 87%, and 79% of frogs ultimately consumed V. simillima, V. analis, and V. mandarinia, respectively, despite being stung into the mouth or even into the eyes. “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,” says Sugiura.

Almost all frogs in the study attacked the hornets, and although the hornets stung the frogs repeatedly, 93%, 87%, and 79% of frogs ultimately consumed Vespa simillima, V. analis, and V. mandarinia, respectively.

© Shinji Sugiura, Ecosphere 2025 (DOI 10.1002/ecs2.70457) (CC BY)

Previous studies have suggested that pain and lethality of venomous stings are not necessarily correlated, with some stinging bees, wasps and ants delivering extremely painful, non-lethal stings while others cause little pain despite high lethality. This could mean that the frogs in this study have developed a double tolerance to these stings, which has enabled them to successfully prey on hornet workers.

This raises an important question for future work, namely whether pond frogs have physiological mechanisms such as physical barriers or proteins that block the pain and toxicity of hornet venom, or whether hornet toxins have simply not evolved to be effective in amphibians, which rarely attack hornet colonies.

SUGIURA Shinji.

These frogs could, therefore, also serve as valuable model organisms for studying the physiological mechanisms underlying venom tolerance and pain resistance in vertebrates moving forward.

Publication:
Sugiura, Shinji. 2025.
Pond Frog as a Predator of Hornet Workers: High Tolerance to Venomous Stings. Ecosphere 16(12): e70457. https://doi.org/10.1002/ecs2.70457

Abstract
Some animals use stingers to repel attackers, and some predators have evolved tolerance to such stings, enabling them to consume venomous prey. For example, social wasps, such as hornets, use modified ovipositors as venomous stingers to inject venom, which can cause intense pain in humans. The world's largest hornet, Vespa mandarinia (Hymenoptera: Vespidae), stores huge amounts of venom in its abdomen, which can kill mammals. Although some animals are known to prey on adult hornets, it remains unclear whether these predators can avoid or tolerate their venomous stings. Adult hornets have been found in the stomach contents of some amphibian predators, including the pond frog Pelophylax nigromaculatus (Anura: Ranidae), suggesting that they can successfully attack and consume hornets. To examine whether frogs avoid or tolerate hornet stings, the pond frog P. nigromaculatus was experimentally presented with stinging females (workers) of three Japanese hornet (Vespa) species—V. simillima, V. analis, and V. mandarinia—under laboratory conditions. Almost all frogs attacked the hornets, and the hornets were observed stinging the frogs during these attacks. However, 93%, 87%, and 79% of the frogs ultimately consumed V. simillima, V. analis, and V. mandarinia, respectively. Hornet stings neither killed nor harmed the frogs. These results suggest a high tolerance of pond frogs to the venomous and painful stings of giant hornets. Frogs may serve as useful model organisms for investigating the physiological mechanisms underlying the intense pain and lethal effects of hornet stings in vertebrates.
INTRODUCTION
Predation has driven the evolution of various defensive strategies in prey animals (Eisner et al., 2005; Endler, 1991; Sugiura, 2020a). Stinging arthropods, including wasps, bees, ants, and scorpions, use venom capable of inflicting intense pain to deter their predators (Schmidt, 2016). However, some animals have evolved a high tolerance to these venomous and painful stings. For example, horned lizards have evolved plasma-based resistance to the venom of harvester ants, allowing them to prey on these highly venomous ants without suffering toxic effects (Schmidt et al., 1989). Grasshopper mice have developed physiological mechanisms that allow them to tolerate the neurotoxic and painful stings of scorpions and consume these prey items (Rowe et al., 2013).

Stinging wasps, bees, and ants (Insecta: Hymenoptera: Aculeata) use modified ovipositors as venomous stingers to paralyze their prey or defend their nests from attackers (Schmidt, 2016). For example, social wasps, such as hornets, use their stingers primarily for self-defense and colony defense, and their venom can cause intense pain in humans and other vertebrates. Hornets typically refer to wasps of the genus Vespa (Hymenoptera: Vespidae), which includes 22 species worldwide that were originally distributed in Asia and Europe (Smith-Pardo et al., 2020.1). Hornets possess large bodies and store substantial amounts of venom, which contains biogenic amines, small peptides, and enzymes. Biogenic amines (e.g., serotonin and acetylcholine) and small peptides (e.g., vespakinins) cause sharp and intense pain, while enzymes (e.g., phospholipases) can cause both local tissue damage and systemic effects such as hemolysis and cardiac dysfunction, potentially leading to death in stung animals (e.g., Herrera et al., 2020.2; Matsuura, 1988). A single sting from a Vespa worker contains enough venom to kill a small-bodied vertebrate (Schmidt et al., 1986), making hornet workers potentially risky prey for vertebrate predators.

The world's largest hornet, Vespa mandarinia, which has a long, venomous, and painful stinger (Figure 1a,b; Video S1), is considered one of the most dangerous insects in the world (Schmidt, 2016). The Asian giant hornet, V. mandarinia, was originally distributed in Asia (Smith-Pardo et al., 2020.1), but after its accidental introduction to North America in 2019 (Zhu et al., 2020.3), it became widely known and feared as the “murder hornet” (Stankus, 2020.4). Although some animals, such as birds and orb-weaving spiders, are known to prey on adult hornets (Matsuura & Yamane, 1990), it remains unclear whether these predators can avoid or tolerate their venomous stings.

FIGURE 1
The Asian giant hornet Vespa mandarinia and its venomous stinger. (a) A V. mandarinia worker. (b) Close-up view of the stinger of the V. mandarinia worker shown in (a). Stinger length: 4.3 mm.
Photo credit: Shinji Sugiura.

Hornets, including V. mandarinia, are abundant in the Japanese satoyama landscape, which comprises a mosaic of mixed forests, rice paddies, grasslands, streams, ponds, and irrigation reservoirs (e.g., Yoshimoto, 2009). Vespa workers are frequently observed sucking floral nectar and collecting water for their nests at pond edges (Figure 2a; Matsuura, 1995; Matsuura & Yamane, 1990), where amphibian predators such as the pond frog Pelophylax nigromaculatus (Amphibia: Anura: Ranidae) are commonly found (Figure 2b). Adult hornets have been reported in the stomach contents of ranid frogs, including P. nigromaculatus, Aquarana catesbeiana, and Glandirana rugosa (Anura: Ranidae), in Japan (Sarashina, 2016.1; Sarashina et al., 2011). In addition, an adult P. nigromaculatus was observed attacking and swallowing an adult V. simillima that was visiting a flower of the wetland herb Triadenum japonicum in Japan (Chiba, 2019). These studies suggest that ranid frogs are predators of adult hornets, although there have been no investigations of whether they consume stinging females or stingless male hornets.

FIGURE 2
The Japanese yellow hornet Vespa simillima and its potential predator Pelophylax nigromaculatus. (a) A V. simillima worker visiting an inflorescence of Causonis japonica (b) An adult of the pond frog P. nigromaculatus.
Photo credit: Shinji Sugiura.

To examine whether ranid frogs avoid or tolerate hornet venomous stings while consuming them, I investigated the behavioral responses of the pond frog P. nigromaculatus to three Vespa species—V. simillima, V. analis, and V. mandarinia—which are among the most commonly observed hornets in Japan.

These findings illustrate, yet again, how the natural world is shaped by continual evolutionary arms races. Frogs and hornets have not been standing still; each has been nudged and refined by selection pressures imposed by the other. The hornet’s potent venom is effective against most would-be predators, but where it meets a species that has lived alongside it for countless generations, selection can favour individuals who tolerate or neutralise its effects. Over time, that advantage becomes encoded in the population’s genome.

None of this sits comfortably with the creationist notion of intelligent design. If all species were crafted fully formed and perfectly equipped for their roles, there would be no need for layer upon layer of counter-measures, no iterative escalation of offence and defence, and no biochemical arms races playing out in ponds and forests. The very existence of venom specialised to deter predation, and predators that have independently evolved the means to overcome it, reveals a world driven by incremental adaptation rather than the whims of an all-powerful designer.

What we see instead is precisely what evolutionary theory predicts: dynamic interactions producing ever-shifting balances of power. These are the signatures of natural selection at work, not the hallmarks of foresight and perfection.

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