Daddy longlegs have been observed eating live frogs larger than themselves in the tropical forests of South America, a new study reports. And this behavior may be more common than scientists expect.
“These animals are being found eating [live] frog It was a complete surprise, we didn’t expect that they would be able to catch them,” study co-author Luis Fernando Garciaa biologist at the University of the Republic in Uruguay told Live Science.
When arthropods, the group that includes animals such as insects, spiders, centipedes, and crustaceans, are observed eating vertebrates, it is usually treated as a rare or isolated event. But jose valdezAn ecologist at Martin Luther University Halle-Wittenberg in Germany, who was not involved in the new study, found that this type of hunting – mostly on frogs, lizards, bats and birds – is actually quite common.
In fact, arthropod predation on vertebrates is less documented, Valdez told Live Science in an email. Valdez’s Research has found It is usually spiders that eat frogs, because frogs have soft bodies and thin layer Make them relatively unsafe.
Yet the harvesters (order Opiliones), also known as Daddy Longlegs technically not spiders; they are part of spider’s class with spiders, but they’re more closely related to scorpions, Valdez said, so observations like this new study are especially noteworthy.
Harvestmen are arachnids that are more closely related to scorpions than to spiders.
(Image credit: Maida Gutierrez-Arboleda)
In a new paper published in the journal on April 21 Ecology and EvolutionThe research team compiled 10 reports of harvestmen in South America eating frogs around their body size. The reports come from field observations in Ecuador and Colombia, scientific papers, and the citizen science platform iNaturalist, which lets anyone upload photos of wildlife and plants from a camera.
“The availability of good quality cameras on mobile phones has greatly helped in recording such interactions and making them available to experts, sometimes through citizen science platforms,” olivier pauwelsA conservation biologist at the Royal Belgian Institute of Natural Sciences, who was not involved in the new study, told Live Science in an email.
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Arthropod predation on vertebrates has been under-documented, researchers say.
(Image credit: Maida Gutierrez-Arboleda)
Of earlier actual report Regarding Daddy Longlegs eating the frog, it is unclear whether the arachnid killed the frog or ate an already dead amphibian.
“What we found is that they are able to catch frogs, because many frogs were still moving around,” Garcia said, suggesting that arachnids may actively hunt frogs.
Researchers don’t know exactly how harvestmen catch frogs, Garcia said, because the arachnids are slow and don’t have venom. They may hunt sleeping or resting frogs, or capture them with their strong front limbs, known as pedipalps, which are similar to the front legs of a praying mantis and can hold prey.
“The most amazing aspect is how these harvestmen are able to subdue their prey without using poison to chemically incapacitate the animal,” Valdez said. “Instead, they must rely entirely on physical restraint,” the study found, an impressive feat considering that some frogs were up to 1.29 times the size of the arachnids that ate them.
“Now we have a new area to explore: the diet and behavior of these animals, which is basically unknown,” Garcia said. “We think it’s opportunistic behavior, they’re generalist hunters.”
New discoveries about the diets of arthropods in tropical regions and their interactions with other species may help scientists understand how to preserve these ecosystems.
“The fate of some species is often linked to that of others,” Pauwels said.
Calvache, E., Villarreal, O., Ávila‐Rojas, C., Bentley, A.G., Brito, K., Correa‐Zanotti, C., Gutiérrez‐Arboleda, M., Iñíguez, K., Narváez, J.C., Proano, L., Reyes‐Vizcaíno, M., & García, L.F. (2026). Harvestmen (Arachnida: Opiliones) as neglected predators of anuran in the Neotropics. Ecology and Evolution, 16(4), e73542. https://doi.org/10.1002/ece3.73542