Daddy Longlegs Hunt Frogs in South America, Study Reveals

A February 2020 night hike at Mashpi Lodge in Ecuador's cloud forest led to a rare observation: a harvestman (daddy longlegs) eating a live frog. Naturalist guides Lizardo Proaño and Juan Carlos Narváez photographed the event. Biologist Esteban Calvache, also at Mashpi Lodge, compiled a study published in April in Ecology and Evolution, documenting only ten known cases of harvestmen preying on adult frogs, all in South America (Ecuador, Brazil, Colombia, Venezuela). The predators were similar in size to their prey, and several frogs were still alive, suggesting active hunting. Harvestmen (Opiliones) are generalist omnivores, lacking venom and silk, and are under-studied. The findings may reshape understanding of tropical food webs, where harvestmen are larger and more robust. Researchers suspect the behavior is more common than documented, as harvestmen are nocturnal and active between midnight and 3 a.m. Future studies may explore capture methods and sexual dimorphism's role.