By Elliott Zajac, Metroparks Natural Resource Research and Monitoring Intern 

This warty harvestman (Leiobunum verrucosum) was spotted with some uninvited “hitchhikers” at Fallen Timbers Battlefield. Often confused with spiders, due to their long limbs, leg-like antennae, and large jaws, harvestmen or “daddy longlegs” are actually members of the order Opiliones, a separate group within the arachnid class-- in the same branch of the evolutionary tree as the mites feeding on them. 

Interestingly, the parasitic mites attached to its body are not only after a free ride, but also a free meal! By clinging to its limbs and joints as it moves through the forest, the tiny, red mites are able to sip on the harvestman’s precious hemolymph-- a nutrient-rich fluid that serves as arthropod blood. Likely belonging to the family Erythraeidae, named for their vivid coloring, the mites will eventually grow out of parasitism and move on to become purely predatory as adults. 

Did you know? Daddy longlegs have no venom or silk glands and consist of one oval-shaped body with all segments joined broadly. Unlike spiders, they tend to be omnivorous, feeding on a mixture of smaller insects, fungi, plant matter, and organic detritus. 

Photo: Stock photo; Video: Elliott Zajac