Opiliones: Harvestmen

Opiliones: Harvestmen

The order Opiliones, generally known as Harvestmen, are the third largest order of Arachnids, following Acari (mites and ticks) and Araneae (spiders). They consist of more than 6,500 extant described species, 50 families, and five suborders: Eupnoi, Dyspnoi, Phalangodidae, and Cyphopthalmi. Opiliones occupy a variety of terrestrial niches, especially soil, where they play an important role as predators and scavengers of small arthropods, worms, fungi, and other decaying organic materials (Giribet, Gonzalo, and P. P. Sharma. 2015. ). Most people will recognize and have shared a living space with the Harvestmen “daddy long-legs” and often associate them with spiders. While their eight legs, pedipalps, chelicerae, and broad body plan might make it easy to group daddy long-legs into the order Araneae (spiders), this is incorrect. Although they share many characteristics with spiders, Opiliones have distinct morphological and behavioral features that define them as a separate order. Opiliones have features that distiguinsh them from other orders of arachnid, like a penis, which they use for direct sperm transfer, odiferous glands, and a fused prosoma and opisthosoma. Unlike spiders, opilionids lack venom, silk glands, rapid striking ability and a strictly carnivorous diet.

Morganne Sigismonti '17, Haleigh Dunk '18, and Paige Browne '18