The Harvestman as played by Pedro Pascal

Kelly’s Field Notes

Common Name: Harvestmen, Daddy Longlegs

Order: Opiliones

Suborders:  Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi

Species of Note Near You (There are 0ver 6,650 known species worldwide, but it is likely there are actually over 10,000 species!):

• Eastern Harvestman (Leiobunum vittatum) found in the eastern United States.

• Western Harvestman (Sclerobunus robustus) found in the western United States.

• European Harvestman (Phalangium opilio) found throughout Europe.

Harvestmen are found on every continent save Antarctica!

What’s In A Name?

“Daddy Longlegs” can refer to several arthropods: crane flies, harvestmen, and cellar spiders. All of these organisms have long, dangly legs. Opiliones are also called harvestmen because they are out in large numbers in the Fall, near harvest time. 

The word Opiliones comes from the Latin word opilio which means “sheep-master.” This is due to the harvestman’s long, stilt-like legs relating to how shepherds used to walk on stilts to better watch their flock.

Description: 

Harvestmen or Daddy Longlegs are Arachnids, but not spiders. They are well known for their long legs, but some species are actually more mite-like in appearance (Suborder Cyphophthalmi). The harvestman has the traditional body plan of head, thorax, and abdomen, but they are all fused together into one segment. They have two pretty distinct eyes on the top of their body. Their long legs are for male-male competition/fighting and to attract females. They do not do a lot of walking.

There are so many species because they do not travel very far. This makes speciation happen pretty quickly when a population is split due to geographic circumstances (a new river or mountain, for example).

Life Cycle: 

Depending on the species, we may know very little about their life cycles. They do not have fangs, but some have strong pincers. They are likely mostly scavengers and feed on a variety of foods: fungi, fruits, vegetation, decaying matter, etc.

Males do not pass a spermatophore to females, they directly copulate. Some species reproduce through parthenogenesis, and do not need males. After mating, the male guards the female as she lays eggs on leaf litter, in soil, or on bark, encased in a thick jelly. This jelly is likely anti-fungal in nature. Generally, they lay a few hundred eggs dispersed in different spots, which can take 1 month or up to 6 months to hatch. Females of a few species will guard the eggs until they hatch, but most lay their eggs and move on. Males of some species will also take care of eggs, grooming them and keeping them safe from egg-eating females. While maternal care is likely due to natural selection, paternal care has been sexually selected.

The harvestmen will go through 4 to 8 instars or molts before becoming an adult. There are about 10 days between each molt. Once it reaches adulthood it cannot regenerate any lost limbs. Their entire life cycle may last a few months, or up to a year. Depending on their location, they can overwinter in all of their life stages.

Super Powers:

• Friends! - Daddy Longlegs are gregarious and will clump together for protection.

• Caustic Chemicals - They produce chemicals from glands on their bodies that are noxious, deterring predators.

• Play Dead - Harvestment will play dead when threatened by a predator, because their camouflage is so perfect once they stop moving it is very hard to see them.

• Vibration Detection - Harvestmen rely on sensing vibration as their eyesight is not great. They have special sensory hairs on their second pair of legs.

• Bobbing - Daddy Longlegs will bop, rapidly vibrating their bodies making it hard for a predator to grab them.

• Detachable Limbs - When grabbed, they can drop a leg off to escape predation. 

• Stridulation - harvestmen have stridulating organs which produce sound when they are caught.

Harvestmen in Culture:

• The artist Salvador Dali’s popular painting Daddy Longlegs of the Evening-Hope was painted in 1940.

• In France, seeing a Daddy Longlegs in the evening brings good luck.

• In Turkey they are good luck, the Turkish name for Daddy Longlegs is mῡfdeci which translates to “a person who brings good news.”

References: 

“Daddy Longlegs (Harvestmen).” Missouri Department of Conservation. https://mdc.mo.gov/discover-nature/field-guide/daddy-longlegs-harvestmen

Kury, Adriano B. "Classification of Opiliones". ArachnoLab. www.museunacional.ufrj.br.

Machado, Glauco, Pinto da Rocha, Ricardo, and Giribet, Gonzalo. “What are harvestman.” Laboratory of Arthropod Behavior and Evolution. http://ecologia.ib.usp.br/opilio/opilio.html

McCarthy, Erin. “16 Fascinating Facts About Daddy Longlegs.” Mental Floss, 2014. https://www.mentalfloss.com/article/59455/15-fascinating-facts-about-daddy-longlegs

“Opiliones.” Wikipedia. https://en.wikipedia.org/wiki/Opiliones

Pinto-da-Rocha, Ricardo, Glauco Machado, and Gonzalo Giribet, eds. Harvestmen: the biology of Opiliones. Harvard University Press, 2007.

Swiger, Sonja and Porter, Pat. “Opilionids.” Extension Entomology, Texas A&M, 2020. https://extensionentomology.tamu.edu/insect/harvestmen/

Tinker, Rowan. “Specimen of the Week 192: The Harvestman.” UCL Culture Blog, 2015. https://blogs.ucl.ac.uk/museums/2015/06/15/specimen-of-the-week-192-the-harvestman/