Harvestmen

 

(A longer version of a column that appeared in the October 7, 2002 Buffalo News.)

 

Daddy longlegs or, as they are also known, harvestmen, are to me among the most fascinating of animals. Science fiction could not come up with more remarkable beasts.

 

Their most obvious characteristic is the one from which they derive their name: long legs. In fact they appear to be almost entirely legs. Their tiny bodies, less than a quarter inch long, are surrounded with eight legs each between one and two inches in length. Just imagine, if our torsos were the size of theirs, our proportionally-sized legs would extend over a span of forty or fifty feet. We could cross roads without setting foot on the pavement.

 

Not only are those legs long but they are delicate, so fine in fact that - like those of water striders - they don't penetrate the surface of water. You would think that this would allow them to walk on water, but they cannot. Their feet easily get trapped by the water's surface tension, one sometimes even pulled off when it is tugged to free it.

 

If our legs were that thin, we would simply collapse. In fact, the 17th century scientist, Robert Hook, estimated that a harvestman with legs only "an hundred and fifty times the strength of man would not keep the body from falling on the breast."

 

Strong, yes, but also sensitive. Those legs, especially the second pair, serve as sense organs, playing a role comparable to our eyes, nose and tongue. Daddy longlegs do have eyes, a tiny pair mounted on a small pedestal atop their torso, but they only scan above their body.

 

These unusual arachnids make an interesting subject for study. Carefully capture several and place them in a glass-covered terrarium and you will find much to observe. One author recommends an 18"x12"x6" box. Cover the floor with a half-inch of earth or coarse sand and be sure to provide water for without water the harvestmen will soon die. Do this with dampened blotters, thus avoiding that problem with water surface tension.  Change the blotters regularly to minimize mold. Finally, add some leaves for hiding places.

 

Food is not a problem. These arthropods will kill and eat many insects and even spiders, but they will also take contributions from your table: tidbits of bread, butter and fatty meat serve very well.

 

When you capture your harvestmen a jar is a good container that will allow you to scoop them up don't worry about their curling up and becoming immobile. They will become active again once they are in a larger space.

 

Now you can watch them and here are some of the things to look for:

 

Motion. How their legs teetering up and down serve as shock-absorbers so that the torso moves along evenly.

 

Cleanliness. How they clean each long leg after a meal, pulling them one at a time through their jaws.

 

Competition. How males joust upon meeting.

 

Mating. How, quite unlike spiders, female harvestmen seem to enjoy sex. (Despite the obvious appropriateness, however, females are not called mommy longlegs or harvestwomen.) These arachnids not only copulate readily upon meeting but they meet often.

 

Egg laying. How the male forms a kind of umbrella over the female while she oviposits eggs into the ground.

 

Molt. How, every ten days or so until they reach maturity, each harvestman unzips its torso covering and proceeds to drag those long legs out of their old skin, a process that takes about 20 minutes.

 

Smell. How, when threatened and possibly also to leave a trail, the daddy longlegs emits a putrid liquid from glands on its flanks.

 

Loss of legs. How many of the harvestmen found in the wild have lost one or more legs. When detached, a leg will continue to twitch for some time, possibly distracting a predator. (Investigators disagree whether lost legs are replaced during molt.)

 

*

 

The name harvestmen probably derives from the fact that these arachnids are most often seen in late summer and fall at harvest time. The French name, faucheux for reapers, is probably similarly derived. Other local names include shepherd spiders, perhaps because of the way males guard females during egg-laying, and grandfather graybeards, adding a generation to their name. Germans call them Afterspinnen or near spiders.

 

House spiders and craneflies are also occasionally called daddy longlegs, further confusing the issue of common names.

 

I am afraid of spiders (my wife considers this a great joke) but I have no corresponding fear of daddy-longlegs. There is no contradiction in this for harvestmen, despite their eight legs, are not spiders; they are more closely related to ticks and mites. Three of their differences from spiders: their two eyes versus the spiders' six or eight; their waistless body head, thorax and abdomen a single unit and their lack of poison. An old wives tale has it that the daddy longlegs is extremely poisonous but that we are safe because it has not the power in its jaws to bite through our skin. They are not poisonous.

 

But my lack of fear of daddy longlegs does not derive from taxonomy or physiology; it derives instead from their delicacy. They are simply nonthreatening.-- Gerry Rising

 

Selected References

 

Berenbaum, May R. 1993. Daddy-Long-Legs (Harvestmen). In Ninety-nine More Maggots, Mites, and Munchers. Urbana: University of Illinois Press.

 

Bishop, Sherman C. 1950. Life of a Harvestman. Nature Magazine 48 (5):264-267, 276.

Carpenter, Anita. 2000. Daddy long-legs: The elegant harvestmen are neither spiders nor insects [visited October 1, 2002.] Available from www.wnrmag.com/stories/2000/jun00/daddy.htm.

 

Comstock, Anna Botsford. 1939. Daddy Longlegs or Grandfather Graybeard. In Handbook of Nature-Study. Ithaca, NY: Comstock Publishing Company, Inc.

 

Headstrom, Richard. 1968. Harvestmen. In Nature in Miniature. New York: Alfred A. Knopf.

 

Hubbell, Sue. 1993. Order Opiliones: Daddy Longlegs. In Broadsides from the Other Orders: A Book of Bugs. New York: Random House.

 

Julien, Don. 2002. Good Bug, Bad Bug: Harvestmen 1999 [visited October 1 2002]. Available from www.bmi.net/roseguy/gbharvst.html.

 

Klee, George E., and James W. Butcher. 1968. Laboratory rearing of Phalangium opilio. Michigan Entomologist 1 (8):275-278.

 

Savory, Theodore H. 1962. Daddy Longlegs. Scientific American 207:119-128.

 

 

unknown. 1968. Daddy-Long-Legs. Forest Preserve District of Cook County (Illinois) [visited October 1 2002]. Available from www.newton.dep.anl.gov/natbltn/300-399/nb315.htm.

 

Vanuytven, Herman. 2002. Opiliones: Harvestmen, Daddy-Longlegs [visited October 1 2002]. Available from www.arachnology.be/pages/Opiliones.html. (This website is especially rich in additional references.)

Vetter, R. S. and P. K. Visscher. 2002. Daddy-longlegs Myth [visited October 1 2002]. Available from spiders.ucr.edu/daddylonglegs.html.