Longlegs and the Hunter
By Terry Morse
Life can be harrowing, even when you’re a predatory spider living in the relative security of a naturalist’s apartment. This became clear to me early on the 17th of September in 1993.
The morning was cool and gray, an autumnal cap to a summer that never quite materialized. At 8:25 a.m., lying in bed reading, my eyes strayed above the page to a 3/4" long reddish-brown spider with a coat of sleek gray fur on its abdomen on the prowl. It was a mouse spider (Scotophaeus blackwalli, family Gnaphosidae), a European species that has become established on the west coast of the United States. An active hunter, it worked its way north along the west side of the apartment where wall meets ceiling, its low-slung body suspended between hairy legs, hugging the surface like a high performance racing car.
A few feet ahead, a pale Daddy-Long-Legs Spider (Pholcus phalangioides, family Pholcidae) hung head down on its near-invisible cob web. Small bowling-pin shaped body suspended between eight spindly legs, it fed on the husk of a dead, silk-wrapped sow-bug.
Continuing north, the hunting spider apparently tripped a strand of the Pholcus’s web, and the gangly spider suddenly rushed over to the sleek hunter and stopped a couple inches above it. The hunting spider froze.
Though Pholcus’s eyesight is poor, its sense of touch is good. It can detect the slightest of disturbances to the diffuse strands of its web. If the hunter were to move, it would betray its location to the longlegs. It remained still. The longlegs plucked strands of the web with its front pair of legs, apparently testing the tension of the strands for a clue to the hunter’s whereabouts. The hunter didn’t move.
After a few moments, the hunting spider attempted to advance, but the longlegs followed and remained poised above it. The hunter turned and slowly stole back south. It progressed about an inch before striking another trip wire. Instantly, the longlegs loomed above it. The mouse spider froze. The longlegs palpated the strands of its web for a hint of the hunter. Finding nothing, it strode north toward the meal it had earlier abandoned.
The hunter tried again to steal away south, but the longlegs immediately rushed back and poised an inch above the larger spider. Again the hunter tried to move, but the longlegs stuck with it like a basketball guard. It closed in on the hunter, which swung around to face the longlegs, raising its front end in defense. The longlegs backed off a short distance, but remained a threat. To me, the hunting spider seemed the more formidable of the pair. Putting myself in the hunters place, however, I imagined how intimidating this nimble, stilt-legged spider must seem, looming above me. The danger is real.
Checking my watch, I saw that thirty minutes had passed, though it felt like only one or two to me, perhaps like a lifetime to the hunting spider. The longlegs moved six inches north of the hunter then turned toward it, as if waiting for the hunter to betray its position. Is it capable of such sophisticated thinking? I don’t know. The hunter remained still.
Longlegs moved another two inches north and paused, facing away from the hunting spider. After about a minute, it turned and advanced toward the hunter, then reversed direction and returned to its sow-bug meal. A distance of two feet now separated the spiders. The hunting spider remained immobile, facing the longlegs.
At 9:01, the longlegs turned with its meal to face away from the hunter. Neither spider moved for 20 minutes. At 9:22, the hunter cautiously maneuvered to two-and-a-half feet from the longlegs and held there. A minute later, it resumed crawling south. The longlegs released its meal and walked 6" further north, away from the hunter, which continued its cautious stalk south. At 9:25, the longlegs palpated its web briefly, then returned to feed on the sow-bug. The hunter, which had frozen momentarily, started walking again. The Pholcus ignored it.
At 9:28, a small spiderling dropped down the wall on a line of silk, out of the path of the oncoming hunter. Small or large, danger is everywhere. The hunter continued forward. Apparently no longer concerned about the longlegs, its pace is faster and its path erratic. It stops periodically to feel about with its front pair of legs, perhaps testing for silk trails or scent tracks that might guide it to a meal.
At 9:44, the hunter approached a spider much smaller than it, squeezed into a corner where two walls and the ceiling meet. The smaller spider started to flee, but the hunter changed tack and the midget returned to its corner. The hunter descended the wall and disappeared among the rocks and cans of bicycle lubricant I keep on a shelf by the door. I let out my breath, which, in the tension of the moment, I had been holding.
Thus ended quietly a drama as spellbinding as any you might witness at some exotic location in Africa, yet I didn’t have to leave home to see it. I watched most of it through binoculars from my bed. You don’t need to travel to distant lands to see exciting wildlife behavior, if your eyes are open to it.
Subsequently, I have seen the whole affair played out again, possibly involving the same hunting spider but a different longlegs spider. In that instance, the longlegs almost caught the hunter, which, in a last desperate maneuver, leaned back and dropped seven feet to the floor. It survived and turned up in a box of laundry soap a week later, from which I rescued it.
Sometimes the Pholcus wins. I haven’t witnessed a kill from the start, but have seen a longlegs wrapping a smaller spider, possibly a younger mouse spider, in silk. Longlegs spiders don’t rush in to bite their prey: they first use their long hind legs to draw silk from the spinnerets on the tip of their abdomen to entangle the prey. Only when it is reasonably restrained do they tentatively approach to deliver a poisonous bite. If the prey moves, they will pull back and wrap it more before trying again for a bite.
It is late spring now, and I haven’t seen a mouse spider in several months. As the weather warms up, I expect them to become active again. The daddy-longlegs spiders will be there, wating.
Mouse spiders are active nocturnal predators. During the day, they rest in a tubular nest of silk. In my home, they construct these in the angle where wall meets ceiling, moving the tip of the abdomen side to side, attaching silk alternately to wall and ceiling. As they do this, they move slowly backward, building a silken tent above them. The ones I see about in daylight are probably males searching for females.
Foelix, Rainer. 1996. Biology of Spiders, 2nd ed. New York: Oxford University Press.
Levi, Herbert W., and Lorna R. Levi. 1987. Spiders and Their Kin. New York: Golden Press.
Preston-Mafham, Rod. 1991. The Book of Spiders and Scorpions. New York: Crescent.
Preston-Mafham, Rod, & Ken Preston-Mafham. 1984. Spiders of the World. London: Blandford.
Updated: 21 July 2004