Outdoorillinois November 2007 Spiders in Illinois
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) . d n a l r a F c M e o J y B o t o h Spiders in Illinois P Spiders in Illinois ( Story and Photos By piders are a diverse and diverse array of enemies or succumb - interesting group of crea - ing to harsh environmental conditions. Hank Guarisco tures found almost every - Through time, the forces of natural where in the state of Illinois. selection have led to the astounding Their ubiquitous nature, diversity of spiders we see today. ability to spin complex webs SaSnd the habit of some species to fre - Food Habits quent homes and gardens often alert us Whether actively hunting their prey, to their presence. waiting in ambush among vegetation or Currently, more than 630 different species are known to inhabit the state. Web-building spiders, such as the Spiders come in many shapes, sizes common house spider, will eat their and colors and make their living in a variety of ways. old web, converting the protein into Any living organism can measure new silk in as little as 30 minutes. success in life by the Goldenrod number of offspring it Crab Spider Crab Spider has produced that grow up to pass on their Characteristics all spiders share genes to future genera - include having eight jointed legs, tions. In order to do an exoskeleton and spinnerets at this, a spider must gain enough energy to main - the end of their abdomen. tain itself and to pro - duce a large number of eggs, while avoiding Common death at the hands of a House Spider 14 / Outdoor Illinois November 2007 Sixspotted Fishing Spider constructing intricate webs to ensnare Illinois spiders exhibit a range of their victims, spiders are consummate feeding habits. Fishing spiders (above) predators. They are able to overcome a can stay under water up to 40 minutes wide variety of insects, arachnids and to capture small minnows and tadpoles. even some vertebrates with the use of Black and Yellow silk and their venomous bites. Although The diet of the black and yellow garden Garden Spider the diet of the black and yellow garden spider is mostly insects. spider, Argiope aurantia , consists dead insects over live ones. Some spi - mainly of insects, one individual cap - had built a web in my college dorm ders occasionally feed on nectar and tured and consumed a skink. Members room overcome a paper wasp ( Polistes pollen as they actively wander over veg - of the hunting spider genus Dolomedes sp.) that had become entangled in her etation in search of prey. Several are commonly called “fishing spiders” web. The wasp repeatedly attempted to species have become more specialized. because several species regularly eat sting the spider as she wrapped it in Pirate spiders (family Mimetidae) creep small minnows and tadpoles. Before silk from a safe distance. Once it was into spider webs and pluck the silk closely approaching an ensnared, fully wrapped, she cut it out of her web strands, mimicking the signals of prey potentially dangerous prey item, web and let it fall to the floor below. or a potential mate. When the host spi - builders, such as the common house Although they are predators, spiders der approaches, it is immediately spider, Achaearanea tepidariorum , are opportunists. Some wolf spiders attacked by the pirate which delivers a will securely wrap its intended victim and jumping spiders will readily scav - paralyzing bite. with silk, then deliver one or more enge dead insects when they encounter The small cobweb spiders in the bites once the prey is rendered immo - them. One researcher recently discov - genus Argyrodes are called “klepopar- bile. Many years ago, I observed a large ered that the brown recluse spider, asites,” but actually make a liv- black and yellow garden spider which Loxosceles reclusa , actually prefers dry, ing in several ways. They can build their own cobwebs and catch insects, they can live in Longlegged Sac Spider the webs of larger spiders and steal their food, or they can kill and consume the host spider. Avoiding Predators While going about the business of life, spiders must avoid being eaten. One way to avoid predators, which include birds, mammals, lizards, A member of the pirate spider family, longlegged sac spiders sneak into the webs of other spiders to gain a meal. November 2007 Outdoor Illinois / 15 amphibians, fish, insects and even other tion by resembling ants. In addition to audax , a jumping spider often found spiders, is to blend into the background looking like ants, these spiders run in homes, turns toward you and or gain protection by resembling some rapidly in the company of ants while seems to be watching you, it is not formidable creature, tapping the ground your imagination! such as an ant. with their first pair of Good vision also explains why many Although some of legs which are held in jumping spiders are brightly colored. the colors, shapes and the air like ant anten - They engage in elaborate courtship patterns of spiders are nae. The imitation is behavior in which the males perform quite striking, their good enough to fool stereotypic “dances” that display bright - owners are virtually even experienced spi - ly colored parts of their anatomy to the invisible in their respec - der collectors. Of female. In this way, jumping spiders are tive habitats. One exam - course, this defense the invertebrate equivalent to birds. ple is the white-banded may backfire in the These courtship displays enable males crab spider, Mis - presence of some and females of the same species to rec - umenoides formosipes , jumping spiders ognize one another, and may even which waits patiently which prefer to feed relate information concerning their among flower petals to Zebra Jumper on ants. In this case, good qualities as prospective mates. ambush insects that the ant-mimics often To ensure reproductive success, come to feed on nectar. The contrasting are attacked more readily than other many female spiders construct intricate stripes of the diurnal zebra spider, Salti - spiders which did not resemble ants. egg sacs which they guard until the cus scenicus , break up its outline as it young are ready to disperse. Nursery - hunts for insects on rocks. Wolf spiders Senses web spiders (family Pisauridae) carry (family Lycosidae), which are usually With the exception of jumping spi - the egg sacs in their jaws until the found in leaf litter and on tree trunks, ders, which possess good vision, most young are about to emerge. At this generally have a striped or mottled spiders rely mainly upon chemical, tac - time, the mother places the egg sac in brown coloration. tile and vibrational cues from their envi - understory vegetation and constructs Several kinds of Illinois jumping ronment. There are long hairs (tri - an elaborate, dome-shaped web around spiders (family Salticidae) gain protec - chobothria) on spider legs which detect it, then stands guard. Spider eggs have a air movements. The legs also possess host of insect predators and parasites, organs that can sense different chemi - and protection by the mother increases Spiders use a variety of techniques to avoid cals, such as pheromones, and slit-sense the chances of her offspring’s survival. predators, including coloration, patterning, organs that are sensitive to different fre - mimicking ants, and, in the case of jumping quencies of vibration. Web-builders use Surviving Winter spiders, jumping 20 times its own body length. vibrational signals transmitted by their Another challenge facing spiders in webs to discriminate among prey, ene - Illinois is winter survival. Particularly White-banded mies and potential mates. brutal winters can devastate popula - Crab Spider The rear, middle pair of eyes of some tions, so choosing a good hibernation ground spiders (Gnaphosidae) can site is critical. detect polarized Many spiders pass the cold months light from the sky as juveniles or which helps them adults. Jumping orient in the land - spiders find shel - scape as they hunt tered locations during twilight out of the wind hours. and rain in which As visually ori - to construct ented organisms thick, silken ourselves, we hibernacula. can more easily Rock crevices relate to jumping Bold Jumper and leaf litter can spiders, which provide good have binocular vision and can see col - winter retreats, especially if the latter is ors via a pair of large, frontally direct - blanketed with a layer of snow. South- ed eyes. Up to a distance of about 1 facing slopes which are exposed to the foot, these spiders have the visual sun are ideal sites. acuity of cats. So when Phidippus 16 / Outdoor Illinois November 2007 Barn Funnel Weaver Most of the more than 600 spiders found in the Prairie State do not bite humans. Only bites of the brown recluse (below) and black widow can be considered dangerous. parachutes that their owners board to be carried off with the wind. Balloon - ing spiders have been found up to 10,000 feet high and many miles away from land. This effective dispersal mechanism allows spiders to colonize Some spiders, including many orb - remote areas. weavers such as the yellow and black Some spiders construct webs to garden spider, spend the winter inside capture prey. The typical orbweb con - egg sacs. Although they may be protect - sists of a framework attached to sup - ed from the cold due to physiological porting objects, such as vegetation and changes that enable them to withstand tree limbs, radii which form the False Widow freezing temperatures, the spiderlings spokes of the wheel-like web, and the in these egg sacs often fall victim to spiral which has sticky, drops of silk birds which discover a ready winter used to ensnare prey. The web’s transmission, and occasionally causes meal.