You may find yourself asking, “are spiders good to have around?” The simple answer is yes, spiders help humans by trapping and killing copious amounts of insects. In fact, per year, spiders consume more than the entire weight of the human population in bugs. But having spiders around may freak out some people. Arachnophobia affects roughly 5% of the population, and it seems to affect more women than men. But, contrary to popular science fiction, spiders aren’t out to stalk humans just to sink their fangs into them. Spiders kill their prey by injecting them with venom in order to paralyze them. Then some species wrap them in silk or cover them in digestive enzymes to reduce them to a “bug smoothie” that they can easily swallow. Spiders cannot chew, which is one of the qualities that makes them unique from other insects. Because spiders are not insects at all, instead, they are in their own family called arachnids. Spiders have eight legs instead of six like most insects. They also do not have wings nor antennae.
Nearly all spiders are venomous, but only a few can be harmful to humans. Comparatively speaking, the venom of a black widow is more toxic than a rattlesnake. Still, because of its size, it cannot deliver as much venom to its victim. Therefore, very rarely are spider bites fatal to humans. Only those with allergies to spiders and the very young and very old should be extra cautious when dealing with a spider bite. You can easily prevent many spider bites by making sure you do not disturb them. There are very few aggressive species of spiders; most are very shy and would prefer to stay far from humans. The only time they do bite is when they feel threatened or trapped. Even then, they are likely to try to run away, rather than bite. You can decrease your risk of spider bites by wearing gloves when working outdoors.
One place that spiders come in quite handy is in your backyard garden. Several species trap and kill flying insects in webs, but there are also many species of spiders that do not spin webs. Rather, they are ambush predators and stalk their prey from the ground. They will lie in wait on flower petals or leaves to jump on them. Others will merely wander around until they bump into something that looks good to eat. Of any of these, having spiders around is a good thing. If you only see them occasionally, then they are doing their job, and it is best just to let them be.
There are about 60 species of spiders found in Florida. Many of them are outdoor spiders. In your garden, you can find several species of spiders in the Argiope genus, including the silver garden spider, banded garden spider, and, more commonly, the black and yellow garden spider. Females specimens from this species of garden spider have more vibrant coloring than their male counterparts. The abdomen is black with patches of bright yellow. Nearly all garden spiders are orb-weavers meaning they spin circular webs. In the center of the web, an X-shaped pattern called a stabilimentum occurs, which many entomologists believe is to alert birds and keep them from flying into the webs. Many species in this genus will leave their web and attach a single thread to where they hide in the underbrush. When a flying insect is caught in the web, the thread vibrates, alerting the spider to come out and spin the caught prey into a cocoon. This practice helps liquify the insect and make it edible for the spider. Spiders in the Argiope genus prefer to build their webs attached to plants in bright sunny areas and feed mainly on flying insects.
Another common garden spider are those in the family Thomisidoa. They are often called crab spiders because of the position of their legs jutting out in a crab-like fashion. These spiders are also referred to as flower spiders because they wait to ambush prey on flower petals and leaves. Many species are well-camouflaged, blending in with the flowers on which they live. They are ambush predators, and most do not spin webs, but rather lie in wait for prey to happen along.
If you happen to live in or near a citrus farm, you may likely encounter the Spiny Orb-Weaver. These spiders are often mistakenly grouped in with crab spiders because of their unique shell-like abdomen. However, they are not part of the family Thomisidoa, which are true crab spiders. They are also orb weavers, spinning a circular web that catches whiteflies, moths, beetles, and other flying insects. These small spiders weave their webs with tufts of silk protruding from the foundation lines. Again, entomologists are unsure of the reason, but suggest that this helps to alert birds not to fly into the webs. Webs are usually found 3-18’ off the ground. Spiny-backed orb-weavers are easily identified by their black legs and white shell-like abdomen with black markings. They also have six red spines protruding from the edges.
The Green Lynx Spider is another common garden spider found in Florida. They are especially useful to have around if you have row crops, as they primarily feed on caterpillars. They have a bright green body with red and sometimes white markings. Their legs are long and slender with black thorn-like spines. This species ranges in size from ½” to just under 1’ in length. Green Lynx spiders are generally found on leaves, in shrubs, and hiding in weeds. They are not web spinners, but rather ambush predators, lying in wait until the caterpillar inches by. They do produce silk and will sometimes anchor themselves with such while they wait for prey.
Other Outdoor Spiders
One of the most despised spiders in Florida is the banana spider. They are one of Florida’s largest spiders with a leg span of nearly 2”. They are orb-web weavers, and the females are much more distinctive in color than males. Featuring a yellow to orange abdomen and yellow and black banded legs. Their front and rear legs are longer, while the middle four legs are shorter in length. These spiders spin massive webs 3-6’ in diameter between trees. Other common names for the banana spider is the golden silk spider, writing spider, calico spider and golden orb weavers. Hikers and hunters alike dislike this spider because of the massive webs they weave, which can range from 3-6’ in width. They often erect these webs across trails and between trees, which is what makes them so detested by outdoor enthusiasts.
On your next outdoor adventure, if you happen to be near water, you may encounter the Long-Jawed Orb-Weaver. While their webs are small in comparison with the banana spider, ranging in size from just 8-12,” they are often found hanging in foilage near water. What is interesting about this spider is that when it is at rest, it will support its weight with the shorter pair of middle leg. At the same time, it will extend the longer front and rear legs, like it is relaxing in the sun. Long-Jawed Orb-Weaver spiders typically feed on small flying insects like mosquitos and flies. Their coloration is varied, but all are thin-bodied and long-legged.
One of the most feared outdoor spiders is the Huntsman Spider. This spider is Florida’s largest species with a 6” leg span. The spider is presumed to have originated somewhere in Asia and prefers subtropical temperate zones such as Florida, Texas, and California. People often mistake the Huntsman for the Brown Recluse, though they differ significantly in size. Huntsman spiders can easily be identified not just by their size, but by the black specks on their legs. Their abdominal markings in a cream to light tan color make a face-like pattern, much like the bottom of a stingray. They are night hunters and feed primarily on cockroaches, crickets, and other arthropods. At night, they can easily be spotted with a flashlight because of the reflective quality of their eyes. When one shines light upon them, they reflect back two small blue eyes. They are most often spotted on the ground or tree trunks. Huntsman spiders can bite, and will do so if threatened. However, the venom is harmless to humans. These spiders have flattened bodies, which makes it easy for them to intrude homes, barns, sheds, and other human habitats. They do not spin webs and are most often found hunting on the ground. Huntsman spiders are sometimes also kept as pets because of their size and unique look.
How can I keep spiders away?
Although it is good to have spiders around, it is best if you are not infested with them. If you see a spider on occasion, just be glad it is taking care of any pests that you may have around your house. All spiders are opportunistic feeders, meaning that if the selection is good, they will stick around. If you happen to spot several spiders congregating in your home, it may be time to call in a pest professional. You may be dealing with a pest problem you didn’t know you had. As will all pests, keeping a clean home, free of clutter and debris, will lessen your likelihood of infestations from pests and their spider predators.
University of Florida, Entomology & Nematology Department:
Bug Guide: https://bugguide.net/node/view/1957/bgimage
Sun Sentinel: https://www.youtube.com/watch?v=5qTuxoTGPpU