NATURE NOTES – Number 97 July 28, 2024
Introduction:
Some of nature’s most fascinating animals, with roots going back over 300 million years based on fossils, and with anatomical and physiological features uncommon to other animals, and animals that many humans fear, are ….
Our current topic: Spiders
This fear, called Arachnophobia, is not readily justified since we live in very close proximity of many of these small creatures daily. In Virginia, we have some 60 species, while North America boosts 3600 species and worldwide, over 50,000 species have been identified. We’ll discuss only a tiny number in this NN.
As far as classification, spiders are of the animal class Arachnids, like scorpions. They are NOT insects, but belong to the order Araneae. Some interesting features of this order are: eight legs (insects have 6), fangs to inject venom into their prey, no antennae, and no external muscles to move their limbs (they use hydraulic pressure). Unlike insects, spiders have two body segments: the combined head-thorax, and an abdomen. Their primary food is insects which they snare in various ways: in their webs, run down with their speed, or ambush. They can only eat liquid food, so some species inject enzymes into the prey and suck out the liquid tissue, leaving behind a hollow body.
Some make webs, some don’t. This unique feature is made possible by having a spinneret, a gland that secretes strong, elastic silk fiber. This high-protein web is similar to insect silk. They also have excellent vision and the ability to “hear” with their legs.
Many species are common outdoors in various settings, but spiders, as we all know, are also common in our homes and other buildings, especially during the winter. Most are relatively harmless, but some do bite. Most of these bites are similar to a bee sting and require no medical attention, but two species are more serious and we will discuss these below. With so many species and different color patterns within a species, identification can be tricky without a good field guide or use of the internet. By simply typing in “spiders of Virginia” you will have lots of identification information, much of it from commercial exterminators ready to help eliminate spiders from you attic, basement, living room, or closet.
These are brief descriptions of some of the more common spiders we may see in our area:
- Cellar spiders: small, very long legs, hangs upside down from ceiling. Poses no risk but a prolific breeder, so it can be troublesome. Very common in homes.
- House spiders: tiny, yellow, most common in houses.
- Crab spiders: usually near flowers. Quite small.
- Grass spiders: 2 white stripes in two sections on an oblong abdomen. Make non-sticky webs, with funnels.
- Wolf spiders: dark brown, yellowish markings, an inch long, covered in hair. Common on the floor. It bites. Does not make webs, but runs down its prey with speed. Many species.
- Sac spiders: long legs, pale, ½” long, common in gardens. A painful bite.
- Orb-Weaver spiders: varies greatly in size and color. Large abdomen. Creates large webs 3’ in diameter with an escape hole in rear. Will bite.
- Yellow Garden spiders: 1” yellow patches on black abdomen. Make large circular webs in sunny places with a zig-zag pattern, which are believed to prevent predators from running into web. Will bite.
- Brown recluse: Dark, violin shape on head and back. Venomous. Painful bite requires medical treatment. Symptoms include fever, restlessness, and an open sore at site. Also hides in dark places, inside and outside.
- Black widow: Black with red hour glass on underside. Venomous, but not aggressive, and seldom bites humans. Normally they stay hidden both outdoors and indoors. The bite affects the nervous system and needs medical attention.
- Daddy Longlegs: technically, not a spiders. They don’t bite. They eat large assortment of insects, fungi, and bird dung. Legs used to capture prey.
Opportunities:
Young people are often either afraid of spiders or totally fascinated by them. Regardless, they can be an interesting animal to observe. Identification can be tricky. Obviously, you need to be very caution with them and not let scouts handle them. Even the non-venomous species can leave a painful and irritating bite. Often people will think they have a mosquito bite that won’t quickly heal, and it is really an annoying spider bite. But in actuality, spiders are quite beneficial, even in your home, for their ability to destroy small insects. We usually don’t like sharing our indoor space with them, but there is generally no reason to destroy spiders found outdoors in their normal habitat. Leaders should, however, make scouts aware of the two venomous spiders we might encounter and stress the importance of medical attention if bitten by one of these. Find photos on the internet to share with scouts. They too are part of nature, just doing their spider thing. Respect that.
Thanks for reading NATURE NOTES. Now go find a spider to watch.
Bob Garst
