Spiders are not actually insects, they belong to the group of arthropods called Arachnids. Insects have six legs and spiders have eight legs. Spiders also have only two body regions, a cephalothorax and an abdomen. Insects have three body regions a head, thorax and an abdomen along with wings and an antennae. Spiders also have six unique organs beneath their abdomen called spinnerets. Spinnerets allow the spiders to produce silk during their entire life cycle.
Spiders have a special mouthpart that has chelicera or jaws and fangs. Most spiders are venomous but they are harmless to humans except the black widow and the brown recluse. Most spiders cannot get their mouth open wide enough to break your skin. Venom is used to paralyze the spiders prey. Keep in mind one thing you are very large and the spiders are usually trying to get out of your way.
Females lay their eggs in the fall. As nature has it the female dies after she lays the egg mass. Most of the time the eggs do not hatch until spring, sometimes the hatchlings will stay protected in the egg masses until spring. In the spring the spiderlings must find a new home and move from their overwintering site. They do this by a process called ballooning. They cast a single thread of silk into the air and fly away to a new home. How awesome is that! If you ever capture this on film please send this amazing event to me.
Spiders are very beneficial in the garden. They eat many insects including aphids, caterpillars, cucumber beetles, flies, grasshoppers, leafhoppers, plant bugs, and thrips. There are over 38,00 species of spiders in America, that is a lot of helping fangs!
How do you encourage spiders to come stay in you garden? Plant tall plants for spiders to cast their webs on. Flowers are also encourage spiders in the garden. Plant cover crops late in the summer so the spiders can have a site to overwinter their egg masses. Leaving a small portion of the garden mulched, for moisture , cover and this will create a place for the spiders to lay their eggs as well. A great way to encourage spiders to stay in your garden is to plant a beneficial insect border or row. Plant this in the spring for beneficial insects and do not till it under. Spiders can lay their egg masses in this area and thrive there. This will encourage your beneficial insect population as well and you will be killing two birds with one stone.
A few things to remember about using spiders as a biological peat control in your garden. They are very sensitive to sprays, so remember even organic controls effect beneficials and spiders. Secondly, they are non selective, so they will catch bees and butterflies from time to time. It is their nature, don’t be frightened. When something flies into their web they can not say “oh, I think I will let you go!”. With the nature of web spinners bugs must come to the spider, not the spider to the bug. So keep this in mind. Spiders will not control large outbreaks of pests as you will not have large populations of them in your garden. The idea is to have a healthy balance in your garden and spiders should be there as part of a healthy ecosystem along with other beneficial insects.
Most spiders complete their life cycle in one year there are a few that live for a few years. The spiders lay eggs in the fall that will either overwinter or may hatch and be protected in the egg mass until spring. Spiderlings move by a unique process called ballooning in the spring.
There are two groups of spiders the hunters and the web spinners. The hunters are very agile and active and track down their prey. You will see these guys on the move most of the time. I find them when I am moving mulch, they are usually running away from me. Wolf spiders are the ones that I usually find in the garden. Wolf spiders have hairy legs and the females carry their babies on their back.
The web spinners create masterpieces of silk to capture their next meal. The spinners start out with one single thread of silk cast into the wind. That silk catches onto a stationary object and the first anchor of the web is formed. Next the spider will tighten that thread of silk up and attach the other end to another stationary object. Then she will reinforce it. After that she will make a “Y” by dropping another line of silk down from the center. I have been amazed at the distance and intricacy of some of the spider webs. In the spring you can see spider webs at Purgatory Park that are 15 feet long spanning from tree to tree. The most common web spider that we see in Texas is the Argiope which is an orb spider. You will notice her by the white zig zag in her web. The webs are about one foot in diameter and the Argiope is a large spider as well. She is black and yellow. The argiope come out in late summer and in fall. She like tall shrubs and flowers. The great thing about her is that she will hang out on your tomatoes and eat leaf footed bugs and stink bugs. The picture of the one up top is the one that hung out in my garden all summer. I called her Baby and she ate so many leaf footed bugs. I told people to be careful not to disturb her because I really like her help with all the bugs that she ate.
Jumping spiders are in the family Salticidae. Jumping spiders can jump over 40 times their body length. They come in many colors and are recognized by their jerky movements. You have most likely seen the black and white jumping spider.
Another spider you have most likely seen in your garden is the crab or flower spider, one such as Misumena vatia. Crab spiders hunt during the day and have enlarged front legs much like a crab. You find them hanging out in flowers many times, hence the name flower spiders.
You have seen the remnants of sac spiders Cheiracanthium inclusum in your house and in your garden no doubt. They are a rather small spider and hide in corners, on bark and underneath plants. These small helpers like to come out and feast on their prey at night.
Funnel Weavers such as grass spiders make a funnel or a hole out of their web. When the prey contacts the web they are quick to attack it.
Sac spiders are another small fellow you may see wandering in you garden. You may also see the retreat sac on leaves of your plants. When you see a small web on a leaf let it be so he can go back in to it when he is done hunting.
Dwarf spiders are super small helpers. They like to capture their prey during the day. They have a unique web pattern that is sheet like.The dwarf spider likes to put this irregular crisscross web on surfaces.