By Judy Stout, Ph.D., Mobile Master Gardener | [email protected]
Q: It seems like this time every year there is an increased abundance of spiders. While the exterminator eliminates them in my house, what should I do about those in my garden?
A: I’m reminded of E.B. White’s 1952 classic, “Charlotte’s Web,” in which the writing spider, Charlotte, tells Wilbur the pig, “I’ll be a friend to you.” And later, when Wilbur gets to know her better, he asks Charlotte, “You mean you eat flies?” and Charlotte responds, “Certainly. Flies, bugs, grasshoppers, choice beetles, moths, butterflies, tasty cockroaches, gnats, midges, daddy longlegs, centipedes, mosquitoes, crickets — anything that is careless enough to get caught in my web.”
Maybe if we all get to know spiders a little better we will look for ways to encourage their presence in our gardens. I know it’s kind of hard since we are so often involuntarily “creeped out” when seeing or even thinking about spiders. It also doesn’t help that our Halloween haunted décor includes spooky spiders!
There are more than 3,000 species of spiders in North America, and they are probably the most abundant land predators in yards and gardens. Spiders have voracious appetites, eating most anything they can catch. They are considered more effective at insect removal than either birds or bats.
Yard and garden spiders rarely ever enter homes. Although most have a form of venom used to paralyze their prey, only a few species have mouth parts strong enough to penetrate human skin or inject harmful amounts of venom. In Alabama, we have two species of widows and three species of recluses considered poisonous to humans. Most are found around the protected outside of buildings, in debris, brick stacks, old boxes and wood piles. The brown recluse can also be a hazard in boxes of papers and old clothes in the house. Poisonous varieties do not usually occur in open, exposed gardens or yards.
Yard and garden spiders capture their prey in several ways. Web weavers construct webs of silk released from spinnerets in their abdomen. Webs may be of random and simple construction or very elaborate.
The most commonly observed web weavers in our area are the black and yellow garden spider or “writing” spider, and the banana spider or golden silk spider. The black and yellow garden spider weaves a two foot-wide web of concentric circles divided into geometric pie wedges. In the center is a dense, characteristic zigzag or zipper of silk where the female hangs out upside down awaiting her prey. She has a shiny, black, oval abdomen with prominent bright yellow spots and stripes on top and two vertical stripes underneath. She can be up to two inches in diameter.
The banana spider female is our largest non-tarantula spider at three inches across. It has a brown to tan background with muted, pale yellow spots on an elongated abdomen. She can be distinguished by the dark, feathery tufts on the mid joints of six of her eight legs. In both varieties, the female is eight to 10 times larger than the male and may eat the male after mating.
A third, much smaller (three-eighths of an inch across) web weaver is the spiny orb weaver, also locally called the “crab” spider because of its appearance from the top. It may be white, yellow or orange with dark spots and pointed spines around its small abdomen.
These three spiders are active in the daytime and construct their web once, repairing it as needed. Excess prey is wrapped in silk cocoons and eaten later. Other orb (web) weavers construct their webs secretively each evening, catching prey throughout the night and taking the silk down early each morning to hide in leaves and branches. They are rarely observed but also are great at pest control in the garden.
Web builders are attracted to vertical structures such as tomatoes, corn and okra stalks and tall sunflowers. You should leave some of these even after harvest as habitat for spiders. Web weavers are also common in the branches of citrus and pecan trees.
Hunting spiders either roam around seeking prey or lie in ambush in ground burrows or debris — and can even chase their prey! Some spiders you want to have in your garden are the wolf spider and jumping spider. They hunt mostly at night but may be seen scurrying across the garden in the daytime or disturbed under mulch and debris, or among plant stems and leaves. To encourage them in your garden, provide coarse mulch, old leaves and small sticks.
To sum it all up from another childhood favorite, “Be Nice to Spiders” (Margaret Bloy Graham, 1967), “The zoo became a peaceful place.” And Joe, the zookeeper, recommends: “Spiders are useful. Be nice to spiders.” Don’t spray them with chemicals and don’t kill them. They are a gardener’s friend.
For more about Alabama spiders, you can request a free color poster of our 58 most common varieties from Legacy, Partners in Education at www.legacyenved.org. For details of biology, habitats and protection from Alabama’s few venomous spiders, view and print the following ANR publications from the Alabama Cooperative Extension Services website: 1039, “The Black Widow,” 1043, “The Brown Recluse Spider” and 2146, “Black Widow and Brown Recluses: Avoiding Venomous Spiders of the Southeast.”
Photo/ Judy Stout – The spiny orb weaver, also called the “crab” spider, may be white, yellow or orange with dark spots and pointed spines around its small abdomen.
YOU ARE INVITED TO THESE UPCOMING GARDENING EVENTS
What: Lunch & Learn, Mobile Master Gardeners
When: Thursday, Nov. 20, noon to 1 p.m.
Where: Jon Archer Center, 1070 Schillinger Road N., Mobile
Topic: Grafting Camellias, Vaughan Drinkard Jr.
What: Master Gardener Greenery Sale and MBG Poinsettia Sale
When: Dec. 1-2 (Friday, 9 a.m. to 4 p.m.; Saturday, 9 a.m. to 1 p.m.)
Where: Mobile Botanical Gardens, 5151 Museum Drive, Mobile
Deadline for pre-order is Nov. 15. For order form, email [email protected].
Master Gardener Helpline: 1-877-252-4769, or send your gardening questions to [email protected].