Kenneth Setzer Fairchild Tropical Botanic Garden
As published in the Miami Herald, MARCH 02, 2017 7:00 AM
Spiny orb weaver, also not a threat. Kenneth Setzer Fairchild Tropical Botanic Garden
Do you run screaming, arms flailing, after inadvertently walking through a spider web?
There’s no need to fear most spiders, though some are nastier than others. Here are the spiders you’re most likely to encounter in the garden.
The biggest, most menacing-looking spider in the south is probably the golden orb weaker, aka banana spider (Nephila clavipes). But it’s mostly bluster. Its huge (up to three feet across) webs are spun with golden yellow silk, dazzling when sunlight hits.
These colorful ladies sport what look like fuzzy black workout armbands on their yellow legs, with orange abdomens spotted in white, and a cephalothorax (like a fused head and thorax) in a silvery gray. Impressive, but essentially harmless. Their venom is said to cause a reaction similar to a bee sting, which is serious only if one is allergic. Otherwise it’s not a dangerous spider, and is even considered hesitant to bite. I handled one, and she was fairly relaxed. I say “she” because those big banana spiders are female; males are small, look little like the females, and wisely stay out of her way.
Everyone encounters Gasteracantha cancriformis, which translates roughly as “thorn belly crab shaped,” loitering along shrubby garden edges. These spiny orb weavers are common throughout the south, with some color variation, though the ones encountered in our region are mostly white with black spots with red spines and look like tiny crabs. They spin a web and hunt at garden edges and woodland perimeters. You may have seen their nurseries: a pale lemon yellow fluffy mass underneath leaves.
Orchard orb weaver spiders (Leucauge venusta), about the size of a quarter, sport translucent green legs, though males are more variable. Its abdomen resembles a tiny metallic oval of red, green, and orange with stripes. Its web is sometimes oriented horizontally, for reasons only truly known to itself. As with most spiders, its fangs are either too small to penetrate our skin or its venom too weak to be significant.
Another large orb weaver is the Argiope. Resembling somewhat the golden orb weaver but smaller, it is colorful, often with a silvery-white appearance and yellow and black bands or spots. Their webs tend to be a few feet off the ground and can be easily disturbed in grassy areas. This may cause them to bite, but the venom is not a threat to a healthy person.
Daddy longlegs and harvestmen, while arachnids, are not spiders. They are distinguished by having only two eyes and a one-piece head and thorax. They’re quite unspider-like: They do not spin silk, are not venomous, many live gregariously and not all are predators, some turning to omnivorous scavenging. I once broke open a rotting log only to disturb hundreds, if not thousands, of cosmetid harvestmen. Shy, nocturnal creatures, they fled from my intrusion. Returning at night, I discovered they fluoresce under a UV light. Magic!
Golden orb weaver spider — large, but harmless Kenneth Setzer
Now those to avoid: Florida does harbor brown, black and (rare) red widows. Southern black widows are shiny black with the classic red hourglass on the abdomen underside. Their webs are messy, nothing like the beautiful orb weavers’ webs, and are usually in a sheltered, undisturbed location under porches, in sheds or in woodpiles. This is where gardeners need to be aware. If you need to reach into such places, wear gloves. But in 20 years here, I’ve never encountered a black widow.
The brown widow is variable, gray to tan or dark brown, with a body shape similar to the black widow. Its underbelly shows an orange or yellow hourglass. A University of Florida publication notes “It usually makes its web on buildings in well-lighted areas,” which is exactly where I’ve seen its web and egg sacs. The widow would not show herself, but the egg sacs are diagnostic, being spikey, off-white balls within the messy web.
The great news: The dreaded brown recluse is not established in our state. They’re hard to positively identify, but as long as you know your spider is not a recluse, there’s little need to worry.
If you are otherwise healthy and not allergic, you don’t have much to fear from the world of arachnids in Florida gardens.
Now go explore a natural area and seek green lynx spiders, countless jumping and wolf spiders, fishing spiders, crab spiders, ogre-faced spiders and dozens of other multi-legged, multi-eyed beings we share the world with. They are beautiful. We are indeed blessed by Mother Nature with a large variety of arachnids.