Big spiders and bugs conspicuous in September

September is prime time for some of Georgia’s biggest — and most fascinating — arachnids, insects and caterpillars.

Among the arachnids, the most prominent attention-getters now are the big orb-weaving spiders, whose huge, wheel-shaped webs seem to be everywhere — stretched between shrubs and trees on hiking trails and garden paths or across porches, windows and decks. We see them and also run into the webs this time of year because the spiders have matured and are completing their life cycles. The smaller webs that they weaved earlier in the year were mostly inconspicuous.

To build their big webs, female orb-weavers eject yards of silk strands from their inch-long-or-less bodies. With scores of silk lines strung across a dozen or more “spokes,” each web is superstrong — a natural engineering feat.

Some common orb-weavers now are the barn, basilica, golden silk and arrowhead spiders. Some may bite, but they are not dangerous.

Another familiar arachnid — though not a true spider — most commonly seen in September and October is the spiderlike daddy longlegs, or “harvestman.” Now fully grown and sexually mature, the gangly, harmless, beneficial arachnid is moving about more now to find mates. As such, daddy longlegs seem to be everywhere.

As for insects, one of Georgia’s biggest and most captivating — and most beneficial — insects, the praying mantis, is most commonly seen this time of year because females are searching for mates. After mating, the female mantis may bite off the male’s head. She lays a sticky mass of up to 400 eggs attached to a tree, branch or twig. The eggs will hatch in spring.

A humongous, scary-looking caterpillar crawling about now is the hickory horned devil, a striking green creature with black and white markings down its sides, spines on its back and red “horns” on its head. All summer it has been gobbling up tree foliage. Now, it’s about 5.5 inches long and looks like a ferocious dragon. But it is harmless.

Soon, it will burrow into the ground to pupate over the winter and emerge next summer as a royal walnut moth.

Beware, however, of another big, green, spiny caterpillar, the saddleback, named for the oval brown spot on its body. Its sting hurts badly. It also will become a moth.

IN THE SKY: The moon will be first quarter on Thursday, Sept. 12, said David Dundee, Tellus Science Museum astronomer. Mercury is very low in the west just after sunset. Venus is in the west at dusk and sets about two hours later. Mars rises out of the east about two hours before dawn. Jupiter rises out of the east just after midnight. Saturn is low in the southwest just after dark and sets shortly thereafter. It will appear near the moon Monday night.