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Wake up to the wonder of nocturnal insects

URBANA, IL -- Remember when you were a kid and the best part of the summer was collecting fireflies in a jar or discovering elaborate spider webs? University of Illinois Extension horticulture educator Kelly Allsup encourages us to reawaken that childlike wonder this summer by exploring natural areas to find the enigmatic inhabitants that come out at night.

Entomologists use “black lights” to find nocturnal insects, which detect light in the ultraviolet spectrum. Shining a black light in front of a white sheet encourages insects to land and be observed. Non-flying insects like walking sticks can be found by placing a white sheet under trees and beating the branches to see what falls off. Although not technically insects, spiders can be found perched in webs or in the distance using a flashlight to reflect their glowing eyes.

“One of the insects you may find flying is the green lacewing,” Allsup says. “Adults are small, pale, and green with delicately veined wings. Eggs are distinctively stalked to avoid predator insects or cannibalism. Larvae, also known as aphid lions, look like miniature alligators. They use their hooked jaws to drain fluids out of prey, including caterpillars, beetles, and aphids. Larvae can eat hundreds of prey, even though they are only in that stage of their life cycle for seven to ten days.”

Another fascinating nighttime insect is the luna moth. Luna moth adults are a bright lime green with a 4-inch wing span and eyespots on their wings, which are meant to startle predators. They hatch from pupae on host plants of walnut, hickory, or persimmon. They emerge in late May to June, with a second generation appearing in late July to August.

“The adults live for only seven to ten days, and their only goal is to reproduce. Females rest on trees and give off pheromones so males can locate them. Mating pairs couple for long periods of time. They lay their eggs on the leaves of host plants. Lime green caterpillars with magenta spots emerge and feed on leaves,” Allsup notes.

Big dipper fireflies are a type of beetle. Their unique yellow flash attracts mates. Some firefly species prey on other species, with the females mimicking their flashing patterns to attract and eat males. Larvae glow, as well. They live in soil eating snails and other insects.

Katydids are more often heard at night than seen. They are 2 inches long, leaf

green, and have oval wings. They live in the tops of trees and on the deciduous shrubs on which they feed. They breed in late summer to early fall, when the males make loud mating calls at night.

Allsup says another interesting insect to look for at night is the northern walking stick.

“Mimicking sticks to evade predators, wingless northern walking sticks eat leaves in a slow and deliberate fashion,” she says. “Eggs mimic seeds, overwinter in leaf litter, and hatch in the spring. Nymphs hide in leaf litter and wait until night to come out and feed on plants. If attacked, they can release a bad smelling liquid, so try not to startle them!”

The yellow garden spider might not be everyone’s favorite nighttime creature. These spiders are large, with females reaching a “legspan” of up to 2.5 inches and with webs up to 2 feet in diameter. Yellow garden spiders make a new web daily with a large zig-zag marking in the center. Young spiders build small webs close to the ground amid vegetation, with webs becoming larger later in the season. Yellow garden spiders prefer sunny areas with little or no wind and plenty of prey species.

Another spider to watch for at night, says Allsup, is the ghost spider.

“The ghost spider has fangs that open laterally. These orb-weaving spiders are sensitive to motion. It is easy to see them at night as their eyes will reflect flashlights. Ghost spiders actively hunt for small insects and other spiders at night. During the day, they retreat behind loose bark, folded leaves, or crevices in the garden,” Allsup notes.

Barn spiders often construct orb webs on manmade structures near lights. They are oval and usually beige. At night they will be seen in the center of the web, but hide during the day. Barn spiders remove, eat, and reconstruct their webs every day.

Wolf spiders are active nighttime hunters that patrol the ground for insects and other small spiders. Once they detect their victim, they chase, capture, and inject it with paralyzing venom. Soon the victim’s dissolved tissues are sucked out. Spookily, their eyes have a layer of light-reflecting crystals that cause them to shine brightly in a beam of light.

“Their activity can sound threatening, but they really just want to be left alone,” Allsup states. “Also, there is no need to worry about infestations, because the female spider will carry her egg sacs on her belly until they hatch and then carry the little spiderlings on her back until they are ready to fend on their own.”

So, grab your flashlight and head outside tonight.