Insects

In general, insects have three-part bodies, six jointed legs, compound eyes and two antennae. Bees, wasps, beetles, mosquitoes, flies, grasshoppers, ants, butterflies and moths, and dragonflies and damselflies are common types of insects that live in DuPage County. With the assistance of grant-funded studies and ongoing field observations, ecologists have identified over 1,000 species in DuPage County forest preserves, many dependent on diverse native plant communities.

Butterflies and Moths

Butterflies and moths are members of the insect order Lepidoptera. Both have four-stage life cycles — egg, larva, pupa and adult — and larvae (i.e. caterpillars) that feed on plants and trees. A few species are pests because their larvae can damage crops or trees.Many adult butterflies and moths are important pollinators.

It can be difficult sometimes to determine if a member of Lepidoptera is a butterfly or a moth. For the most part, butterflies are active during the day and moths at night, but not always; and although most butterflies have large, brightly colored wings, some species are predominately tan and brown. However, butterflies almost always have club-shaped antennae with small bulbous tips; moths that live in DuPage County do not. Instead, moths usually have feathery or threadlike antennae.

In May, June and July, resident butterflies will emerge as adults. During this time, they visit flowers to forage for nectar. They may also find suitable mates and host plants on which to lay their eggs. For example, you may see the caterpillars of a monarch butterfly (Danaus plexippus) feeding on milkweed plants or black swallowtail (Papilio polyxenes) caterpillars feeding on Queen Anne’s lace and golden Alexanders.

Forest Preserve District of DuPage County ecologists and volunteers, in collaboration with the Butterfly Monitoring Network and the Peggy Notebaert Nature Museum in Chicago, survey butterfly populations in over a dozen forest preserves. These efforts have produced observations of over 100 species, including several rare or habitat-dependent species, such as the bysuss skipper, pipevine swallowtail and Edward’s hairstreak. Ecologists have also identified over 400 species of moths and collected over 750 study specimens, including common native species like the Henry’s marsh moth, painted lichen moth and slant-lined owlet.

Check out this photo gallery to see butterflies commonly found in DuPage County.

The Baltimore Checkerspot Project 

Baltimore Checkerspot ProjectThe Baltimore checkerspot (Euphydryas phaeton) is rare in the Chicago region. Recently, the Peggy Notebaert Nature Museum bred and raised the species in captivity and released the butterflies in the wild. Through its Baltimore Checkerspot Project, the Forest Preserve District is hoping to do the same.

First, however, they need to locate wild populations that are large enough to tolerate the removal of individuals needed for breeding without affecting the greater population. Since 2010 they’ve been using the “mark-and-recapture” method of estimating populations to do just that.

During a sampling session, which usually lasts about an hour, ecologists capture Baltimore checkerspots using cloth mesh insect nets. At the end of the session, they identify the sex of each insect and use a fine-tipped indelible marker to delicately mark the wings of each butterfly with a code that corresponds to a unique number, a technique that scientists Paul Ehrlich and Susan Davidson published in 1960. This system allows ecologists to identify previously sampled Baltimore checkerspots during future sessions. (Studies have shown that the process does not harm the butterflies or shorten their lifespans.) Ecologists use mathematical formulas to compare the number of marked and unmarked butterflies from a sampling session to estimate the size of the population. Long-term data from these samplings can help them determine if populations are increasing, declining or staying the same.

Once ecologists begin to breed Baltimore checkerspots and release them in an appropriate area, they’ll likely need to release adults over several seasons to create a self-sustaining, genetically diverse population.

The District is also surveying the abundance of turtlehead (Chelone glabra), fen betony (Pedicularis lanceolata) and mullein foxglove (Seymeria macrophylla) in areas where Baltimore checkerspots are present and absent. The three species are the insect’s main host plants, which means they’re primarily where adults lay their eggs and developing caterpillars feed. As a result, the presence or absence of these plants can directly affect populations of Baltimore checkerspots, so ecologists may need to propagate the plants as well as the butterflies.

For more information about District’s volunteer monitoring programs, see the Natural Resource Management Volunteer Program page.

If you’d like to provide habitat for butterflies in your own backyard, consider adding native plants to your landscaping. Check out this list of native species that support the most species of butterflies and moths. (http://bringingnaturehome.net/native-gardening)

Dragonflies and Damselflies

Dragonflies and damselflies are members of the insect order Odonata. Both have large multifaceted eyes, two pairs of transparent wings, and elongated bodies, and both eat mosquitoes and other small insects, such as flies, bees and ants. They are usually found around lakes, ponds, streams and wetlands because their larvae, called “nymphs,” live and develop in the water.

There are a few subtle differences between these two Odonates. Adult dragonflies typically hold their wings away from their bodies when at rest; most damselflies either hold their wings next to their bodies or at a 45 degree angle. Damselflies are also usually smaller and weaker fliers than dragonflies and have widely separated eyes.

In collaboration with the Dragonfly Monitoring Network, Forest Preserve District of DuPage County ecologists and volunteers survey dragonfly populations at several forest preserves and have observed over 60 different dragonfly and damselfly species. Use this dragonfly guide to help you identify dragonflies.

Featured Native Dragonfly of DuPage Forest Preserves

Hine’s Emerald Dragonfly

Waterfall Glen Forest Preserve in Darien is one of a few places in the world where the federally endangered Hine’s emerald dragonfly lives.

To successfully mate and reproduce, the Hine’s emerald dragonfly depends highly on groundwater-fed springs, rivulets and wetlands where dolomite and limestone bedrock are close to the soil surface. The larvae of this species are highly dependent on small rivulet channels that flow from these springs because they spend almost their entire lives in these aquatic systems. These dragonflies also require intact, high-quality natural areas with open vegetation that allow them to set up patrolling, foraging and mating locations.

Unfortunately, in the past 50 years, gravel mining, development, erosion, invasive plants and the affects of high-capacity groundwater wells have degraded much of the Hine’s emerald dragonfly’s habitat. As a result, the Forest Preserve District of DuPage County is working with other local government agencies to restore habitat in DuPage County. Much of the work involves restoring areas that already support these dragonflies by selectively removing invasive and exotic plants, carefully applying herbicides on invasive plants that resprout, seeding with native species, and using prescription burns.

Recently, the District partnered with the Illinois State Toll Highway Authority to develop new breeding grounds at Waterfall Glen. The project, which is near existing Hine’s emerald dragonfly habitat, is in response to the increase in development along the Des Plaines River corridor, which contains most of the state’s remaining habitat for this species. The goal is to expand this habitat and reduce the decline of the Hine’s emerald dragonfly in Illinois.

To date, the District has constructed artificial breeding areas by harnessing groundwater from old artesian wells in the preserve to create rivulets comparable to natural conditions. Scientists are monitoring the project to see if the new habitat will support the dragonfly larvae. To do so, they are studying the growth rate of Hine’s emerald larvae that were temporarily located to the project area to see if they are able to get the proper nutrition necessary to grow into adults. There is also hope that the Hine’s emerald dragonfly might naturally colonize the site over time.

In addition, researchers from the University of South Dakota, experts in Hine’s emerald dragonfly biology, have been studying this insect at Waterfall Glen since 2006. In exchange for the use of District buildings for their experiments, the researchers have given the District countless hours of pro bono consultation on Hine’s emerald dragonfly-related management issues and annual reports on their work at Waterfall Glen. Their findings will help regional conservation agencies manage natural areas for this rare and endangered species.

Mosquitoes

Mosquitoes are known for their irritating bites, but they’re also important members of the food chain. Mosquito larvae (aka juveniles) help keep marshes and ponds clean by eating bacteria, algae, and microscopic plants and animals. (Just one can filter half an ounce of water a day, so a summer’s worth provides a significant environmental service.) In turn, both larvae and adults are food for dragonflies, frogs, fish, turtles and other animals.

Adult mosquitoes live in the shade of shrubs, grasses and other plants but breed in areas near water, where females lay their eggs. Some lay their eggs on the surface of ponds and marshes or on floating vegetation; others look for areas only periodically wet, such as depressions in the ground, bird baths or buckets.

When the weather is warm, mosquito eggs can hatch into larvae within a few days. The larvae remain in the water, but because they need air they’re usually near the surface. They swim around by making jerky movements with their bodies, which gives them the name “wigglers.” In about a week they develop further into pupae, which stay in the water for a few days before emerging as adults.

Both male and female adult mosquitoes get their energy from eating nectar and other plant juices. They use a long tubular mouthpart called a “proboscis” to suck up the liquid. With most species, the females also take in blood but not for food. Some cannot produce eggs without the proteins found in blood; others can produce eggs on their own but lay more after a blood meal.

As a result, even though male and female proboscises have the same basic six parts, those on a female are sized and shaped differently. Two of the parts cut through the skin, two likely help keep it open, one pierces the blood vessel and sucks out the blood, and one deposits saliva. The saliva contains a chemical that keeps the blood from clotting (and causes bites to itch), but it may also help the insects locate vessels in the first place. The saliva is also the substance that carries diseases from infected mosquitoes into the animals they bite.

Mosquitoes and Human Health
Not all mosquitoes bite, and of those that do only a few are capable of transmitting certain diseases to humans. For information on Forest Preserve District efforts to monitor specific types of mosquitoes and ways to avoid bites in your own backyard, click here.

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