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
The 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)