Enchanting Butterflies

July 18, 2011 under CANR News

Sheila Vincent may be the only person in Delaware who gets paid to catch butterflies. Every summer day, Vincent heads out with a net and collects butterflies, caterpillars and larvae to stock Ashland Nature Center’s Butterfly House.

As group program coordinator for the Delaware Nature Center, Vincent spends the bulk of her time teaching natural history programs and only about 15 minutes with her butterfly net. “I really look forward to butterfly catching. It’s a bit of peace and quiet during hectic workdays,” she says.

Last season was a “spectacular butterfly season,” according to Vincent and this summer looks to be shaping up to be a good one, too.

“Most years, butterflies are abundant in Delaware from June through August,” says Brian Kunkel, an entomologist with University of Delaware Cooperative Extension. “Mid-July to mid-August is typically the peak of activity.”

But bad weather or insufficient food sources can be game changers. Two years ago, the butterfly season was lackluster because of too many cool, rainy days. Other times, host plants may not be well developed.

Delaware is a good place for butterfly watching. There are about 120 species of resident breeding butterflies in the state. Some entomologists make a distinction between butterflies and skippers – in which case, there are 70 species of butterflies and 50 of skippers. Named for their rapid flight pattern, skippers have small, angular wings and bodies that are proportionately larger than true butterflies, says Kunkel. There’s even a skipper known as the Delaware skipper because it was first spotted here.

But speedy skippers aren’t good for teaching purposes. Monarchs are Vincent’s go-to butterfly for nature programs, especially when she’s working with kids. Monarchs are fairly slow, abundant and easily recognizable. Her own personal favorites include the pipevine swallowtail, a relatively rare species that has orange spots and iridescent blue wings. Vincent also appreciates what she calls the “somber beauty” of the mourning cloak butterfly, which is dark brown with yellow borders around the wings and a row of blue spots.

The black swallowtail butterfly, which has distinctive yellow and bright-blue markings, tops Kunkel’s list of favorites. His wife grows herbs on their deck and always plants dill or fennel, which attract black swallowtails and their caterpillars. Kunkel also likes the Eastern-tailed blue. The males are usually light blue and the females a charcoal color but some varieties are pink or purple.

When Kunkel was a boy, he saw scores of Eastern-tailed blues in his yard every summer. That’s because his parents weren’t perturbed by a bit of clover in the their lawn.

“The caterpillars of Eastern-tailed blues feed on clover,” says Kunkel. “If you eradicate every piece of clover in your yard, I guarantee you won’t see any Eastern-tailed blues.”

Kunkel says he’s a “lawn guy,” who loves a carpet of green, but he’s happy to let clover or wild strawberries coexist with turf. He also can handle a little leaf damage on ornamental plants for the sake of the butterflies.

“Don’t get overly excited about caterpillars on your plants,” he says. “Yes, they’ll munch on some leaves but if you want butterflies, you’ve got to have host plants for the larvae, too.”

Vincent has incorporated plenty of host plants for caterpillars, as well as food plants for butterflies, into her New Castle yard. Her perennials include butterfly weed, milkweed, phlox, asters and goldenrod.  She also plants parsley and fennel in the ornamental beds to attract black swallowtails.

If your yard isn’t lepidoptera friendly just yet, there are other places to spot butterflies. To see the largest number, as well as the most species, choose a sunny, open location – like a meadow or field – that features plant diversity. Vincent recommends the meadow at Ashland Nature Center, Middle Run Natural Area, and White Clay and Brandywine Creek state parks.

Kunkel suggests the UD Botanic Gardens, which opened its Lepidoptera Trail in 2009. This self-guided interpretative trail showcases trees, shrubs, wildflowers and native grasses that provide food for butterflies and moths during both the caterpillar and adult stages. Right now, the Trail is abundant with butterflies.

Special events

• Open House in the Native Plant Teaching and Demonstration Garden will be held Monday night, July 18. Join Kunkel for a plant, pest and beneficial insect walk. Get your questions answered about butterflies, caterpillars and other insects. New Castle County Cooperative Extension Office, Newark. 6-8 p.m. For more information, call 831-COOP or email cjmurphy@udel.edu.

• A Mid-Summer Night’s Stroll through the Gardens will be held Wednesday, July 20. Watch butterflies feast on natives on the Lepidoptera Trail and enjoy all the mid-summer blooms in the UD Botanic Gardens. Live steel drum music and light refreshments. 4-6:30 p.m. Reserve a spot by contacting Donna Kelsch, 831-2531 or botanicgardens@udel.edu.

Article by Margo McDonough

Photo by Danielle Quigley

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Stink bugs shouldn’t pose problem until late summer

April 1, 2011 under CANR News, Cooperative Extension

Last fall, Stephanie Sturmfels battled stink bugs at her Pike Creek home and yard. “Stink bugs were on my deck, they were on my front porch, some were even in my house,” recalls the mother of two small children. “My four-year-old daughter, Madison, would go around and collect stink bugs in pieces of tissue.”

Now that spring has arrived, Sturmfels is worried that stink bugs may return in full force. So far, she has seen a few stink bugs but nothing like the invasion last September and October.

Brian Kunkel, a UD Cooperative Extension entomologist, has some good news for Sturmfels and anyone who despises the brown marmorated stink bug. “The adult stink bugs that were driving people crazy last fall will be giving birth this June and dying off soon afterwards. From now until then, they will be too busy feeding on plants in the landscape to spend much time around houses.”

“Their offspring — the nymphs — will spend most of the warm-weather months outside as they mature. They don’t feed in houses so you shouldn’t expect to see many on decks and patios or inside houses this summer,” adds Kunkel.

Best yet, nymph stink bugs can’t fly — they have wingbuds but not mature wings — so they can’t land in your hair, on your shoulders, or in a bowl of potato salad, the way those annoying adults were doing last autumn.

So rest easy and host a Memorial Day or Fourth of July cook-out, says Kunkel. You shouldn’t worry about scads of brown marmorated stink bugs crashing the party. However, when Labor Day rolls around, your guest list could unexpectedly rise.

“By late August, the nymphs have become adults and are able to fly,” says Kunkel. “What’s more, they start to congregate in houses, decks, garages and other warm spots during this time period. There is a lot that researchers don’t yet understand about the stink bug’s behavior but we do know that cooler temperatures at night motivate them to seek shelter.”

Twenty-six states now have populations of the non-native brown marmorated stink bug. If you have friends in other regions who shrug off stink bugs as a minor annoyance, you may have already guessed that Delaware has more of the critters than most places.

“This region is the epicenter of the stinkbug outbreak,” says Kunkel. Brown marmorated stink bug were first found in this country in Allentown, Pa. They arrived in 1998, as stowaways in packing crates from Asia, where they’re native. Here in the U.S., they have few natural predators. Some spiders, including arboreal spiders, feed on the brown marmorated stink bug.

“Don’t get rid of spiders in your yard and garden,” notes Kunkel. “Spiders are beneficial. In addition to stink bugs, they eat a wide variety of other pests.”

Keep in mind, though, that not all of Delaware’s stink bugs are bad guys; a native stink bug known as the spined soldier bug eats aphids and other pests. Delaware is home to three other native stink bugs: green, brown and dusty.

The brown marmorated stink bug has been more of a nuisance than a pest in the home landscape, thus far, but Delaware’s agricultural industry is monitoring the insect closely. This stink bug feeds on many plants, including lima beans and sweet corn, but is a particular threat to fruit-bearing trees.

“There are some orchards in other states that may go bankrupt this year because they had so much fruit damage from the brown marmorated stink bug last year,” says Kunkel.

He and other UD experts are launching several research projects aimed at protecting Delaware’s growers. One project will focus on when the stink bugs arrive in fields or at greenhouses, their life cycle, and the natural enemies (native parasitoids, predators) attacking this pest. Another project will evaluate the effectiveness of insecticides against the brown marmorated stink bug.

According to Kunkel, current insecticides provide little help in keeping this pest out of the house. Exclusion is the best approach. “Seal up every opening — caulk around windows, repair screens, install screens over your attic vents and replace any rotten wood on your house,” says Kunkel.

And take comfort in the fact that you won’t have stink bugs landing in your hair until later in the summer.

Article by Margo McDonough

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How insects survive the long, cold winter

February 3, 2011 under CANR News

Baby, it’s cold outside. Time to put another log on the fire, wrap up in a thick sweater, or make a steaming mug of tea. These human adaptations to cold weather are quick, easy and get the job done. Even more effective, of course, is the central heating that is ubiquitous in our homes, offices and schools.

It takes a lot more effort for other mammals, birds and insects to make the necessary adaptations to survive harsh weather. Next week, we’ll look at animal and bird strategies; today we’ll see how insects make it through the winter.

In many species, insects adapt to the cold by dying off; it’s the larval stage of the species that goes through winter. Insects that do over-winter as adults usually enter a hibernation-like state called diapause.

“Insects don’t technically hibernate in winter but many go into diapause, a dormant state that allows them to withstand cold temperatures,” says Brian Kunkel, a UD Cooperative Extension entomologist.

The mourning cloak butterfly exists in a type of diapause called freeze susceptible. It avoids freezing in much the way that car owners do — by adding anti-freeze. This butterfly replaces the water in its body with antifreeze compounds — called cryoprotectants — which supercool its bodily fluids and tissues.

The other form of diapause, called freeze tolerant, is used infrequently by North American insects but is a common strategy of Southern Hemisphere insects. In this type of diapause, the insect freezes its bodily fluids.

Not all insects go into diapause in winter. A few, like the stonefly and mayfly, can be seen out and about in their adult form. The best time to look for stoneflies is after a snowfall — these small dark critters are much easier to spot in the snow.

The social insects take a middle-of-the-road approach to winter. They don’t enter diapause, like many butterflies, but they’re not bounding about, full of pep, like stoneflies. Social insects that live through winter in Delaware include honeybees, termites and a number of different ants.

Many of the social insects, including ants, consolidate their living quarters during the winter, says Deborah Delaney, an assistant professor in the Department of Entomology and Wildlife Ecology in UD’s College of Agriculture and Natural Resources. In late fall they move deeper into their nests and close up the exit with soil, leaves and other organic materials.

Honeybees slow down in winter and stick close to the hive. The focus is on eating and huddling close to each other on cold days, notes Delaney.

When the hive temperature drops below 64 degrees, honeybees cluster together into a carefully organized, compact ball. The interior bees generate warmth by vibrating their wing muscles. The outer bees are motionless, acting as an insulation layer. The colder the temperature outside, the tighter the cluster. A single bee can increase heat production 25-fold.

The honeybees take turns enjoying the warmth in the middle of the huddle and then move to the outside. Not surprisingly, the queen bee reigns supreme in the middle and never takes a turn on the outskirts of the huddle.

Despite huddling and other strategies, winter takes a toll on honeybees, says Delaney. Hives that may have had a peak of 60,000 bees in the summer may diminish to 20,000 bees by mid-winter. Some hives are totally lost, due to insufficient food or other factors.

Worker honeybees toiled long hours in the fall, collecting nectar to feed and maintain the colony until spring. If their work wasn’t adequate, there is nothing they — or Delaney — can do about it now, in the depths of winter.

Nonetheless, Delaney checks on the hives at UD’s Apiary about two to three times a week this time of year. “I hold my ear to each hive and if I hear buzzing inside, I know everything is good,” she says.

“The hives are kind of like my fourth child,” admits Delaney, who is the mother of three small children.

Article by Margo McDonough

This article can also be viewed online on UDaily by clicking here.

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Changing seasons provide varied birding opportunities

January 10, 2011 under CANR News, Cooperative Extension

One of the things that Derek Stoner likes most about living in Delaware is that every season brings new things to see and enjoy outdoors. Birding is a great example of nature’s diversity throughout the year.

“Birding in January, when owls are breeding, is a lot different than birding in July, when shorebirds flock to the Delaware Bay during their southward migration,” notes Stoner, the past president of the Delmarva Ornithological Society.

Here are some of the avian highlights that each season brings. How many of these birds will you spot in 2011?

Winter

As the New Year begins, the woods come alive with the calls of owls. Delaware’s most-common woodland owl, the great-horned owl, begins nesting now. Listen for its territorial hooting calls at night. The Eastern screech owl is also active and makes a trilling call. So how do you identify all those trills and hoots? Before heading out, Stoner suggests listening to owl calls at this website.

In February, take part in the Great Backyard Bird Count, a citizen science project throughout the U.S. and Canada. Last year’s count tallied more than 11 million birds of 602 species. Beyond the important scientific data that’s collected, the count generates excitement for birders, notes Chris Williams, UD assistant professor of wildlife ecology. Get involved by visiting this website.

Spring

In late April and the first half of May, birders flock to White Clay Creek State Park, where warblers, tanagers, orioles and other migrants are attracted to the large expanse of healthy woodlands. The best time to see lots of migrants, says Stoner, is after a night with steady winds from the south.

If you want to see red knots in the spring, there’s one place to go — Mispillion Harbor on the Delaware Bay, which attracts up to 90 percent of all the red knots in the world during this time period. Red knots fuels up on horseshoe crabs at the harbor. Check them out from the observation deck of the DuPont Nature Center. For a map and directions, visit the DuPont Nature Center website.

Summer

Summertime to Carrie Murphy means the return of the American goldfinch. This small finch is attracted to native perennials in her garden, including echinacea, black-eyed Susan and hardy ageratum. In its spring plumage, the brilliant yellow-and-black male looks like he belongs in a tropical rain forest instead of a Delaware backyard. Murphy, horticultural agent for New Castle County Cooperative Extension, says the goldfinch also likes annual sunflowers.

In July, look for blue grosbeaks, gorgeous blue birds with silvery bills. Doug Tallamy finds a pair nesting in his dogwood tree every July. “The male sings from May to September every morning for two hours,” says Tallamy, the chair of UD’s Department of Entomology and Applied Ecology.

Want to attract blue grosbeaks to your own yard? “Blue grosbeaks like to include snake skins in their nests, so if you hang a snake skin up on a fence, you’re more likely to get them,” notes Tallamy.

Late summer is prime time for migrating shorebirds all along the Delaware Bay. Visit the impoundments at Fowler Beach and Broadkill Road of Prime Hook National Wildlife Refuge to see black-necked stilts, black-bellied plovers and many varieties of sandpipers.

Fall

“I like watching hawks fly out of trees to kill unsuspecting rodents during the fall,” says Brian Kunkel, an entomologist with UD Cooperative Extension. If the thought of watching hawks feasting on rodents makes you lose your lunch, just keep your eyes skyward. The northern tip of Delaware is the place to see hundreds of migrating broad-winged hawks on their way to South America. Check out the Ashland Hawk Watch page.

In November thousands of ducks, geese and swans funnel into the First State to take advantage of the abundant food and resting places. Places like Thousand Acre Marsh, Woodland Beach Wildlife Area and Silver Lake in Rehoboth offer great viewing.

Wrap up the year by taking part in the Christmas Bird Count, the world’s longest-running biological survey. Seven Christmas Bird Counts take place in Delaware. Learn more at the Delmarva Ornithological Society website.

Article by Margo McDonough

This article can also be viewed online on UDaily by clicking here.

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Fireflies light up the summer sky

July 7, 2010 under CANR News

Fireflies may not light up the sky as bright as Fourth of July displays but this season they’re putting on quite a show.

“This is a fantastic year for fireflies, probably because we got so much rain last summer,” says Doug Tallamy, chairperson of the Department of Entomology and Wildlife Ecology at the University of Delaware. “As larvae, fireflies like moist leaf litter and things stayed moist last year.”

“Nature’s fireworks” continue long after July 4th — fireflies are at their peak now and stick around Delaware until the end of July.

Although most of us call them fireflies or lightning bugs, these luminescent creatures are more properly known as Lampyridae, which in Latin means “shining fire.” And they are actually beetles, not flies, says Brian Kunkel, an entomologist with UD Cooperative Extension.

Summer out West certainly has its pleasures, such as less humidity in most places than here in the Mid-Atlantic. But one thing you can’t enjoy in Beverly Hills or Boise is fireflies.

“Fireflies aren’t found west of the Rockies,” says Kunkel.

There are several species of fireflies native to Delaware. The beach region of Sussex County is home to the coastal firefly, which prefers sandy, even salty, soil and generally stays close to the ground. Inland Sussex and Kent counties are home to yet another species. But the greatest diversity in firefly species is found north of the Chesapeake and Delaware Canal, says Kunkel.

“Fireflies are especially abundant in the piedmont region, in the northernmost part of Delaware,” he says. “Most firefly species favor ‘old field habitat.’ In New Castle County, that type of habitat is most commonly found around the White Clay and Red Clay creeks and along the Brandywine River.”

At first glance, one species of firefly may not look much different from another. But pay close attention to fireflies as they begin to light up. “If you look closely, you’ll start to notice some distinct variations,” says Kunkel.

There are three characteristics that differentiate firefly species:

  • Where the fireflies are located. Some species like to be very close to the ground; others prefer shrubs and low trees.
  • The flight track, or style of flying, varies from species to species. Some fly in a “J” pattern then swoop down low, others take looping flights.
  • The pattern of the bug’s flashing. Think of the flashes like Morse Code — do they resemble a dash-dash-dash pattern or dash-dot-dash?

As for why fireflies light up, it’s for the same reason that tight clothing and flashy jewelry are a staple at nightclubs — to attract the opposite sex. Adult fireflies, both male and female, flash coded messages to attract prospective mates. Males fly about while they flash, females usually flash while hanging out in bushes. It’s all about “speed dating” not lengthy courtships — there’s no time to waste since adulthood lasts just two weeks.

There’s also another reason why fireflies light up, at least in the case of juvenile larvae. Almost a decade ago, UD scientists led by Tallamy discovered that baby fireflies light up to keep predators at bay.

Previous studies had shown that mice and other would-be predators shun adult fireflies because of a compound in fireflies’ body that produced a bitter taste. The UD study demonstrated that baby fireflies flash to advertise that they also exhibit this bitter taste.

“A flashing neon sign may lure hungry humans to an all-night diner but the bioluminescence of firefly larvae sends a very different message to would-be predators,” says Tallamy.

If your kids like to catch fireflies and put them in a jar, go for it, says Kunkel, as long as you punch some holes in the lid and release the fireflies after a few hours. Fireflies are beneficial insects because they may feed on insect pests in the garden so it’s important not to harm them.

Article by Margo McDonough

You can also see this article and accompanying photo on UDaily by clicking here.

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