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Swallowtail butterflies are having a banner year in Harford

If you feel like you've been surrounded by beautiful, winged insects everywhere you go in Harford County lately, you're not just seeing things.

Butterflies – specifically the large, showy kind – are everywhere this summer, whether they're zipping across the road, flitting by flowers or hanging around watering holes.

Warmer weather always means prime time for bugs of all kinds.

But butterfly enthusiasts agree some members of the Lepidoptera (the scientific order that includes butterflies and moths) have really been taking off this summer around the region.

Rick Cheicante usually counts about 100 swallowtails during his annual July butterfly count at Havre de Grace's Swan Harbor Farm.

This year, he counted 340.

"Swallowtails, in particular tiger swallowtails, have been off the charts," said Cheicante, a Bel Air resident who is the mid-Atlantic compiler for the North American Butterfly Association, as well as an active member of the Harford Bird Club.

Some might mistake the eastern tiger swallowtail, which is usually black-and-gold, for the well-known monarch butterfly. But monarchs have actually been dwindling around the country this year, for unknown reasons.

The swallowtail, meanwhile, has chosen 2013 to multiply like mad.

Cheicante said he has seen them in much larger numbers on flowers like Joe-Pye weed, a butterfly favorite.

"It's pretty impressive, really," Cheicante said.

Besides the yellow-colored swallowtails, there have been a lot of black tiger swallowtails, which are black with blue-and-yellow edges. They are both the same species, however.

The red-spotted purple butterfly, a dramatic black butterfly tipped with blue, has also been making its presence felt, Cheicante said.

Other Harford residents have noticed the upswing in large butterflies as well.

Lisa Fleming has several butterfly bushes at her Street home, and said she observed "in the past couple of weeks that they are inundated with the orange-and-black, and then [just] black, and yellow-and-black [butterflies]."

Fleming, who has had the bushes for 15 years, estimated the number of butterflies is about 50 percent higher than normal.

"They are pretty. I love butterflies, so I really took note when I noticed how many were there," she said.

Fleming noted that when she posted some butterfly pictures on Facebook, many of her friends agreed that butterflies have been on the rise.

"A lot of people have been saying that, to be honest with you," she said. "I don't know if that has to do with the weather, or the amount of rains we have had lately."

Maryland has about 150 species of butterflies, Cheicante said, and overall, their numbers are actually down.

It is only the "showier" butterflies that have made butterflies seem more prominent.

"Many of us are really saying that butterfly numbers on the whole look very low," Cheicante noted.

Michael Raupp, an entomology professor and extension specialist at University of Maryland, said he wrote a whole entry about swallowtails on his blog, BugoftheWeek.com, after hearing from a lot of people about the large numbers of butterflies they have been seeing this year.

"This has just been a spectacular year for plant growth, with all the rainfall," he said, adding he has never seen so many swallowtails at his Columbia home. "For whatever reason, these guys are just having a great year."

"It's not just the good guys, it's not just the swallowtails. This has been a pretty spectacular year for all kinds of Lepidoptera," Raupp said.

Tent caterpillars and the fall webworm, which build those bulky-looking web sacks on trees everywhere, are also blossoming, as are cankerworms, he said.

So why are all these bugs suddenly doing so well?

"That's the million-dollar question that not many people could probably give you an honest answer to," Cheicante said.

He said the last few years have been "tumultuous," climate-wise, but this year was one of the most "normal" springs and summers the region has seen in a while.

That could also contribute to the overall decrease in butterflies, swallowtails notwithstanding.

"We have actually had some long, cool rainy spring days. That makes it tough for butterflies to reproduce," he said.

The ups and downs of Lepidoptera numbers are always a mystery.

Raupp did not know exactly why some butterflies are doing so well, but said it is probably either because they have a better food supply or fewer predators. He was leaning toward the theory of a better food supply.

On his blog, he wrote: "Forces of nature that underlie upswings and downturns in populations of butterflies are not fully understood, but an abundance of high quality food for caterpillars, favorable temperatures for growth of larvae and foraging of adults, and a relative absence of natural enemies benefit butterflies."

Tiger swallowtail caterpillars are also "masters of disguise," Raupp wrote, with coloring that mimics bird droppings to get birds to pass them by.

Adult swallowtails also eat plants with repellent chemicals that give the butterfly a nasty flavor so predators learn to avoid them, Rapp wrote.

With the reason behind the butterflies' sudden fertility still being anybody's guess, the only real advice for Harford residents is: sit back, relax and enjoy the show.

And remember: it won't be long before the stink bugs are back in town.

"We think it's going to be a banner year for stink bugs," Raupp warned.

Copyright © 2014, The Baltimore Sun
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