Expert: Dry weather is hard on butterflies

A spicebush swallowtail feeds on a flower. Residents are seeing the second brood of spicebush swallowtails emerging now.

The lack of rainfall in the region earlier this summer could have a negative impact on butterflies, according to Jerry McWilliams, curator of the insect collection at the Tom Ridge Environmental Center Natural History Museum in Erie.

“Dry weather is never a good thing for many insects, especially butterflies and moths,” McWilliams said.

Extended periods of dry weather are especially hard on early stages of development. When it is dry, young new plant shoots are the first to dry up, he said.

McWilliams said butterfly and moth larvae depend on the young shoots for food.

“When the plant dies so does the larvae,” he said.

He also said when butterflies and moths pupate they depend upon rainfall to encourage them to emerge and spread their wings.

McWilliams said succulent plants are usually the first to dry up.

Succulents and newer plant growth are both used as host plants for insects in their early stages.

Rainy relief

Meanwhile, recent rains could provide a little relief for area plants and insects.

“It’s going to help out a quite a bit,” said Bob Coblentz a meteorologist with the National Weather Service in Pittsburgh.

But whether the drought watch for area counties will be lifted remains to be seen.

Coblentz said the Department of Environmental Protection is in charge of issuing those declarations, not the weather service.

When Coblentz compared this year’s rainfall numbers with last year’s through July, the two weather service reporting stations in Franklin and Tionesta both recorded a deficit.

But the numbers were pretty much on target when they were compared with the average rainfall for the region, Coblentz said.

Last year through July, 29.03 inches of rain was reported in Franklin compared to 24.42 inches this year for the same period. The average for Franklin is recorded as 25.13 inches.

Last year’s total through July for Tionesta was 30.27 inches compared with 25.78 inches so far this year. The average rainfall for this period for Tionesta is 25.74 inches.

Coblentz said the DEP will probably re-evaluate the situation after the recent rains.

While he said it does look like the area is right on track for rainfall, the state looks at other factors and criteria in determining drought declarations.

He said the region has the potential to receive two to four of inches from the recent damp weather.

The chance for rain will remain in the forecast through Monday, Coblentz said.

He said the region is sandwiched in between two systems and that will maintain the threat of showers.

Coblentz said the real story is the dew points. The region is seeing dew points in the 70s.

“Seventy degree dew points are pretty extreme for us,” he said. “That’s what they get in New Orleans or Houston.”

While the humidity is intolerable, it will help to bring some much needed rain, according to Coblentz.

“It’s gotta wring out somehow,” he said.

As for the longer term weather outlook, Coblentz said the pattern will remain warm.

The region will “still stay pretty warm. We will get breaks every once and a while,” he said.

How to help

While the rain may jump start some plant growth, area residents can help butterflies by cultivating various plants.

“It always a good idea to let at least a part of your property go back to nature with plantings of native plants, especially milkweeds, asters, wild bergamot, coneflower, and joe pye weed,” McWilliams said.

“If you already have these plants growing be sure to keep them watered during these dry spells,” McWilliams added. “Do not use pesticides or herbicides in areas designated for butterflies,” he said. “In my opinion they should not be used anywhere on your property.”

McWilliams also provided information on the types of butterflies that are out and about in the region right now.

He said the last brood of monarchs, the migrant population, is emerging now and will begin their long journey to Mexico as soon as they emerge.

In the past week, tiger, spicebush, black and giant swallowtails have emerged, and they are the second broods of the year, McWilliams said.

“Also emerging now are the anglewings, including red admirals,” he added. “As summer progresses southern species will begin to move northward making it a good time to look for southern strays like pipevine swallowtail, little yellow, cloudless sulphur, white M hairstreak, common buckeye, painted lady, fiery skipper and Ocola skipper.”