Low Butterfly Population

Worries Some Observers

By Nancy K. Crevier

They are as colorful as the flowers they rely on for nectar and their descriptors — brush foot, skippers, dusky wings, gossamer wings — are as delicate as butterflies themselves. And as sure as dandelions will dot the lawn, the appearance of the butterfly each spring is a given.

Vicki Maresca is concerned about butterflies, though — or rather, the lack of butterflies. The Newtown resident has made a concerted effort over the years to develop her property to attract wildlife, including planting plenty of coneflower, bee balm, black-eyed Susans, and butterfly bush that generally appeal to a wide variety of butterflies.

“This year we have not seen any butterflies,” said Ms Maresca. “The butterfly bush, especially, is usually a magnet for them, a tonic, but so far this year, the butterflies are not coming.”

Ms Maresca has not made any changes to her gardening techniques, she said, and she does not use pesticides or fungicides that might hurt butterflies. She does not even apply deer repellant to the plants. She is mystified as to why the butterfly show that she and her husband enjoy viewing every summer has failed to materialize.

The rainy weather in June appears to be a key factor affecting the butterfly population, said David Wagner, professor of ecology and evolutionary biology, and co-director of the Center for Conservation and Biodiversity at the University of Connecticut. According to an early July butterfly count in Salisbury, said Dr Wagner, “numbers are down by about 50 percent.”

In a message that Dr Wagner provided to those who assisted him with that count, he noted: “This will be the lowest total for numbers of individuals, relative to numbers of counters, that we have seen in a good while.”

A total of 46 species were identified that day, said Dr Wagner, including just one metalmark butterfly and one columbine skipper, both of which are species that appear to be rapidly disappearing from the Connecticut landscape. He also noted that swallowtails, hairstreaks, and skippers were counted in numbers below normal across the state.

Connecticut Department of Environmental Protection wildlife technician Laura Saucier said the DEP has noticed that things seem to be a little late this year, where butterflies are concerned.

“The ‘first of years’ — the documentation of the first time a species appears each spring — are later this year,” said Ms Saucier. Butterflies are very much tied into the weather and vegetation growth, said Ms Saucier, and while the Eastern comma, the mourning cloak, and the Compton tortoiseshell butterflies overwinter in Connecticut, hibernating in holes in trees, the majority of butterflies follow a pattern of caterpillars that emerge in the spring, morph into butterflies, and die at the end of the warm season. The cold, rainy weather this spring did delay the emergence of the caterpillars.

An emergence delay of even a week can affect the population, said Ms Saucier. Vegetation that the caterpillars feed on could be past its prime, or like many plants this year, also underdeveloped, and in just one week, more and different predators could be on the scene, devouring a greater number of caterpillars before they have the chance to change into butterflies.

Butterfly watchers should not be overly concerned at this point, though, she believes.

“We are not too worried this year. The delayed emergence could mean we may have some species hanging around longer this summer, even into September. The low numbers could be just a blip on the radar,” she said. “It is next year’s count that will prove interesting,” said Ms Saucier. If this year’s decline appears to be random, there is nothing to worry about. A continued low count next year might indicate a problem, however.

Butterflies play an important place in the food web, said Ms Saucier, so a notable decline in population could adversely affect the birds and animals that rely on the winged creatures for sustenance.

“Butterfly larvae are huge sources of food for young birds, for example, and butterflies do add to the pollination service of plants,” Ms Saucier said. “There is a symbiotic relationship with the environment. There are so many relationships in nature that we do not yet understand,” she added.

Victor DeMasi of Redding, a member of the National American Butterfly Association (NABA), is also not unduly concerned with the decreased population of butterflies so far this summer. “Things change from year to year. You can’t make any long range predictions based on one bad year,” said Mr DeMasi.

As he has for many years, Mr DeMasi took part in the NABA national Fourth of July count this summer. He and about ten other counters visited the same open spaces and meadows in the Redding/Ridgefield area that they do every year.

“All of the normal varieties are around,” said Mr DeMasi, “just not in great numbers.”

Like Dr Wagner and Ms Saucier, he believes it is the unusually chilly and wet June weather that has delayed the emergence of butterflies in this area. Plentiful rain means in some instances that caterpillars have a lot of lush vegetation on which to feast when they do come out, or the vegetation can be adversely affected by the rain, succumbing to molds.

The reason the casual observer is not seeing so many butterflies is that the season is very late, he said. “It is at least two weeks behind.” As an example, Mr DeMasi said that the ringlet butterfly, normally abundant in early June, was not seen in great numbers until the end of June and early July this year.

“I wouldn’t worry, though,” said Mr DeMasi. He suggested that the late season and low numbers might mean that butterfly observers will have to be a bit more patient this summer, and accept that 2009 may just be a down year for the Lepidoptera order of insects.