Are butterflies barometer of environment change?


By Paul Mayne
Thursday, June 19, 2008
PORT ROWAN, Ont. -- With a cool breeze coming off Lake Erie, Caroline Williams and Daria Koscinski are strolling through fields of flowers near Long Point.
Caroline Williams, left and Daria Koscinski prepare to check an Eastern Tiger swallowtail they have just caught. The biologists are capturing butterflies as part of their ongoing research.
While it sounds like the perfect day away from the office, the biologists are actually on the hunt – for butterflies. For more photos of the butterfly wrangling, click here
Williams, a PhD student, is looking for female swallowtails (Eastern Tiger, Spice Bush, Giant or Black) for her work on the effects of warming winters on the insect’s energy use over the winter. She’s looking at species at their northern range limit or the middle of their range.
She’ll bring the butterflies back to Western, where they’ll lay eggs and will be exposed to different wintering temperatures to measure lipid and carbohydrate stores.
“My hypothesis is that warmer winters will have a negative effect, for example less energy stores left, which means less energy to turn into a butterfly due to the raised metabolic rate and ectotherm experiences at warmer temperatures.”
Williams will use different species and locations to make comparisons, with the west coast of Vancouver Island as the northern range and Oregon as the middle of the range.
Koscinski, a post-doctoral fellow, is looking at population genetics for the swallowtails.
“I want to see if the various habitats have affected their movement,” she says. “Why is the population strong here, but a few kilometres away it’s not?”
Koscinski gets a DNA sample from the butterflies through a small wing sample - which does not harm the butterfly – before releasing it. For a true test sample, she expects to have to wrangle a few hundred butterflies. Williams wants 40 female butterflies for her work.
The pair will return to the Long Point area and venture to Skunk’s Misery near Bothwell, Ont. for samples.
After day one of what will become a daily summer endeavour for the pair and their volunteers, Williams returned home with just one female. But she’s quick to put things in perspective.
“I’m out with a net catching butterflies; it’s never a bad day.”
Want to help capture butterflies? Volunteers can contact Caroline Williams at

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