So many insects, so little time.
Frost is coming (if it hasn’t hit between the time I write and the time its published) and with it, many insects will go. Some will be ready for the winter, having adaptations such as migration, dormancy, sheltering and even antifreeze proteins that will keep them alive until warmer times.
Others, ones that aren’t prepared to overwinter, will be toast when a hard frost hits. And I worry for those, some more than others. I won’t miss the mosquitoes, but am concerned for the monarch chrysalis that I observed during my outdoor shower (yep, still holding on to that pleasure) that was still green as of Tuesday, with a butterfly waiting to emerge.
Another recently observed late bloomer is an Eastern Tiger Swallowtail that I was surprised to see in the second week of October. The large yellow butterfly was high in a tree but still stood out. Sightings of these butterflies peak in July and August and decline quickly in September. October is unusual.
According to INaturalist, there were only 15 documented observations in October. Of those, two were on the Cape and none were reported on the Island.
The one I saw was likely on its last legs (or last wings). Late-season Eastern Tiger Swallowtails are often tailless due to wear and predators nipping at them. They also tend to be faded. Both were characteristics of the one I observed, yet the yellow and black striping were unmistakable.
While this specimen made its identity crystal clear, that pigment and pattern are not always typical. This tiger can change its stripes. The coloring of these butterflies is variable and depends on sex and location.
Males are yellow with those black tiger stripes, while females can have that yellow pattern or be black. The female’s dimorphism exists as an adaptation for protection. This butterfly is not toxic, but the black form resembles pipevine swallowtails, which are toxic. One is more likely to see the black version further south, where pipevine swallowtails are more plentiful.
And another interesting color quirk can occur because Eastern Swallowtails are gynandromorphic. Gynandromorphism is when one individual has both male and female characteristics observable — in this case, the coloring of both genders being exhibited by a single individual.
Another question that crossed my mind was whether this late-stayer might be a Canadian Swallowtail subspecies that was recently distinguished from the Eastern version. Unfortunately, they are difficult to differentiate; perhaps only those with the eye of the tiger might be able to spot the variations.
While I might be the last person to see and photograph this particular Swallowtail, which as adults live only about two weeks, an early rendering of this species was credited to colonial settler John White. In the 1580s, White and others tried to establish the Roanoke Island Colony in what is now North Carolina. The outpost didn’t make it, becoming known as the Lost Colony.
However, it was during one of White’s visits that he created watercolor paintings of the place, its Indigenous inhabitants, and some of the beautiful creatures he observed. The Eastern Tiger Swallowtail was one of those paintings, and it is recognized as the first image of a North American butterfly.
White’s painting and my photograph captured the iconic butterfly in its species’ unchanging beauty. There are variations, however, visible in individual specimens; and now there may be also deviations in its range, habitat, and time of year for flourishing. Let us hope our Vineyard population of Eastern Tiger Swallowtails continues to be more successful than White’s Lost Colony.
Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.