By Catie Resor
Board Member, Middlesex Land Trust
You’ve probably had the experience of walking along a trail in the fall and finding a little wooly bear caterpillar trundling along underfoot. When I start finding them out and about on a warm fall day, I usually pick them up and transport them off the trail so as to not get stepped on. Whether this is effective or not, I really don’t know, but it makes me feel useful. They march along with such purpose, but it’s hard for us to know where exactly they are headed. In the past, I have taken for granted that they appear in the fall, only to make themselves scarce the rest of the year. Where do they go?
With the cool nights and beautiful sunny days of fall, you might notice a number of different insects doing their “fall” things. Orb weaver spiders seem to suddenly become more ubiquitous in early fall: they seem to be larger, more abundant, and certainly more noticeable when the morning river fog clings to their webs. The bees in my garden rest for the night on the few blossoms remaining, as if they ran out of steam mid-forage the night before and the cool mornings are just not warm enough to get them going again. The crickets are still a constant background chorus, more noticeable on the calm, warm fall days as the birds get quieter. They’ll keep going until they abruptly stop around the first hard frost.
I mention these quintessentially fall activities of insects because with winter coming soon, I’ve realized how little I actually know about what’s next for these insects. The extent of my spider life cycle knowledge was informed by Charlotte’s Web. A quick google search confirms that indeed most species of orb weavers don’t survive the winter, but they leave their eggs behind to hatch in the spring.
And what about the wooly bear? Is there any truth to the folklore correlating the width of their black band to the severity of the winter? No. But apparently, the wider the band, the older the caterpillar and the better its growing season and summer resources have been. The conspicuous movement of the wooly bears every fall corresponds to when they leave the plants they have been feeding on and begin to look for a suitable spot to overwinter, under bark or a downed log. Remarkably, their “perfect” spot doesn’t prevent them from freezing. However, they produce an antifreeze agent that controls and slows the freezing process so they can literally freeze nearly solid. Some survive temperatures as low as -90F. There is even an arctic variety of wooly bear that can survive in a climate with a warm season of only a few weeks. Within a couple of weeks of emerging in the spring, the wooly bears will pupate into an isabella tiger moth, and the cycle continues.
As for the sleeping bees? For many years, my understanding was that bumble bees are solitary creatures – but I was wrong. Most bumble bees have small colonies with division of labor similar to honeybees. Unlike honeybees, however, only the queen survives the winter, hibernating alone, below ground, perhaps under a rotten log or a bed of moss. She starts a new hive from scratch the next summer! So the bees I often see, who look so cold and sluggish each morning, indeed are unlikely to live to spring, although their genes may.
What does this have to do with Middlesex Land Trust, you might wonder. We are surrounded by innumerable life cycles and goings-on that many of us know very little about. We notice the wooly bears or the orb weavers or the bumble bees when they are conspicuous, but we forget about them when they are not. An intact ecosystem requires pollinators and insects to support decomposition, plant life, and animal life. Indeed, bird reproduction here in Connecticut is made possible by the quantity of insects that adult birds have available to feed their young. Insects require food and shelter at all stages of their life cycle and during all times of year. They require appropriate places to overwinter, whether that is a fallen log or a deep layer of leaves, and they require protection from pesticides. In short, they require intact natural spaces. You might think butterflies just need flowers but learn a bit more and you will realize that a beautiful spicebush swallowtail needs the native spicebush that grows in the swamps. Those wooly bears? They are generalists as larvae, but they still thrive on native plants like violets, nettles, maples, and birch trees. To protect biodiversity and the very backbone of our food web, we need native vegetation and natural spaces – spaces that Middlesex Land Trust seeks out and preserves.