Butterflies are funny creatures. They seem so fragile and ethereal, yet they are quite durable and adaptable. In grade school we learn of their life cycle: Egg, larva (caterpillar), pupa (chrysalis), and adult that starts it all over again with egg laying. Here in the Northeast, most of our butterflies overwinter in the chrysalis stage, often protected by camouflage attached to a stick or stem or buried amid the leaves on the ground. They emerge as spring warms up, and they “know” there is an ample supply of flowers ready to supply the nectar they need for sustenance. By the time they are ready to lay eggs, there is also plenty of herbaceous material, leaves and grasses of specific types, available for their caterpillars to feast on and grow.
We have one outstanding exception, another FIRST - Butterfly of Spring: The Mourning Cloak. It is a good sized butterfly, with a deep mahogany color on its wings, which are edged with a band of creamy yellow. It is not hard to identify, there are no others like it.
Take a walk in the woods on a warm spring afternoon, and you may be surprised to see something take flight, then quickly disappear. Look again and you may spot it take off, flitting quickly in the sunlight before coming to rest on a tree trunk or on the ground. These butterflies overwintered as adults. They hibernated in cracks and crevices, in tree holes and even rocky outcrops. They are roused by the warmth of these early spring days, fly about, but will go dormant again if the weather turns back to cold for a spell. This has already happened several times this year. But what do they survive on? There are no flowers out so early in the spring, and surely none in the woods. The answer is in the trees themselves. The butterflies rely on tree sap instead of nectar. After all the wind and storms this winter, there are abundant broken twigs. The warm days bring sap flowing upward into the trees, the same conditions that those who tap Sugar Maples for their syrup look forward to, and when the sap hits a break in a stem, it begins to drip. The sweet sap is perfect food for the butterfly. By mid-April temperatures are more consistent, and the butterflies remain more active. By May and June, their host food plants, willows, including pussy willows, have leafed out. When the butterflies lay their eggs on the host plant, the caterpillars emerge and are voracious! Many eggs are deposited on the same plant, and a large hatch can really chew a lot of leaves. The caterpillars are black with red spots and black spikes. They will go through their metamorphosis during the summer, and by later summer and fall, the newly emerged adults reappear on the scene to gather nutrition prior to their winter hibernation. And so the cycle continues.
Photo used under creative commons from wanderingnome
The First Mourning Cloaks were out a few weeks ago. We saw one today, 4/2, on the Peck Preserve in Stonington. Look for them as you walk the wooded trails in the warm spring sunlight.
An added Bonus: I know first-hand that the Monarchs have arrived in South Florida. We still have many weeks to go before the first ones are spotted here in CT. Spring is making its way up the coast.
Written by Beth Sullivan.
To learn more about the mourning cloak visit Butterflies and Moths of North America.