by Regina Cutter Edwards
As the days get shorter and the temperatures cooler, what happens to all the beautiful butterflies? This is a common question in the mid to upper portions of the United States. The answer can be short and sweet; most are still there. But for the curious mind, that does not answer the important and exciting question of “where?”
Understanding the Butterfly Life Cycle
The critical component to understanding the answer to this popular question is understanding the butterfly’s life cycle. There are four stages; egg, larva (caterpillar), pupa (chrysalis), and adult. For more detailed information regarding the life stages, please read the ‘The Mysteries of Life’ article. Let us talk about the cold for those already familiar with the life cycle.
Butterflies are cold-blooded, which means they do not regulate their body temperature; they depend a lot on their environment. A butterfly can fly when temperatures are around 60-100°F, but their body temperature must be at least 85°F. This is the reason butterflies often bask in the sun, to increase their body temperatures. When temperatures begin to get cooler in the fall, butterflies have to find a safe place to overwinter. It is at this time they seem to disappear. So where do they go?
Do Butterflies Hibernate or Migrate?
Many butterflies, such as the Common Buckeye, Painted Lady, Red Admiral, and Cloudless Sulphur migrate each year to warmer locations. The Monarch butterfly completes the most popular and furthest migration of all the butterflies, reaching up to 2000 miles. These migrations are fascinating and not completely understood; please refer to the ‘A Rhythm in Nature’ article for more information.
What is Diapause in Butterflies?
Diapause is a form of hibernation in the insect world. It occurs when the juvenile hormone, which is triggered by light and/or temperature, decreases in the butterfly. The butterfly enters an inactive state, metabolism slows down, and feeding and reproductive behavior cease. This occurs on a predictable cycle and begins before the unfavorable environmental conditions, such as cold weather. The butterfly will come out of diapause when environmental conditions again become favorable. The Monarch butterfly, although it migrates, stays in a diapause state while in Mexico overwintering.
Where do Hibernating Butterflies go in the Winter?
In the adult stage of their life cycle, butterflies that do not migrate will stay in the same location throughout winter. They will find a small crack or crevice in a rock, tree, or building to squeeze into for protection from wind and predators. To prevent freezing, insects produce an anti-freeze compound in their bodies that prevents ice from forming in their hemolymph (insect blood). On a sunny day, if their body temperature gets warm enough, it is possible to see a butterfly in the middle of winter. The Mourning Cloak, Question Mark, and Comma are a few of the butterflies that will stick around during the winter months. Overwintering butterflies are usually angle-winged butterflies and are a dark color.
How do Butterfly Chrysalises Overwinter?
Many butterflies, such as swallowtails, some whites, and sulphurs overwinter in the pupa stage. They are usually the species that feed on woody host plants and the chrysalises have a silk harness that is attached in the middle of the chrysalis to the twig. This extra silk thread is for additional support from the winter winds. It is also not uncommon to find a chrysalis underneath leaf litter in the spring, so be careful when cleaning out the flower beds in the spring.
How do Butterfly Caterpillars Overwinter
Some butterflies can make it through winter while they are in the larval stage. The Viceroy butterfly, for example, will overwinter in a curled-up leaf of the host plant. The caterpillar enters diapause and the body functions slow down and the caterpillar ceases to eat until favorable environmental conditions return. The Baltimore Checkerspot is another butterfly that overwinters as a caterpillar; it hibernates at the base of plants in leaf litter.
What Happens to Butterfly Eggs in the Winter?
The Banded Hairstreak is one type of butterfly that overwinters as an egg. The eggs are laid on the leaves of their host plants (i.e. Hickory, Walnut, or Oak) and will hatch in the spring. The Poling’s Hairstreak is a butterfly that lays eggs singly on twigs and they overwinter. The Karner Blue butterfly is another butterfly that overwinters as an egg. There really are not many butterflies that go through winter as an egg but it does occur.
Life Cycle of Butterflies
The life cycle of butterflies is amazing, and butterflies have the ability to successfully survive winter in all stages of their life. In winter, when you are walking outside in the cold, think of the lovely butterflies hibernating nearby and are waiting for the warm weather. It will give you another wonderful reason to look forward to spring.
