Our last post on saving the birds got me thinking, how do all those butterflies and other pollinators live through the winter? In some very interesting ways, I discovered!
As we now know, birds feed their young primarily caterpillars and other insects in the spring. But insects are also critical food sources for many other animals, and if they disappear, those animals will starve and our food web will collapse.
So where do insects live in the winter months?
Some migrate south like monarchs and dragonflies, but most hunker down right here in our yards and neighborhoods. Crickets and grasshoppers telescope their abdomens deep into cracks in the soil and lay their eggs a few inches deep. These eggs stay safely underground to wait for spring to hatch. Some katydids glue rows of eggs to the underside of branches of their favorite plants, or host plants, like viburnum and dogwood. Others use sharp sword-like ovipositors to cut the stems of plants like goldenrod and aster and lay their eggs safely inside. Praying mantids enclose their eggs in a coating that looks like styrofoam and glue them to dead meadow stalks or tree trunks (similar to the invasive spongy moth egg masses we collected last winter).
Adult luna moth photo by Amy Funkhouser
Most butterflies and moths spend the winter as chrysalids – the pupa of an adult enclosed within a cocoon – which are hung upside down from stems or branches in trees. Our vivid green luna moth spins papery brown cocoons that fall into the leaf litter. There in the fallen leaves, the luna moth pupa remains and grows to its beautiful adult form. Fritillaries, those orange butterflies that look like small monarchs, overwinter as larvae in the leaf litter near their host plant, violets, and then emerge in the early spring when the violets are beginning to bloom.
Native mining bee Andrena dunningi photo by Heather Holm
Many bee species build nests a few inches under the soil surface and hibernate there as eggs, larvae and adults near the plants they forage in the spring, summer, and fall. Others build chambers in cut plant stems and overwinter there. There are also many insects that tough it out as adults hiding in the moist damp leaf litter of the forest floor – or our gardens and under our trees where we’ve left the leaves.
How do they survive the cold?
According to Doug Tallamy, Chair of Entomology at the University of Delaware, insects can survive freezing temperatures either as eggs, larvae, pupae, or adults because they produce an antifreeze (glycerol), in their bodies. The glycerol keeps the water in their tissue cells from freezing, expanding, and tearing their cell walls, as long as they can find the stems, open ground, tree branches, or leaf litter they need.
How can we help?
Luna moth chrysalis
Helping our pollinators and other insects in the warmer months is easy – grow a variety of native flowering plants for them to eat and refrain from using pesticides. But what about during the cold of winter? These small creatures have developed many ways to survive our harsh winters. We can help them by understanding how they do this and creating or protecting the habitat they need. After all, our survival depends on theirs!
Read more about insects in winter from Doug Tallamy http://www.hgcny.org/docs/Tallamy%20Insects%20in%20Winter.pdf
Learn how to create nesting sites for bees from Heather Holm https://u.osu.edu/dist/1/117433/files/2022/10/heather-holm-StemNestingBees-copy.pdf
If you are fascinated by the luna moth like I am, read more about them here https://hgic.clemson.edu/factsheet/luna-moth/
