Do you ever wonder what happens to your favorite pollinators, like butterflies and bees, during winter? Once the temperature turns cold and the snow begins to fly, where do pollinating insects go? More importantly, what can gardeners do to help these beneficial insects survive in harsh climates?
Pollinators and Winter Survival
Chances are, you won't see pollinators out and about on cold winter days. Where they go and how they survive the cold tends to be species-specific. As a whole, pollinating invertebrates have adapted several methods for surviving harsh winter weather.
When we think of pollinators, we often think of honeybees. To survive the winter, these hive-dwellers cuddle together and vibrate their bodies to create heat. Along with a sufficient supply of honey, it takes a special generation of bees during winter months to sustain the hive. These winter bees have plumper bodies and live longer than those inhabiting the hive during the summer.
Bumblebees have a slightly different approach. The entire hive, except for the queen, dies off in the fall. The adult queen bees hibernate underground, often in rodent holes. They emerge In the spring and restart their colonies by laying eggs.
In contrast, many species of solitary native bees overwinter as pupae. Some of these bees hibernate underground or they pupate closer to the surface by burrowing into leaf litter. Others survive above ground by taking up residency in hollow stems or in holes created by wood-boring insects.
Butterfly Overwintering Methods
Like swallows, finches and orioles, some species of butterflies migrate to warmer climates in the winter. Most noted is the Monarch, which can travel 3000 miles to take up winter residency in Mexico.
Yet, not all migratory species of Lepidoptera travel south in the fall. Populations of the Painted Lady butterfly overwintering in warm climates migrate north in the spring, but northern populations die out in the fall rather than make the return journey.
The majority of butterfly and moth species don't migrate, but survive the winter by entering diapause. This period of suspended development is often referred to as butterfly hibernation. In this state, they can overwinter in one of the four life stages.
Which stage is dependent upon the species of butterfly or moth. For example, the Purplish Copper handles butterfly overwintering as an egg, while the Baltimore Checkerspot survives in caterpillar form. Luna moths and Swallowtail butterflies overwinter as chrysalises.
Often called the harbinger of spring, the Mourning Cloak butterfly survives the winter as an adult. They have adapted this butterfly overwintering technique by replacing the water in their bodies with an antifreeze-like compound. You may even see them out on sunny winter days, feeding on tree sap.
Protecting Butterflies, Moths and Bees During Winter
Pristine, leaf-free yards that homeowners love are the nemesis of overwintering pollinators. Cleaning up fallen leaves, pulling up dead annuals and pre-winter rototilling disturbs many of the places where pollinators overwinter.
Does this mean gardeners should leave their yards a mess until spring? Not necessarily, but consider leaving a few undisturbed areas to shelter butterflies, moths and bees during winter months. Here are a few ideas you can try:
- Gently gather fallen leaves and spread them 2-3 inches (5-7.6 cm.) high on garden beds.
- Keep up the curb appeal of your home by only cleaning the front and leaving the backyard undisturbed.
- Wait until spring to trim back perennial stems and remove dead annuals. They may even add winter interest to the garden.
- Refrain from disturbing bare soil in the fall. Instead, rototill in the late spring after the hibernating bees have emerged.
Are you concerned your neighbors might not appreciate your pollinator conservation efforts? Consider printing out a sign advising others of your intentions. Who knows? Maybe they will follow your lead!