This article was written by Elizabeth Poulson, Minneapolis Parks and Recreation Board Naturalist, North Mississippi Regional Park
During a typical Minnesota summer, insects are everywhere. It’s nearly impossible to walk outside and not see bees and butterflies floating from flower to flower, or mosquitoes and other bugs buzzing around endlessly, crickets chirping, grasshoppers hopping, and ants marching. As temperatures begin to drop and winter settles in, we no longer see insects all around us until the warmer weather returns. Many of us are familiar with the winter survival strategies of other animals – migration, hibernation, staying active – but what about insects? How do they manage to seemingly disappear and reappear in just a matter of months?
Interestingly, insects adopt similar strategies as humans and other animals in order to survive winter. In northern climates insects avoid the chill of winter altogether, which can be achieved in a few different ways. Honeybees keep warm by huddling together in their hives. They shiver to create collective body heat which then acts like a micro-radiator, warming the colony. Many insects seek out shelter for overwintering and then enter a hibernation-like state, with a lower metabolic rate known as diapause. Junebug larvae and Swallowtail butterfly pupae for example practice this survival strategy.
Another strategy that some insects, such as woolly bear caterpillars, use in conjunction with diapause is the production of an anti-freeze like substance that prevents ice crystals from forming inside their bodies. Woolly bears are often seen moving about in late September through October in search of places heavy with leaf litter, like our backyard garden beds, to hunker down – so be sure to keep some leaves on the ground for them. Along the same lines, some critters take this tactic to the next level by actually allowing their bodies to freeze. They are able to survive because their bodies utilize special proteins that regulate how their bodies freeze in order to protect them from cell damage.
Some insects will also wing it to a warmer place for the winter. Monarch butterflies are probably one of the most well-known insect migrants, traveling distances up to 3,000 miles in a single trip. Another Minnesota insect that migrates is the Common Green Darner dragonfly that makes the trip to the Gulf Coast in the fall and its offspring making the trip back north the following spring.
In Minnesota and other climates where freezing temperatures reign for a few months, up to half the year, one of the simplest strategies for many bugs is to exist only seasonally. In other words, many simply can’t survive the colder months. However, they have adapted and evolved to ensure that future generations proliferate. Often, they will lay their eggs and leave them behind in the ground for their offspring to emerge in the springtime. Crickets, grasshoppers and katydids are common backyard bugs that have adopted this strategy.
Other insects, such as hornets and wasps, live in what are known as annual colonies. Queens that have overwintered emerge in the spring, begin constructing a nest and then laying eggs. They raise several workers while continuing to lay eggs. In time, the workers take over the care of larvae while the queen keeps laying eggs. Over the course of the summer, new queens and males are produced and the colony eventually begins to decline as the founding queen lays fewer eggs. New queens mate before flying off to seek out a suitable place to overwinter. The nest itself stays active until cold temperatures ultimately kill off the workers and males that are left. In Minnesota, paper wasp and hornet nests are unable to survive the subzero weather, even indoors, as there are no food sources for them to take advantage of. Nests are used for only one season and will remain vacant for the next season.
Visit the Kroening Interpretive Center to see a hornet’s nest up close, meet the giant millipede or hold a hissing cockroach. Learn more about the winter survival strategies of Minnesotan critters and test your own at our Winter Survival Challenge program on Saturday, January 25 from 1:30-3:30 p.m. Be sure to check out a pair of snowshoes for free from the front desk each weekend, Saturdays 11 a.m.-3 p.m. and Sundays 1-3 p.m.
Public programs in January – Free for all ages unless noted otherwise
Saturday, Jan. 4 – Bird Watching: Winter Woodpeckers, 3-4:30 p.m.
Thursday, Jan. 9 – Homeschool: Northern Life, 1-3 p.m. $5, ages 5-13.
Friday, Jan. 10 – Snowshoeing: Full Moon Hike, 6:30-7:30 p.m. $3, ages 8+.
Saturday, Jan. 11 – Nature Art: Candle Making, 2-3 p.m., $5.
Sunday, Jan. 12 – Nature Tots: Slithering Snakes, 3-4 p.m. $ 5, ages 2-6.
Tuesday, Jan. 14 & 28 – Phenology Hike Club, 4-5 p.m., ages 16+.
Friday, Jan. 17 – School Release Day: Winter Fun & Games, 8 a.m.-4 p.m. $25, ages 6-12.
Sunday, Jan. 19 – Family Funday: Winter Arts & Animals, 1-3 p.m.
Thursday, Jan. 23 – Campfire Mingle, 6-8 p.m. $5, ages 18+.
Saturday, Jan. 25 – Winter Survival Challenge, 1:30-3:30 p.m., $5.
Sunday, Jan. 26 – Nature Tots: Under the Ice, 3-4 p.m. $5, ages 2-6.
Sunday, Jan. 26 – Nature Book Club, 4:30-6 p.m. $2, ages 18+.
Find registration for these programs and more at minneapolisparks.org or call 612-370-4844 for details. Do you have a question about nature in your own backyard? Then send it our way by emailing northmississippi@minneapolisparks.org and it could appear in a future article. Like us on Facebook to stay in the loop about what is happening at your park.