Where Do Insects Go During The Wintertime?

By Shiran Hershcovich, Lepidopterist Manager

Invertebrates have some of the most impressive and unique survival strategies in the entire animal kingdom, which have allowed them to colonize some of the harshest habitats on Earth. You can find invertebrates thriving anywhere from the depths of the ocean to the canopies of dense rainforests. And yes, you can even find them in the middle of winter! You just may have to look a little harder. Each year, snow blankets our Colorado backyards, and insects prepare for winter in a lot of different ways. In butterflies, you can find a whole range of impressive strategies for coping with cold temperatures and short daylength.  Colorado’s state insect is the Colorado hairstreak butterfly (Hypaurotis crysalus). Before winter hits, adults will lay eggs on twigs of their host plant, the Gambel oak (Quercus gambelii). The butterflies will spend the cold months as eggs. In the spring, caterpillars will hatch from eggs and feed on oak leaves to fuel their growth and metamorphosis into the iconic metallic blue butterflies we love to see. Colorado swallowtails, like the spectacular two-tailed swallowtail (Papilio multicaudata) will spend the winter inside their chrysalis. Once warmer temperatures arrive, they will emerge as butterflies ready to forage for nectar in flowers and lay their eggs in the leaves and flowers of their host plants, which include cherries (Prunus sp.) and ashes (Fraxinus sp.). Black swallowtails (Papilio polyxenes) will rely on dill and other members of the carrot family (Apiaceae) as their hosts. Some butterflies can even overwinter as adults! The mourning cloak butterfly (Nymphalis antiopa) will find warm nooks and crannies to spend their winter in, like bark or leaf litter. On warmer winter days, they may even fly about! If you spot a medium-sized dark butterfly on a February day, there’s a good chance you’re looking at a mourning cloak!  One of the most impressive winter adaptations goes to the North American monarch (Danaus plexippus plexippus). To cope with the changing of seasons, they will undertake one of the most incredible migrations known to life. Each winter, monarchs will travel up to 3,000 miles from their summer range in the US and Canada to their winter homes in Mexico and California. In the spring, they will begin a journey north, and subsequent generations will reach the grounds their grandparents and great grandparents once foraged on. Did you know that Colorado is also home to native fireflies? Despite being often associated with warm and humid climates, select riparian habitats along Colorado house these bright beetles! As adults, they will only fly for around two weeks in the summer. Scientists presume they spend the winter burrowed underground in their larval stage, where temperatures are warmer and more stable than above ground. Butterfly Pavilion researchers are working on deciphering the Colorado native fireflies’ life cycle mysteries. There is still much to be known about our local microfauna! 

You can support native invertebrates this winter by supporting the habitats that give them a safe and warm home. 

• Leave the leaves! This winter, leave the fallen leaves from fall on the ground. Many invertebrates rely on leaf litter as cover from the elements. This includes a variety of butterflies and moths (like the incredible luna moth, Actias luna), spiders, millipedes, spiders, bumblebees, and more! 
• Protect your gardens from pesticides. Pesticides can harm beneficial insects and drastically reduce their numbers. One of the biggest ways you can help your local critters thrive is by avoiding pesticides in your backyard spaces. 
• Take a lazy approach with your gardening. Avoid excessive pruning or branch removal. Leave fallen logs and stumps in your backyard. These are valuable spaces for native insects in the winter. 
• Plant native! If spring feels far away, get excited about flower season by planning your garden early! Look to include a variety of native flowers that provide nectar for pollinators, and host plants for butterflies. Look for pesticide-free native seeds in your local nurseries and plant providers. 
• Join a community science program! Get curious about your resident invertebrates and volunteer with a local community science initiative for a fun, impactful, and hands-on way to recreate outdoors.  
• Learn more about invertebrates by visiting Butterfly Pavilion 

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