Will Our Warm Winter Bring More Spring Insects?

I know what you’re thinking. Will the unseasonably warm winter and early spring temperatures in the Northeast affect the bug* activity on your property this spring?

The answer: It depends.

Some insects that over-winter above ground might have fared easier in the mild temperatures. However, the absence of snow cover on the ground for most of this winter also left those critters fully exposed to the frigid temperatures on those “gotcha” days. The fluctuations between freezing and thawing temperatures can kill them.

For bugs that over-winter below ground, the mild temperatures did not greatly affect them, since the soil temperatures are fairly stable regardless of what’s happening above.

But all insects react to ambient temperatures. In the fall, they slowly acclimate to the increasing cold temperatures, and then stay dormant until spring. But some of those mild winter days may have fooled them into emerging early to start reproducing. They need food to stay active, though, and a scarcity of food supply in winter will cause some of them to starve to death before they can access spring’s bounty.

The impact of the warm winter will likely impact on how early we notice insects and pests on our properties, rather than how many we will see overall. The early warm days may give insect populations a head-start on their reproductive cycles. As a result, we could see higher populations of pests earlier in the summer rather than later in the summer. But we should keep in mind that the same climate factors that impact the “bad” bugs will also impact the “good” ones. For instance, the conditions that cause an early proliferation of harmful pests like aphids and caterpillars will also foster the bugs that eat them, like the green lacewing.

Mother Nature is a master at checks and balances.

*(Apologies to our entomologist colleagues: we’re using “bugs” as a convenient catch-all for insects, spiders, beetles – the whole swath of flyers and crawlers.)


Erin Hodgson and Laura Jesse, “What Does This Warm Winter Mean for Insects?,” Iowa State University Extension and Outreach, Department of Entomology and, Plant and Insect Diagnostic Clinic, February 17, 2012, accessed April 4, 2017,  http://crops.extension.iastate.edu/cropnews/2012/02/what-does-warm-winter-mean-insects

Andrea Mustain, “A Mild Winter’s Surprising Downsides,” LiveScience, February 7, 2012, accessed April 4, 2017, http://www.livescience.com/18351-mild-winter-surprising-downsides-warm-weather.html

Jaime Pinero, “What Does This Warm Winter Mean for Insects?,” Integrated Pest Management, University of Missouri and Lincoln University, March 1, 2012, accessed April 4, 2017https://ipm.missouri.edu/MPG/2012/3/What-Does-This-Warm-Winter-Mean-for-Insects/