HOW WARM WINTER WEATHER AFFECTS INSECT POPULATIONS

A question that may be on many people’s minds is if the warm winter weather will increase insect populations in the spring. This also applies in other years with how extremely cold winters may affect insects the following spring and summer. The answer to both scenarios may surprise you as winter weather actually has little influence on insect populations for the following spring, but this does not mean it does not play a role completely. Many assume a warmer winter would spike insect populations, but if anything, the warmer winters and extremely cold winters alike will both produce lower insect populations at the beginning of spring.

The reason winter weather has little influence over future insect populations is that insects have developed excellent strategies to survive. Insects are grouped into two categories — freeze tolerant and freeze avoiding.

Freeze avoiding insects don’t hang around or expose themselves to cold conditions. Basically, this group of insects either seek shelter from the cold or migrate. A common example of this group that seek shelter are Japanese beetles who burrow into the ground and an example that migrate is the monarch butterfly. Freeze tolerant insects are able to withstand freezing temperatures. Basically, this group of insects are able to produce compounds in their bodies prior to winter that are similar to the antifreeze we put in cars. These compounds will prevent them from freezing solid and ultimately it is not the cold that affects them, but rather it’s the freezing and thawing process that may cause insect death.

With that said, the best predictor of insect survival is more so the weather condition during which insects emerge. When they emerge from the winter, they need energy (i.e. food). As the weather may delay crop planting, this may directly prevent some insects from the food source they need which would then cause the first generation of the season to be greatly reduced. Then, insect populations which rely on these insects for their food will also be limited on their food supply which will affect their population as well.

It is not so much a matter of if insects can survive but rather how many insects will survive. Ultimately, it is a chain reaction when it comes to most insect population survival which reveals insects role in the interconnected web we call the ecosystem. While we cannot look at just one single parameter to predict how this interconnected system will respond to changes, our current warm winter weather will not affect the upcoming spring and summer insect populations much.

You may be wondering now what weather conditions are likely to cause the greatest decrease in insect populations across the midwest since there is still a possibility there is some influence. With the consideration of the current weather across Indiana and Kentucky, insect populations could be lower early on in the spring but overtime will return to normal by the time the summer months hit. As mentioned, both extreme cold temperatures through the winter as well as above average temperatures may play a role in a decrease of insect populations rather than what most people would expect to be increase. The weather reasons as to why include:

• Wet weather, particularly wet but not frozen soils with lack of snow or ice cover, will cause the greatest or at least the most common decrease in survival of overwintering insects in Indiana and Kentucky*
• Extreme cold temperatures that are not moderated by snow or ice cover increases insect mortality but is a rather rare event
• Repeated wide swings in temperature, alternating warm and cold during the traditionally cold months (e.g. December – March)*
• A long, warm period late in the traditionally cold season followed by a quick return to very cold conditions

*Common weather occurrence as of recently in 2017

Don’t forget that year-round pest control is the best method of prevention in your home and business with the winter treatments often being the most important! To keep yourself protected from pests, consider Black Diamond’s Exterior Service Program (ESP) and the No Problem Plan for year-round protection.