New Brunswick is home to an estimated 25,000 insect species, adding complexity to how cold winters affect their populations.
Steve Heard, a biology professor at the University of New Brunswick (UNB), explained the impact of winter weather varies widely depending on the species and its overwintering strategy
Different weather conditions affect insect populations in distinct ways. For instance, Heard noted that mosquito populations are heavily influenced by spring weather.
“A wet spring can lead to an increase in mosquitoes due to more standing water, which provides breeding grounds for their larvae,” Heard said
He explained that this summer’s insect populations will likely depend on spring weather conditions, which influence the presence of mosquitoes and other species.
The biology professor at UNB highlighted the challenges invasive species bring to local ecosystems.
The Hemlock Woolly Adelgid, a pest of hemlock trees, can be knocked back by harsh winters. However, the Emerald Ash Borer, which targets ash trees, requires temperatures as cold as minus 30 to 35 degrees Celsius to see a population decline.
“Despite feeling cold, the recent winter was not cold enough to impact these pests,” Heard said.
Climate change introduces additional complexity to predicting insect dynamics, according to Heard.
He stated that some insects, like Monarch butterflies, avoid cold winters by migrating south.
Others have developed various overwintering strategies to survive harsh conditions. These adaptations influence how different insect species respond to changing temperatures.
“Insects play crucial roles in the ecosystem, from pollinating flowers and crops to serving as food for birds, bats, and fish,” Heard said.
“Changes in insect populations can have cascading effects on these ecosystems.”
Heard provided an example of how warming temperatures in streams are shifting the makeup of freshwater insect communities in ways that may not be great for salmon.
He also noted that early-season wild bees may emerge later if spring thaws are delayed, impacting pollination.
Predicting the impact of climate change on insect populations remains challenging.
Heard explained researchers, including himself, are working to understand these complex interactions, but much remains uncertain.
