More than 2,000 species of moths are also enjoying the favourable weather conditions in Calgary this summer causing an influx of the furry little pollinators, just in time for National Moth Week starting July 20, 2024.

It appears the heavier rains early on this year, mixed with the sunshine and heat have been the ideal conditions for the fluttering critters to flourish. The numbers have Calgarians noticing.

“I’ve lived in Calgary my whole life and I’ve never seen anything like it, I went camping and there were so many massive moths,” says 25-year-old Calgarian Haley Jackson. 

According to Dr. Jackie Lebenzon, an insect physiologist at the University of Calgary, the reason we might be seeing so many moths is because of the weather. Warmer winters, increased precipitation and hot summers are a recipe for vegetation, which is especially important to moths during the caterpillar phase. 

“If there’s lots of precipitation and lots of rain, it means there’s more food for the caterpillars that will eventually become moths, so there could be a boom in the population just because we’ve had such a wet year,” said Dr. Lebenzon.  

Milder winters can also increase the chances of survival for certain species of moths, which may also be contributing to moth party in Calgary. 

Moths are important nocturnal pollinators and as an important part of our ecosystem. The Wilder Institute / Calgary Zoo suggests some ways you can support them such as making butterfly baths, reducing artificial outdoor lighting to increase the efficiency of moths and mowing less and using mulch to create pollinator habitats. 

While most of these moths are harmless, certain species such as the diamondback moth are pests that feed on canola crops making them less than ideal for farmers. The indianmeal moth, also known as the pantry moth, is another common pesky moth that takes over pantry staples in homes. 

Some ways to deal with these bothersome moths are pheromone moth traps or light traps, said Dr.Lebenzon.  

“If it’s just native populations, let them be. But if it’s a pest then it’s a bit of a bigger issue, whether it’s an agricultural pest or a pantry moth,”  

You can use Insectsofalberta.com to help identify which moths you are seeing in your area. The City of Calgary also has a page dedicated to to moths as important pollinators.

Caddis Flies: commonly mistaken for moths 

A frequent misconception Calgarians are having are that the moths are flocking to the water. However, this is likely a similar looking insect called a caddisfly. 

Caddisflies are insects common in freshwater habitats. They are neat little creatures starting as aquatic larvae, they grow into terrestrial adults and are a common food source for aquatic predators like trout and other fish. 

Caddisflies are often mistaken for moths due to their veiny, fuzzy wings, long legs and antennae.  

“The larvae build these ornate cases out of rocks, twigs and sand in the water. They hang out in these cases until they are ready to emerge as adults, at which point they fly out. They are closely related to moths, and so also nocturnal, but pose no threat to humans,” said Dr. Lebenzon. 

“I think the idea that this past winter was mild definitely could be playing a role in caddisfly populations. They spend winter as eggs or larvae under water, so if the winters are warmer then ponds, rivers or lakes might not be frozen through, and thus the caddisfly larvae/eggs are less likely to freeze and more likely to survive the winter so they can come up as adults when spring comes.” 

It can be expected that the overpopulation of both insects will soon decrease as dragonflies and bats become more active in the later summer months. Other predators like frogs and birds are likely also thankful for the copious amounts of tasty nocturnal insects.  

To learn more about moths, The Wilder Institute / Calgary Zoo’s Enmax Conservatory has many different species on display.