Swarms of invasive red and black bugs are taking over Ontario this time of year

With fall rapidly approaching, you might spot swarms of this invasive species congregating around your property — and while they might look threatening, the bugs are practically ecologically harmless.

European or red firebugs (Pyrrhocoris apterus) are particularly active in Ontario this time of year, as they search for areas in and around your home to stay warm through the cooler months. The species is native to Europe and western Asia (hence its name), and was first recorded in North America in 2008.

Since its introduction, the species has spread rapidly across the continent, including here in Ontario, where you'll often find large clusters of the red and black bugs on homes and nearby trees.

Dozens of sightings have already been reported throughout the province this month on the biodiversity social network, iNaturalist, with a heavy concentration in the GTA.

A European firebug observed in Toronto last week. Photo: drew_baxter/iNaturalist.

In June, female red firebugs begin laying eggs and can produce anywhere between 40 and 80 of them throughout their lifetime. Adults can live for up to two years, and can be identified by their oval-shaped bodies, which feature a bright red base and black markings, including two black spots or circles.

The bugs mainly feed on fallen seeds from specific trees and plants, including linden, mallow, hollyhocks, and hibiscus.

Thanks to its red-and-black appearance, the European firebug is commonly mistaken for the Eastern box elder bug, which primarily feeds on the developing sets and sap from female boxelder trees.

Since red firebugs don't have an impact on tree health, the City of Toronto doesn't provide any treatment or control services for them. Although they are a nuisance, European firebugs don't spread diseases, damage plants, or pose a threat to humans, pets, or plants.

A cluster of European firebugs found in Etobicoke last month. Photo: emilyjane13/iNaturalist.

If you do want to remove them from your property, the last thing you'll want to do is crush or squish them, as these bugs are known to emit a foul odour and can stain carpets or fabrics.

The best way to keep these bugs off your property is through preventative methods, including sealing small gaps around your windows and doors, making sure your screens are intact, and repairing any cracked foundations.

If you're already dealing with an infestation, you can either vacuum the bugs as a removal method or have exterior insecticide treatments applied in the fall to your home's siding, windows, and foundations.

If you want to take a more DIY approach, you can also use a high-pressure hose to dislodge the insects or use a spray solution composed of cooking oil, dish soap, and water to knock the bugs off any surfaces.