Some lady beetles bite. Here's how to tell which ones.

·2 min read
Some lady beetles bite. Here's how to tell which ones.
Some lady beetles bite. Here's how to tell which ones.

They're reddish, with black spots, and they are flying high this time of year.

We're talking about lady beetles and as it turns out, there are more than one species in Canada. Globally there are about 6,000 lady beetle species. About 166 of those have been documented in Canada, and not all of them are native.

In Canada, native species tend to be docile, and they feed on pests insects, like crop-damaging aphids.

One way to tell different them apart is by looking at their colour and markings, Christine Noronha, a research scientist at Agriculture and Agri-Food Canada, tells The Weather Network.

lady beetles
lady beetles

Invasive Asian lady beetles (left) have an "M" pattern at the back of their head, while native species (red) do not. Lady beetles. (Andreas Trepte/Zachi Evenor/Wikipedia)

Native lady beetles are red with black spots. The multicoloured Asian lady beetle can range in colour from tan to yellow, to orange, to red. Another way to tell them apart is by looking at the back of the head, the thorax, which has a black 'M' shape. Their bodies are also slightly longer and more oval, whereas native lady beetles are rounder.

Asian lady beetles are aggressive, and they tend to take over habitats, displacing native species. They also bite, unlike native species.

"It's like a pinch," Noronha says, "but they can break the skin."

lady beetle
lady beetle

Asian lady beetles (pictured here) range in colour from tan to yellow, to orange to brown. Graphic created by Cheryl Santa Maria. Image courtesy: Andreas Trepte/Wikipedia

GREAT, THANKS. WHY ARE THERE SO MANY OF THEM IN MY HOUSE?

"They're just overwintering," Noronha says, "so they won't reproduce [or] do anything else in your house."

In other words, they won't chew holes in your wood or clothing, and they don't spread disease. They do, however, have an unsettling parlour trick.

It's called "reflex bleeding," and if threatened they'll bleed from their joints, releasing a substance that Noronha describes as "very smelly," and it can leave behind a stain.

If you find a few Asian lady beetles in your home, make sure to wipe down the area once they're gone.

Unlike other insects, which only live for a few weeks, this species can live up to three years. When it finds a spot it likes, it will lay down a pheromone so it can return the following year.

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