Ladybug, ladybug and more ladybugs

Posted: November 5, 2015 - 14:53 , by ROM
Biodiversity | Comments () | Comment

You may have seen lots of ladybird beetles flying about recently. Unlike our native species which are adapted to Canadian winters, the Asian Multicoloured Ladybird Beetle (Harmonia axyridis) has to find a place to hibernate over the winter, usually indoors. With the warm weather we have had this week; they have been scouting out the best south facing walls of buildings (like here at the ROM). We were out collecting a few for a gallery exhibit on invasive species.

Harmonia axyridis and Brenna Wells holding some samples. Photos by A Guidotti

Since they aggregate indoors to hibernate, large numbers may become a nuisance but they do not feed during the winter. At temperatures below -5oC, they cannot survive. Also unlike native species, they have been known to bite if handled. I've held many though and haven't been bitten yet!

Introduced intentionally by the US government in the 1970s to combat aphid populations, the Asian Multicoloured Ladybird Beetle is now the predominant species of ladybird beetle in North America. It was first recorded in Canada in 1994. This species occurs in a wide variety of colour forms, but all have a white M-shaped mark on the pronotum (behind the head). They may have no dots, or a few dots or many dots, so you can't count them to figure out the species! Ladybird beetles are beneficial and this species is no exception since they feed on aphids which are plant feeders.

On the negative side, this species appears to be out-competing our native species. Once common native species have become rare, some possibly even extirpated. Some examples include the nine-spotted ladybug (Coccinella novemnotata), the transverse ladybug (Coccinella transversoguttata) and the two-spotted ladybug (Adalia bipunctata). Ontario has recorded over 80 species of ladybird beetles but now the most often seen one is the Asian Multicoloured Ladybird.

To record native ladybird sightings visit