This week I was prepping our raised beds and in the process of moving some soil in the wheelbarrow noticed a rather large (about half the length of my thumb) dark beetle. I thought at first it might be darkling beetle but the body shape and colouration wasn’t quite right so I took a second look.
This beetle is an introduced European Ground Beetle (Carabus nemoralis), commonly found in gardens on both coasts of North America. The field marks make it both beautiful and relatively easy to identify – look for the purple and blue tinting around the edge of the beetle’s body as the most obvious feature. From different angles, the hardened wing coverings and pronotum can appear to be a metallic brownish-green or purple – the head is usually dull in comparison. There are three rows of dimples in each wing covering.
The natural history of this, and other introduced beetles from Europe, makes for interesting reading. A paper by H. Goulet suggests that many non-native species arrived in the ballast of ships. Barrels full of earth (and a variety of insects) from Europe were carried across to North America where they were emptied. Newly arrived beetles became established and have gradually spread towards the interior of the continent. Today, the European Ground Beetle can be found in every Canadian province except Manitoba. In Canada, they are more common in eastern Canada and coastal British Columbia.
Since finding this first beetle I’ve started to see them in other places in the garden – beneath last year’s leaves and plant debris, showing up in the soil as I dig the beds over, and under anything that can provide shelter during the day. They don’t seem to move too fast initially and then start digging in and trying to get underneath anything that is handy. I’m definitely glad to see them since they eat all sorts of soft invertebrates, introduced European slugs (how convenient) and other garden pests – they’re beneficial!
As you get your own gardens and flower beds ready for the coming gardening season keep an eye open for these simply gorgeous beetles!
Read more about the European Ground Beetle.