All Things Bright and Beetleful

Written by Aurora Sarchet, a Conservation Science resident.

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Today, I am going to introduce you to a beetle.

“What?” you say, “A beetle? I don’t really like those. Too many legs.”

“Too bad!” I reply. “You need to meet this beetle. Besides, in the grand scheme of things six legs isn’t really that many. Have you heard about octopuses? Millipedes? Calm down.”

While living at A Rocha Canada’s BC Centre for the Tatalu Conservation Residency, I’ve had a chance to meet some of my quieter neighbours. Easily overlooked and undemanding, beings like insects and plants are all around us; their quiet work holds earth’s ecosystems together. I haven’t always given these neighbours the attentiveness they deserve; armed with the iNaturalist app, I’ve gotten to know and appreciate them a bit better.

Today, I want to introduce you to one of these neighbours – chances are, they might be your neighbour too. Although originally from Europe, this species has been introduced to North America, and is especially populous in the southeastern and southwestern parts of Canada. Here’s a map of their distribution in North America based on iNaturalist observations. You can see more of the map and observations here.

The creature I am talking about is the Bronze Ground Beetle – Carabus nemoralis to be science-y. It would be more accurate to call it the “Black with a Bronze Sheen and Purple or Bluish Highlights Ground Beetle,” but for some reason that name hasn’t caught on. Besides their colorful carapace, these ground beetles (carabids) are quite large – reaching lengths of up to 2.5 cm (around the size of a pecan half, but much crunchier). They are predatory beetles that feed on many garden invertebrates, like slugs and insects.

This is a photo of a slug caught eating holes in our cabbages! Notice the guilty expression.

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Of the 47 farm species I’ve observed and ID’d to species with iNaturalist, 35 are introduced. Many of these species are considered weeds or pests – but others, like bronze ground beetles or seven-spotted lady beetles, help keep those pests in check. This discovery has complicated my understanding of introduced species. I am inspired to ask new questions:

What are the roles (negative and positive) that introduced species play in human-managed ecosystems? In wild ecosystems?

Do introduced species that benefit human-managed areas (like predatory beetles on the farm) harm native species and wild ecosystems?

Conversely, do farm weeds or pests provide habitat and food for native species?

And many more…

I have a feeling that the answers to these questions are very, very complicated – but I’m excited to keep exploring, understanding my neighbours a bit better. This last photo is of the beetle’s face. It’s a bit wrinkly looking, with large, round eyes and bristly mouthparts. Maybe you will think this beetle is cute. Maybe not. Personally, I find them quite beetleful.