Biothon tiger (beetles)

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I’m a fan of tiger beetles. Pretty much any open dirt or rocky trail in the summer will have at least one or two of these gorgeous metallic-green beetles. I usually notice them first when they’re flushed; they fly up  from the ground with a bright glint of colour that catches the eye. Once they’re landed they can be a bit harder to pick out, but on a bare dirt path, and in the sun, they really stand out.

There are a number of tiger beetle species, found in every state and province, but by far the most common here in the east is the Six-spotted Tiger Beetle, Cicindela sexguttata. The only other species I’ve seen before was Green-margined Tiger Beetle, C. limbalis, along the road where we lived by the lake. I saw lots of Six-spotted on the biothon, hunting in sunny spots along open dirt trails. Tiger beetles, as their name implies, are predators. You can’t really see it in this photo, but they have huge, sharply-toothed mandibles that they use for catching their prey. Their large eyes are used for hunting visually, and their long legs make them swift.

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I was absolutely delighted when I turned up this second species of tiger beetle on the second day of biothoning. I didn’t recognize this one at the time, other than to know it wasn’t a Six-spotted; but it happens to be the same species I found along the road by the lake house, a Green-margined Tiger Beetle. This beauty caught my eye as it scurried across some open rock at the crest of a low roll (I’m not sure it was high enough to call it a hill) in a small treed meadow I checked out.

It was remarkably unflighty, which I found interesting, and even more so when I note that in my post from a few years ago, where I shared the lake house individual, I commented that that one was also pretty calm. Six-spotteds are so difficult to photograph because you really have to sneak up on them and even then they may take off before you get really close. But this one sat calmly for me (as did the lake house beetle); I was even able to lift off a twig that it had scuttled under and which was partially obstructing the photo. Species-specific temperaments in beetles?

Strangely, I wrote in that post:

In this case, Marshall notes, “The Green-margined Tiger Beetle lives on clay soils across Canada and the northeastern states.” BugGuide.net, my number one online reference for all things six-legged, adds that the habitat is “usually steep, moist bare clay soil, including… dirt roads”.

Except there really wasn’t any moist bare clay soil, dirt roads or otherwise, in the area where I found this one. It was on an open crown of granite amid quite a lot of grassy meadow. There were other patches of rock here and there, but I’m not sure there was even much open dirt along the trail, which was some distance away anyway. So that’s somewhat odd.

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I actually found this third species on the first day, not the second, so I’m presenting these a bit out of order. But this was the only one whose identity I needed to look up because I didn’t think I’d seen it before. Using this site of Ontario’s tiger beetles (created, interestingly, by a prof at my alma mater, University of Guelph, with whom I did an entomology course to Ecuador), I’ve tentatively ID’d this guy as a Twelve-spotted Tiger Beetle, C. duodecimguttata.

I found this one along the short dirt trail that led down to the gravelly beach. It paused to rest on a bit of rock, where I took this photo of it. It was much flightier than the Green-margined, more like the Six-spotted, and after snapping this photo (this is a tight crop from a much farther-away shot) I pressed my luck trying to get closer and it took off, not to be relocated.

On the Ontario page the habitat is given as gravel dams as well as areas with mixtures of moist sand and organic soil, tending to prefer sheltered spots rather than open beaches or dunes (the habitat favoured by most tiger beetles). BugGuide, meanwhile, says it’s found along the edges of streams and ponds. The lake we were camped at was hardly a pond, but it wasn’t huge, either.

When I found all these tiger beetles one of the first thoughts to cross my mind was “I’ll have to share these with Ted!” (Author of the wonderful entomology blog Beetles in the Bush, and an expert on beetles with a particular interest in tigers. He’s already corrected the ID of the fuzzy flower beetle of my last beetle post!) So Ted, hope you don’t mind confirming the identifications I’ve made here!

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8 responses to “Biothon tiger (beetles)

  1. Wish you a very happy new year, Seabrooke! The tiger beetles of Ontario are really amazing and diverse. I had the opportunity to document several species while I was up there.

  2. Nice, and all of your IDs are correct. We have these three species in Missouri also, with C. sexguttata being the most and C. duodecimguttata the least commonly encountered of the three. I do find C. limbalis most often on clay banks and 2-tracks in northern Missouri, but in southern Missouri I can find it also associated with rock exposures in dolomite, sandstone, and rhyolite glades with little exposed clay soil. Sometimes habitat notes for species are biased towards habitats more commonly explored by entomologists (e.g. dirt roads).

    • Thanks, Ted! I knew you’d be able to confirm them for me – glad I got the IDs right. It’s interesting what you say about the habitat notes – perhaps not surprising, especially for lesser-studied organisms like insects, but it’s still sometimes unexpected.

  3. Very nice collection of tiger beetles for 2 days searching! Also, coo to hear you’re another Guelph Entomology Field Course alum! I’ve heard many tales about that trip to Ecuador!

  4. Since there is 6-spotted and 12-spotted, I really think that middle one should be 6-spotted-2-squiggles beetle.

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