Monday, August 16, 2010

A Tropical Tiger Beetle

I have a huge backlog of postable photos from my recent Bolivia and Peru tours. Here's a tiny sample of a particularly attractive one to keep this blog active.

Tiger Beetles (Cicindelinae) are one of the many subfamilies of the ground beetle family, Carabidae. Despite being just one of many subfamilies of beetles, it's an incomprehensibly diverse order of insects. In North America alone there are 109 species of tiger beetles, and more than 2000 worldwide. Almost every insect group is more diverse in the tropics, but it's surprising how rarely I come across tiger beetles on my travels in South America. And even rarer yet that one poses long enough for me to photograph it.

This is Odontocheila cayennensis, the Cayenne Forest Tiger Beetle.

Luckily, I know one of the world's foremost authorities on tiger beetles. David Pearson lives here in Arizona and is also an avid birder. We bump into each other occasionally while birding here and were roomates for a week in Gambell, Alaska a couple years ago when I was cooking for the WINGS tour he was a participant on. So whenever I come across a tiger beetle, off I send the photo to him. He also noticed the red mites on its thorax, which in the field I mistook for red pigmentation. They're apparently not parasitic, merely hitching a ride. This sort of commensalism is called phoresy.

A few years ago in Bolivia I met some researchers who were specifically studying a group of tiger beetles that prey solely upon dung beetles in Amazonian rainforests. To find their quarry, they had to first attract the dung beetles with traps. I won't go into the details as to how they actually did this, but perhaps you can fill in the gaps if I mention that it involved the cooperation of the tourists staying at that lodge, as well as a well-paid volunteer.

6 comments:

Margarethe Brummermann said...

A real beauty! And others prey on dung beetles? They must be huge - of course, some scarabs are tiny...We were just Tiger hunting in Willcox, AZ, but we didn't catch many spp. even though we saw some great ones. How long will you stay in SA?

Birdernaturalist said...

Hi Margarethe,

Yes, it would take a huge tiger to go after the dung beetles that saved you from being swept away by the flash flood. Did you see Doug Taron's post about tigers at Willcox? http://gtapestry.blogspot.com/2010/07/another-adventure-at-willcox-playa.html

I'm back home for just another 9 days, then back to Bolivia & Peru for six weeks.

Doug Taron said...

Gorgeous photos. I must confess to no small amount of envy for your opportunity to see this species. I was at first puzzled by the choice of dung beetles as a prey item. Having thought about it, I'm guessing that they feed on the grubs rather than adults. Any idea if this is correct?

Birdernaturalist said...

Good question Doug. I can't remember the details, if the researchers told me any back then – this was six years ago. Maybe the prey is just very small dung beetles? If it were the larvae, they'd have to be pretty patient tiger beetles to show up already at the dung traps. I actually know a Bolivian expert in dung beetles, and maybe she'll know.

Isa T said...

Hi! I came across your blog as I was trying to identify a tiger beetle that I recently encountered on the shores of the River Beni in Rurrenabaque during my last trip to Bolivia. I wasn't able to get a picture, but it had a distinctive electric magenta colour. Any idea? Thanks!

Birdernaturalist said...

Hi Isa – thanks for the comment. I'm sure your tiger beetle was quite beautiful. Without a photo I doubt there's much that can be done though, and we'd have to rely up on an expert to examine it anyway.