Friday, May 30, 2008

An Interesting Tiger Beetle

Tiger beetles (genus Cicindela) are among our most interesting insects. They have have ornately marked carapaces (shells), which lend them a beautiful, almost showy appearance, and some species are blindingly iridescent. Bold and adept hunters, most species are active during the day, and thus are somewhat easy to observe. But, just as their sharp vision aids them in spotting prey, it also keys them into us and tiger beetles can be hard to approach closely.

Which makes the following photos all the more amazing. Sent to me by naturalist extraordinaire Warren Uxley, they are of Cicindela formosa. Too bad no one yet has made the effort to give all of these charismatic beetles - there are only about 100 North American species - interesting common names. But I don't know of one for this particular beetle. However, formosa means "handsome", and that would be an apropos moniker: Handsome Tiger Beetle.

Cicindela formosa, a creature adapted for life on the run. At slightly under an inch long, it's not a heavyweight, but if you were a smaller insect caught out on the open sands, this would be your worst nightmare. Tiger beetles have proportionately massive jaws, and move in incredibly speedy bursts. Once suitable prey is spotted, it probably has little chance. Look at the legs on this guy! In addition to using those long legs for exceptional mobility, tiger beetles also use them as tools that assist in an interesting thermo-regulation technique called "stilting". When at rest on hot summer sands, they elevate themselves high off the substrate, sort of like a car being lifted on jacks. And thus get some relief from the baking sands below.

Look at the striking markings of the upper shell. This showy intricate pattern is no doubt what inspired Thomas Say to name the species formosa when he described it in the early 1800's. Oh, that's the same Say for whom the Say's Phoebe is named. Like his ornithological counterpart Alexander Wilson, who was dubbed the "Father of American Ornithology", Thomas Say was called the "Father of American Entomology". Say was quite the all-around naturalist - a very rare breed these days - and described many other animals other than insects to science. Some of the birds first described to science by Say, in addition to the aforementioned phoebe, include Western Kingbird, Lark Sparrow, Lazuli Bunting, and Orange-crowned Warbler.

Finding tiger beetles is akin to discovering showy, colorful living gems, or panning up a gold nugget after lots of looking. They aren't very common, and seldom occur in large numbers. Once spotted, the observer must employ his patience and wits to make a close approach. If successful, the beetle-hunter will be well rewarded with the opportunity to admire a fascinating insect, both in appearance and habits.

Thanks to Warren for tracking this beast down, and sharing his amazing photos from his recent safari to the Oak Openings.

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1 comment:

Beetles In The Bush said...

Hi Jim - just happened upon your blog, nice! Actually, most U.S. tiger beetles do have common names - Cicindela formosa is called the "big sand tiger beetle" in reference to its size and sand habitat preference. Populations in the eastern U.S. are assigned to subspecies generosa - the dark coloration of the specimens in your photos is typical of that subspecies.
best regards -- ted