Monday, July 28, 2014
There are about twenty species of tiger beetles in Ohio, and all of them are formidable hunters. If you have an eye for insects, you've probably seen some. Most common is the Six-spotted Tiger Beetle, Cicindela sexguttata, a glittering emerald-green beetle that frequents paths, woodland openings, gravel lanes, and other open habitats. All of the tiger beetles hunt by sight, as you might have guessed by the giant goggle eyes of the beetles in the photo. One would not want to be a potential victim in a tiger beetle's sights. They are said to be among the fastest land animals, proportionate to their size, their long stiltlike legs capable of propelling the beetle in astonishingly rapid bursts.
One prey is caught, it is sliced and diced with the beetle's long tusklike mandibles. While the adult beetles sound like bad news for victims, they're nothing compared to their larvae. I was recently with Laura and David Hughes, and they were kind enough to bring along a trio of tiger beetle larvae that they had captured and were keeping in captivity. Thus, I was able to make some images of these terrifying predators; something I had long wanted to do.
The beetle larva's tactic is to remain frozen in place and flush with the ground. When an unsuspecting ant, or anything small enough to be overpowered moseys by, watch out! The larva will burst from the hole with impossible speed, and grab its victim. The fringe of white cilia-like hairs ringing the head may be there to help defend against the larva's predators. It doesn't matter how bad you are, there will always be something out to get you. In this case, it is certain parasitoid flies and wasps that atempt to get their eggs down in the hole with the tiger beetle. The eggs hatch quickly, and the parasitoid's larvae begin to consume the beetle larva. Perhaps those hairs, which form a sort of fence around the hole's perimeter, reduce the chances of this happening.
Before long, the grub began trying to tunnel itself back under the sand. It is using its strong mandibles to excavate its burrow in this shot.
Well. You just never know what might be lurking underfoot. My appreciation goes to Laura and David for making this photo shoot possible, and for sharing their tremendous knowledge of natural history with me.