On a botanical survey last summer, we encountered scattered iridescent green beetles in multiple locations, perched on gravel like little half-inch long jewels. Unlike most beetles, as we got within 3 feet of them, they darted away in a low erratic flight, landing on another nearby rock. If you were colored this brightly, you too would take evasive measures to avoid being eaten.
Tiger beetles earn their name from their speed as they run and pounce on prey. All tiger beetles are capable of running fast in short spurts due to their disproportionately long legs. Even their larvae attack ants and other arthropods with lightning speed. Like the wolf in Goldilocks, they have large eyes and jaws, "the better to eat you with," especially if you happen to be a small arthropod.
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| "My what big teeth you have" - normalbiology |
Their large white mandibles
give these beautiful insects a ferocious appearance. Predominately daytime hunters, they can even capture their prey in flight. Wikipedia reassures me that "Although they are
strong enough to subdue their prey, they do not bite humans unless
handled." Good news, they don't hunt humans!
The large eyes are a valuable asset if you are a predator, focusing on your prey. A tiger beetle is fast but has to run in spurts and stopping frequently as it runs faster than speed of (its) sight! Research by Cornell professor Cole Gilbert describes it this way.
"The answer is that the insect's ability to see shuts down after it accelerates toward prey. If the tiger beetles move too quickly, they don't gather enough photons (illumination into the beetle's eyes) to form an image of their prey," explained Cole Gilbert, Cornell professor of entomology. "Now, it doesn't mean they are not receptive. It just means that at their speed during the chase, they're not getting enough photons reflected from the prey to make an image and locate the prey. That is why they have to stop, look around and go. Although it is temporary, they go blind."
So just how fast are tiger beetles? It varies between the 100+ species world wide but all are speedy. His research shows that comparing his tiger beetles with Olympic superstar Michael Johnson on the basis of their length, the beetle is 10 times faster.
Tiger beetles live independently except for mating. Like some other beetles, the male stays mounted on the female for a while to discourage other potential mates. Different tiger beetle species have very specific requirements for the soil the female tunnels into. The larva seen here have a different hunting technique.
"The females lay eggs in sandy patches, and the larvae burrow into the ground when they hatch. Here they lie in wait until small arthropods walk by, where then the larvae pounce much like jack in the boxes. The beetles stay in larvae form for about one year before pupating. The beetle has a total lifespan of just under 5 years." Wikipedia
Tiger beetles have wings, seen above on this specimen which in technical terms is referred to as "squished." When threatened by a predator they can fly 20 to 30 feet away, then turn to face their predator, making them hard to capture even with a net.