Last Saturday, I participated in a tiger hunt. These tigers are fearsome predators, pursuing their hapless victims with incredible speed, and I was armed not with a gun, but with my camera. Happily, however, the only danger I was in was that of sunburn. The tigers we were hunting were the five local members of the large tiger beetle family, Cicindelinae.
Taking a break from birding, I joined the Mile High Bug Club for a field trip to Lake Pueblo State Park, led by entomologist “Bug Eric” Eaton. Eight of us braved the unseasonably gorgeous day (sunny with a light breeze and highs in the mid-80s!) to hopefully find and photograph these fascinating insects.
I learned that the species we were hunting for tend to hang out in bare, sandy areas next to a stream or lake, which is why we aimed for the Osprey picnic area below Pueblo Dam. Their speed, combined with very competent flying skills, makes these beetles hard to photograph. The minute they see you approach, they take off! We quickly adopted a stealthy stalk, eyes peeled.
The first two species we encountered were the Oblique-lined Tiger Beetle (right), and the Bronzed Tiger Beetle (above). Both of these are tan, and quite hard to see against the glaring sand we were hiking on. We went several rounds of, “Do you see it? There, by the rock. No, the pale rock. Yes, next to the dried grass. Do you see it?” but eventually everyone got a good look. Next thing you know, the photographers in the group were prone in the dirt, trying to get a good shot or two from beetle-eye-level.
The ground was quite warm, baking in the sun, and the beetles had raised themselves high on their spindly legs in an attempt at thermoregulation. The heat also sped them up, adding to the challenge.
It’s a good thing tiger beetles are small. They truly are aggressive, and they can reach impressive speeds for a creature only a half inch or so in length.
In fact, an Australian tiger beetle, Cicindela hudsoni, holds the record as the world’s fastest insect; it has been clocked at 5.6 miles per hour! Incredibly, tiger beetles run faster than their eyes can process images, so they’re literally running blind. They have to stop every so often to reorient themselves. In the meantime, they rely on their stalwart forelimbs to prevent collisions.
The mandibles of a tiger beetle resemble a pair of serious-looking scimitars with a couple of sharp daggers thrown in for good measure. These prominent blades are huge, especially compared to the size of the beetle.
Once a beetle has nabbed its prey, there is no escape. Those jaws can quickly slice and dice a victim into pieces. If the beetle is in a bigger hurry, it can douse its meal with digestive juices, so they can get a head start dissolving the prey. Then the beetle just has to suck up the resultant insect goop.
I was quite excited to realize that several of the Oblique-lined Beetles were paired up. Eric explained that the female has dents on either side of her carapace that exactly fit the males’ claspers. That’s an excellent way to ensure species fidelity! The coupled pairs were still mobile, but were sufficiently distracted that we were able to zoom in for some close-ups. At one point, I even noticed that a female was ovipositing (laying eggs), burying them in the loose soil.
Those eggs will hatch into larvae—grubs—that are also efficient predators. They dig small tunnels in the ground, then wait below for dinner to appear. When their oblivious victim happens by, the grub will lunge upward and close its mandibles around its victim, dragging it back into the tunnel to be dismembered and eaten.
Now that we had excellent views of the brown beetles, Eric led us up and away from the stream edge, hoping to spot the more colorful species. Sure enough—next up was the Green Claybank Tiger Beetle. “Green” doesn’t do it justice. The beetles, shining in the sun, reminded me of emeralds scattered along the path.
The last species I saw was the Festive Tiger Beetle. They have the same metallic, emerald-green head and thorax, but a red-orange carapace֮—very festive indeed.
There was one more species we hoped to see, the Splendid Tiger Beetle. It looks very similar to the Festive Tiger Beetle. Apparently some in the group saw it, but at the time they didn’t realize it was a different species.
That’s all right. I was pretty thrilled with the species I saw, and now I have an excuse to go back and try again. Who knew that we had wild tigers so close to home?