When I first saw this curious insect, I couldn’t help but notice its huge eyes. But upon closer inspection, I saw that they are not really eyes at all. They are “false eyes,” likely developed to fool or scare off predators. Nearly two inches long and found across the eastern U.S., as far west as Texas, this gray, black, and white insect is one of the largest members of the click beetle family.
We had click beetles when we were living in Maryland, but this is the first time I’ve seen one with huge fake eyespots. Known as the eyed click beetle (Alaus oculatus), we found the specimen pictured below at the edge of our woods in Virginia. The insect’s true eyes are much smaller and located at the base of its saw-toothed antennae.
If you take the time to learn about them, nature’s creatures are all amazing and the click beetle is no exception. Despite their differences in appearance, all click beetles have a startling behavior that demonstrates how they got their name. When confronted by a predator, click beetles flip over onto their backs, pull their legs and antennae in close to their body, and remain very still, “playing possum” until the predator loses interest. If further threatened, they arch their back and straighten out quickly with a snapping motion, resulting in an audible click, and launch themselves several inches into the air. This burst of movement, from the predator’s perspective, seems to make the beetle suddenly disappear.
In nature, there’s a reason for everything and that reason has to do with survival. For instance, the sometimes dramatic difference in coloring between a male and female bird of the same species has to do with increasing the survival chances of the species. In the case of cardinals, the bold coloring of the male catches the female’s eye and since studies show that females seem to prefer bright red males, the rich red color seems to signal to her that he will be a good provider for their offspring. The drab coloring of the female, on the other hand, helps her stay hidden while sitting on the nest and not draw the attention of predators.
So the eyespots of the click beetle are related to the specie’s survival, but why, then, did the click beetles we saw in Maryland not evolve to develop these eyespots, and, conversely, why did the click beetles with giant eyespots develop them in the first place? I’m certainly not qualified to answer this question. But what I do know is that since not all click beetles evolved in this way, it suggests a form of divergent evolution; that is, an ancestral species “splits off” at some point, and the two divergent but closely related species adopt different survival strategies, with the exception of the click.
The theory behind the fake eye spots is that if a predator, say a bird, is tracking the beetle by following the very obvious eyespots, once the beetle senses the predator and flips onto its back and remains still, it might cause the bird that was focusing on the eyespots to think the beetle is dead or has vanished. If this ploy fails, the beetle suddenly vaults into the air, further confusing the bird, and perhaps giving it just enough time to crawl away and hide.
I found this specimen in the woods. In this setting, the beetle’s eyespots actually acted as camouflage. If I wasn’t picking up broken limbs, I probably would never have seen this beetle in the first place, so perfectly did it blend with the twigs, leaves, acorns, and stones on the forest floor.
I’ve often wished that I had a biologist to follow me around when I’m outside so I could pose these types of questions to someone with more knowledge about such things. Instead, if I can’t find the answer through research, I dwell on it until another question about something entirely different pops into the forefront of my brain. The unanswered questions languish in my thoughts, reminding me how complex nature is. For me, looking for an answer only seems to lead to another question. Maybe when we realize how much we don’t know about nature, the smarter we’re actually becoming! If that’s true, I’m well on my way to genius.
Come forth into the light of things, Let Nature be your teacher. William Wordsworth