We received a very interesting question a while ago about some sort of insect that looks “like a blade of grass” (or a stick, to our eyes). The reader referred to the creature, which he found in a state park in Pennsylvania, as a “really weird worm,” but also added that it might not actually be a worm. Based on the video he sent in, it appears that the grass-like creature is an insect, not a worm. What kind of insect is, of course, the question. Below we investigate what this insect that look likes grass might be. (As mentioned, we think the insect looks a bit like a stick as well, so we’ll be using “grass” and “stick” to basically mean “some sort of elongated plant material.”)
Although the video was helpful and entertaining to watch, it was quite short, so we decided to include only a still frame from one of the clearest parts of the video:
The insect in question is more or less in the middle of the image. It is kind of hard to see, however, as it does look approximately like one of the many blades of grass that surrounds it. The reader speculated that the insect disguised itself in such a way as to “trick some bugs and then eat them.” While this is reasonable suggestion, we suspect that the insect is actually disguising itself to avoid predation. This is in fact a common defense mechanism known as mimicry, whereby various creatures mimic some other animal or plant to avoid being eaten. This is what insects that are disguised as leaves, which we recently wrote about, are up to, and this is also why certain caterpillars appear to have large eyes. (When they appear to have large eyes, they look less like harmless caterpillars and more like harmful snakes, which can deter birds and various other predators from trying to eat them.) So, the “grass insect” is not hiding in order to prey on anything, but rather to avoid being preyed on.
The video is not clear enough for us name any particular species of insect, but it does seem like our reader found something that belongs to the order Phasmatodea, a grouping that includes various types of “stick bugs” and other insects that resemble parts of plants. (The leaf insects referenced above are in this order, for instance.) We think our reader found one of these stick insects for obvious reasons: what he found is a living creature that looks like a stick. Moreover, the one thing the video did show is the creature swaying back and forth, which is something that many species in the order Phasmatodea do to enhance their camouflage. A stick insect rocking back and forth looks a lot like a regular twig swaying in the breeze. Finally, the location in which the reader found the insect – Pennsylvania – does not preclude this suggestion. There are lots of stick insects in the U.S., and although particularly high concentrations are found in the southeast, there would be nothing unusual about finding one in Pennsylvania, especially in state park of all places.
So, we are reasonably confident that our reader found some sort of stick insect (or stick bug), although we are unsure exactly which species. However, if our reader wanted to do a little more research into the particular species of stick insects in his area, perhaps by speaking with the staff at the state park he visited – they generally love to answer these types of questions – he might be able to determine exactly what he found.