What You Probably Don't Know about Costa Rica's Phantom Insect aka the Stick Bug

If you've been in Costa Rica for even a little while, it's likely that you've encountered a stick insect at some time. Or, perhaps you've walked right by them without a glance as they are pretty crafty at looking like ... well, sticks! If they show up on your window or painted wall that bit of camoflague is pretty useless as it was for this specimen on our house the other day.

Long stick insect on stucco wall
No, really! I'm just a harmless twig, move along, nothing to see.
There are a wide variety of "stick bugs" throughout tropical and sub-tropical regions, more than 2500 species! Taken together, they are referred to as phasmids, a word whose Greek root refers to "phantoms." Their most well-known characteristic is that, aside from their odd appearance, they hold the record for longest bug on planet Earth. One species is up to 22 inches long including the legs, 14 inches just counting the body. I know they get quite a bit bigger than the one in the picture down on the coasts, but this one, at 8 inches is about as big as they get up here in the mountains.

Here are a few other interesting facts about these critters:
  • No need to look "under the hood" to tell which sex is your stick bug. They are nearly all females. They don't need a male to produce viable eggs, in fact. Only when they do mate with a male are their offspring likely to be 50/50 male and female. For the geeky readers, that means they are parthogenic.
  • They don't bite, but they can issue a foul odor from their leg joints. They actually make pretty good pets and can live on a diet of blackberry leaves. If you want to keep one indoors, be sure to only pick it up by the body, not the legs.
  • You may have guessed that, yes, they can regenerate limbs if one breaks off. In fact, they have a special muscle in the top joint where the leg meets the body that is specifically for breaking off a leg if they think that will save them from a predator.
  • The females scatter their eggs at random. The nymphs that hatch eat their own skin for nourishment and to hide traces of their presence.
closeup of costa rican stick insect
If you look closely at the leg joints, you'll see some juice-sucking parasites

Though these gals can usually remain motionless for hours on end, they can move pretty fast if they want to, which is something you might not expect from their ungainly looking body architecture. We don't see them that often, but some species of them can be damaging to crops and wood lots, especially in the southern U.S. Here, I don't think they have much pest potential and we always stop to look at them in wonder when they visit.

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Thanks so much for your comment! - Casey