Today’s column focuses on a true bug (in the Hemiptera order) that looks like a reptilian
insect or tiny dinosaur. The first time I saw this Phymata genus bug, on coyote brush in
Mt. Pisgah’s south fields, I only got a good look at its back. I figured it was some kind of
shield bug, but I didn’t get any good pictures of it from the side before it flew away. I got
home and looked it up and discovered I’d found an ambush bug, a tiny predator
equipped with all kinds of deadly tools. The Jagged Ambush Bug has pointed spines, a
spear-tipped snout and an enlarged front claw with teeth on it. I really wanted to see
another one.
I read that ambush bugs live up to their names, and that they’ll wait, unmoving, until
they snag their prey. It’s often easier to find them by checking flowers for a motionless
insect, then looking to see why it’s immobilized. After a couple of failed searches, I did
indeed see the dead fly first, and then I saw the ambush bug pictured above. Take note
that this bug chose a dinner far bigger than its own head—they’ve been known to hunt
even larger insects.
In one picture above, the big claw gripping the fly’s face is the bug’s only hold on the fly,
and the bug’s rostrum is tucked under its head. In the other picture, the prey is being
held by the extended rostrum, and the claws are repositioning the fly. If any of this
makes you squeamish, you may want to skip to the next paragraph, but I find it
fascinating. When I looked at all my pictures in order, I could see how the insect used its
claws and its beak to manipulate the fly and spear it in multiple places, front and back.
Ambush bugs inject their prey with a digestive enzyme so they can basically drink the
liquefied insides of their kill through a biological straw.
Ambush bugs blend in with the flora. Their color can vary and some are more green or
white, but this one’s yellow and black pattern camouflages nicely with Oregon’s
yellowing fall plants. Most males are darker and smaller than females, and an article
referenced below explores the fact that darker males can get moving faster on cold,
sunny days, and therefore win the mating game. In addition, it was just shown earlier
this year that some ambush bugs can change color to become more yellow when
they’re on yellow backgrounds, but that they were not able to become more white.
Beware: If you try to do a web search on the ambush bug, it’s also the name of an odd
and ineffective DC comics hero. I like this character better.
Stay curious!
Karen Richards
Sources:
Jeff Mitton, Colorado Arts and Sciences magazine, “Why Are Male Jagged Ambush
Bugs Darker Than Females?” December, 2015. Accessed 10/20/20.
Julia Boyle, British Ecological Society, “Plasticity and habitat choice match colour to
function in an ambush bug,” Jan. 2020. Accessed 10/20/20.
