While I was sweeping the patio, I came across this pretty little caterpillar on my lawn chair. Something in the back of my mind reminded me that if an animal is colorful, it is often a danger sign.
My instincts were right on. The yellow hairy guy is the caterpillar stage of the American Dagger Moth (Acronicta americana), common in oak/maple forests. Although it is not known to sting, handling the caterpillar’s hairs may cause irritation to the skin.
In ecological terms, the caterpillar’s hairs and coloration are known as a predator defense, characteristics a species possesses to protect it from predation. Predator defense comes in many forms. Here are some of the more common defense characteristics you will find in our area:
Chemical release – alarm pheromones used to discourage close interaction - skunks
Flashing coloration – distraction behavior and body traits - white-tail deer flipping up their tails when running, the white underside distracts the predator and alerts the other deer to danger
Cryptic coloration – color and body patterns that allow the animal to blend in with their environment - pheasants
Object resemblance –body shapes that resemble another object - walking sticks
For my caterpillar, its defensive mechanism was its warning coloration, a strong color or pattern that alerts potential enemies. Although it was fuzzy and a beautiful yellow color, the caterpillar was telling me to stay away. It may have taken me all summer to smarten up but at least this time, both insect and I came out of this encounter safe and unharmed.
