Walking sticks

When I was a kid, I was obsessed with finding one of these:

Photo by C. Sohl

I never could find one in the wild, partly because they're so good at camouflaging with their surroundings. The above walking stick is from our own teaching collection. This particular specimen is about 4 inches long, but walking sticks can grow to a foot long or more! Walking sticks are in the order Phasmatodea, and as you can see, they are masters at disguise. Some resemble brown twigs, while others look more like leaves.

http://en.wikipedia.org/wiki/File:Phyllium_bilobatum,_male_larva.jpg

Some will even rock back and forth in a swaying motion, as plants will do in a breeze.  Below is a you-tube video of a walking stick in motion. You can see the rocking motion here, too.

Walking sticks have compound eyes, which is the same type of eye on a fly. Interestingly, the eyesight of a walking stick improves with age, each time that the insect molts. They can also see particularly well at night, which is when they are most active. In fact, daylight can actually harm their sensitive eyes. I imagine this did not help in my quest for finding one of these creatures.

Another aspect that is unusual about these insects is their mating behavior. Walking sticks have a tendency to stick together - mating can go on for days at a time. It's thought that this is due to defense mechanisms - if the male stays close, he can protect the female from any other males that may try to mate with her. This way, he can be sure that she'll lay his eggs. In addition, dealing with two of these insects can be more challenging for anything that might try to eat them. Many female walking sticks have the ability to lay eggs without the need for a male - perhaps this is a reason why the males do not want to let go of the females so easily! 

Below is a coupling of male and female walking sticks. The male is actually the smaller of the two, and apparently clinging to her for dear life. 

http://en.wikipedia.org/wiki/File:Anisomorpha-male-female.jpg

You can keep your eyes open for these, but you may not be able to find these quite so easily as other insects. I haven't given up just yet myself.

Happy Friday!