“Grandpa, there’s a stick walking up the screen door.”
“Don’t worry, Delphine. It’s probably a Diapheromera femorata which, in large numbers can defoliate certain hardwood trees, but the good news is since the Han dynasty they have been considered good luck and were kept as pets in bird cages.”
Walking stick insects belong to the order of herbivorous insects referred to as phasmids. There are more than 3000 species and they are found on every continent except Antarctica, but mostly in temperate to tropical climates. The island of Borneo hosts more than 300 species, some of which fly, suddenly spread their wings to flash bright colors when threatened and even rub their wings together to make a scary noise.
Another survival adaptation is some phasmids can lose a leg, perhaps a bird is pulling it, and simply grow another one.
Both Borneo and Vietnam claim phasmids 21 inches long, which, for those of you keeping score at home, is from my shoulder to the middle of my palm. One skinny insect as long as my arm.
In Arkansas, however, all our walking sticks look like sticks, they do not have wings and I’ve never heard a peep out of them. They are the largest insects in Arkansas, and I have seen stout specimens almost 10 inches long (antennae included) in northern Madison County.
Being skinny like they are, they don’t have room for much rumination, so in goes the leaves and out goes the googoo. I’ve never identified much damage in their wake, but there are reports of infestations so huge in the Ouachita National Forest with defoliation so severe that entire branches and even entire trees died.
And you might not notice them if they are right in front of you. All phasmids are sneaky and clever that way. On their skinny legs they will waver side-to-side to resemble nearby twigs in a breeze.
The Indian walking stick (Carausius morosus) changes color to match its surroundings. This particular species has been especially popular in the pet trade. Apparently it was because of the pet trade some communities in Southern California now have walking stick problems.
Individuals that escaped or were released settled into well-maintained suburban landscapes, but often eggs discarded accidentally caused the problem. Most walking sticks are parthenogenic, which means the female does not need to be fertilized to produce eggs that will bear future female walking sticks. The eggs are delivered into the nesting material in the cage in autumn, and the fastidious and watchful pet owner will clean the cage and innocently discard the litter thereby releasing the eggs into the community… and the beat goes on.
The eggs hatch in spring, and the sticks mature quickly and live up to two years. According to the University of Arkansas Arthropod Museum, female walking sticks can lay up to a dozen eggs a day for months.
But no insect mates like phasmids mate. The female is almost always larger than the male, and a male will “climb on” for what can be an impressive duration while mating. There is a species in India known for maintaining the mating position for weeks, and the record for coupling is reportedly 79 days! So who was watching and counting and why? Did the evening news give daily reports?
Determined scientists wanted to know if birds that eat walking stick eggs help to disperse them in the environment, so they collected eggs of three species, fed them to chickens and Japanese quail, and then carefully examined the poop! Yes, they did, and, lo and behold, only one egg out of 1000 made it through providing us with one more reason why birds are our friends.
And walking sticks, except for the defoliating part, seem like good neighbors, too.