A Walking Stick on Lynne's Hand
A Walking Stick on a Lilac bush.
Walking Sticks are just about on the top of my list of things in natural world that are just truly amazing. I rarely get an opportunity to see them, and so it was an exciting moment when I heard Richie shouting from outside that he had found one on the car door. He carefully moved it to the screen door where it stayed quite still with its front legs sticking straight out in front along side its long antenna, very much resembling a four legged pine needle. I closely examined its three inch long, slender copper colored body. How curious that its abdomen was segmented in similar fashion to the damselfly!
Wanting to learn more about them, I researched the subject on the internet, using walking sticks as a key word and was amazed by the amount of information that is out there about them. I was surprised to learn that they are quite popular as pets, and though I don’t recommend this treatment for any wild creature, they are relatively easy to keep, providing that there is a year round supply of fresh blackberry leaves and water. (Needless to say for those of us in this north eastern climate this can be problematic.)
In the last 15 years that we have lived in Greenwich, this is only the second time that we have had the opportunity to see them. They are so well camouflaged that they are quite difficult to find. In fact, their family name Phasmid comes from the latin term “phasma” meaning “ghost’. There are over 2,700 species worldwide of insects that resemble both sticks and leaves ranging in size from 1/2 inch to 13 inches long and some species (especially the larger ones) can live for up to two years! The United States is home to about 30 species.
Stick insects lay eggs which take 1 to 18 months to hatch depending on the species. Some eggs are dropped to the ground or are buried, and there are some that adhere their eggs to leaves or bark. I found it remarkable to learn that the variety of eggs which are dropped to the ground possess a rather large 'capitulum’ - a small cap like protrusion on the egg that contains a substance that is attractive to ants. The ants take the egg back to their nest, cut off the capitulum and feed it to their brood. The egg is then discarded in the ‘garbage dump’ where it is left to hatch relatively free from danger of birds or other predators. What I find so extraordinary about this is that seeds from certain plants contain a food body called ‘eliasomes’ that attract ants in a similar manner where the seeds are collected and brought back to the ant nest to nourish the young. Walking sticks imitate the plant world not only in their physical shape as adults, but also in their egg state as well! It has been found that the eggs that have been adhered to leaves or bark tend not to have the capitulum, or it is reduced greatly in size.
After hatching, the nymph resembles a miniature adult, and will go through 5 (for males) to 6 (for females) molts to full maturity. They grow by climbing out of their skins while hanging upside down. These stages are called "instars". After the final molt, or instar, they can reproduce. This final stage is also when wings develop only in the males of some species. Generally, females are much larger than males as their abdomen must be large enough to accommodate their rather large eggs and need a sizable mouth to eat more food.
If there are no males available, some species can reproduce by parthenogenesis - where the unfertilized egg can develop on its own to produce another female. There are even species of walking sticks where there are no males!
After several minutes of observation, we placed the walking stick on the leaf of a nearby lilac branch where it made no move to escape. He may have thought of himself as invisible, but after several moments of in plain view, I picked him up and placed him safely under a large honeysuckle bush, where he trundled steadily away.
photos by R. Bittner