A few weeks ago I was at the Placerita Nature Center when a docent, all excited, asked me if I had seen the walking stick. Well, we have a nice collection of fancy walking sticks in the gift shop. They sell slowly, and although they are really pretty, many of our visitors come prepared with their own. So I was not sure what all of the excitement was about. Did we get a new shipment? A new style? One that sparkled?
She must have realized by my puzzled look that I was lost – so she grabbed my hand and brought me to the front of Apollo’s cage. Apollo is our resident turkey vulture. Here was a walking stick hanging on the side of the cage.
The walking stick is one of the oldest forms of insect known to man. The first form of walking stick can be traced to 200 million years ago during the geologic time called the Triassic age. It is a long, strange-looking insect that appears to be made of a few dry twigs.
It is such an expert at camouflage that you really have to look closely to make sure it is an insect. If I had given the cage only a passing glance, I would have thought a little twig was caught in the cage and would not have looked again.
To make the situation even trickier, the body of the walking stick seemed to be swaying gently in the wind, the way a branch would move. That is another way they camouflage their body, taking cues from their environment. They actually bend their knees to make this little movement. It is hard to notice a walking stick unless it is isolated on a window screen or, in this case, on the side of the cage.
If it feels threatened, it plays dead, falling to the ground like a dead twig. If you were a bird, intrigued to eat it, you would shrug it off and look for a real lunch … or at least this is what the walking stick is hoping for.
Like a lizard which can sacrifice its tail, some walking stick species can even sacrifice a leg to escape from a predator, and the leg will grow back in a few weeks.
They are usually nocturnal, feeding and otherwise active at night, so that makes it even harder to spot them. Their body length ranges from 1/2 inch to 13 inches.
They can be found in many parts of the United States but are most plentiful in the warmest part of the country and are known by many colorful names: devil’s riding horse, devil’s darning needle or witches’ horse. Its taxonomic name comes from the Greek word “phasma,” meaning phantom or apparition. I think this name was particularly well chosen, and I’ll bet you will this so, too, if you look at the photos.
It looks like a stick but the body is formed of three parts: the head, thorax and abdomen. In the head there is the brain and mouth, but no apparatus for breathing. They breathe through the thorax and abdomen using structures called “spiracles.”
They have eyes that can detect images, motion and color, as well as antenna that can sense hot or cold and can check on smells. They have three pairs of long legs ending in small claws and a suction pad on their feet, helping them climb even on smooth surfaces.
They eat plants and seem more interested in the leafy part of the plant. Certain species eat only one type of plant, so it can be a problem for that plant if there is a large infestation of walking sticks. However, because they do not have wings, the insects’ reach to higher parts of the plant is usually limited.
They are the prey of birds, reptiles, spiders, rodents, praying mantis, and because they are nocturnal, bats eat them, too.
The life span of a walking stick is usually about a year, so mating and producing eggs is important for their survival. The couple, while mating, can be attached together for hours, days or even weeks. But even if the female cannot find a partner, she can still have viable eggs.
Eggs produced without a male can only become female walking sticks. Animals that can reproduce asexually are described as having the characteristic of “parthenogenesis.” That can be a very useful way for a species to survive one or two difficult seasons in one specific area, but it cannot last for much longer than that, I imagine.
The eggs are dropped to the ground into leaf litter. For some species, the eggs are even buried in the ground by ants – a good way to have them protected from predators. They look like seeds, so being hidden underground is just perfect. In springtime, the eggs hatch, the nymph climbs into a tree to become an adult, and the whole circle starts again.
Walking sticks are strange creatures. They have perfected the art of mimicry, since they look in almost every respect like a small twig. The purpose of mimicry is to trick your enemies into thinking you are not good to eat. (Why eat a twig?)
It is obvious that their appearance helps the walking stick deter many predators, but some other animals use mimicry not only in copying appearance, but even making the sound of another animal to survive. The robber fly (without a stinger) makes the same sound as the bumblebee (with a stinger). If you are a predator, you do not want to check too closely; you have learned you do not want to get stung, so you will leave the robber fly alone.\
Some butterflies are poisonous, and birds have learned not to eat them – but some other butterflies have similar patterns and color and take the benefit of that notoriety to stay alive.
Sometimes, a dangerous or venomous animal will develop a bright color pattern, and it usually means stay away. Red and yellow are meaningful colors in this respect. I am thinking of the coral snakes that really advertise, “do not touch me,” with its red and yellow bands. However, there are quite a few harmless copycat snakes with similar patterns, riding on the help those colors provide. The more they resemble the deadly snake, the more they will succeed.
With all of this discussion, it’s worth remembering that this evolution is a long process. Nothing in nature happens quickly. However, if all survivors of the predators had those specific markings in common, those are the traits that are going to become prevalent for the species, helping them to survive and passing those genes to the future generations.
Just like we dress up for Halloween, assuming a new identity and playing at being someone else, these animals that look like a stick, a piece of bark, a stone or a different dangerous animal do that for survival and have certainly refined their technique.
I doubt the walking stick will still be there the next time you visit the Nature Center – but remember that something you see might not be quite what you assume it is.
Take the time to look carefully, and you might get a great surprise like I did.
Evelyne Vandersande has been a docent at the Placerita Canyon Nature Center for 28 years. She lives in Newhall.