Monday, September 27, 2010

Praying for Mantises

I don't remember much about praying mantises from my childhood. I have to think that I didn't see very many of them if I saw any at all. Surely anything that fascinates me so much as an adult would have grabbed my attention as a curious youngster. Oh, and rest assured I was curious if nothing else. I examined everything and brought way too much of it home. Many of my childhood fascinations have followed me into adulthood. Since I cannot remember them from childhood, I have to assume that praying mantises came relatively late into my life. Oddly, though, I don't remember when that might have happened. But  it did happen and for a long time since they have occupied a prominent place in my consciousness, especially at certain times of the year.

It is usually in the late Summer and early Fall. I go into a state of high vigilance as I go on the lookout for one of those most interesting of insects, the praying mantises. When the weather is hot and the vegetation is lush in mid season, I almost never see them. It is not that they are not there. It is that they are secretive, stealthy hunters who are well camouflaged in the vegetation they use for ambush. They are busy eating and growing in the run up to the mating season when their normally solitary existence begins to change to something more social. Once the Summer starts to fade into Fall, I know I can count on seeing one or two of them, usually females, somewhere in my yard.  Nevertheless, there is always an element of suspense to my annual search. I never know for sure when and where I will have that first sighting. I just know I can't wait.

Perhaps I should call it a hunt even though that sounds too predatory for the way I feel. If I am the hunter or predator in this case, it is only with my eyes and my camera. My shot does not ring out with the explosion of gunpowder and my target does not fall fatally wounded from a high tech projectile hurled from ambush. I do not stuff their murdered bodies and mount them in my den for all to see and I don't eat them. I am only after the image and maybe the connection with this most interesting creature, not the body and not the soul. I have to trust that those are simply wrong who believe that by capturing an image I am imprisoning a soul .

The first sighting of an adult mantis is always a thrill. This year it was a real bonanza. There were three different mantises in one bush at the same time. They were in a place I always check because at least one seems to show up there every year. I worried that these three might encounter each other and that some sort of conflict might ensue. Nothing happened that I could see. The three of them stayed there for most of the last part of Summer. They were all females and it was egg laying time. Conflict with others was probably the last thing on their minds.

Finding that first mantis is one thing. Getting the photograph I want is another. Don't get me wrong. It is very easy to get a picture of a mantis  once you have found the insect. They are very cooperative in that way. It is almost as if they can't wait to pose for the camera. And that is precisely the problem. Getting a candid shot of a mantis is a bit of a challenge because the are difficult to sneak up on.  Here I have spotted one deeply concealed in a bush but I can get only one shot off before she turns  and looks me straight in the eye. So much for mantis candids.

 They are very wary but show little or no fear of humans. If they do feel threatened, they either move away or turn toward the threat and show a threatening posture of their own. Even though they can fly, that doesn't seem to be their first impulse when confronted.

This one has assumed a threat/defense posture which is telling me that I have gotten too close and should back off. Students of the martial arts, especially Kung Fu, will recognize the classic raised arms of the Praying Mantis Style. If one persists in getting too close, some mantises might actually attack by jumping toward the threat. That despite the fact that they represent absolutely no real danger to humans. They have no stingers and the grasping forelegs that are deadly to smaller insects can barely penetrate human skin. Nevertheless, the quick strike of a defensive mantis can be an intimidating experience, even for old school nature lovers like myself. I am forever grateful that they do not get much bigger. A two-foot mantis would be something to contend with.

Both of the adult mantises in this entry (one brown and one green) are female and both are heavy with eggs. Hence the large abdomens. In late Summer they lay their eggs in foamy secretion that forms a surprisingly tough bell-shaped case once it is dry. The foam comes out as a very wet, bubbly, sticky foam not unlike that expandable foam used by builders to insulate and fill cavities in home construction. It hardens quickly to form a tough, almost impenetrable place for the eggs to develop. The small case shown below was deposited late in the season by the very same female shown above in threat posture.  The case is small as she was nearing the end of her egg supply and the end of her life cycle. Her last few eggs were probably laid in the smaller, incomplete case just to the right. She will spend the remaining days in a weakened state and vulnerable to predation by other creatures seeking provisions for the upcoming Winter.

If all goes well and some pesky parasitic wasp doesn't find the egg case right away, the little ones are safe for now. Over the cold months of Fall and Winter, they begin their slow development, accelerating when there are warm spells and slowing down during the coldest periods.

(I once made the mistake of bringing one of these egg cases home after finding it during a fall hike. I left it out on a warm window sill in my kitchen. You can guess what happened. One day in December I noticed lots of little grayish "ants" crawling all around the egg case and well beyond. They weren't ants at all. They were what seemed like hundreds of little praying matises busy trying to make a life for themselves. Sadly none of them survived. The few I managed to capture just ate each other until only one or two remained. They did grow a bit but finally succumbed despite my best efforts to feed them fruit flies and some small bugs that I managed to find outside in Winter.)

By Springtime they are ready for the world and the end of anything even close to safety. The little ones hatch as soon as it starts to get warm in early Spring. They emerge by the dozens, maybe hundreds, from the egg cases and begin life as formidable little hunters. Barely over a quarter of an inch long, they come out as nymphs, fully formed preying mantises except for the wings. They are complete with over-sized eyes and those lightning fast front legs that have inspired martial artists for centuries. They emerge as minuscule but very effective little predators.  The little ones will attack and eat anything that moves as they disperse quickly from the egg case. Often that means attacking and eating any of their kin they happen to encounter. For many of them, life is a simple zero sum game to be played out first with siblings and later with other small creatures. Eat or be eaten is the rule. One is either the diner or the dinner. It is just that simple. These two youngsters are in just such a standoff. In this mini-drama, the one on the left must decide whether to turn and face the advancing sibling or leap for the closest branch. In this case discretion proved to be the better part of valor. He made the leap.

Most mantises don't survive their infancy. Those that do have made it through a gauntlet of spiders, wasps, birds, big raindrops, their own kin, and lots of other potential misfortunes. At least they do not have to worry about adult mantises. None of those will have survived the previous Fall or Winter. The big ones are all gone. Some of the new ones will grow up to be adults in their own rights and take their places among some of the top predators of the insect world.

Here is one of the adult females at work gathering in the last bits of nutrients for the season. She has caught a grasshopper. This is the same mantis that was looking so threatening in one of the photos above. For now she is getting just enough nutrition to see her through the physically demanding process of laying her eggs. While it might be difficult to tell them apart by color and some elements of structure, there is no mistaking their different roles. Mantis and grasshopper are diner and dinner respectively. It may not be pretty but it is what there is to be seen. So I watch and learn and share, another carryover from childhood.

And so it goes every season with little variation. I plan to be there again in the Spring to watch it unfold all over again. Maybe next time I will get lucky and see something I have never seen before. That, after all, is why I keep looking. If I am really fortunate I'll have my camera close at hand. In any case, you know I will share.

Tuesday, September 07, 2010

Butterfly No More

In some sense this is a continuation of the Cicada Story from a previous blog, but not really. There are no cicadas involved here and that turns out to be a real mystery. That will make more sense if you have read the previous entry. In any case . . .

It was in the mid nineteen seventies, many years after that first encounter with the cicada killer wasp, the one that took down Grandpa Cricket right before my eyes. I was spending a beautiful late Summer afternoon walking along the shore of Kerr Lake in Warren County, NC when I heard a strangely familiar sound. It was a kind of dull buzzing, almost brittle rattle.  Maybe like the sound of a crumpling cellophane candy wrapper, only not so brittle. But this was not paper and nothing so sweet as candy. This was a ruckus and it was coming from a patch of pine straw and dried leaves that only served to amplify the noise. As I went to investigate I somehow felt that I knew that sound and knew what I would find.

I was almost right.

There in the leaf litter a cicada killer wasp was wrestling with her prey. The ruckus I heard was the sound of clashing wings and rustling leaves. It didn't take long for all the struggling to stop and the victim to fall motionless and quiet. Quiet? Well, actually the victim never uttered a sound that I could hear, not even during the struggle. There was only the sound of the wings and the leaves.

I don't think I had seen one of those wasps up close for years, not since I saw one take down Grandpa Cricket, that larger than life figment of my childhood imagination. This time she had a surprise for me. Her prey was not a cicada. It was a butterfly! The cicada killer had attacked a butterfly, a tiger swallowtail. I had arrived just in time to watch the drama unfold. There was a brief struggle then all was quiet. She straddled the butterfly, grasped it by the body and tried to fly away with it. It should have been an easy task for her. After all, a butterfly is much lighter than her normal prey. But it was not to be. The load was light enough but much too cumbersome. The large butterfly wings were interfering with the wasp's flight. Each time she lifted off with the quarry, she had to drop it to the ground or fall out of the air herself. Her normally quick, graceful and powerful flight looked clumsy and amateurish. I watched her make several attempts to take the butterfly to the tomb she had prepared for him, a tomb that was in fact a nesting chamber for her soon-to-be brood. She was failing every time.

After many attempts she gave up or so I thought. Instead she had a  plan B. That is when I saw the most remarkable thing. She dropped the butterfly for the last time, landed on the ground nearby, crawled over to the victim, and  began to chew off the wings! First one wing, then another dropped to the ground. It was absolutely surgical. She methodically removed all four wings right where they attached to the thorax. Then she picked up the wingless butterfly body and flew away. They were gone in an instant, just like before. I stood there absolutely stunned. That little wasp had solved a problem in a very elegant way. I had already held the cicada killer in some esteem. After all, it was she who reduced Grandpa Cricket to a mere insect of manageable size. But now she had raised the bar. This insect could think! She had solved a problem right before my eyes.

After some moments of reflection, I picked up one of the butterfly wings and went home. That was enough adventure for one day. It supplied me with a story that I have shared many times, this being the latest. One of the great mysteries of that day is why I only took one of the wings. I left the others there, perhaps as testimony to what had happened. Not that anybody would be able to decipher the story from that little piece of evidence.
When I got home, I placed the wing in an envelope, quickly penciled in some notes, stuffed it in a notebook, and forgot about it. I think I had a haiku in mind when I made the notes but didn't want to take the time to properly construct one. It was some years later when I rediscovered that lone butterfly wing while browsing through one of my notebooks. It was badly deteriorated so I decided to mount it and keep the notes as they were, some form of imperfect, unrefined "lowku" with way too many syllables and lines to be anything else. I suppose I could use the first line as a title, then it would come close but that is not how I originally wrote it. Here is how it appeared in the notebook:

Butterfly no more
Paper-thin rattle
A burden for the hunter
Just baggage
No more

Now the wing, along with the original note, is matted, framed, and placed where I can see it from time to time. Nevertheless it has continued to deteriorate. The color has faded, pieces are missing, and the tiny scales that make up the mosaic of the design are falling off.  No doubt, though, this one lasted much longer than its mates, the three others I left lying there on the shore to tell the story to anybody who happened by and who was willing to listen.

Added Note:
(Warning: This part is kind of geeky. Don't read it if you think it might spoil the story for you.)

Over the years I have continued to doubt myself and this accounting. Did I really see it? Would a cicada killer really switch prey species? Under what circumstances? What would the next generation prey on if they developed a taste for butterfly? I do know that prey switching is not uncommon in other predatory species. What about the parasitoids, do they switch? Could it have been another predatory wasp that large with those markings or another kind of predatory insect? How about a robber fly? No, not the right kind of mouth parts for the surgery. I have finally decided that this one was certainly a cicada killer who might have been adding extra provisions to a nesting cell for a female egg. The female larvae are bigger and require more food. There already could have been  a cicada or two in the chamber. The butterfly was just a little extra insurance (or dessert if you prefer). Entomologists please weigh in here. 

I would love to have added one of my own photos of a cicada killer wasp but I wasn't able to get one this year. If you want to know what one looks like try this external link. Just be sure to come back here.