Thursday, June 28, 2012

Botfly Lessons

There are a lot of creatures in this world that get bad press. Think of rats which hide beneath old boxes in garages, and that linger in our memories as the carriers of plague. Or consider rattlesnakes that slither in tall grass and bite unsuspecting passersby. Or the yellow jacket that interferes with our picnicking and stings us when we least expect it.
Of course we recognize that these creatures have their place. And in our more reflective moments – safe in a clean and comfy easy chair – we will grant them a place in the created order, far away from us. There are a handful of things, however, that hardly ever make it even to this guarded list of acceptable nuisances. Mosquitoes, for example, come to mind. What good do they provide? Not many of us have the understanding (or the desire) to accept their immature stages as an ecological plus - as fish or frog food. They are just pests, plain and simple.

And then there is the little known but greatly despised botfly, an insect about the size of a honeybee. Bots make their living by burrowing into the bodies of animals, including humans. Female flies drop eggs either directly onto the skin of animals or they capture another creature, like a mosquito or a tick, and lay eggs on it. These smaller creatures then find their normal warm-blooded hosts and when the young botflies (now having become small worms) sense warmth, they drop onto the new host. In either case, the little worms then burrow under the skin of their unsuspecting benefactors.

I remember a number of years ago, a friend of mine told the story of his mother’s encounter with one of these noisome insects. She had been visiting tropical America with her husband and must have picked up the parasite during their travels. She didn’t notice the bump on her skin until the bot was half grown.

And in fact this is not unusual. As small worms, the botfly larva can burrow under the skin without detection for several days. They artfully consume living tissue while leaving the nerves untouched. The human bot cases that I know of have not experienced pain of any kind. Remarkably, even the initial act of burrowing into the skin is not felt.

When my friend’s mother discovered her parasite, she was alarmed at first and then fascinated. She is a hardy sort of lady with a passion for natural history and her curiosity soon overcame her anxieties. She decided to let the insect emerge. Several days later, it did just that as she was taking a bath. The fully-developed larva broke through her skin around the neck and dropped to the ground. In the wild, the worm then hides itself in the soil to pupate, before emerging as an adult to start the process over again.

In North America (where I live), this doesn’t happen very often. We have a handful of botflies but these are parasites of non-human animals. People that have the misfortune of carrying one almost always pick them up from the tropics, where the human botfly (Dermatobia hominis) lives.

But there are exceptions. Occasionally a disoriented botfly will mistake a human for a sheep, a horse, or some other creature. I know this from personal experience.

A few years ago, while travelling on the dusty back roads of eastern Wyoming, I had a botfly land in my hair and lay at least one egg. I didn’t realize at the time what had happened. I thought it was just an ordinary prairie fly that was unfortunate enough to get blown into a slow-moving truck (of a foraging entomologist).

Several days passed. I was now at home in Windsor, Colorado taking a shower and noticed a lump on my neck. This worried me and over the course of several days I became convinced that I had cancer. The thought was constantly on my mind, although I kept it to myself. I wasn’t sure how to deal with it.

Then one morning I lay in bed longer than usual (it was a Sunday). While I was in that half-conscious state between sleep and wakefulness, I realized what had happened. I remembered the Wyoming fly buzzing around in my hair and knew that it must have been a botfly. I quickly ran my hand over the area of my head where the fly had landed. Sure enough, there was a bump.

Now if I had been a little more restrained and in control of my reflexes, I might have left it alone and waited for the larva to come out. I wasn’t and I didn’t. As an immediate reflex, I buckled my fingers and punched myself on the head. Not just once, mind you, but several times. Kathy, who was asleep next to me, rolled over and mumbled something incoherent. After a few minutes, it was all over. Then I remembered the lump on my neck. It was still there and I realized that it was an enlarged lymph node. My body had been fighting the parasite in its own way without my knowledge. The lump stayed on my neck for several days before going away. Slowly my body cleansed itself of the worm, and my head – bruises and botfly behind – began to heal.

It’s understandable that we would despise botflies. If the very thought of one doesn’t give you the willies, I challenge you to find a picture of one emerging from its host. Unless you happen to have a truly unusual stomach, I guarantee that you will lose your appetite in short order.

What are we to make of such creatures? I know of no Victorian descriptions or essays of natural theology dealing with botflies. Such stories were often written during the 19th Century with the intent to draw a moral lesson from the Creation or to gain insight into the mind of the Creator Himself. The botfly, it seems, is hard to make sense of in this sort of doctrinal milieu.

It is clearly a creature of mortality – of the fallen Darwinian order. It is one of those threads – woven into the fabric of Creation – that ensures a future dissolution. Its very existence is a hint that evil cannot be escaped in this mortal sphere. And maybe this is its purpose. This part of our divine curriculum involves death and suffering and bots are one of its purveyors.

In certain parts of the world and to some animals this fallen fly requires a very real vigilance. The tropical American oropendolas are one of these. They are fairly large birds that are known for their large well-crafted nests that hang like grassy gourds from high branches of trees. A golf-ball sized hole is the entrance to the nest. And, as you may have guessed, sometimes botflies make it inside and feed on the young oropendola nestlings. When they do, the young birds often die.

But often the botflies don’t bother the birds. When there are wasps or wild bees living nearby, the flies stay away. The oropendolas also have another line of defense. It comes from an unlikely place. In fact it comes from a bird that we often despise. It is a parasite known as the cowbird, and it lays eggs in the nests of other birds so it doesn’t have to do the hard work of raising a brood itself. And since the cowbird hatchling is more aggressive than the baby oropendola, it gets more food from the dutiful oropendola parents. This unsolicited adoption at first might strike us the wrong way. But, in fact, there is a benefit to the young oropendola. Cowbird chicks are quite good at eating botfly larvae. In fact they can even snap up an adult fly now and then. When bee swarms are not around to protect oropendola nests from bots, letting cowbird chicks into the nest is the next best strategy. In fact adult oropendolas are known to aggressively keep cowbirds away when bees are around. When they aren’t, they let the cowbirds lay an egg in their nests. This is a surprising level of sophistication for a bird.

It is also an uncommonly good window into the ways of mortality. With parasites and predators all around us, our decisions often revolve around choosing between two evils. Do we let botflies feed on our family or do we agree to pay the mafia boss (cowbird) to protect us from such a scourge?

Or maybe the decision is less obvious. Do we decline an important business dinner or skip our child’s choir performance? Do we go without a car repair or eat beans and rice for a month? Sadly mortality is full of such dually dislikable decisions. And in the end they get the better of us. Mortality always wins Round One (or is it Round Two, or Round Twenty Two?).

To someone who believes in the Created Order the legions of bots and their ilk can leave us wondering about the priorities of Heaven. If the Creator can paint such a beautiful sunset and design the tail of a peacock, what on earth is the reason for parasites?

There haven’t been many good answers to this dilemma. There is, however, an unavoidable conclusion if we are willing to admit it. The experiences of actual life on earth are meant to include suffering and ultimately death. This may seem unreasonable to many of us. After all, we spend so much of our time and resources intentionally mitigating the bad in the world. How can divinity do anything less?

The truth is that such an avuncular deity as our democratic world contrives is not necessarily the same transcendent being that our ancestors worshipped, nor is it the Heavenly Father of our sacred texts. The truth is that there is no necessary conflict between the realities of a divine Creator of beauty and a divinely established decay.

Our wise teachers and leaders have always provided us with challenges to overcome. We acknowledge that there is no royal road to learning. In fact the exams we face often get progressively more difficult as we move from kindergarten up through high school and college. Why should grade earth be without its own challenges?

One solution to all of this is to recognize that part of our earthly curriculum is to be bothered by bots, to be beaten by disease. This is the way mortality is meant to be. I don’t mean that we should resign ourselves, as some belief systems encourage, to the exsanguinating insults of insects. (I, for one, still swat every skeeter that I can.)

But consider for a moment what this suggests: there is amazing beauty in the world in spite of our aches and pains. Surely, then, beauty is possible without them. If death is imposed now, what will life be like when it isn’t? Or maybe more immediately: how can life be improved if we admit to the terms of the test?

For starters, we might realize that humility is the correct approach to a fallen world that we cannot escape. And with an eternal perspective, this humility can develop into gratitude. We can decide to take a hint from the Creation and accept bots for what they are – a possible essay question on a mid-term exam.


For a discussion of oropendolas and cowbirds see Don Moser’s Central America Jungles (one of The American Wilderness/Time-Life Books, 1975) starting on page 97.

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