LIVING TOGETHER

Sometimes the most important truth can be hidden in plain sight. There are over 250,000 flowering plants that have been described. That is probably a modest estimate, but I am not a Botanist and don’t want to over-sell. There are over 750,000 insects described. That number is actually much bigger and is expected to go over a million.

Together this means that two thirds of all life forms are monopolized by these two groups. This is not an accident. These two groups of living things live together in an intimate way. Flowering plants could not exist without the service of insects to aid them in sexual reproduction, which we call pollination. And most insects could not exist without the shelter, surface, and food (nectar, pollen and plant parts) provided by the plants. These two groups are completely symbiotic: dependent on living together.

This concept of living together is a delicate and changing arrangement. There are flowers like Passiflora incarnata, the Maypop, common in the southern United States in areas like Tennessee, that are only pollinated by Xylocopa virginica, a carpenter bee. If the bee is lost, the flower will also become extinct. Or the “bearclaw poppy”, Arctomecon humilis, which is only pollinated by a solitary bee, named Perdita meconis, unknown until just a few years ago. If the flower is lost the bee will go extinct. These last two live near the Virgin River in Southwest Utah, or Northwest Arizona, as you see it.

Sometimes this balance between organisms is upset and we call the result predation, or parasitism, or disease, or extinction, or pollution or some other term. The problem is that it is very difficult to know what will upset the balance between any two or three organisms. How do we know what to avoid, or how to avoid it. It is akin to a complex structure built out of toothpicks. It is hard to predict which tooth pick can be removed and which cannot without causing the collapse of the whole system. Generally humans don’t have a clue what we are doing in this regard.

Mankind has put a lot of energy into killing insects. Many insects compete with us for our food. Some insects transmit diseases. But ironically, mankind relies heavily on the flowering plants for food and fiber. High mountain peaches, cherries, apples, pears, and apricots are just a few of the hundreds of plants we find desirable that rely on insects. So if plants need insects, and insects need plants, and man needs plants, then doesn’t man need insects?

KILL THE INSECTS?

Sometimes the most important truth can be hidden in plain sight. There are over 250,000 flowering plants that have been described. That is probably a modest estimate, but I am not a Botanist and don’t want to over-sell. There are over 750,000 insects described. That number is actually much bigger and is expected to go over a million. Together this means that two thirds of all life forms are monopolized by these two groups. This is not an accident. These two groups of living things live together in an intimate way. Flowering plants could not exist without the service of insects to aid them in sexual reproduction, which we call pollination. And most insects could not exist without the shelter, surface, and food (nectar, pollen and plant parts) provided by the plants.

This concept of living together is a delicate and changing arrangement. Sometimes this balance between organisms is upset and we call the result predation, or parasitism, or disease, or extinction, or some other term. The problem is that it is very difficult to know what will upset the balance between any two or three organisms. How do we know what to avoid or how to avoid it. It is akin to a complex structure built out of toothpicks. It is hard to predict which tooth pick can be removed and which cannot without causing the collapse of the whole system. Generally humans don’t have a clue what we are doing in this regard

Mankind has put a lot of energy into killing insects. Ironically mankind relies heavily on the flowering plants for food and fiber. High mountain peaches, cherries, apples, pears, and apricots are just a few of the hundreds of plants we find desirable that rely on insects. So if plants need insects, and insects need plants, and man needs plants, then doesn’t man need insects?

LUNCH WITH BLOODSUCKERS

When I was young I reveled in Edgar Rice Burroughs “Tarzan” books. I don’t know if I read all twenty three or not, but I read a lot of them. And while I didn’t exactly know what a tsetse fly was then, I knew it was dreaded and carried deadly disease. So I was excited years later when I found myself in a class studying African sleeping sickness, transmitted by the “dreaded tsetse fly”.

Tsetse flies are large flies, about the size of our western horsefly, that are only found in Africa. They feed during the day, and both males and females feed exclusively on blood. In feeding they transmit a microscopic parasite called a Trypanosome that in turn causes African Sleeping Sickness.

Now, there is a great fascination by young boys, of almost any age, with gory things like blood sucking. It is a recent phenomenon that so many young girls and women have become interested in blood sucking.

One fascinating subject is how a blood sucking insect finds its food. It is surprising to me how little is known about the insect food-selection process.

It quickly becomes apparent that the simple act of getting lunch, is actually a multistep, multisensory, complex, interaction of senses, behaviors and environmental cues for an insect. For example, how does an insect even know when it’s time to eat? It is generally thought that mosquitoes feed at dusk. But how do they know when it is dusk? Is it by day length and light? That certainly seems to be one cue. However, mosquitoes kept in captivity will become restless, act “hungry”, and feed when kept in constant light conditions, if presented with other cues. Then there are those species that feed at two in the morning; you know the one that wakes you up with that dreaded buzzing in your ear.

Blood sucking insects can’t really expect dinner to remain in a fixed position until the next meal, like a McDonald’s resteraunt. So how do they locate a blood source? It is commonly thought that they follow a carbon dioxide plume, but carbon dioxide is actually only an exciter. The mosquitoes get excited whenever the concentration of carbon dioxide changes, whether it increases or decreases. They don’t follow the carbon dioxide as much as they react to it. Since carbon dioxide levels fluxuate continually, why don’t they react then? When presented with several selections on the menu, why do they always pick me? How do they decide between an arm and a leg, and which position on the arm is most attractive? The questions seem endless.

This is all complicated by the fact that there are over 3000 species of mosquito in the world and each has its own peculiar time, place, and preferred host for feeding.

Now for the amazing part: only half of mosquitoes take a blood meal, the females. The males feed entirely on plant sources of sugar. Females only require blood during reproduction. The rest of the time she lives on plant nectar also. So various floral and plant sources provide the great bulk of day-to-day mosquito energy needs. Yet our knowledge of when, where, why, and how they seek floral nectars is minimal.

Better understanding of the feeding habits of blood sucking insects would aid in the development of better control strategies, and improved disease prevention since most blood sucking insects are capable of transmitting disease. Answering questions like “How do tsetse flies know when it is dinnertime?” and “What flowers do mosquitoes prefer?” are what biologists do.

I have a couple of ideas about how to answer these questions. If you’re interested, wait until you are moved upon by some mysterious change in the carbon dioxide concentration and give me a call. We’ll do lunch.

SYMBIOSIS

Sometimes significant truths are hidden in plain sight.

You might be surprised to know that there are more parasites than free-living animals. Every free-living animal that has been carefully examined has had at least one animal that lives exclusively in, or on, the host. This fact alone, if borne out by continued studies, would make the number of animals living on other animals equal to the number of hosts. But in addition, most animals host much more than one other animal that are shared with, perhaps, numerous other hosts. So if there are a million free-living animal species, there must surely be at least a million other animals that live on them.

Of course, “parasite” may not be the correct word for all of these animals, but that is a semantic discussion, not relating to whether such animals exist in large numbers or not. I may discuss that very issue in a later essay.

Another group of animals that live exclusively in, or on, another living species are the pollinators. The biological connection between the flowering plants and pollinators is so strong that one simply would cease to exist without the other. The majority of flowering plants require an animal to move pollen from one flower or plant to another. But the pollinator requires the flower to supply pollen and/or nectar, absolutely essential to the pollinator’s survival. The two are entwined in an ecological dance that is absolute, and mutually dependent.

Approximately a quarter of a million plants, and three quarters of a million insects, has been described by scientists on the earth today. Together this accounts for fully two thirds of all known organisms on our planet. This is not an accident. These two groups are interdependent for food and reproductive services. There are literally thousands of partnerships between insects and plants. Most are fragile, many are very specific, and often they include third party arrangements. If one partner is lost or diminished, the others will also be lost or diminished. The world does not consist of species. The world consists of ecosystems and partnerships.

The German mycologist (fungus specialist) Heinrich Anton de Bary coined a term as long ago as the late 1800’s for these kinds of relationships: symbiosis. He defined them as “the living together of unlike organisms”. This term has been modified over the years to have slightly different meanings. But I think the original meaning captures a concept that has not been properly appreciated in scientific circles.

Important common phenomena are sometimes underappreciated, while the new, the esoteric or the scandalous captures our attention. In the years since Darwin, evolution has become a dominant scientific principle. “Survival of the fittest” is a common metaphor. But what if the “fittest” doesn’t mean the strongest, or fastest or best adept at hiding, or most prolific as is popularly thought? What if “fit” actually means the ones best at living together? There are literally million of examples that this might be the case. And the pollinators may be the best example we could study.

The study of symbiosis may be one of the true unifying principles of Biology, and one that could more productively be applied to human existence than the results of social Darwinism.