If you spend time in a museum, aquarium, zoo or similar type of place you’ll notice that the visitors get really excited (I mean really excited) about one thing in particular: feeding time. I’ve volunteered and worked in several places like this and the story is always the same. Kids will go nuts and crawl over one another to see snakes chase down and eat mice; they’ll push each other out of the way when tarantulas stalk and feed on cockroaches; and everyone is completely awestruck watching praying mantises hunt down crickets before snatching and eating them alive. It’s at times like these when people consider animals to be at their most exciting: the pursuit and the capture. Some people find it horrible, but wonderfully so.
The universal fascination with predation means that it comes as no surprise to others when I tell them that predator-prey interactions are one of my favorite things about nature and something I choose to pursue in my research. Everything thing about animals eating other creatures is fascinating. Considering all of this, one of my favorite concepts in predator-prey interactions will always be the “Red Queen’s Hypothesis.” The father of the Red Queen’s Hypothesis, Dr. Leigh Van Valen, died yesterday from leukemia at the age of 75.
The theory behind Van Valen’s Red Queen’s Hypothesis is that plants and animals are locked in a life or death struggle with other plants and animals over evolutionary time. To distill this down into a single example, I’ll use that of bats and moths, on which I wrote a recent post. In this example, bats began navigating the night sky using echolocation to avoid obstacles and find prey (moths). In response to bats’ use of sonar for hunting, moths evolved (through natural selection) behaviors to avoid or avert echolocating bats (like erratic flying and dropping to the ground). As a response to this, some bats evolved calls that were quieter so they could “sneak up” on the moths. Essentially, the RQH describes an ever-escalating, evolutionary arms race between two sides that are forced to develop of strategies and counterstrategies in order to survive. It’s an idea that’s as vivid and elegant in its conception as its title.
Van Valen came up with the name for the Red Queen’s Hypothesis from a verse uttered by the Red Queen in Lewis Carroll’s work Alice: Through the Looking Glass.
“It takes all the running you can do, to keep in the same place.”
Alice finds that in the world she’s entered, one must run hard just to retain his or her position in space. In terms of bats and moths, it means that when one side develops an ecological adaptation that gives them an advantage, the other has to then develop a counter adaptation to survive or face extinction. Each player must actively evolve in order to maintain their relative effectiveness against the other species. It makes sense and seems intuitive and most biologists can rattle off a dozen or more examples of the RQH in action. Yet it wasn’t really established until Van Valen laid it out in 1973.
The RQH was only one of his many fundamental contributions to biology. Van Valen also gave us the Ecological Species Concept, which is one of the dozen-or-so definitions of what a species is. While the average person may not give a flip, the definition subscribed to makes all the difference in terms of species conservation laws and their enforcement. For instance, there are between 1 and 12 different species of brown bear (Ursus arctos), depending on whom you ask and which species concept they subscribe to.
Dr. Van Valen, a member of the Ecology & Evolution faulty at The University of Chicago, was also a talented mathematician and conceptualized “fuzzy sets” which are used to quantify qualitative criteria. The formulae help to assign a “degree of membership” to any number of things making it possible to draw mathematical conclusions from non-mathematical concepts. He was also a force in the fields of thermodynamics, logic, epistemology and probability theory. His life was prolific and his death is a great loss to science.