The Red Queen Hypothesis of Selective Adaptation

— This article by Jerry Cates, first published on 1 March 2010, was last revised on 29 April 2016. © Bugsinthenews Vol. 11:03(02).

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The Red Queen Hypothesis is based on a passage from Chapter II of  Charles Dodgen’s (under the pen name of Lewis Carroll) 1871 book “Through the Looking-Glass.”

Sir John Tenniel’s drawing of Alice’s First Meeting with the Red Queen.

The principle set forth by this hypothesis was formalized, slightly more than a century later–in 1973–by Leigh van Valen, in a paper published in Evolutionary Theory, entitled “A New Evolutionary Law.” In Dr. van Valen’s words: “For an evolutionary system, continued development is needed just to maintain its fitness relative to the systems it is co-evolving with.”

This is counterintuitive. We presume an evolutionary development in a species to be, intrinsically, a move “upward.” Yet, if that development merely counters an adversarial development in a competing organism, stasis (lateral movement that maintains the status quo), and nothing more, results.

Snakes, for example, illustrate the Red Queen principle when, in their evolutionary development, they develop more effective venom glands, stronger fangs, and musculature and ligaments that assist in their exploitation, in order to counter the development of armor, immunities to venom, and improved escape behavior used by their prey. Even snake species supposedly bereft of venom glands or fangs have developed specialized salivary glands (i.e., actually a form of venom gland, so that the distinction between Duvernoy’s glands and “venom glands” is somewhat controversial) that produce proteins with phospholipase A₂ activity, for that same reason. If those specialized (Duvernoy’s) glands produce a marked improvement in the snake’s ability to survive and thrive, their secretions tend to grow more powerful over time.

The Red Queen Principle works in the opposite direction, too. Certain ants commonly called acrobat ants, now placed in the genus Crematogaster, were initially equipped by their ancestors with powerful abdominal venom glands, along with hardened stingers manipulated by strong muscles. At some stage in their evolutionary development they acquired, through a chance mutation, a pedicel that attached to the dorsal thorax. This enabled them to swing their stingers upward, over their bodies, the moment a predator threatened.

Acrobat Ant (Crematogaster spp); Temple, Texas, 04.19.10–dorsal view

Today acrobat ants in the genus Crematogaster have only vestigial structures for venom production, stinging, and ejection of venom from reservoirs through the stingers. The attachment of the pedicel to the dorsal thorax, however, not only remains, but is now assisted by highly specialized muscles that swing the abdomen upward at the slightest provocation.

This lets these ants vigorously display what appears to be a serious, deadly capacity to sting, and that display, alone, has proven sufficient to discourage predatory attacks. The stingers and their associated venom glands, etc., are no longer needed. Because, in the distant past, these ants used their stings purely for defense, and not for food production, any evolutionary developments that atrophied the stinger, musculature, and venom glands conferred a survival advantage on them, enabling them to thrive at levels superior to those with intact stingers and venom production systems,  simply because the absense of these structures enabled them to transfer the energy previously spent on those structures to other, more productive, pursuits.

Anyone wishing to learn what the Red Queen Principle is all about must read Matt Ridley’s book by that title, first published in 1993. Ridley’s book is subtitled “Sex and the Evolution of Human Nature,” which suggests a narrow focus. He admits that his book is an inquiry into the nature of human nature and its evolution, and is based on the presumption that the central theme of that evolution is sexual. He goes on to assert that “there is nothing in our natures that was not carefully ‘chosen’ in this way for its ability to contribute to eventual reproductive success.” Yet, though human sexuality is Ridley’s focus, he uses a multitude of non-human examples to illustrate and prove his points.

THIS PAGE, and this topic, are constantly being revised and extended, and will be fleshed out more as time permits…