Religious Supplicant, Seductive Cannibal, or Reflex Machine? In Search of the Praying Mantis

The original, prescientific Western belief that the mantis is a pious, helpful creature became a widely held explanation for the mantid's unique resting (apparently prayerful) posture, and for one of its cryptic displays (extending the forelegs straight out). This belief was a characteristic part of a broader discourse about nature in which ancient authority, religious beliefs, and superstition, but few original observations, mixed freely. Gradually, the belief in mantid gentleness and piousness became a commonplace through the continual retelling of the myths and superstitions surrounding this fascinating insect. By the seventeenth century, a growing interest in observation had begun to replace blind reliance on established wisdom and ancient authority. However, the various young sciences to which the period gave rise did not progress equally, and neither did the subdisciplines within each scientific field; biology, especially entomology, was particularly slow to free itself from past beliefs and contemporary superstitions. In the specific case of the praying mantis, the situation may have been at its worst. Early observers of nature found evidence that seemed, at first, to disconfirm the well-established belief that mantids are gentle creatures. These few observers, faced with startling firsthand information about mantid voraciousness, created a new characterization of mantids as merciless predators and then often juxtaposed the two images in their descriptions. However, it was not until the beginning of the nineteenth century that the two characterizations-gentleness versus cruelty—became reconciled. An amalgamation of these seemingly mutually exclusive characterizations was achieved by an interesting accommodation of each to the other. That is, while it could no longer be maintained that mantids are simply gentle insects, neither could it be accepted that they are all cruelty and viciousness. The melding of the two characterizations yielded a hybrid explanation which claimed that the praying mantis actually hastwo sides to its character! On the one hand, and like other creatures, mantids must nourish themselves, and do so quite reasonably by capturing small insects for food. However, even when “well nourished,” and without “the excuse of hunger,” their other, vicious side may surface; when this happens, the darkest of behaviours, cannibalism, is the result. To understand the remainder of the story one must pause to consider what had happened in the other sciences up to this point. In the mid-seventeenth century, professional scientific societies (such as the Royal Society of London, the Academic Royale des Sciences in France, and the Accademia del Cimento in Florence) were established throughout Europe. The societies, and the various journals and periodicals that they produced or encouraged, represented an institutionalization of both science and its special, structured discourse. However, as we have stated, entomology lagged behind; and in the case of some insects, superstitions and anthropomorphisms did not fade from descriptions of their behavior for centuries to come. By the time the new scientific discourse was applied to mantids the creatures were already firmly shackled with a dual personality, and this assumption was never challenged. In fact, it was functionally impossible to disconfirm. Captures of small prey were considered part of the mantid's normal side; captures of large prey (including conspecifics) were considered part of the mantid's abnormal side. There was no alternative explanation. As luck would have it, by the time that the strictures of scientific discourse had tightened sufficiently to disallow the use of anthropomorphisms in the explanation of insect behavior, another acceptable explanation of mantid cannibalism became immediately available: cannibalism became part of mantid mating behavior. That is, the fundamental explanatory model remained unchanged; it was merely couched in more appropriate terms. The acceptance of this new explanation for cannibalism was virtually immediate and complete. For instance, no one ever asked the following questions: If the headless male remains able to mate as a putative precaution against female cannibalism, for what reason does the headless female remain able to fashion “a perfectly constructed ootheca”? Or: If female-on-male cannibalism plays a role in mating behavior, what role is played by genderindifferent cannibalism, especially that among immature mantids? The latter phenomena were simply ignored — they were just uninteresting artifacts of insect life. However, the grand logic of nature was immediately apparent in the headless male's ability to mate. The ruling theory, to use Chamberlin's term, had been able to accommodate itself to, and assimilate, the new scientific discourse. It remained unscathed. A persistent question posed by several historians of this particular topic has been, Why did not the results of Ken Roeder's experiments debunk the myth that males are regularly cannibalized by the females with which they mate? The reason, which we hope is now clear, is that there were (and are) two interdependent ruling theories operating here. If one accepts the argument that mantids' cannibalism is simply a normal part of their prey-catching behavior, then one attacks not only the theory that mantids have two separate predatory strategies, but also the more recent theory that mantids have evolved to be the ideal fly-catching machines. This second theory found its first confirming support in the centuries-old (fortuitous) practice of feeding flies to captive mantids. Again, the disconfirming evidence of mantids eating prey of various sizes had no impact on the theory. Confirming observations were accepted: disconfirming observations were seen as anomalies. Additional confirmation of both ruling theories was garnered in experiments done in the mid-twentieth century. These experiments were based on the assumption that the original conceptualizations were correct, and consequently they did not test other hypotheses. The combined strength of the two theories is evidenced especially in the Raus' failure to account for the fact that their empirical observations were at odds with many of the conclusions that they drew, and in the fact that Roeder's work is still used to support the belief in the regularity (or necessity) of mating-related cannibalism despite the fact that Roeder, himself, argued the opposite. with both theories well entrenched, it is virtually impossible to promote an alternative theory of mantid behavior: namely, that mantids are generalized, opportunistic predators that manage to survivein spite of the fact that cannibalism sometimes occurs.