The praying mantis, an insect recognized for its distinctive prayer-like forelegs, often sparks curiosity due to a widely circulated belief about its mating habits. Many sources suggest that female mantises routinely consume their male partners during or after copulation. This common perception has fueled a sensationalized image of the mantis reproductive process.
Unpacking the Myth: Does It Happen?
Sexual cannibalism does occur in praying mantises, but its frequency is often exaggerated in popular culture. In the wild, this behavior is observed in less than 30 percent of mating interactions. The widespread notion that it is a routine event likely stems from early laboratory observations, where stressful, confined environments and scarce food lead to higher instances of cannibalism.
Several factors influence whether a female mantis will consume her mate. A primary driver is the female’s hunger level or nutritional state; those in poorer states are more prone to cannibalism. The male’s approach also plays a role, with the most dangerous times for a male being during his initial approach or the mating act itself. Despite the dramatic nature of this behavior, male mantises often escape, doing so in 70 to 100 percent of encounters in some wild populations.
The Evolutionary Rationale
When sexual cannibalism does occur, it provides tangible benefits to the female, primarily through nutritional gain. Consuming the male provides the female with protein and nutrients that contribute to producing more and healthier eggs. Studies have shown that cannibalistic females produce heavier egg cases and a greater number of eggs compared to those that do not consume their mates. His body material, including amino acids, incorporates into her reproductive tissues and developing eggs.
Surprisingly, this behavior can also offer an evolutionary advantage to the male’s genes. If the male is consumed, more of his biological material is transferred to the female, potentially leading to a higher number of his offspring. Furthermore, a male mantis can continue to copulate even after being decapitated. This is because his abdominal ganglion controls copulatory movements, allowing the process to continue and potentially increasing fertilization success. This extreme sacrifice can be seen as a form of “terminal reproductive effort,” maximizing the male’s genetic contribution to the next generation.
Beyond Cannibalism: Mantis Mating Habits
Outside of the instances of cannibalism, praying mantis mating involves a careful, prolonged process. The male typically initiates courtship with a cautious approach, sometimes swaying or using his antennae, signaling intentions. Males often prefer mating with well-fed females, which reduces their risk of being eaten. They also adjust their approach speed, moving faster when the female is preoccupied with feeding.
Successful mating can occur without cannibalism, and the male often survives to mate again. After copulation, the female lays her fertilized eggs in a protective case called an ootheca. These egg cases contain hundreds of eggs, from which nymphs hatch, resembling miniature adults.