The Preying Mantis

MantisThe preying mantis is of the mantodea order of insects, related to termites and cockroaches, which are all within the superorder dictyoptera. Distributed worldwide in temperate and tropical habitats, mantises fall within 15 families that contain over 2,400 species in about 430 genera, the largest family being mantidae (“mantids”). They have triangular heads with two bulging compound eyes, three small simple eyes, a pair of antennae, a beak-like snout and mandibles. The articulation of a mantis’s neck is also remarkably flexible; some species of mantis can rotate their heads nearly 180°. All mantises have forelegs that are greatly enlarged and adapted for catching and gripping prey; their upright posture, while remaining stationary with forearms folded, has led to the common name praying mantis.
Mantises have two spiked, grasping forelegs (“raptorial legs”) in which prey items are caught and held securely by a set of discoidal spines, usually four in number, preceded by a number of tooth-like tubercles, which give the foreleg of the mantis its grasp on its prey.
Mantises are long-winged, short-winged, vestigial-winged, or wingless.
Mantises have stereo vision. They locate their prey by sight; their compound eyes contain up to 10,000 ommatidia. A small area at the front called the fovea has greater visual acuity than the rest of the eye, and can produce the high resolution necessary to examine potential prey. The peripheral ommatidia perceive motion; and a mantis will rapidly move or rotate its head to bring the object into the visual field of the fovea. The eyes are widely spaced and laterally situated, affording a wide binocular field of vision and precise stereoscopic vision at close range.
As their hunting relies heavily on vision, mantises are primarily diurnal and when engaged in nocturnal flight can be attracted to artificial lights. Nocturnal flight is especially important to males in locating less-mobile females by detecting their pheromones. Flying at night exposes mantises to fewer bird predators than diurnal flight would.
Mantises are generalist ambush predators of arthropods, feeding upon live prey within their reach. They camouflage themselves and remain stationary, waiting for prey to approach.
Most mantises chase tempting prey if it strays close enough, and will go further when they are especially hungry. Once within reach, mantises strike rapidly to grasp the prey with their spiked raptorial forelegs.
Mantises are preyed on by vertebrates such as frogs, lizards, and birds, and by invertebrates such as spiders and ants. Generally, mantises protect themselves by camouflage, most species being cryptically colored to resemble foliage or other backgrounds. When directly threatened, many mantis species stand tall and spread their forelegs, with their wings fanning out wide. If harassment persists, a mantis may strike with its forelegs and attempt to pinch or bite. As part of the bluffing, or deimatic, threat display, some species may also produce a hissing sound by expelling air from the abdominal spiracles. When flying at night some mantises are able to detect the echolocation sounds produced by approaching bats as the frequency rapidly increases, and they will stop flying horizontally and begin a descending spiral toward the safety of the ground.
The mating season in temperate climates typically takes place in autumn, while in tropical areas, mating can occur at any time of the year. To mate, a male usually leaps onto the female’s back, clasping her thorax and wing bases with his forelegs. He then arches his abdomen to deposit and store sperm in a special chamber near the tip of the female’s abdomen. Sexual cannibalism is common among most predatory species of mantises in captivity and has sometimes been observed in natural populations, where about a quarter of male-female encounters result in the male being eaten by the female. Adult males typically outnumber females at first, but their numbers diminish as females selectively eat the smaller males. Upon beginning orgasm, an undisciplined male’s head may droop forward over the female’s shoulder. She will use the agile dexterity and flexibility of her neck to place her mouth at the back of her mate’s head and she will then begin to eat her way into and through his brain. So engaged is the male at the point that he hardly knows what is happening. Upon the devouring of his frontal lobes, the male xperiences the most powerful climax imaginable and that’s all there is, brother! There is no more. Chinese mantises that had been fed to the point that they were no longer hungry displayed elaborate courtship behavior when left undisturbed. The male engages the female in a courtship dance, to change her interest from feeding to mating. The reason for sexual cannibalism has been debated; experiments show that females on low quality diets have a higher chance to engage in sexual cannibalism compared to females on high quality diets. Some scientists believe that submissive males gain a selective advantage by producing offspring, which is supported by a quantifiable increase in the duration of copulation among males which are cannibalized, in some cases doubling both the duration and the chance of fertilization. However, males are likely to approach hungry females with more caution, and some males that actively avoid cannibalism may mate with multiple females. Hungry females generally attracted fewer males than those that were well fed. The act of dismounting after copulation is dangerous for males, for at this time, females have an opportunity to cannibalize their mates. An increase in mounting duration appears to indicate that males wait for an opportune time to dismount a hungry female, who would be likely to cannibalize her mate.
The female lays between 10 and 400 eggs, depending on the species. Eggs are often preyed on, especially by several species of parasitoid wasps. In a few species, female mantises guard the eggs. In temperate climates, adults do not survive the winter and the eggs undergo a diapause, hatching in the spring. Mantises go through three life stages: egg, nymph, and adult. Eggs hatch in three to seven weeks. The lifespan of a mantis depends on the species; smaller ones may live 4–8 weeks, while larger species may live 4–6 months.

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