By any name, these fascinating insects are formidable predators. They have triangular heads poised on a long "neck," or elongated thorax. Mantids can turn their heads 180 degrees to scan their surroundings with two large compound eyes and three other simple eyes located between them. Typically green or brown and well camouflaged on the plants among which they live, mantis lie in ambush or patiently stalk their quarry. They use their front legs to snare their prey with reflexes so quick that they are difficult to see with the naked eye. Their legs are further equipped with spikes for snaring prey and pinning it in place.
Breeding and Behavior
Moths, crickets, grasshoppers, flies, and other insects are usually the unfortunate recipients of unwanted mantid attention. However, the insects will also eat others of their own kind. The most famous example of this is the notorious mating behavior of the adult female, who sometimes eats her mate just after—or even during—mating. Yet this behavior seems not to deter males from reproduction. Females regularly lay hundreds of eggs in a small case, and nymphs hatch looking much like tiny versions of their parents.
AnatomyMantises have large, triangular heads with a beak-like snout and mandibles. They have two bulbous compound eyes, three small simple eyes, and a pair of antennae. The articulation of the neck is also remarkably flexible; some species of mantis can rotate their heads nearly 180°. The mantis thorax consists of a prothorax, a mesothorax, and a metathorax. In all species apart from the genus Mantoida, the prothorax, which bears the head and fore legs, is much longer than the other two thoracic segments. The prothorax is also flexibly articulated, allowing for a wide range of movements of the head and fore limbs while the remainder of the body remains more or less immobile. Mantises have two spiked, grasping fore legs ("raptorial legs") in which prey items are caught and held securely. In most insect legs, including the posterior four legs of a mantis, the coxa and trochanter combine as an inconspicuous base of the leg; in the raptorial legs, however, the coxa and trochanter combine to form a segment about as long as the femur, which is a spiky part of the grasping apparatus (see illustration). Located at the base of the femur is a set of discoidal spines, usually four in number, but ranging from none to as many as five depending on the species. These spines are preceded by a number of tooth-like tubercles, which, along with a similar series of tubercles along the tibia and the apical claw near its tip, give the fore leg of the mantis its grasp on its prey. The fore leg ends in a delicate tarsus used as a walking appendage, made of four or five segments and ending in a two-toed claw with no arolium.
Mantises can be loosely categorized as being macropterous (long-winged), brachypterous (short-winged), micropterous (vestigial-winged), or apterous (wingless). If not wingless, a mantis has two sets of wings: the outer wings, or tegmina, are usually narrow and leathery. They function as camouflage and as a shield for the hind wings, which are clearer and more delicate. The abdomen of all mantises consist of 10 tergites, with a corresponding set of nine sternites visible in males and seven visible in females. The abdomen tends to be slimmer in males than females, but ends in a pair of cerci in both sexes.
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 are concerned with perceiving motion; when a moving object is noticed, the head is rapidly rotated to bring the object into the visual field of the fovea. Further motions of the prey are then tracked by movements of the mantis's head so as to keep the image centered on the fovea. The eyes are widely spaced and laterally situated, affording a wide binocular field of vision and precise stereoscopic vision at close range. The dark spot on each eye that moves as it rotates its head is a pseudopupil. This occurs because the ommatidia that are viewed "head-on" absorb the incident light, while those to the side reflect it.
As their hunting relies heavily on vision, mantises are primarily diurnal. Many species, however, fly at night, and then may 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. Many mantises also have an auditory thoracic organ that helps them avoid bats by detecting their echolocation calls and responding evasively.
Diet and predation
Mantises are generalist predators of arthropods. The majority of mantises are ambush predators that only feed upon live prey within their reach. They either camouflage themselves and remain stationary, waiting for prey to approach, or stalk their prey with slow, stealthy movements. Larger mantises sometimes eat smaller individuals of their own species, as well as small vertebrates such as lizards and frogs. 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 fore legs. Some ground and bark species pursue their prey in a more active way. For example, members of a few genera such as the ground mantises, Entella, Ligaria, and Ligariella run over dry ground seeking prey, much as tiger beetles do. The fore gut of some species extends the whole length of the insect and can be used to store prey for digestion later. This may be advantageous in an insect that feeds intermittently. Chinese mantises live longer, grow faster, and produce more young when they are able to eat pollen.