Evolution and systematics
The order Mantophasmatodea (heel-walkers, gladiators) was found in 2001 and formally described in 2002 based mostly on two specimens that had been saved for many years within the pure historical past museums of Berlin and Lund (Sweden). With its 12 extant species, assigned to 9 genera and three households, the Mantophasmatodea is the smallest insect order. The intently associated genera Namaquaphasma (one species), Karoophasma (two species), Lobophasma (one species), Hemilobophasma (one species), and Austrophasma (three species) comprised within the household Austrophasmatidae, differ in particulars of the female and male genitalia. The genera Mantophasma(one species) and Sclerophasma (one species), which collectively represent the household Mantophasmatidae, in addition to Tanzaniophasma (one species) all show putting percularities within the copulatory organs. Praedatophasma (one species), whose systematic placement is unresolved, is exclusive in its spiny thorax (“gladiator”). The solely recognized fossil genus is Raptophasma (two species) from Baltic amber, which is about 45 million years previous. These creatures resemble extant Mantophasmatodea, however the thornless legs represent a conspicuous difference. Using different insect orders as a measure, the origins of Mantophasmatodea in all probability return to a lot earlier occasions. Anatomical particulars of the belly spiracles and the ovipositor of the feminine, for instance, present that regardless of missing wings, the Mantophasmatodea belong to the Pterygota, the group comprising all winged bugs in addition to many who have misplaced their wings secondarily (equivalent to Mantophasmatodea). It is unclear which different insect order is the closest relative of the Mantophasmatodea; the ice-crawlers (Grylloblattodea) and the stick bugs (Phasmida) are the most definitely candidates.
The persistently wingless Mantophasmatodea have a really uniform physique form, which superficially resembles that of sure grasshoppers or stick bugs. The physique size (with out the antennae) ranges from 0.35 to 0.94 in (9–24 mm), males often being considerably smaller than females. The primary colour of the physique is brown, grey, inexperienced, or yellow; totally different tints of these colours, a whitish element of various extent, and— in some species—black dots kind a sample of mottles and/or longitudinal stripes. Coloration varies between and likewise inside species. Nymphs resemble the adults in look. The antennae are lengthy and have many segments. The compound eyes are nicely developed, albeit of various dimension, however ocelli are missing. The chewing mouthparts are generalized and directed downward. The femora are distinctly thickened within the forelegs and considerably thickened within the midlegs, however they’re very slender within the hind legs. The tibiae of the forelegs and midlegs bear on their inside surfaces (opposing the femora) two rows of brief thorns, which render the legs appropriate for greedy different bugs. The tarsi comprise 5 tarsomeres, however the three basal ones are fused (with grooves indicating the borders). A big adhesive lobe (arolium) originates from between the claws. The stomach consists of 10 well-developed segments and a diminished eleventh section. In the females, segments eight and 9 bear three pairs of processes (valves) that collectively kind a brief ovipositor. The second and third valves are largely fused, and the latter are very laborious and conspicuously clawshaped. The genital opening lies behind the eighth sternite, which varieties a subgenital plate. In the male, the ninth sternite is elongated to kind a subgenital plate, which covers the retracted, largely membranous male genitalia ventrally. For copulation the genitalia turn into everted, thus displaying two or three small sclerites and two small sclerotized hooks. The one-segmented cerci are brief within the feminine however pretty lengthy and curved within the male, which makes use of them as accent copulatory constructions. The tenth belly tergum, which bears the muscle tissues transferring the cerci, is way wider within the male than within the feminine. While the center a part of the stomach is widest in females (as a result of it harbors the ovaries), in males the hindmost half often is widest due to the expanded tenth tergum. Derived options distinguishing Mantophasmatodea from different bugs are the placement of the anterior tentorial pits (anterior invagination factors of the endoskeleton of the top) far above the mandibular articulation, a peculiarly formed differentiation of the antennae (e.g., with in a different way formed basal and distal segements) and a rounded projection on the center of the male’s subgenital plate.
Extant Mantophasmatodea are recognized solely from Africa: Namibia (two species), westernmost South Africa (eight species), and Tanzania (one species). Raptophasma from Baltic amber reveals, nevertheless, that within the early Tertiary the group additionally occurred in Europe. The species recorded from South Africa appear to occupy pretty restricted, mutually largely unique geographic areas. This excessive diploma of endemism renders the Mantophasmatodea a really fascinating group for research of the biogeographical historical past of southern Africa.
Mantophasmatodea inhabit three of the foremost biomes present in western South Africa and Namibia: nama karoo, succulent karoo, and fynbos. The former location is characterised by (poor) summer time rainfall and the 2 latter by winter rainfall (poor in succulent karoo), however all are reasonably or extraordinarily dry all through the remainder of the 12 months and virtually naked of bushes. Broad variations between temperatures throughout the day and at night time (with frost in winter) are regular. During and shortly after the humid season, the species-rich natural world bloom. Localities harboring Mantophasmatodea present a variety of vegetation density. Some species steadily are present in tufts of grass (Poaceae) or Cape reed (Restionaceae, which superficially resemble grasses); they happen both on the backside between the culms or on high of the culms, the place they’re nicely camouflaged by their mottled and striped coloration. The habitat of the Tanzanian Tanzaniophasma subsolana is unknown.
Mantophasmatodea basically dwell singly, however a male and a feminine usually might be discovered collectively in the identical tuft of grass, and inside appropriate habitats an space of a number of hundred sq. yards (meters) could harbor a sound inhabitants whereas no heelwalkers are discovered within the surrounding areas. There seems to be each nocturnal and diurnal exercise. Movements usually are fairly gradual, however they are often speedy when prey is caught or a male mounts a feminine for copulation. When strolling, Mantophasmatodea usually have their basal tarsomeres on the bottom, whereas the fifth tarsomeres and the terminal claws and arolia are held in an elevated place (therefore the title heel-walkers). The males use the projection of their subgenital plates to knock on the bottom, which can serve for communication.
Feeding ecology and eating regimen
Mantophasmatodea eat different bugs of assorted varieties, up to their very own dimension. They grasp and maintain them by the use of their highly effective, spiny forelegs, moreover utilizing the midlegs for giant prey. Each mandible has a pointy edge for slicing the sufferer to items; all components, besides the legs and wings are devoured. Cannibalism additionally happens.
Courtship is unknown. For copulation the male jumps onto the feminine and bends his stomach apart and downward to carry his copulatory organs into contact with the hind a part of the feminine’s stomach. The act of copulation, with the male sitting on the feminine’s again, can final up to three days. The feminine then produces a number of sausage-shaped egg pods, which comprise about 10–20 lengthy, oval eggs lined by a tough envelope constructed from sand and gland secretions. The ovipositor serves for shaping the egg pod and for correct placement of the eggs into it. The nymphs hatch firstly of the rainfall interval, molt a number of occasions, attain maturity close to the tip of the humid season, and die throughout the early dry interval. Consequently, life cycles are diametrically totally different relying on whether or not precipitation falls predominantly in summer time or in winter.
As of 2002, no species of Mantophasmatodea have been listed on the IUCN Red List. Mantophasmatodea should not unusual in Namibia and western South Africa. Nothing is understood, nevertheless, about how widespread the varied species are. The apparently small distribution areas of some species may make them delicate to extinction. Nonetheless, the discovering of a wealthy inhabitants instantly alongside a street signifies that not all species endure from this facet of human civilization. Only a single specimen has been recorded from Tanzania, and it’s unknown how widespread Mantophasmatodea are on this a part of Africa.