Mecoptera
Mecoptera Temporal range:
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Panorpa communis, male | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
(unranked): | Antliophora
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Order: | Mecoptera Packard, 1886 Comstock, 1895 |
Families | |
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Mecoptera (from the
The Mecoptera are closely related to the
Early Mecoptera may have played an important role in pollinating extinct species of gymnosperms before the evolution of other insect pollinators such as bees. Adults of modern species are overwhelmingly predators or consumers of dead organisms. In a few areas, some species are the first insects to arrive at a cadaver, making them useful in forensic entomology.[9]
Diversity
Mecopterans vary in length from 2 to 35 mm (0.1 to 1.4 in). There are about six hundred
Distribution of mecopterans is worldwide; the greatest diversity at the species level is in the Afrotropic and Palearctic realms, but there is greater diversity at the generic and family level in the Neotropic, Nearctic and Australasian realms. They are absent from Madagascar and many islands and island groups; this may demonstrate that their dispersal ability is low, with Trinidad, Taiwan and Japan, where they are found, having had recent land bridges to the nearest continental land masses.[10]
Evolution and phylogeny
Taxonomic history
The European scorpionfly was named Panorpa communis by Linnaeus in 1758.[12] The Mecoptera were named by Alpheus Hyatt and Jennie Maria Arms in 1891.[13] The name is from the Greek, mecos meaning long, and ptera meaning wings.[14] The families of Mecoptera are well accepted by taxonomists but their relationships have been debated. In 1987, R. Willman treated the Mecoptera as a
Fossil history
Among the earliest members of the Mecoptera are the
Extinct Mecoptera species may have been important pollinators of early
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Juracimbrophlebia ginkgofolia (Cimbrophlebiidae) reconstruction, Jurassic; China
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Jurassipanorpa sticta (Panorpidae), Jurassic; China
External relationships
Mecoptera have special importance in the evolution of the insects. Two of the most important insect orders,
It is unclear as of 2020 whether the Mecoptera form a single clade, or whether the
(a) Mecoptera (clades in boldface) is paraphyletic, containing Siphonaptera:[26][27]
part of Holometabola |
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(b) Mecoptera is monophyletic, sister to Siphonaptera:[26]
part of Holometabola |
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Internal relationships
All the families were formerly treated as part of a single order, Mecoptera. The relationships between the families are, however, a matter of debate. The cladogram, from Cracraft and Donoghue 2004, places the Nannochoristidae as a separate order, with the Boreidae, as the sister group to the Siphonaptera, also as its own order. The
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Biology
Morphology
Mecoptera are small to medium-sized insects with long beaklike
The fore and hind wings are similar in shape, being long and narrow, with numerous cross-veins, and somewhat resembling those of primitive insects such as mayflies. A few genera, however, have reduced wings, or have lost them altogether. The abdomen is cylindrical with eleven segments, the first of which is fused to the metathorax. The cerci consist of one or two segments. The abdomen typically curves upwards in the male, superficially resembling the tail of a scorpion, the tip containing an enlarged structure called the genital bulb.[23][29]
The caterpillar-like larvae have hard sclerotised heads with mandibles (jaws), short true legs on the thorax, prolegs on the first eight abdominal segments, and a suction disc or pair of hooks on the terminal tenth segment. The pupae have free appendages rather than being secured within a cocoon (they are exarate).[29]
Ecology
Mecopterans mostly inhabit moist environments although a few species are found in semi-desert habitats. Scorpionflies, family Panorpidae, generally live in broad-leaf woodlands with plentiful damp leaf litter. Snow scorpionflies, family Boreidae, appear in winter and are to be seen on snowfields and on moss; the larvae being able to jump like fleas. Hangingflies, family Bittacidae, occur in forests, grassland and caves with high moisture levels. They mostly breed among mosses, in leaf litter and other moist places, but their reproductive habits have been little studied, and at least one species, Nannochorista philpotti, has aquatic larvae.[10]
Adult mecopterans are mostly scavengers, feeding on decaying vegetation and the soft bodies of dead invertebrates. Panorpa raid spider webs to feed on trapped insects and even the spiders themselves, and hangingflies capture flies and moths with their specially modified legs. Some groups consume pollen, nectar, midge larvae, carrion and moss fragments.[10] Most mecopterans live in moist environments; in hotter climates, the adults may therefore be active and visible only for short periods of the year.[23]
Mating behaviour
Various courtship behaviours have been observed among mecopterans, with males often emitting pheromones to attract mates. The male may provide an edible gift such as a dead insect or a brown salivary secretion to the female. Some boreids have hook-like wings which the male uses to pick up and place the female on his back while copulating. Male panorpids vibrate their wings or even stridulate while approaching a female.[10]
Hangingflies (Bittacidae) provide a nuptial meal in the form of a captured insect prey, such as a caterpillar, bug, or fly. The male attracts a female with a pheromone from vesicles on his abdomen; he retracts these once a female is nearby, and presents her with the prey. While she evaluates the gift, he locates her genitalia with his. If she stays to eat the prey, his genitalia attach to hers, and the female lowers herself into an upside-down hanging position, and eats the prey while mating. Larger prey result in longer mating times. In Hylobittacus apicalis, prey 3 to 14 millimetres (0.12 to 0.55 in) long give between 1 and 17 minutes of mating. Larger males of that species give prey as big as houseflies, earning up to 29 minutes of mating, maximal sperm transfer, more oviposition, and a refractory period during which the female does not mate with other males: all of these increase the number of offspring the male is likely to have.[30]
Life-cycle
The female lays the eggs in close contact with moisture, and the eggs typically absorb water and increase in size after deposition. In species that live in hot conditions, the eggs may not hatch for several months, the larvae only emerging when the dry season has finished. More typically, however, they hatch after a relatively short period of time. The larvae are usually quite caterpillar-like, with short, clawed, true legs, and a number of abdominal prolegs. They have sclerotised heads with mandibulate mouthparts. Larvae possess compound eyes, which is unique among holometabolous insects.[31] The tenth abdominal segment bears either a suction disc, or, less commonly, a pair of hooks. They generally eat vegetation or scavenge for dead insects, although some predatory larvae are known. The larva crawls into the soil or decaying wood to pupate, and does not spin a cocoon. The pupae are exarate, meaning the limbs are free of the body, and are able to move their mandibles, but are otherwise entirely nonmotile. In drier environments, they may spend several months in diapause, before emerging as adults once the conditions are more suitable.[23]
Interaction with humans
Scorpionflies are sometimes described as looking "sinister", particularly from the male's raised "tail" resembling a scorpion's sting.[33] A popular but incorrect belief is that they can sting with their tails.[34]
References
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- ^ a b "Southeast Texas Applied Forensic Science Facility". STAFS.
- ^ ISBN 978-1-4020-6242-1.
- ^ "Scorpionflies (Order: Mecoptera)". Amateur Entomologists' Society. Retrieved 5 July 2020.
- Systema naturaeper regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Laurentii Salvii, Holmiae [= Stockholm]. Vol. Tomus I, Editio decima, reformata: i–ii, 1–824.
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Recently, a close affinity between Siphonaptera and Mecoptera has been convincingly demonstrated via morphology (Bilinski et al. 1998) and molecular data (Whiting 2002), rendering Mecoptera paraphyletic, but making the clade including Mecoptera and Siphonaptera monophyletic
- ^ bioRxiv 10.1101/2020.11.19.390666.
- ISSN 2624-2834.
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- ^ ISBN 978-1-118-84616-2.
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- ^ Rutsch, Poncie (22 January 2015). "Finding Crime Clues In What Insects Had For Dinner". NPR. Retrieved 22 June 2015.
- ^ "Weirdest Looking Bugs". EnkiVillage. 2015-05-13. Retrieved 22 June 2015.
- ^ Newton, Blake. "Scorpionflies & Hangingflies". University of Kentucky. Retrieved 25 February 2017.