Nepidae

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Nepidae
Temporal range: Aptian–Recent
Nepa cinerea01.jpg
Nepa cinerea
Ranatra.linearis.jpg
Ranatra linearis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Heteroptera
Infraorder: Nepomorpha
Superfamily: Nepoidea
Family: Nepidae
Latreille 1802
Subfamilies, Genera

See text

Nepidae is a family of exclusively aquatic Heteropteran insects in the order Hemiptera. [1] They are commonly called water scorpions for their superficial resemblance to scorpions, due to their raptorial forelegs and the presence of a long slender process at the posterior end of the abdomen, resembling a tail. [2] There are 14 genera in the family, in two subfamilies, Nepinae and Ranatrinae. Members of the genus Ranatra , the most widespread and species-rich genus, are sometimes called needle bugs or water stick insects as they are slenderer than Nepa . [3]

Contents

While water scorpions do not sting with their tail (it is used for breathing), [4] they do have a painful bite (strictly speaking a sting by their pointed proboscis), but this is much less harmful to humans than a true scorpion's sting. [5]

Range and habitat

Nepidae are found on all continents except Antarctica. They mostly inhabit stagnant or slow-moving freshwater habitats like ponds, marshes, canals and streams. [6] [7] Exceptionally they have also been recorded from hypersaline lakes and brackish lagoons, [6] the Australian genus Goondnomdanepa is restricted to flowing waters, [7] and Nepa anophthalma is adapted to life in caves in Romania. [8]

Appearance and ecology

Nepa cinerea with open forewings, revealing its usually hidden hindwings and red abdomen Water scorpion (Nepa cinerea).jpg
Nepa cinerea with open forewings, revealing its usually hidden hindwings and red abdomen
Nepidae have a tail-like siphon or breathing tube, which in some species like this Laccotrephes can be even longer than the body Laccotrephes cf brachialis, Pretoria, j.jpg
Nepidae have a tail-like siphon or breathing tube, which in some species like this Laccotrephes can be even longer than the body

Nepidae are brown insects, but some species have a bright red abdomen that can be seen when the wings are open. Their body is broad and flat (subfamily Nepinae) or long and thin (subfamily Ranatrinae). They are rather poor swimmers and typically crawl about on aquatic vegetation. [9] They can fly, but this is infrequently seen. [7] In most species the body is between 1.5 and 4.5 cm (0.6–1.8 in) long, [9] although the largest such as the East Asian Ranatra chinensis and South American R. magna can approach 6 cm (2.4 in). [10] [11]

Respiration in the adult is achieved by means of the caudal process, which consists of a pair of half-tubes capable of being locked together to form a siphon. Air is conducted through it to the tracheae at the apex of the abdomen when the tip of the tube is thrust above the surface of the water (similar to a snorkel). [12] [3] [9] In some species the siphon is longer than the body, [9] but in others it is shorter, in a few even less than one-tenth of the body length. [13] In immature forms the siphon is often underdeveloped and respiration takes place through six pairs of abdominal spiracles. [12] [3]

To keep their orientation in the water they have three pairs of “static sense organs”, small oval structures closely associated with the fourth, fifth, and sixth abdominal spiracles. [14]

Their frontal legs are modified into raptorial appendages that are used to grab their prey. They feed primarily on aquatic invertebrates such as other insects, but occasionally take small fish or tadpoles. The eggs, which are laid above the waterline in mud, decomposing vegetation, the stems of plants or rotting wood, are supplied with air by filamentous processes which vary in number among the genera. [3]

Subfamilies and genera

With about 100 species, Ranatra is the most diverse genus Ranatra chinensis.jpg
With about 100 species, Ranatra is the most diverse genus

Nepidae has around 250 species in 14 genera divided into two subfamilies, Nepinae and Ranatrinae. [3] [10]

Among these the most diverse are the widespread Ranatra (about 100 species) [10] and Laccotrephes (about 60), [15] but the family also includes species-poor genera, like the Ethiopian Borborophilus, Nepella, Nepitella and Paranepa (each with one species), [13] Indian Montonepa (one species), Philippine Borborophyes (one species), [16] and Australian Austronepa (one species) and Goondnomdanepa (three species). [17]

Araripenepa from the Early Cretaceous (Aptian) Crato Formation of Brazil is the oldest known member of the family, and is the sister group to remaining genera. [18]

Ranatrinae

Authority: Douglas & Scott, 1865 (sometimes called "water stick insects")

Genera in this subfamily include: Austronepa and Goondnomdanepa are restricted to Australia. Cercotmetus is from Asia to northern Australia and resembles Ranatra (Worldwide distribution), although the former has a distinctly shorter siphon. [10]

  1. Austronepa Menke & Stange, 1964
  2. Cercotmetus Amyot & Serville, 1843
  3. Goondnomdanepa Lansbury, 1974
  4. Ranatra Fabricius, 1790

Nepinae

Authority: Latreille, 1802 (sometimes called "water scorpions")

See also

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The Heteroptera are a group of about 40,000 species of insects in the order Hemiptera. They are sometimes called "true bugs", though that name more commonly refers to the Hemiptera as a whole. "Typical bugs" might be used as a more unequivocal alternative, since the heteropterans are most consistently and universally termed "bugs" among the Hemiptera. "Heteroptera" is Greek for "different wings": most species have forewings with both membranous and hardened portions ; members of the primitive sub-group Enicocephalomorpha have completely membranous wings.

<span class="mw-page-title-main">Pentatomoidea</span> Superfamily of true bugs

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<span class="mw-page-title-main">Veliidae</span> Family of true bugs

Veliidae is a family of gregarious predatory insects in the suborder Heteroptera. They are commonly known as riffle bugs, small water striders, or broad-shouldered water striders because the segment immediately behind the head is wider than the rest of the abdomen. Species of the genus Rhagovelia are also referred to as ripple bugs.

<i>Nepa cinerea</i> Species of true bug

Nepa cinerea is a species of water scorpion (Nepidae), found in most of Europe, including the British Isles, as well as North Africa and southern and northern Asia.

<span class="mw-page-title-main">Notonectidae</span> Family of true bugs

Notonectidae is a cosmopolitan family of aquatic insects in the order Hemiptera, commonly called backswimmers because they swim "upside down" (inverted). They are all predators and typically range from 0.5 to 1.5 cm (0.2–0.6 in) in length. They are similar in appearance to Corixidae, but can be separated by differences in their dorsal-ventral coloration, front legs, and predatory behavior. Their dorsum is convex, lightly colored without cross striations. Their front tarsi are not scoop-shaped and their hind legs are fringed for swimming. There are about 350 species in two subfamilies: Notonectinae with seven genera, and Anisopinae with four genera. Members in the former subfamily are often larger than those in the latter.

<span class="mw-page-title-main">Belostomatidae</span> Family of true bugs

Belostomatidae is a family of freshwater hemipteran insects known as giant water bugs or colloquially as toe-biters, Indian toe-biters, electric-light bugs, alligator ticks, or alligator fleas. They are the largest insects in the order Hemiptera. There are about 170 species found in freshwater habitats worldwide, with more than 110 in the Neotropics, more than 20 in Africa, almost as many in the Nearctic, and far fewer elsewhere. These predators are typically encountered in freshwater ponds, marshes and slow-flowing streams. Most species are at least 2 cm (0.8 in) long, although smaller species, down to 0.9 cm (0.35 in), also exist. The largest are members of the genus Lethocerus, which can exceed 12 cm (4.5 in) and nearly reach the length of some of the largest beetles in the world. Giant water bugs are a popular food in parts of Asia.

<i>Ranatra</i> Genus of true bugs

Ranatra is a genus of slender predatory insects of the family Nepidae, known as water scorpions or water stick-insects. There are around 100 Ranatra species found in freshwater habitats around the world, both in warm and temperate regions, with the highest diversity in South America and Asia. Fewer are found elsewhere, but include several African, some in North America, three from Australia and three from the Palearctic, notably the relatively well-known European R. linearis. Since Ranatra belongs to the family Nepidae which in turn belongs to the order Hemiptera, ranatrids are considered "true bugs".

<span class="mw-page-title-main">Nepomorpha</span> Infraorder of true bugs

Nepomorpha is an infraorder of insects in the "true bug" order (Hemiptera). They belong to the "typical" bugs of the suborder Heteroptera. Due to their aquatic habits, these animals are known as true water bugs. They occur all over the world outside the polar regions, with about 2,000 species altogether. The Nepomorpha can be distinguished from related Heteroptera by their missing or vestigial ocelli. Also, as referred to by the obsolete name Cryptocerata, their antennae are reduced, with weak muscles, and usually carried tucked against the head.

<span class="mw-page-title-main">Water treader</span> Family of true bugs

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<i>Lethocerus</i> Genus of true bugs

Lethocerus is a genus of the hemipteran family Belostomatidae, known colloquially as giant water bugs, toe biters and electric light bugs, distributed in tropical, subtropical and temperate areas of the world. The greatest diversity of species occurs in the Americas, with only a single species in Europe, two in Africa, two in Australia and three in Asia. It includes the largest true bugs with species capable of reaching a length of over 12 centimetres (4.7 in). The South American L. grandis and L. maximus are the only species to commonly exceed 9 cm (3.5 in), with more typical lengths for the remaining species being between 4.5 and 9 cm. Lethocerus sp. are distinguished from other genera in the Lethocerinae by two symmetrical furrows in the inner pad of setae on the fore femur, the external borders of parasternites II and III narrowed and nearly straight, and with the setae of the tarsomeres following the line of the tibial setae.

<span class="mw-page-title-main">Tessaratomidae</span> Family of true bugs

Tessaratomidae is a family of true bugs. It contains about 240 species of large bugs divided into 3 subfamilies and 56 genera.

<i>Nepa</i> (bug) Genus of true bugs

Nepa is a genus belonging to the family Nepidae, known as water scorpions. There are six species found in freshwater habitats in the Northern Hemisphere.

<i>Ranatra linearis</i> Species of true bug

Ranatra linearis is a species of aquatic bug in the Nepidae family. It is native to Eurasia and North Africa, and primarily found near aquatic plants in ponds, marshes and other freshwater habitats, but has exceptionally been recorded from hypersaline lakes and brackish lagoons.

<i>Belostoma</i> Genus of true bugs

Belostoma is a genus of insects in the hemipteran family Belostomatidae, known colloquially as giant water bugs. Members of this genus are native to freshwater habitats in the Americas, with the greatest species richness in tropical South America. Most species in the family Belostomatidae have historically been included in Belostoma, but several of these have been moved to other genera. 9 species are claimed to be found in Northern America, but the genus Belostoma is actually divided into 16 subgroups containing about 70 species.

<i>Laccotrephes</i> Genus of true bugs

Laccotrephes is a genus of water scorpion belonging to the family Nepidae. They are carnivorous insects that hunt near the water surface. They are not aggressive, but may inflict a painful bite if not handled carefully, which may cause a local reaction. There are about 60 species found in shallow stagnant or slow-moving waters in warm parts of Africa, Asia and Australia.

<span class="mw-page-title-main">Mesoveliidae</span> Family of true bugs

Mesoveliidae is a family of water treaders in the order Hemiptera. There are about 16 genera and at least 50 described species in Mesoveliidae.

Curicta is a genus of waterscorpions in the family Nepidae native to freshwater habitats in the Americas. There are more than 15 species, with most restricted to South America. There are only two species in the United States: C. pronotata and C. scorpio.

Cercotmetus is a genus of water bugs in the subfamily Ranatrinae. The recorded distribution of this genus is from is from mainland Asia to New Guinea and northern Australia.

<i>Laccotrephes tristis</i> Species of insect

Laccotrephes tristis is a species of water scorpion also commonly known as a toe-biter, that occurs Australia-wide and is part of the family Nepidae. They are an aquatic predatory insect that breath air. Australian water scorpions inhabit shallow stagnant water, part of freshwater creeks, waterholes and gorges.

<i>Nepa anophthalma</i> Species of insect

Nepa anophthalma is a species of troglofaunal insect in the Nepidae family, and in the genus Nepa. It holds the distinction of being the only known cave-adapted water scorpion so far discovered. Like with most troglobites, this genus has a limited distribution range, with it only being found in Movile cave, a cave in Romania known for its unique ecosystem supported by chemosynthesis, and with little oxygen. It is often considered a top predator within the aquatic environments of this cave, with very little competition with other animals.

References

  1. ↑ Nepidae, Tree of life project
  2. ↑ Chisholm 1911.
  3. 1 2 3 4 5 I. Lansbury (1974). "A new genus of Nepidae from Australia with a revised classification of the family (Hemiptera: Heteroptera)". Australian Journal of Entomology. 13 (3): 219–227. doi: 10.1111/j.1440-6055.1974.tb02176.x .
  4. ↑ "Water Scorpions". Archived from the original on 2002-08-27.
  5. ↑ "Water scorpion | insect".
  6. 1 2 Ye.V. Anufriyeva; N.V. Shadrin (2016). "First Record of Ranatra linearis (Hemiptera, Nepidae) in Hypersaline Water Bodies of the Crimea". Hydrobiological Journal. 52 (2): 56–61.
  7. 1 2 3 "Nepidae". The Murray-Darling Freshwater Research Centre. Retrieved 6 April 2018.
  8. ↑ Vasile Decu; Magdalena Gruia; S. L. Keffer; Serban Mircea Sarbu (1994). "Stygobiotic Waterscorpion, Nepa anophthalma, n. sp. (Heteroptera: Nepidae), from a Sulfurous Cave in Romania". Annals of the Entomological Society of America. 87 (6): 755–761. doi:10.1093/aesa/87.6.755.
  9. 1 2 3 4 5 6 Randall T. Schuh; James Alexander Slater (1996). True Bugs of the World (Hemiptera:Heteroptera): Classification and Natural History (2 ed.). Cornell University Press. pp. 114–116. ISBN   978-0801420665.
  10. 1 2 3 4 5 P. Chen; N. Nieser; J.Z. Ho (2004). "Review of Chinese Ranatrinae (Hemiptera: Nepidae), with descriptions of four new species of Ranatra Fabricius". Tijdschrift voor Entomologie. 147 (1): 81–102. doi: 10.1163/22119434-900000142 .
  11. ↑ Heckman, C.W. (2011). Encyclopedia of South American Aquatic Insects: Hemiptera - Heteroptera. Springer. ISBN   978-94-007-0704-7.
  12. 1 2 Wikisource-logo.svg One or more of the preceding sentences incorporates text from a publication now in the public domain :  Chisholm, Hugh, ed. (1911). "Water-scorpion". Encyclopædia Britannica . Vol. 28 (11th ed.). Cambridge University Press. p. 386.
  13. 1 2 S.L. Keffer; J.T. Polhemus; J.E. McPherson (1989). "Notes on Critical Character States in Telmatotrephes (Heteroptera: Nepidae)". Florida Entomologist. 72 (4): 626–629. doi:10.2307/3495037. JSTOR   3495037.
  14. ↑ The Semiaquatic and Aquatic Hemiptera of California
  15. ↑ Polhemus, John T.; Keffer, Steven L. (Spring 1999). "Notes on the Genus Laccotrephes Stål (Heteroptera: Nepidae) in the Malay Archipelago, with the Description of Two New Species". Journal of the New York Entomological Society. 107 (1): 1–13. JSTOR   25010286.
  16. ↑ Lansbury, I. (1974). "Montonepa gen.n. from India with notes on the genus Borborophyes Stål (Hemiptera-Heteroptera, Nepidae)". Zoologica Scripta. 2 (2–3): 111–118. doi:10.1111/j.1463-6409.1974.tb00742.x. S2CID   84909022.
  17. ↑ Lansbury, I. (1978). "A review of Goondnomdanepa Lansbury (Heteroptera: Nepidae)". Australian Journal of Marine and Freshwater Research. 29 (1): 117–126. doi:10.1071/MF9780117.
  18. ↑ Nel, André; Pella, Cristian (2020-06-30). "The oldest water scorpion discovered in the Early Cretaceous Crato Formation (Hemiptera: Nepidae)". Palaeoentomology. 3 (3): 301–308. doi:10.11646/palaeoentomology.3.3.10. ISSN   2624-2834.
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