Ranatra | |
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Ranatra chinensis | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hemiptera |
Suborder: | Heteroptera |
Family: | Nepidae |
Subfamily: | Ranatrinae |
Genus: | Ranatra Fabricius, 1790 |
Ranatra is a genus of slender predatory insects of the family Nepidae, known as water scorpions or water stick-insects. [1] 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 (almost 50 species) and Asia (about 30 species, reviewed in 1972 [2] ). 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 . [3] Since Ranatra belongs to the family Nepidae which in turn belongs to the order Hemiptera, ranatrids are considered "true bugs".
These brown insects are primarily found in stagnant or slow-moving water like ponds, marshes and canals, but can also be seen in streams. [3] Exceptionally they have been recorded from hypersaline lakes and brackish lagoons. [4]
The front legs of bugs in Ranatra are strong and used to grasp prey. They typically eat other insects, tadpoles and small fish, which they pierce with their proboscis and inject a saliva which both sedates and begins to digest their prey. They are sit-and-wait predators that reside among water plants and position themselves head-down with their grasping legs extended out to surprise passing prey. [3] At least one species will also swim in open water at night to catch zooplanktonic organisms. [5] Like other members in the family they have a long tail-like siphon, or breathing tube, on the rear end of their body. [5] The adult body length is generally 2–6 cm (0.8–2.4 in) depending on the exact species, and females average larger than males of the same species. The siphon is typically almost the same size, but varies from less than half the body length to somewhat longer. Two of the largest species are the East Asian R. chinensis and South American R. magna. [3] [6] Ranatra do have wings and they can fly. [4]
The adults are active year-round, except in extreme cold. Their eggs are positioned on plants just below the water surface, but in some species they can be placed in mud. [3] The eggs typically take two to four weeks to hatch and the young take about two months to mature.[ citation needed ]
Among the four genera in the Ranatrinae subfamily, Austronepa and Goondnomdanepa are restricted to Australia. Cercotmetus from Asia to New Guinea resembles Ranatra, although the former has a distinctly shorter siphon. [3]
The Global Biodiversity Information Facility lists: [7]
Data sources: i = ITIS, [8] c = Catalogue of Life, [9] g = GBIF, [7] b = Bugguide.net [10]
Corixidae is a family of aquatic insects in the order Hemiptera. They are found worldwide in virtually any freshwater habitat and a few species live in saline water. There are about 500 known species worldwide, in 55 genera, including the genus Sigara.
Nepidae is a family of exclusively aquatic Heteropteran insects in the order Hemiptera. 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. 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.
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.
Naucoridae is a small family of insects commonly known as the creeping water bugs and saucer bugs. They are similar in appearance and behavior to Belostomatidae, but considerably smaller, at 0.5–2 cm (0.2–0.8 in) long. Naucoridae are found around the world, but the greatest diversity is in tropical regions. They inhabit a wide range of freshwater habitats, ranging from still waters like ponds, to flowing rivers and even torrential streams. There are about 400 species in 46 genera in 8 subfamilies.
Water treaders, the superfamily Mesovelioidea, are insects in the order Hemiptera, the true bugs. They are semiaquatic insects that live in moist and wet habitat and on wet plant matter in several types of aquatic habitat.
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.
Gerris is a bug genus in the family Gerridae.
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.
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.
Nerthra is a genus of toad bugs in the family Gelastocoridae. There are at least 90 described species in Nerthra.
Mesovelia is a genus of water treaders in the family Mesoveliidae. There are more than 30 described species in Mesovelia.
Limnocoris is a genus of creeping water bugs in the family Naucoridae. There are more than 70 described species in Limnocoris.
Ambrysus is a genus of creeping water bugs in the family Naucoridae. There are more than 90 described species in Ambrysus.
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.
Ochterus is a genus of velvety shore bugs in the family Ochteridae. There are more than 70 described species in Ochterus.
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.
Limnometra is a genus of water striders in the family Gerridae. There are more than 30 described species in Limnometra found in Indomalaya and Oceania.