Halobates
Halobates Temporal range:
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Halobates hayanus (zoological specimen seen from above with first leg pair not visible and remaining moved towards the rear) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hemiptera |
Suborder: | Heteroptera |
Infraorder: | Gerromorpha |
Superfamily: | Gerroidea |
Family: | Gerridae |
Genus: | Halobates Eschscholtz, 1822 |
Species | |
More than 40, see list |
Halobates or sea skaters are a
They were first collected by Johann Friedrich von Eschscholtz, a doctor who was part of a Russian expedition aboard the Rurik between 1815 and 1818.[2][4]
A fossil species H. ruffoi is known from 45 million year old deposits in Verona, Italy.[5]
Close relatives of the genus include Austrobates and Asclepios.[6]
Appearance
They are small insects with a body that is up to 6.5 mm (0.26 in) long and 3 mm (0.12 in) broad,[1] and a leg span up to at least 15 mm (0.59 in).[2] They lack wings, have long antennae, short front legs used for catching prey (and, in the male, for holding the female during mating), long middle legs used for propulsion, and somewhat shorter rear legs used for steering. The nymphs resemble miniature versions of the adult. The sexes are quite similar, except that males are thinner than females and have the rear part of the body modified into genitalia, and when gravid the females may have a notably plump abdomen. The various species closely resemble each other in general appearance.[1]
Range and abundance
Halobates are found in tropical and
The five offshore, pelagic species are H. micans, H. germanus, H. sericeus, H. splendens and H. sobrinus, of which the last four are found in the Indian and/or Pacific Oceans. H. micans has a circumglobal range, occurring offshore in warmer seas around the world from about 40° north to 40° south, and it is the only one found in the Atlantic Ocean, including the Caribbean.[1][7]
Their occurrences are generally patchy, but where found they can be very common. During scientific surveys with relatively fast-moving surface nets, they are caught in more than 60% of the tows (less in slow-moving tows, likely because of their ability to avoid them).[2] Studies show that densities locally can be as high as 1 individual per 19 m2 (200 sq ft) in the oceanic species,[8] and 120 individuals per m² (11 per sq ft) in breeding aggregations of the coastal species.[1]
Behavior and predators
They are
The coastal species lay their eggs close to the water surface on rocks, plants, and other structures near the shore, while the oceanic species attach their egg masses on floating objects such as
Some species of storm petrel actively feed on Halobates, sometimes splashing the water with their feet to attract or detect sea striders.[10] Other seabirds (especially noddies) and a range of surface-feeding fish will also eat them.[1][9]
Open research questions
Apart from understanding how exactly Halobates sp. came to be the only genus of insects to live on the open ocean – in spite of insects making up the majority of all animals – those animals offer unique research questions that could have applications in materials sciences. For example, it is still unknown how they can move on the water surface without slipping, but yet their legs are capable of effortlessly detaching from the surface in order to jump.
Incapable of diving or hiding, Halobates must protect themselves from ultraviolet radiation. Although it is known that the
References
- ^ S2CID 86774669.
- ^ ISBN 978-0-8493-2727-8.
- ^ a b c Marine Insects Archived 2009-10-03 at the Wayback Machine. Halobates Life. Retrieved on 9-09-2009.
- ^ Herring, Jon L (1961). "The genus Halobates (Hemiptera: Gerridae)" (PDF). Pacific Insects. 3 (2–3): 223–305.
- .
- .
- ^ Cheng, L. (1975). Insecta Hemiptera: Heteroptera, Gerridae, Genus Halobates. Fich. Ident. Zooplancton 147 (PDF).
- .
- ^ a b Big rise in North Pacific plastic waste BBC
- ^ Cheng, L.; Spear, L.B.; Ainley, D.G. (2010). "Importance of marine insects (Heteroptera: Gerridae, Halobates spp.) as prey of eastern tropical Pacific seabirds" (PDF). Marine Ornithology. 38: 91–95.
- S2CID 248154708.
External links
- Halobates Archived 2017-06-25 at the Wayback Machine