Australian Biological Resources Study

Australian Faunal Directory


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Compiler and date details

October 2010 - Dr G. Cassis, University of New South Wales, Sydney, NSW


The Hydrometridae, commonly called marsh treaders or water measurers, are a cosmopolitan gerromorphan family. They are most diverse in tropical and subtropical regions and presently comprise seven genera and 126 species (Slater 1982; Smith 1988; Zoological Record 1980–1994; Henry 2009; Polhemus, J.T. pers. comm.).

Hydrometridae are usually elongate, parallel-sided and slender, with thread-like appendages. The body length varies from 2.7 to 22 mm. The head is very long, particularly in front of the eyes, and is armed with three pairs of cephalic trichobothria inserted in cuticular pits. Ocelli are reduced. The antennae are long, slender, subflagelliform and 4-segmented, with the ultimate segment invaginated. The labium is elongate and 4-segmented. The winged adults have the pronotum covering the mesonotum and the scutellum is not exposed. Wing polymorphism is common. The forewing venation is reduced with four or fewer closed cells. The metathoracic scent apparatus is absent in all Hydrometrinae but present in the other two subfamilies. The larvae lack dorsal abdominal gland openings. The tarsi are 3-segmented and the claws are terminal. The abdomen is elongate and the ovipositor is reduced in Hydrometra Latreille. The male pygophore is simple and protrudes from the abdomen (Andersen 1977, 1982; Slater 1982).

Hydrometrids are slow-moving semiaquatic bugs. They are found mainly in freshwater but are also known from saltwater and brackish water (Polhemus & Chapman 1979) and from rock surfaces above water (Smith 1988). Hydrometra species are found in quiet waters, usually walking on emergent vegetation. Some plesiomorphic hydrometrid species are terrestrial. Hydrometrids are predators and scavengers, feeding on dead or disabled arthropods. Typical prey includes midges, mosquito larvae, bloodworms, Cladocera and Collembola (Hungerford 1920; Sprague 1956). Hydrometrids lay their eggs either in terrestrial situations, usually several centimetres above water level, or on the vertical surfaces of plant stems. Cobben (1968) described the unique hydrometrid egg which has a multilayered shell. Andersen (1982) summarised hydrometrid biology. No biological studies have been conducted on Australian hydrometrid species. Accounts of extralimital species include Sprague's (1956) and Dolling's (1991) summaries of British Hydrometra species. China & Usinger (1949) and China et al. (1950) established the current suprageneric classification of the Hydrometridae. It comprises three subfamilies: the Heterocleptinae (two genera from the Afrotropical and Neotropical regions), the monogeneric Limnobatodinae (Neotropical Region), and the cosmopolitan Hydrometrinae. Andersen (1977, 1982) proposed a comprehensive classification of the Hydrometridae and a phylogeny of the genera.
Regional works include Torre-Bueno's (1926) revision of Western Hemisphere Hydrometra species. Hungerford & Evans (1934) revised Hydrometra globally, described many new species and provided a checklist of species. Drake & Lauck (1959) described new species of Hydrometra from the Americas. Polhemus & Chapman (1979) reviewed the Hydrometra of California. Froeschner (1981) provided a key to the hydrometrid genera of the Neotropical Region. Polhemus and Polhemus (1995) and Polhemus and Lansbury (1997) revised the genus Hydrometra , as it occurs in Australia, Melanesia, South Pacific, Indochina and Western Malay Archipelago.

The Australian Hydrometridae comprise eight Hydrometra species. Lansbury (1981) indicated that four of these species have Torresian distributions, H. strigosa Skuse a Bassian distribution, and H. ribesci Hungerford is known from Australia, New Caledonia and New Zealand. Carver et al. (1991) summarised information on the distribution and habits of Australian species.

Andersen & Weir (2004A, 2004B) revised the Australia fauna of Hydrometridae with a key and phylogeny to all the Australian fauna of Gerromorpha.


General References

Andersen, N.M. 1977. A new and primitive genus and species of Hydrometridae (Hemiptera, Gerromorpha) with a cladistic analysis of relationships within the family. Entomologica Scandinavica 8: 301-316

Andersen, N.M. 1982. The Semiaquatic Bugs (Hemiptera, Gerromorpha). Phylogeny, adaptations, biogeography and classification. Denmark : Scandinavian Science Press Entomonograph Vol. 3 455 pp.

Andersen, N.M. & Weir, T.A. 2004. Australian Water Bugs. Their Biology and Identification (Hemiptera-Heteroptera, Gerromorpha & Nepomorpha). Entomonographen Denmark : Apollo Books Vol. 14 344 pp.

Andersen, N.M. & Weir, T.A. 2004. Mesoveliidae, Hebridae, and Hydrometridae of Australia (Hemiptera: Heteroptera: Gerromorpha), with a reanalysis of the phylogeny of semiaquatic bugs. Invertebrate Systematics 18: 467-522

Carver, M., Gross, G.F. & Woodward, T.E. 1991. Hemiptera (bugs, leafhoppers, cicadas, aphids, scale insects, etc.) [with contributions by Cassis, G., Evans, J.W., Fletcher, M.J., Hill, L., Lansbury, I., Malipatil, M.B., Monteith, G.B., Moulds, M.S., Polhemus, J.T., Slater, J.A., Štys, P., Taylor, K.L., Weir, T.A. & Williams, D.J.]. pp. 429-509 in CSIRO (ed.). The Insects of Australia. A textbook for students and research workers. Melbourne : Melbourne University Press Vol. 1 xiii 542 pp.

China, W.E., Usinger, R.L. & Villiers, A. 1950. On the identity of Heterocleptes Villiers 1948 and Hydrobatodes China and Usinger 1949 (Hemiptera: Heteroptera Families Reduviidae and Hydrometridae). Revue de Zoologie et de Botanique Africaines 43: 336-344

China, W.E. & Usinger, R.L. 1949. A new genus of Hydrometridae from the Belgian Congo, with a new subfamily and a key to the genera. Revue de Zoologie et de Botanique Africaines 41: 314-319

Cobben, R.H. 1968. Evolutionary Trends in Heteroptera. Part I. Eggs, architecture of the shell, gross embryology and eclosion. No. 151. Wageningen : Centre for Agricultural Publishing and Documentation Mededeling 475 pp.

Dolling, W.R. 1991. The Hemiptera. Oxford : Oxford University Press ix 274 pp.

Drake, C.J. & Lauck, D.R. 1959. Descriptions, synonymy, and check-list of American Hydrometridae. Great Basin Naturalist 19: 43-51

Froeschner, R.C. 1981. Heteroptera or true bugs of Ecuador: a partial catalog. Smithsonian Contributions to Zoology 1981(322): iv 1-147

Hungerford, H.B. 1920. The biology and ecology of aquatic and semiaquatic Hemiptera. University of Kansas Science Bulletin 11: 1-328

Hungerford, H.B. & Evans, N.E. 1934. The Hydrometridae of the Hungarian National Museum and other studies in the family. (Hemiptera). Annales Historico-Naturales Musei Nationalis Hungarici (Zoologica) 28: 31-112

Lansbury, I. 1981. Aquatic and semi-aquatic bugs (Hemiptera) of Australia. pp. 1195-1211 in Keast, A. (ed.). Ecological Biogeography of Australia. The Hague : Dr. W. Junk Vol. 2(4).

Polhemus, J.T. & Chapman, H.C. 1979. Family Mesoveliidae/water treaders. pp. 39-42 in Menke, A.S. (ed.). The Semiaquatic and Aquatic Hemiptera of California (Heteroptera: Hemiptera). Berkeley : University of California Press.

Polhemus, J.T. & Lansbury, I. 1997. Revision of the genus Hydrometra Latreille in Australia, Melanesia, and the Southwest Pacific (Heteroptera: Hydrometridae). Occasional Papers of the Bernice P. Bishop Museum 47: 1-67

Polhemus, J.T. & Polhemus, D.A. 1995. Revision of the genus Hydrometra Latreille in Indochina and the western Malay Archipelago (Heteroptera: Hydrometridae). Bishop Museum Occasional Papers 53: 9-72

Slater, J.A. 1982. Hemiptera. pp. 417-447 in Parker, S.P. (ed.). Synopsis and Classification of Living Organisms. New York : McGraw Hill Book Co.

Smith, C.L. 1988. Family Hydrometridae Billberg, 1820. The Marsh Treaders. pp. 156-158 in Henry, T.J. & Froeschner, R.C. (eds). Catalog of the Heteroptera, or True Bugs, of Canada and the Continental United States. Leiden : E.J. Brill xix 958 pp.

Sprague, I.B. 1956. The biology and morphology of Hydrometra martini Kirkaldy. University of Kansas Science Bulletin 38: 579-693

Torre-Bueno, J.R. de la 1926. Limnometra skusei: a new name. Bulletin of the Brooklyn Entomological Society 21: 129


History of changes

Note that this list may be incomplete for dates prior to September 2013.
Published As part of group Action Date Action Type Compiler(s)
05-Dec-2012 05-Dec-2012 MODIFIED
15-Aug-2012 15-Aug-2012 MODIFIED
20-Oct-2010 20-Oct-2010 MODIFIED
12-Feb-2010 (import)