dcsimg
Image of Brown hydra
Creatures » » Animal » Cnidarians » Hydrozoans » » Hydridae »

Brown Hydra

Hydra oligactis Pallas 1766

Untitled

provided by Animal Diversity Web

Hydras have well developed powers of regeneration and grafting. Very little is known about the length of life under normal conditions. In the lab, hydras have been known to live for three to twelve months or more. Males outnumer females, an unusual situtation in most fresh water invertebrates.

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Weinberger, J. 1999. "Hydra oligactis" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hydra_oligactis.html
author
Jana D. Weinberger, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Benefits

provided by Animal Diversity Web

Hydra oligactis is a hatchery nuisance because it may kill fish fry.

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Weinberger, J. 1999. "Hydra oligactis" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hydra_oligactis.html
author
Jana D. Weinberger, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Trophic Strategy

provided by Animal Diversity Web

Hydra oligactis, as in all Cnidaria, are strictly carnivorous and eat many different kinds of small metazoans, including annelids, copepods, cladocerans, and insects. Hydra capture their food by paralyzing and killing the food organism by means of nematocysts, which are discharged into the prey. The prey is brought to the mouth (proctostome) by the tentacles, a response that is induced glutathione. This is considered the key mechanism in digestion. The organism is then taken in through the mouth, which is star-shaped or circular. Hydras have been known to feed on the organic material of the substrate when the food supply is insufficient. This behavior, however, is not considered normal. Digestion is both extra and intracellular.

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Weinberger, J. 1999. "Hydra oligactis" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hydra_oligactis.html
author
Jana D. Weinberger, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Distribution

provided by Animal Diversity Web

The brown hydra is commonly found in the Northern Hemisphere and parts of Australia.

Biogeographic Regions: nearctic (Native ); australian (Native )

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Weinberger, J. 1999. "Hydra oligactis" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hydra_oligactis.html
author
Jana D. Weinberger, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Habitat

provided by Animal Diversity Web

Hydras are are well known as the faunas of ponds, spring brooks, unpolluted streams, rivers, and the littoral zone of lakes.

Aquatic Biomes: lakes and ponds; rivers and streams

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Weinberger, J. 1999. "Hydra oligactis" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hydra_oligactis.html
author
Jana D. Weinberger, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Morphology

provided by Animal Diversity Web

Other Physical Features: ectothermic ; radial symmetry

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Weinberger, J. 1999. "Hydra oligactis" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hydra_oligactis.html
author
Jana D. Weinberger, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Reproduction

provided by Animal Diversity Web

The common asexual method of reproduction by hydras is budding. Buds originate at the junction of the stalk and gastric regions. The bud begins as a hemispherical outpouching that eventually elongates, becomes cylindrical, and develops tentacles. The bud then pinches off and a new individual becomes independent. Buds are produced every two to three days under favorable conditions. Following unfavorable conditions, such as injuries or periods of scarce resources, hydras occasionally reproduce through transverse and longitudinal fission.

Parental Investment: no parental involvement

license
cc-by-nc-sa-3.0
copyright
The Regents of the University of Michigan and its licensors
bibliographic citation
Weinberger, J. 1999. "Hydra oligactis" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hydra_oligactis.html
author
Jana D. Weinberger, University of Michigan-Ann Arbor
original
visit source
partner site
Animal Diversity Web

Biology

provided by Arkive
The brown hydra, although largely a sessile species is capable of moving by gliding along on the 'basal disc', the part of the body that attaches to the substrate. They may also move by bending the body around, attaching to the substrate with the tentacles, and then 'somersaulting' or 'looping' forwards (3). This species is carnivorous; it feeds on small aquatic invertebrates that are paralysed by the stinging cells when the prey comes into contact with the tentacles. The prey item is then brought to the mouth by the tentacles and taken into the body of the hydra (3). Reproduction in hydras typically takes place asexually by a process known as 'budding', in which a bud-like growth on the body of the 'parent' hydra eventually grows into a new individual that becomes separated from the parent. When conditions are harsh, or there is a shortage of food, hydras can reproduce sexually; a single individual may produce both male and female sex cells, which are released into the water where fertilisation occurs. The egg develops into a larva, which is covered in tiny hair-like structures known as cilia. The larva may either settle immediately and develop into a hydra, or become surrounded in a tough outer layer that allows it to survive harsh conditions (4).
license
cc-by-nc-sa-3.0
copyright
Wildscreen
original
visit source
partner site
Arkive

Conservation

provided by Arkive
The brown hydra is not listed under any conservation legislation.
license
cc-by-nc-sa-3.0
copyright
Wildscreen
original
visit source
partner site
Arkive

Description

provided by Arkive
Hydras are freshwater animals that belong to the same group as jellyfish, corals and sea anemones (2). The sac-shaped 'body' is topped with a mouth surrounded by a crown of tentacles that feature stinging cells used to stun prey (2).
license
cc-by-nc-sa-3.0
copyright
Wildscreen
original
visit source
partner site
Arkive

Habitat

provided by Arkive
This hydra is found in freshwater ponds, brooks, rivers, and streams as well as at the edges of lakes, and typically attaches to aquatic plants, stones, twigs and debris (3).
license
cc-by-nc-sa-3.0
copyright
Wildscreen
original
visit source
partner site
Arkive

Range

provided by Arkive
The brown hydra is a widespread species, found throughout the northern hemisphere and parts of Australia (3).
license
cc-by-nc-sa-3.0
copyright
Wildscreen
original
visit source
partner site
Arkive

Status

provided by Arkive
Common and widespread in Britain (2).
license
cc-by-nc-sa-3.0
copyright
Wildscreen
original
visit source
partner site
Arkive

Threats

provided by Arkive
This species is not threatened.
license
cc-by-nc-sa-3.0
copyright
Wildscreen
original
visit source
partner site
Arkive

Hydra oligactis

provided by wikipedia EN

Hydra oligactis, also known as the brown hydra, is a species of hydra found widely dispersed in the northern temperate zone. It is a common organism found in still waters from early Spring to late Autumn.

It is commonly found attached to the stems of water plants, the undersides of leaves, submerged twigs and on the surface of stones. When disturbed it retracts to a small brown blob which is easily overlooked. Gently sweeping through a clean weedy pond and allowing the collected water and leaves to stand in a jar will often reveal Hydra emerging after only a few minutes.

When in feeding mode, the fully extended tentacles are very long and may exceed 1 inch (25 mm) in length. In this condition the tentacles are very difficult to see with the naked eye and are often only revealed when a prey animal such as Daphnia is caught. The relative length of the tentacles compared to the body is characteristic of the species and serves to differentiate it from any other brown Hydra of cool temperate waters.

When a cold sensitive strain of H. oligactis is subjected to temperature stress, it undergoes a shift from asexual budding to sexual reproduction.[2] This shift involves an upregulation of genes involved in gametogenesis, cellular senescence, apoptosis and DNA repair, and a downregulation of genes involved in stem cell maintenance.

Hydra oligactis is preyed upon by the flatworm Microstomum lineare, which incorporates Hydra stenoteles into its own epidermis.[3][4]

References

Wikimedia Commons has media related to Hydra oligactis.
  1. ^ a b c d e f g Schuchert, P. (2015). Schuchert P (ed.). "Hydra oligactis Pallas, 1766". World Hydrozoa database. World Register of Marine Species. Retrieved 2015-06-29.
  2. ^ Sun S, White RR, Fischer KE, Zhang Z, Austad SN, Vijg J. Inducible aging in Hydra oligactis implicates sexual reproduction, loss of stem cells, and genome maintenance as major pathways. Geroscience. 2020 Aug;42(4):1119-1132. doi: 10.1007/s11357-020-00214-z. Epub 2020 Jun 23. PMID 32578072; PMCID: PMC7394996
  3. ^ Krohne, Georg (2018). "Organelle survival in a foreign organism: Hydra nematocysts in the flatworm Microstomum lineare". European Journal of Cell Biology. 97 (4): 289–299. doi:10.1016/j.ejcb.2018.04.002. ISSN 1618-1298. PMID 29661512.
  4. ^ Krohne, Georg (2020). "Hydra nematocysts in the flatworm Microstomum lineare: in search for alterations preceding their disappearance from the new host". Cell and Tissue Research. 379 (1): 63–71. doi:10.1007/s00441-019-03149-w. ISSN 1432-0878. PMID 31848750. S2CID 209380951.
license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Hydra oligactis: Brief Summary

provided by wikipedia EN

Hydra oligactis, also known as the brown hydra, is a species of hydra found widely dispersed in the northern temperate zone. It is a common organism found in still waters from early Spring to late Autumn.

It is commonly found attached to the stems of water plants, the undersides of leaves, submerged twigs and on the surface of stones. When disturbed it retracts to a small brown blob which is easily overlooked. Gently sweeping through a clean weedy pond and allowing the collected water and leaves to stand in a jar will often reveal Hydra emerging after only a few minutes.

When in feeding mode, the fully extended tentacles are very long and may exceed 1 inch (25 mm) in length. In this condition the tentacles are very difficult to see with the naked eye and are often only revealed when a prey animal such as Daphnia is caught. The relative length of the tentacles compared to the body is characteristic of the species and serves to differentiate it from any other brown Hydra of cool temperate waters.

When a cold sensitive strain of H. oligactis is subjected to temperature stress, it undergoes a shift from asexual budding to sexual reproduction. This shift involves an upregulation of genes involved in gametogenesis, cellular senescence, apoptosis and DNA repair, and a downregulation of genes involved in stem cell maintenance.

Hydra oligactis is preyed upon by the flatworm Microstomum lineare, which incorporates Hydra stenoteles into its own epidermis.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN