''Epiactis prolifera'', the brooding, proliferating or small green anemone, is a species of marine invertebrate in the family Actiniidae.Fautin, D. (2010). ''Epiactis prolifera'' Verrill, 1869. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=283435 on 2011-07-20 It is found in the north-eastern Pacific. It has a feature rare among animals in that all individuals start life as females but develop testes later in their lives to become

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

Description

The brooding anemone grows to three centimetres high and up to five centimetres in diameter and varies in colour, usually being greenish-brown but sometimes brown, pink, red or dull green. There are fine white lines starting at the mouth and spreading radially across the oral disc and further white lines occur on the column and pedal disc.''Epiactis prolifera
Cowles, David. Walla Walla University
/ref> The lower part of the column and pedal disc are occasionally blue. There are often radiating pale and dark lines on the edges of the pedal disc and the lower part of the column. The mouth is surrounded by 48 to 96 short, conical tentacles each tipped with a terminal pore.

Distribution and habitat

The brooding anemone is found in shallow areas of the north-east Pacific Ocean. The highest density is on or under rocks in the sublittoral zone, in surge channels, on rock shelves and areas exposed to wave action. It is often found in areas encrusted with coralline algae and sometimes grows on the leaves of eelgrass. It cannot tolerate exposure to the drying air and sunlight. The brooding anemone moves around over the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

to a greater extent than do other anemones.

Biology

''Epiactis prolifera'' is a protogynic hermaphrodite. The young all start life as females but when the pedal disc is about two centimetres in diameter, they develop testes on the

mesentery The mesentery is an organ that attaches the intestines to the posterior abdominal wall in humans and is formed by the double fold of peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestines ...

and spend the rest of their lives as hermaphrodites.Encyclopedia of Life
/ref> This means that the population consists of a large number of young females and a small number of older hermaphrodites. Reproduction is not limited to any particular season. Sperm is released into the water column and after cross-fertilisation (or sometimes self-fertilisation), the young remain within the mother's gastrovascular cavity during their early development. The mother then expels a mass of eggs and mucus through her mouth and they spread across her oral disc. Cilia move some of them down the column and they become attached to the base of the column with mucus, and perhaps also nematocysts. The larvae develop tentacles of their own and grow in this protective environment for at least three months. When they reach about four millimetres in diameter, they separate from their mother and move away to live independently. If the anemone is damaged and broken in pieces, the various fragments are each able to grow into a new individual. The diet consists of small fish,

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s and jellyfish. The prey is immobilised by the nematocysts in the tentacles which inject toxins, then passed by the tentacles through the mouth and into the gastrovascular cavity. Any undigested remains are expelled through the mouth.

Ecology

Despite their stinging nematocysts, brooding anemones are a favoured prey for certain other animals. Many nudibranchs seem to be immune to the toxin and both eat them and can store the unused nematocysts for their own defence. Predators include the nudibranch '' Aeolidia papillosa'', the leather star ''

Dermasterias imbricata The leather star (''Dermasterias imbricata'') is a sea star in the family Asteropseidae found at depths to off the western seaboard of North America. It was first described to science by Adolph Eduard Grube in 1857. Description The leathe ...

'' and certain fish. This anemone sometimes displays mutualism by attaching itself to a hermit crab or decorator crab. The anemone provides protection for the host from predators and itself benefits by being able to consume food fragments discarded by the crab. The

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

, '' Doridicola sunnivae'', is an

ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

of the brooding anemone.World of Copepods
/ref>

References

{{Taxonbar, from=Q2241181 Actiniidae Cnidarians of the Pacific Ocean Animals described in 1869 Taxa named by Addison Emery Verrill