Life History & Behaviour

Feeding & Excretion

Like all cnidarians, the coelenteron of A. veratra serves as a blind gut. Food captured by tentacles is passed to the mouth, travels down the actinopharynx to the coelenteron where it is digested. Undigested food is expelled through the mouth. The principle form of nitrogenous waste is ammonia (Shick, 1991), but there are no specialised structures for waste excretion. Siphonoglyphs (ciliated groves on either side of the mouth and actinopharynx) and cilia on the actinopharynx create water currents that carry oxygen in, and waste out (Hickman 201; Moore, 2006).

Most sea anemones are carnivores (Moore, 2006; Tsurpalo and Kostina, 2003). The diets of sea anemones that similarly inhabit intertidal zones may give insight into the diet of A. veratra. Crustaceans, gastropods, bivalves, chitons, bryozoans, polychaetes, nematodes, insects and small fish have commonly been found in the coelenterons of sea anemone species from intertidal zones across the globe (Chintiroglou & Koukouras, 1991; Chintiroglou & Koukouras, 1992; Tsurpalo & Kostina, 2003; Krugeret al., 2011). Various species of crustaceans, gastropods, bivalves, chitons, bryozoans and small fish were observed in the intertidal rockpools at Point Cartwright where specimens of A. veratra were observed and collected, and likely form part of their diet.

Movement

Contraction of muscles against the water-filled coelenteron, which serves as a hydrostatic skeleton, allows anemones to move and contract their tentacles, as well as change the shape of their column. While some anemones are capable of burrowing and swimming, these behaviours have not been observed in A. veratra. A. veratra appears to be capable of crawling or gliding with their pedal disc. Crawling was not directly observed, but inferred as individuals in an aquarium that were initially settled on the top side of a rock were later found on the underside of the same rock.

Reproduction

A wide variety of reproductive modes are found within the Actiniaria. Individual species may reproduce through sexual modes, asexual modes, or both. In addition to sexual reproduction, anemones can reproduce asexually through transverse fission, longitudinal fission, pedal laceration, autotomy of tentacles, and parthenogenesis (Bocharova & Kozevich, 2011) (Figure 1).

The modes of reproduction utilised by A. veratra are not known, but as only female specimens have been observed (Edmands &Fautin, 1991; Fautin et al., 2008), it is likely to be primarily asexual.


Figure 1: Modes of asexual reproduction in the Actiniaria. (a) transverse fission, (b) longitudinal fission, (c) tentacle autotomy, (d) pedal laceration. Adapted from Bocharova and Kozevich (2011).