Interspecific and Intraspecific Acrorhagial Aggressive Behavior Among Sea Anemones: A Recognition of Self and Not-Self

Abstract

iiolot/ical Science. Floriilii Slute ['nii'crsity, 'I'ulliiliussci'. Florida 32306 Coelenterates have long been considered primitive or simple animals. Although some aspects have heen known for a long time, coelenterate behavior and its physiological and morphological bases are still poorly understood. Studies have now

Predation by hydromedusae on hydrozoan embryos and larvae: planktonic kin selection?

“…This argument is only partly valid. Where both types of aggression are mediated by the same 'sensor-effector systems' (nematocysts and their sensors; Buss et al 1984), the distinction between competition and predation is arbitrary (Bigger 1980, Lubbock 1980. For example, scyphistomae may well cannibalize planulae and ephyrae because they use the same sensor-effectors in both predatory and competitive interactions.…”

“…In contrast, studies of competitive aggression among benthic hydrozoans have found extremely 'fine-tuned' sensory discrimination at both interspecific and intraspecific levels (reviewed by Buss et al 1984, Grosberg 1988: hydroids are able to identify genetically distinct colonies as nonself and to compete with them, whether or not the compehtor is of the same or another species. The effectors in these interactions are nematocysts , and the sensory discrimination is genetically based (Ivker 1972, Bigger 1980, Buss e t al. 1984, McFadden e t al.…”

Suspected chemoreceptors in coelenterates and ctenophores

“…When such anemones make physical contact with one another, usually with their tentacles, after initial tentacle withdrawals, if the anemones do not perceive each other as inert objects and if they are unable to avoid further contact with one another (e.g., by bending or releasing their pedal discs from the substrates and passively floating away), an acrorhagial attack takes place (Abel, 1954;Bigger, 1980Bigger, , 1988Bonnin, 1964;Brace, 1981;Brace and Pavey, 1978;Francis, 1973). After making contact, the acrorhagi expand and are repeatedly applied to the target organism.…”

“…Acrorhagi have two morphologically and functionally separate regions: the distal tip and the peduncle (Bigger, 1980(Bigger, , 1982Doumenc, 1972;Sebbins, 1984). In Anthopleura and Bunodostorna, the receptors that initiate the behav- ioral response and the subsequent ectodermal peeling are located at the tip; only the distal tip produces a peel (Bigger, 1976(Bigger, , 1980(Bigger, ,1982.…”

The Main Protein of the Aggregation Factor Responsible for Species-specific Cell Adhesion in the Marine Sponge Microciona prolifera Is Highly Polymorphic

“…Immune recognition is widespread in invertebrates (1), and allograft rejection has been described in ascidians (2,3), earthworms (4,5), molluscs (6), coelenterates (7)(8)(9), sponges (10), echinoderms (11)(12)(13), and insects (14,15). Allogeneic reactions have also been observed in vitro with isolated cells, at least in urochordates (16), and in sponges (17)(18)(19), indicating that invertebrate allorecognition is a direct cellular response.…”