death when they meet an individual of the same sex, but when a male and 

 female meet, the female assumes the subordinate position, and a long- 

 lasting pair is formed (V. R. Johnson, 1969). In this behavior we can see 

 the primordial form of monogamy inherent in vertebrates, indicating the 

 convergent evolution of behavioral mechanisms in various branches of the 

 animal kingdom (Wickler, Seibt, 1972). Analysis of behavior as one aspect 

 of ecologic adaptation (Reese, 1964; Fricke, 1973) shows that convergent 

 evolution is unavoidable. Thus, aggressive behavior in species which are 

 territorial should be suppressed for successful mating, which is achieved 

 by the use of the subordinate pose by one of the partners, though the 

 specific manifestations of this ritual in various taxonomic groups are 

 different. General systems of behavior, characteristic for certain life 

 forms, change, adapting to the specific demands of each species. Therefore, 

 in highly specialized commensals, programming of behavior varies most 

 widely from the general system. The specific manifestations of the general 

 features of behavior depend greatly on the development of receptors. For 

 example, in lower crustaceans and gastropods, ritualization (if it is 

 present) depends to a greater extent on the perception of the chemical and 

 vibrotactile stimuli than visual stimuli. Naturally, behavioral adaptations 

 are particularly complex in wery complex biotopes with sympatric speciation. 



The trigger mechanisms of group reactions may depend on any receptor 

 system. The key stimulus may be either an abiotic signal or information 

 from another organism. The capability for group reactions may be initiated 

 by the diurnal rhythm of abiotic factors. For example, the distribution of 

 male Ilea pugilator crabs is group-determined before the tide flows, while 

 during the flow of the tide it is random; during tidal flow, the females 

 form groups (Rajendran, 1974). Individual burrowing decapods Goneplax 

 rhomboides and Nephrops norvegicus are usually active during the dark hours, 

 but the presence of other individuals of the same species inhibits this 

 activity (Atkinson, 1974). The presence of other individuals is also 

 significant in other respects; disruption of territoriality, e.g., in 

 lobsters, results in atypical migration, making them prey to predators 

 (Chittleborough, 1974). 



Orientation among other similar animals is a result of complex 

 functioning of receptors; territorial behavior, as a variety of group 

 behavior, does not always include continuous communication with another 

 individual of the same species. Arbitrary interruptions in communication 

 are permissible with wave translation. The reception of information by 

 means of vibrotactile receptors is widespread. It is in this manner that 

 sagittae detect Copepoda: The hunting sagitta hangs motionless in the 

 water until it senses vibrations at a specific frequency. Possibly, each 

 species of chaetognaths has its own specific range of perceived frequencies 

 (Newbury, 1972). In the land crab Gecarcinus lateralis , intraspecies 

 communication is achieved by the vibration of the substrate by each indi- 

 vidual with a definite sequence of pulses (Klaassen, 1973). The Ocypode 

 crabs also react to vibrations of the substrate, emitting response signals 

 at the corresponding frequency (Horch, Salmon, 1972). The threshold 

 frequency for beating of the barnacles is species-specific; therefore, 

 representatives of different species respond differently to the identical 



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