Collected reprints: Abstract 3521
Collected reprints
Abstract
Heip, C. (1975). On the significance of aggregation in some benthic marine invertebrates. Proc. 9th Europ. mar. biol. Symp. : 527-538
Populations of most benthic marine invertebrates show an aggregated spatial pattern. This has been shown to be the case for Foraminifera, Gastropoda, Bivalvia, Polychaeta, Oligochaeta, Nematoda, Copepoda, Ostracoda, Amphipoda and Isopoda. Only among the Bivalvia does there seem to be important exceptions to this rule.
Evidence is presented that pattern formation is the result of two opposing forces: (1) the need for sufficient energy in which space is more evenly partitioned amongst individuals; and (2) the necessity for contact between individuals when copulation is part of the reproductive scheme. Since aggregation is the rule, the strategy in the majority of benthic marine invertebrates appears to be a reduction in the risk of failing to find a partner at the cost of an increase of the risk of not finding enough food.
It appears that aggregation in Ostracoda and Copepoda is not mechanical but an active process. The relationship m = (kV)1/2 between mean, variance, and the degree of aggregation for populations which are aggregated following the negative binomial distribution, and the constant variability v = (1/k)1/2 when density increases, shows that the degree of aggregation becomes constant at least at high densities. This degree of aggregation appears to be the same in different populations, indicating that the optimum strategy is the same for otherwise very different populations.
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