Settlement requirements of molluscan larvae: New data on chemical and genetic roles

摘要: Abstract Recent studies in the author's laboratory and elsewhere indicate that a high degree of substratum chemical specificity is necessary to induce settlement metamorphosis number molluscan species. The nature natural artificial inducers, as well inducer-larval interactions, provides insights into both stimulus response aspects metamorphic process. Larvae Phestilla sibogae undergo rapid complete soluble, coral-produced substance. These larvae slow but choline, GABA, some related compounds; they exhibit partial presence certain catecholamines. Reversible inhibition (habituation) occurs when are exposed an inducer prematurely. Analysis these observations allows formulation new models for induction. It may be single model will not appropriate all marine molluscs. Both age at competence concentration elicit competent known show wide variance among larvae. Long-term selective inbreeding experiments have failed obvious genetic components observed variances. High even egg masses single, highly inbred individual with mate.