Settlement and recruitment of benthic marine invertebrates are complex processes, determined by the interaction of biotic and abiotic factors which operate at different temporal and spatial scales. This review analyses the settlement process, attempting to integrate aspects related to different levels of organization (i.e. ecological-physiological-molecular). This is important because many factors that act at any of these levels and at different times can explain by themselves the patterns of settlement andlor recruitment of a large number of species. From an ecological perspective, progress has been made in the identification of causal factors of vanations in larval availability for settlement. Many physical and ethological factors that act during settlement have, however, not received much attention. Likewise, since the great majority of settlement studies have been carried out at restricted spatial scales, fewer works consider different biological and physical factors acting at different scales simultaneously. Settlement patterns are frequently inferred from recruitment. In this sense, a density-independent action of post-settlement mortality has been cons~dered as prerequisite for thls type of inference. This has, however, recently been challenged on the basis that settler-recruit and mortality-settler density relationships change in time. At the physiological-molecular level, different settlement-inducing chemical cues have been identified. Those cues have, however, not yet been characterized to understand better the signal transduction mechanisms involved in larval responses. It is likely that the nervous system is involved. The use of artificial inducers would be useful in studying settlement induction, until more effective natural inducers are isolated and characterized Although few studies have analysed the acquisition of competence, stages of larval development have been related to changes in protein patterns or enzymatic levels of the nervous system. An inopportune exposure of larvae to inducers may delay settlement and may even have a negative impact on growth and subsequent survival of juveniles.

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Although ontogenetic changes in resource use within species are common in animals, these changes have not been widely considered in studies of guild structure within communities. The occurrence of one or more shifts in resource use in an individual of a given species during its life should mean that it would also belong to different guilds at different life stages. We specifically addressed this issue by describing the feeding habits of ten species of carnivorous fishes occurring in tidepools in rocky intertidal areas along the coast of central Chile. Most of these species undergo clear ontogenetic dietary shifts and a feeding guild structure of this group of fishes was established that takes these dietary shifts into account. Each species was divided into a number of size classes. Dietary overlap values between both intraspecific and interspecific size-class pairs in the entire group of ten species were used to construct a phenogram of dietary similarity through an UPGMA cluster analysis. Numbers of guilds and their memberships were established objectively by applying a bootstrapping procedure. Four "ontogenetic" feeding guilds (OFGs), each consisting of size-classes of species, were recognized. The majority of species belonged to more that one guild. Interestingly, when the bootstrapping procedure was applied to a phenogram based on the diets of "taxonomic" or complete species, only one significant guild was found. The implications of these ontogenetic dietary shifts for interspecific interactions are substantial because the identity of the species with which each fish species shares resources change through their lives. The usefulness of taxonomic species for investigating potential competitive interactions in this assemblage is greatly undermined.

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