Experiments (see “Transplantation,Removal, and Caging Experiments,”p.246) have shown that this zonation re-sults from a combination of the barnacles’larval settlement pattern, how well they tolerate desiccation, and competition andpredation (Fig. 11.18). The larvae of bothspecies settle over a wider range than thatoccupied by adults. The upper limit of both species appears to result from emer-sion, because larvae that settle too high in