QUANTIFYING HERMIT-CRAB RECRUITMENT RATES AND MEGALOPAL SHELL SELECTION ON WAVE-SWEPT SHORES

The availability of shells has been shown to limit populations of adul t hermit crabs and alter the outcome of interspecific interactions. Ho wever, few studies have addressed such issues in newly settled crabs. A major impediment has been the absence of techniques to quantify the use of shells by settling crabs. Here we present a simple technique fo r assessing hermit crab recruitment in rocky habitats. The method appe ars to measure differences in settlement rates among sites without sub stantial bias. By offering several different species of microgastropod shells, we also found that settling Pagurus hirsutiusculus have disti nct shell preferences. Such shell preferences may lead to resource lim itation at the juvenile stage which may have cascading effects on the distribution, abundance, or shell use patterns of adult hermit crabs.