Recent research has demonstrated that the topography of defensive reactions depends on factors that are extraneous to the stimulus that elicits the defensive response. For example, hermit crabs will withdraw more slowly to the approach of a simulated visual predator (i.e., the eliciting stimulus) when in the presence of a coincident acoustic stimulus. Multiple properties related to the magnitud...

The diversity on coral reefs has long captivated observers. We examine the mechanisms of speciation, role of ecology in speciation, and patterns of species distribution in a typical reef-associated clade-the diverse and colorful Calcinus hermit crabs-to address the origin of tropical marine diversity. We sequenced COI, 16S, and H3 gene regions for approximately 90% of 56 putative species, inclu...

The zoeal and the megalopal stages of the land hermit crab Coenobita violascens Heller, 1862 are described and illustrated from laboratory-reared material, and compared with larvae of nine other described coenobitid species. The larvae developed through four planktonic zoeal stages to the megalopal stage. Coenobita violascens had characteristics of zoeal pleomeres and megalopal antennules typic...

Fighting animals use a variety of information sources to make strategic decisions. A neglected potential source of information is an individual's own performance during a fight. Surprisingly, this possibility has yet to be incorporated into the large body of theory concerning the evolution of aggressive behaviour. Here, by experimentally dampening the impact of their shell rapping behaviour, we...

We report a rich faunal assemblage from the Tyrrhenian (Late Pleistocene) of Trumbacà, located in the southern area of Reggio Calabria (Calabria, southern Italy). The only brachyuran reported to date from this locality is Ranilia constricta (A. Milne Edwards, 1880) by Vazzana (2008). The studied specimens have been assigned, as follows: ?Corallianassa sp., Dardanus arrosor (Herbst, 1796), Darda...

We outline a framework for evaluating scientific evidence of sentience, focusing on pain experience. It includes eight neural and cognitive-behavioural criteria, with confidence levels each criterion reflecting the reliability quality evidence. rationale apply our to controversial sentience candidate: decapod crustaceans. have either high or very that true crabs (infraorder Brachyura) satisfy f...

The pagurid hermit crab genus Trichopagurus de Saint Laurent, 1968 is currently represented by three shallow water spe- cies from the tropical Indo-West Pacific region. In this paper, three species of the genus, including one new species, are reported. Trichopagurus tenuidactylus n. sp. is described on the basis of a single ovigerous female from the Bohol Sea, the Philippines, and compared with...

For small colleges, the use of invertebrates in undergraduate learning laboratory experiments may be a valuable alternative to the use of vertebrate species. This article describes a habituation experiment using terrestrial hermit crabs. All of the materials required are inexpensive and readily available. What makes this experiment unique is that although the instructor sets basic parameters, s...

Shell resource utilization in two common species of hermit crabs, Calcinus latens (Randall) and Calcinus gaimardii (H. Milne Edwards), from intertidal and subtidal zones at Kenting, southern Taiwan, was studied. Field data were compared with laboratory results in shell-selection tests. Shell parameters examined included shell length, shell width, aperture length, aperture width, and weight in s...