Distributions of land hermit crabs (Decapoda: Coenobitidae) on the coast of the tidal lagoon, Nagura Amparu, on Ishigakijima Island, Japan.

　We investigated the distributions of land hermit crabs on the coast of the tidal lagoon, Nagura Amparu, on Ishigakijima Island, Japan, through six surveys conducted during the period from October 2011 to September 2013. Nagura Amparu is a brackish estuary system with a tidal flat and mangrove tree areaseparated from the outer sea bay by a sandbank. Land hermit crabs were captured using bait traps at three sites along the shoreline of the sandbank facing the inner tidal flat and at one site in the coastal forest on the sandbank. Four land hermit crab species, Coenobita brevimanus, C. cavipes, C. rugosus, and C. violascens, were collected. Almost all collected crabs were C. violascens, and a few C. rugosus were collected on the shoreline. On the other hand, C. cavipes was dominant, followed by C. violascens, and a few C. brevimanus were captured in the coastal forest. Coenobita violascens were juveniles and adults, and they widely inhabited the shoreline and coastal forest. All C. cavipes were juveniles, suggesting that this species utilizes the coastal forest as a nursery ground. Our results highlight the importance of the Nagura Amparu as habitat for juveniles and adults of C. violascens and juveniles of C. cavipes

Characterization of Aquimarina hainanensis isolated from diseased mud crab Scylla serrata larvae in a hatchery

Mass mortality due to necrosis signs occurred in hatchery‐reared zoea stage larvae of the mud crab Scylla serrata in Okinawa, Japan, and a causative bacterium was isolated. In this study, we identified and characterized the bacterium by genome analysis, biochemical properties and pathogenicity. The bacterium was a Gram‐negative, non‐motile, long rod, forming yellow colonies on a marine agar plate. It grew at 20–33°C (not at 37°C) and degraded chitin and gelatin. Phylogenetic analysis of the 16S rRNA gene sequence identified the bacterium as Aquimarina hainanensis. Genome sequence data obtained from Illumina MiSeq generated 29 contigs with 3.56 Mbp in total length and a G + C content of 32.5%. The predicted 16 chitinase genes, as putative virulence factors, had certain homologies with those of genus Aquimarina. Experimental infection with the bacterium conducted on larvae of four crustacean species, brine shrimp Artemia franciscana, freshwater shrimp Caridina multidentata, swimming crab Portunus trituberculatus and mud crab S. serrata, revealed that this bacterium was highly virulent to these species. The present study suggests that the bacterium caused mass mortality in mud crab seed production was A. hainanensis and can be widely pathogenic to crustaceans

Activation of AMPK-Regulated CRH Neurons in the PVH is Sufficient and Necessary to Induce Dietary Preference for Carbohydrate over Fat

Food selection is essential for metabolic homeostasis and is influenced by nutritional state, food palatability, and social factors such as stress. However, the mechanism responsible for selection between a high-carbohydrate diet (HCD) and a high-fat diet (HFD) remains unknown. Here, we show that activation of a subset of corticotropin-releasing hormone (CRH)-positive neurons in the rostral region of the paraventricular hypothalamus (PVH) induces selection of an HCD over an HFD in mice during refeeding after fasting, resulting in a rapid recovery from the change in ketone metabolism. These neurons manifest activation of AMP-activated protein kinase (AMPK) during food deprivation, and this activation is necessary and sufficient for selection of an HCD over an HFD. Furthermore, this effect is mediated by carnitine palmitoyltransferase 1c (CPT1c). Thus, our results identify the specific neurons and intracellular signaling pathway responsible for regulation of the complex behavior of selection between an HCD and an HFD

Ontogenetic change of body color patterns in laboratory-raised juveniles of six terrestrial hermit crab species

Hamasaki, Katsuyuki, Tsuru, Takuma, Sanda, Tetsuya, Fujikawa, Shunsuke, Dan, Shigeki, Kitada, Shuichi (2017): Ontogenetic change of body color patterns in laboratory-raised juveniles of six terrestrial hermit crab species. Zootaxa 4226 (4): 521-545, DOI: https://doi.org/10.11646/zootaxa.4226.4.