Melatonin has been identified in a variety of invertebrate species, but its function is not as well understood as in crustaceans. The effects of melatonin on hemolymph glucose levels and tissue carbohydrate metabolism in the Chinese mitten crab, Eriocheir sinensis, were fully investigated in this study. Moreover, whether the eyestalk (an important endocrine center in invertebrate species) invol...

Previously, high concentrations of cadmium have been found in the hepatopancreas of the edible or brown crab (Cancer pagurus) sampled from positions north of about 67° N, compared to regions further south along the Norwegian coast, with no clear understanding why. In order to study a similar organism in the same ecosystem, the present study analyzed 210 shore crabs (Carcinus maenas) from four d...

Land crabs produce isosmotic urine but reduce salt loss by reabsorbing salt via the gills to produce a dilute excretory fluid (P). This branchial salt reclamation is regulated in response to changes in dietary salt availability. The regulation of branchial Na reabsorption and osmotic status was investigated in the terrestrial crab Gecarcoidea natalis on Christmas Island. Confinement within fiel...

Nonlethal predator effects can significantly influence trophic interactions, and in this study we examined how size relationships between predators and prey would influence the ex pression of nonlethal predator effects. We assessed how size and vulnerability to predators would influence nonlethal effects in bivalve species common to oyster reefs. We used 2 size classes of mussels Ischadium recu...

The aim of this study was to determine the diets of Portunus pelagicus in the large Peel-Harvey and Leschenault estuaries in south-western Australia in order to ascertain whether the dietary composition of this crab changes with body size during two different moult stages and differs between the two estuaries. Portunus pelagicus, ranging in age and carapace width from ca. 2 months and 12 mm to ...

Theories of large-scale (kilometres) movement of carbon within and from estuaries are often not supported by empirical data, and this provided the basis for a smaller-scale (i.e. <100 m) analysis of carbon movement and assimilation between adjacent habitats. We tested 3 models that potentially explained the movement and assimilation of carbon by resident animals in estuarine habitats at differe...

Molecular identification of sex pheromones in marine crustaceans has proven to be very difficult, and so far no unequivocal identification for any decapod crustacean has been published. Some of these difficulties are common to other animals – pheromones are often blends of molecules at low concentrations. Some difficulties are more specific to marine crustaceans – pheromones are often small and...

The spatial vanabllity in population structure of the shore crab Carcinus maenas was studied In a shallo\v-water fiord in the lsland of Fyn, Denmark The fjord compnses an enclosed area whlch is geomorphologically divlded into a shallo~v cove (mean depth 2 m) , known as Keitinge Nor, and a deeper narrow area closer to the open sea, known as Kerteminde Fjord Tidal range IS small (ca 20 cm) Sex-ra...

Coenobita compressus (H. Milne Edwards) walk forward on six legs using an alternating tripod gait similar to that of insects. The first walking leg provides the driving force for locomotion aided secondarily by the second walking leg, while the chelipeds act largely as supports. The left appendages are longer and heavier than the right, and they extend further laterally from the midline during ...

Blue king crabs (Paralithodes platypus) are commercially and ecologically important in Alaska, USA, but population abundances have fluctuated over the past several decades likely resulting from a combination of environmental and biological factors, including recruitment variability. Cannibalism between cohorts may be a source of mortality limiting recruitment success in the wild, but the degree...