the astacus leptodactylus specimens were collected from four sites of aras reservoir, north-west of iran and examined for the epibionts during 2009. protozoan epibionts from ciliophora (one genus and seven species) and tracheophyta were isolated from the cuticular surface of different body parts of narrow-claw crayfish, a.leptodactylus. seasonal prevalence of infestation was determined in 394 i...

Acclimation temperature influenced the acute preferred temperature of the crayfish Orconectes obscurus. This species preferred a higher temperature than its acclimation temperature for those acclimation temperatures ranging from 6 degrees to 26 degrees C. When acclimated to 30 degrees and 33 degrees C, the crayfish preferred a lower temperature than its acclimation temperature. The final temper...

In crayfish claw closer muscle, the giant sarcomeres are 8.3 microm long at rest, four times longer than vertebrate striated muscle sarcomeres, and they are extensible up to 13 microm upon stretch. Invertebrate connectin (I-connectin) is an elastic protein which holds the A band at the center of the sarcomere. The entire sequence of crayfish I-connectin was predicted from cDNA sequences of 53 4...

Appendages are important sources of sensory information for all animals that possess them but they are commonly damaged in nature. We describe how the tactile system of the crayfish Cherax destructor functioned when subjected to the kind of damage found in wild-caught or cultured animals. Touch information was methodically varied by the removal of antennae and chelae. The resulting behaviour wa...

The National Wildlife Refuge system is a vital resource for the protection and conservation of biodiversity and biological integrity in the United States. Surveys were conducted to determine the spatial and temporal patterns of fish, macroinvertebrate, and crayfish populations in two watersheds that encompass three refuges in southern Indiana. The Patoka River National Wildlife Refuge had the h...

The major molecular and anatomical substrates of drug related reward in mammals have received considerable attention. In contrast, molecular mechanisms and specific neuroanatomical targets of drug associated reward in invertebrate models of drug addiction have gone largely unexplored. With a modular nervous system amenable to molecular techniques, crayfish offer a novel system for simultaneousl...

An unequal resource distribution is commonly seen in dominance hierarchies, in which the individual with the higher status is more successful in obtaining the resource. One possible resource is preferred temperature. When situations allow, ectotherms regulate their body temperature by behaviourally selecting different environmental conditions, achieving, when possible, a preferred temperature. ...

OBJECTIVES The aim of the study was to investigate effects of the triazine herbicide metribuzin on signal crayfish Pacifastacus leniusculus Dana by determining oxidative stress (thiobarbituric acid reactive substances) and antioxidant indices (total superoxide dismutase, catalase, glutathione reductase) in hepatopancreas, muscle, and gill as well as assessing their histopathology. DESIGN Cray...

Intra-specific genetic diversity is important not only because it influences population persistence and evolutionary potential, but also because it contains past geological, climatic and environmental information. In this paper, we show unusually clear genetic structure of the endangered Japanese crayfish that, as a sedentary species, provides many insights into lesser-known past environments i...

Prey naiveté has been hypothesized to be one of the major driving forces behind population declines following the introduction of novel predators or release of inexperienced prey into predator rich environments. In these cases, naïve prey may lack sufficient antipredator behavior and, as a result, suffer increased mortality. Despite this, some evidence suggests that many prey utilize a generali...