We demonstrate that the probability of the crayfish, P. clarkii, to tail flip in response to a touch on the dorsal tail fan is dependent on both the size and the behavioral state of the animal. Alterations in the animal's internal physical state, such as when the animal autotomizes its chelipeds, will cause larger-sized animals to tail flip; if they were not autotomized, then no tail flip respo...

Rapid transitions in ecosystem structure, or regime shifts, are a hallmark of alternative stable states (ASS). However, regime shifts can occur even when feedbacks are not strong enough to cause ASS. We investigated the potential for ASS to explain transitions between dominance of an invasive species, rusty crayfish (Orconectes rusticus), and native sunfishes (Lepomis spp.) in northern Wisconsi...

The specific binding of concanavalin A (Con A) to semigranular (SG) and granular (G) cells of the crayfishes Pacifastacus lelliusculus and Astacus astacus was shown by in vitro agglutination of fixed haemocytes and by direct labelling with fluorescein isothiocyanate-conjugated Con A (FITCCon A). When non-fixed cell monolayers from both species of crayf~sh were treated with FITC-Con A, capping o...

The biogenic amine serotonin is thought to play an important role in aggression in many species, including man. This paper summarizes experimental approaches which attempt to link this neuromodulator with ®ghting in a cray®sh model for which the complex agonistic behavior is well characterized. Based on a quantitative analysis of ®ghting we demonstrate that the infusion of small amounts of sero...

Crayfish stocks collapsed in Turkey in mid 1980’s due to crayfish plague epidemics, with up to 25% survival in some cases. The collapsed stocks have then recovered slowly and commercial crayfish fishery was reinitiated gradually within a decade. We examined the prevalence of Aphanomyces astaciDNA in the narrow clawed crayfish (Astacus leptodactylus) collected from two Turkish lakes, Lake İznik ...

Crayfish (Astacus astacus) muscle stretch receptors show strong homology to mammalian muscle spindles and bipolar neurons in D. melanogaster. All are typical, non-ciliated, stretch-sensitive, afferent neurons. Such receptors are observed in many species and perform an important sensory role. However, they are poorly characterised. A previous study reported a bio-mechanical and behavioural model...

Invasive non-indigenous crayfish species (NICS) are a major threat to the existence of native populations in European freshwater ecosystems. The discovery signal Pacifastacus leniusculus, marbled Procambarus virginalis, and spiny-cheek Faxonius limosus Estonia has increased risk extinction Estonia’s only species, noble Astacus astacus. aim this study was give an overview status, distribution, i...