The effects of ammonia loading in the terrestrial isopod Porcellio scaber were studied by exposing animals to atmospheres of high PNH3. Isopods show a remarkable tolerance of elevated ambient PNH3, with an LD50 of 89 Pa for a 7-day exposure. However, haemolymph total ammonia concentrations generally remained below 5 mmol l-1 (PNH3=0.37 Pa) over the range of ambient ammonia levels used (6.6­...

The k-shy mutants of Paramecium tetraurelia are altered in several Ca2+-dependent functions which regulate ciliary motility. The isolation, genetics, and phenotypes of these mutants are described. Of six independent isolates, all contained recessive single-factor mutations and comprise two unlinked loci, ksA and ksB. All k-shy strains showed prolonged backward swimming responses to depolarizing...

In order to elucidate the cues for, and the biochemical mechanisms of, the transition to ureogenesis in the gulf toadfish Opsanus beta, experiments on the effects of confinement/crowding were carried out. Confinement of toadfish to small volumes of water initiated a switch to nearly complete reliance on ureogenesis for nitrogen excretion within 24­48 h. Further experiments suggested that th...

Newly emerged adult dragonflies are physiologically immature in a number of ways, including the mass, ultrastructure and biochemistry of their flight muscles. In Libellula pulchella dragonflies, adult maturation of flight muscle is accompanied by striking changes in thermal physiology. Vertical force production during fixed flight attempts in newly emerged adults (tenerals) shows a broad platea...

While differences in individual personality are common in animal populations, understanding the ecological significance of variation has not yet been resolved. Evidence suggests that personality may influence learning and memory; a finding that could improve our understanding of the evolutionary processes that produce and maintain intraspecific behavioural heterogeneity. Here, we tested whether...

Ontology-based query answering asks whether a Boolean query is satisfied by all models of a logical theory consisting of an extensional database paired with an ontology. The introduction of existential rules (i.e., Datalog rules extended with existential quantifiers in rule-heads) as a means to specify the ontology gave birth to Datalog+/-, a framework that has received increasing attention in ...

A proposal is made for a classification of Oligocene European cricetids. Various problems concerning the evolu­tion Eucricetodon and Pseudocricetodon are discussed. new species described from level slightly lower than oldest occurrence genus, known so far.&nbsp