Résistance du gardon (Rutilus rutilus L.) à des variations brusques de température

Factors affecting between-lake variation in the occurrence of epidermal papillomatosis in roach, Rutilus rutilus (L.).

The theory of island biogeography predicts that the probability of a species occupying an island depends on a dynamic equilibrium between extinction and colonization. Epidermal papillomatosis is a disease manifesting as skin tumours on fish. We studied the factors affecting the occurrence of the disease in roach, Rutilus rutilus (L.), in 34 lakes. The results of discrimination analysis suggest ...

Sperm quality, secondary sexual characters and parasitism in roach (Rutilus rutilus L.)

According to sperm competition models, a male spawning in a disfavoured role should have spermatozoa with higher velocity but shorter longevity compared with a male spawning in a favoured role. Moreover, immunosuppressive androgens are needed to produce both secondary sexual characters and sperm cells. The ‘sperm protection’ hypothesis suggests that the immunosuppressive action of androgens has...

Recherches pour la détermination du degré des propriétés antigéniques de quelques souches vaccinales du virus de la maladie de Newcastle administrées par voie oculaire à des poulets

Laboratory and field studies with 32P labeled Toxorhynchites rutilus rutilus.

Females and eggs of Toxorhynchites r. rutilus were labeled with 32P by feeding fourth-stage larvae 32P labeled Aedes aegypti larvae. Eggs from females up to 3 weeks in age had detectable levels of radioactivity and individual eggs contained ca. 0.3% of the mother's total radioactivity. Comparisons of labeled and unlabeled females in indoor and outdoor cage tests indicated that survival and fecu...

Experimental demonstration of a behavioural modification in a cyprinid fish, Rutilus rutilus (L.), induced by a parasite, Ligula intestinalis (L.)

Behavioural changes in parasitized hosts have been experimentally investigated by comparing the swimming behaviour of roach, Rutilus rutilus, infected by the tapeworm Ligula intestinalis with that of uninfected roach when they were exposed to the same overhead heron stimulus. Before the stimulus was presented, infected fish swam close to the surface and uninfected fish were preferentially found...