Suchergebnisse

This is the case for Leucochroa candidissima (Drap.), which was studied in Western Provence (France). In its natural environment, this xerrophile and sterohygre animal spends, during the annual cycle, two latent life periods (winter and summer) alternating with two periods of activity (spring and autumn). The latter are, in fact, only a succession of short periods of activity spiked by periods of rest under epiphragme. The modalities of water absorption are considered. The variations in tissue hydration observed in animals coincide with the seasonal cycle, but vary depending on the organ. The use of a radioactive tracer (tritium oxide ingested by mouth) makes it possible to specify how water is stored and lost in various organs selected (digestive tract, heart-rein, paedious sole, hepatopanccreas, pallleal bumrelet). Differences in velocity of water loss between organs are explained by the existence of an accumulative function ; International audience ; This is the case for Leucochroa candidissima (Drap.), which was studied in Western Provence (France). In its natural environment, this xerrophile and sterohygre animal spends, during the annual cycle, two latent life periods (winter and summer) alternating with two periods of activity (spring and autumn). The latter are, in fact, only a succession of short periods of activity spiked by periods of rest under epiphragme. The modalities of water absorption are considered. The variations in tissue hydration observed in animals coincide with the seasonal cycle, but vary depending on the organ. The use of a radioactive tracer (tritium oxide ingested by mouth) makes it possible to specify how water is stored and lost in various organs selected (digestive tract, heart-rein, paedious sole, hepatopanccreas, pallleal bumrelet). Differences in velocity of water loss between organs are explained by the existence of an accumulative function ; Un des problèmes essentiels pour les Mollusques terrestres des milieux xériques est le contrôle de l'économie de leur eau. C'est le cas ...

By the action of variable periodic acoustic signals in terms of their duration parameters, it was possible to explain the phenomena of sister edges in the Rainette, the stimulation of call sequences, the organisation of calls in duos, trios, and the loss of this organisation when more animals are present. These different appearances of choir activity can be explained by a single mechanism: the sound signals, provided they have the appropriate acoustic frequencies, are stimulating voice activity. The stimulus effect is accompanied by a delaying effect that postpones the response beyond the actual stimulating time. The effects of this mechanism can be summarised under four rules: 1 — the deviation rule: The duration of discrepancies between responses can be changed but never goes beyond the discrepancies between spontaneous calls of the species. 2 — the alternance rule: If the duration of the stimulating signal is not too long the response starts in the break as the deviation rule can be respected. 3 — the latency rule: When the alter nance rule is applied, the response follows the sound stimulation after a typical latency time of the parameters of the estimating signal and the state of the animal. 4 — the sound level of stimulation rule: The more intense the sti mulation, the more stimulating the signal is, but the longer the delaying effect that accompanies the stimulus effect is lasting. These rules are sufficient to explain the noise interactions in the choir, but choir activity is made more complex by individual differences in activity and response. These rules also shed light on a number of other aspects of behaviour, such as the transmission of rivalry and rain signals. They also make it possible to consider, at least in part, hearing measures; sound activity level and a quantification of the reactogenic power of the signals. They also show that the scope for responses goes far beyond what is used by the species in swabbing conditions and that these rules are likely to belong to a wider set of rules ...