The role of prior agonistic experience in dominance relationships in male crickets Gryllus bimaculatus (Orthoptera: Gryllidae).

Experiments were carried out to study the effect of social conditioning (prior experience of dominance and submission) in dominance relationships between adult male Gryllus bimaculatus. The dominance status of a male cricket appears to be directly linked to its immediate prior agonistic experience. An experience of dominance increases the probability of victory and one of submission decreases it. The effect is maximum when one opponent has experienced dominance and one subordination. The aggressive behavior of males is significantly influenced by prior agonistic experience for 6 h and the effect disappears entirely after 24 h. The cost and benefit of a conflict appears to be dependent on the motivational state of each opponent, in turn modulated by the outcome of prior agonistic interactions.

Stability of dyadic dominance status and recognition of the opponent in male crickets Gryllus bimaculatus (Orthoptera: Gryllidae).

In dyads of adult male Gryllus bimaculatus, a dominance relationship is established at the first agonistic interaction between the two insects. The comparison of the aggressive behaviour displayed by adult males shows that field crickets act in an identical manner when confronted with an unfamiliar opponent or with one already encountered in a different environment. In contrast, analysis of five successive conflicts in a given environment shows that the dynamics of the interactions varies according to whether the opponents are always the same or one is changed at each encounter. The conflicts are solved more rapidly when the interactions involve the same opponents.

Philopatry in mouflon rams during the rutting season: Psycho-ethological determinism and functional consequences.

Our study of mouflon (Ovis musimon) rams in the Caroux-Espinouse massif (southern France) shows that several forms of philopatry occur. Some of the rams were sedentary, as were the ewes, up to the age of four years. Most of the rams, however, started to enlarge their home range from the age of two years. Rams of intermediate age visited their birth ranges during various periods of the year, whereas the adult males returned only during the rut. As potential mates were present on the home ranges of most of the dispersive males, it is difficult to interpret this process merely in terms of adaptation. We propose, instead, a psycho-ethological explanation, whereby the physiological disturbances intervening during the rut alter the significance of the range, the ram having to update the whole set of its sensory-motor past. This interpretation suggests that the animal has no representation of any pre-defined place, nor of any fixed aim. Rams would be able to reduce the imbalances they experience by creating a type of behaviour driven by a self-referential process, where spatial investment would outweigh any other evaluation, as an adaptative cost related to a possible inbreeding. This approach leads to reconsider the importance of spatial investment in animal's cognition and generally speaking the way an animal relates to its environment.