Abstract: Third-party interventions are defined as the interruption of dyadic interactions by third animals through direct physical contact, interposing or threats. Previous studies focused on the analysis of interventions against agonistic encounters. However, there have been no evaluations of interventions against affiliative behaviours, particularly in relation to the intervening animal�s social relationships and its social and spatial position. Horses, Equus caballus, are an interesting model species, as interventions against affiliative interactions occur more frequently than against agonistic interactions. In this study, 64 feral horses displayed 67 interventions in affiliative interactions and eight interventions in agonistic interactions within the observation period. We analysed the interventions in affiliative encounters, and found that it was mainly higher-ranking females that intervened in the affiliative interactions of group mates in the stable horse harems. The intervening animals took an active part in affiliative and agonistic encounters within the group, but did not occupy particular social roles or spatial positions. They intervened in affiliative interactions in which group mates with which they had social bonds interacted with other members of the group. They targeted the nonbonded animal and approached the one with which they were socially bonded. We suggest some species use third-party interventions in affiliative interactions to prevent competition for preferred social interaction partners from escalating into more costly agonistic encounters.

Abstract: Third-party intervention is the interruption of a dyadic interaction by a third animal. We observed such interventions in affiliative interactions in free-ranging Esperia-ponies (Equus caballus). It is known that horses intervene in affiliative contexts especially when a preferred partner is involved, probably to protect their social bond to this preferred partner. To prove this hypothesis the present study investigated whether the preferred partner was targeted, i.e. challenged, or supported by the intervener or both randomly. Therefore we examined the social relationship between the intervener and both dyadic interacting individuals. We found that interveners usually supported individuals to which they have stronger social bonds than to other group mates, while they have no particular relationship to the targeted animals. This indicates that interveners in stable horse groups protect their social bonds to the supported animals by challenging their interaction partners. Of all observed horses only some mares showed intervention behaviour. Their social position, reflected by their position in the dominance hierarchy, social networks, and the spatial group structure were investigated. We found that interveners occupy no unique position, but they are involved in a high amount of affiliative interactions, high-ranking, and relatively aggressive. KW -

Abstract: As a part of our research on the evolution of social learning in insects, we examined socially influenced behaviour and social learning in desert locust (Schistocerca gregaria) nymphs and adults. In the nymphs, the only positive effect we documented was an increased tendency to feed while in the company of another locust than alone. The adults, on the other hand, showed significant preference for joining others (local enhancement) in both the contexts of feeding and egg laying. Neither nymphs nor adults, however, showed social learning. Our preliminary analyses pointed to locusts as a likely insect that might possess social learning. Our research, when taken together with research on phase-shifts and swarm/marching behaviour of gregarious locusts, suggests that the behavioural dynamics of gregarious locusts may make local enhancement but not social learning beneficial. The possible difference we documented between the nymphs and adults could enable us to further explore the proximate and ultimate mechanisms that underlie socially influenced behaviour.

Abstract: This study investigated drinking behaviour of unhandled, semi-feral Dartmoor ponies. Aspects studied were drinking behaviour, latency to drink from novel unfamiliar drinkers after transport, preferences for different types of artificial water drinkers, effects of mixing with unfamiliar ponies and group size, on drinking behaviour, and the effect of a simulated market on the latency to drink. Ponies were tested in groups of three or six animals, or as individuals in test pens that were equipped with three water drinkers: bucket, automatic drinking bowl, flowing water trough. Behaviour was recorded using time-lapse video. An individual pony drank on average 10 l per day. Ponies also drank, but at a lower rate, during the night. The latencies to drink after 4.5 h of transport showed large variation, but most ponies drank within the first hour after being transported (all groups 80.5 ± 32.94 min, mean ± SEM). In the individual choice tests, the preferred drinkers were the bucket and the flowing water trough, but not the automatic drinking bowl (drinking time 25.2 ± 4.66, 11.5 ± 4.26, 2.4 ± 2.23 min for bucket, trough and bowl respectively, mean ± SEM; paired t-tests, bowl versus other drinkers, all tests p < 0.02). A possible reason for the avoidance of the automatic bowl was the noise it made when filling. After mixing a group of three ponies with a group of three unfamiliar animals, the ponies did not express their individual drinker preferences anymore. The use of the previously preferred bucket decreased significantly and the use of the initially, non-preferred, bowl increased significantly. This was likely caused by the fact that ponies were either intentionally or accidentally obstructing drinkers in certain areas of the pen and unfamiliar ponies did not want to push past them. In the simulated market, the differences in latencies to drink between ponies in the home pen and market groups did not reach significance. No significant effect of group size (groups of three versus six ponies) on drinking behaviour was detected. The results have implications for situations where only automatic water bowls are provided, such as during pony sales at livestock markets. Preventing ponies from expressing their drinking choice, either by offering non-preferred drinkers or by mixing with unfamiliar animals, could adversely affect their welfare especially if this happens in conjunction with other stressful events such as transport and markets, and potentially weaning.