Extended and cumulative effects of experimentally induced intergroup conflict in a cooperatively breeding mammal

Conflict between rival groups is rife in nature. While recent work has begun exploring the behavioural consequences of this intergroup conflict, studies have primarily considered just the 1–2 h immediately after single interactions with rivals or their cues. Using a habituated population of wild dwarf mongooses ( Helogale parvula ), we conducted week-long manipulations to investigate longer-term impacts of intergroup conflict. Compared to a single presentation of control herbivore faeces, one rival-group faecal presentation (simulating a territorial intrusion) resulted in more within-group grooming the following day, beyond the likely period of conflict-induced stress. Repeated presentations of outsider cues led to further changes in baseline behaviour by the end of the week: compared to control weeks, mongooses spent less time foraging and foraged closer to their groupmates, even when there had been no recent simulated intrusion. Moreover, there was more baseline territorial scent-marking and a higher likelihood of group fissioning in intrusion weeks. Consequently, individuals gained less body mass at the end of weeks with repeated simulated intrusions. Our experimental findings provide evidence for longer-term, extended and cumulative, effects of an elevated intergroup threat, which may lead to fitness consequences and underpin this powerful selective pressure.

The Role of the Dopamine D₁ Receptor in the Negative Symptoms of Schizophrenia

<p>Diminished motivation is a core feature of schizophrenia that has been linked to impaired functional outcomes. A mechanism thought to contribute to diminished motivation is impaired anticipatory pleasure. Impaired anticipatory pleasure is associated with disrupted reward prediction and reduced engagement in reward-seeking behaviours. To investigate the role of the dopamine D₁ receptor in anticipatory pleasure, D₁ mutant rats and WT rats performed five experiments. Reward prediction was examined using the anticipatory locomotion experiment and successive negative contrast experiment. It was found that D₁ mutant rats have impaired anticipatory responses to expected reward. However, as the WT rats did not show the expected response to an alteration in reward expectation, it was impossible to assess the role of the D₁ receptor. Together, these findings suggest that the D₁ receptor may be involved in aspects of reward prediction. Reward-seeking behaviour was examined using the social approach experiment, scent marking experiment, and the separation induced vocalization experiment. It was found that the D₁ mutant rats have an impaired ability to engage in social and sexual reward-seeking behaviours, but have relatively normal ability to engage in maternal reward-seeking behaviours. Together, these findings indicate that the D₁ receptor is involved in certain aspects of reward-seeking behaviours. In conclusion, there is compelling evidence that a D₁ receptor dysfunction is a likely contributor to diminished motivation in schizophrenia.</p>

The Role of the Dopamine D₁ Receptor in the Negative Symptoms of Schizophrenia

<p>Diminished motivation is a core feature of schizophrenia that has been linked to impaired functional outcomes. A mechanism thought to contribute to diminished motivation is impaired anticipatory pleasure. Impaired anticipatory pleasure is associated with disrupted reward prediction and reduced engagement in reward-seeking behaviours. To investigate the role of the dopamine D₁ receptor in anticipatory pleasure, D₁ mutant rats and WT rats performed five experiments. Reward prediction was examined using the anticipatory locomotion experiment and successive negative contrast experiment. It was found that D₁ mutant rats have impaired anticipatory responses to expected reward. However, as the WT rats did not show the expected response to an alteration in reward expectation, it was impossible to assess the role of the D₁ receptor. Together, these findings suggest that the D₁ receptor may be involved in aspects of reward prediction. Reward-seeking behaviour was examined using the social approach experiment, scent marking experiment, and the separation induced vocalization experiment. It was found that the D₁ mutant rats have an impaired ability to engage in social and sexual reward-seeking behaviours, but have relatively normal ability to engage in maternal reward-seeking behaviours. Together, these findings indicate that the D₁ receptor is involved in certain aspects of reward-seeking behaviours. In conclusion, there is compelling evidence that a D₁ receptor dysfunction is a likely contributor to diminished motivation in schizophrenia.</p>

Behavioural interactions among Canada Lynx (Lynx canadensis) during pre-estrous

Information is lacking on the behaviour of free-roaming Canada Lynx (Lynx canadensis) during the breeding season, likely because they are rarely observed in the wild. Other wild solitary felid males compete with each other to mate with promiscuous females. However, the behavioural context or sequence of this competition among wild male Canada Lynx remains unreported. We describe the behaviour of three adult wild lynx during the breeding season. We observed the first two lynx together; an adult male and an inferred adult female remained together non agonistically for nearly 2 h before they were interrupted by another adult male. Our observation of interaction between the two males includes agonistic behaviours, vocalizations, scent marking, fighting, and a long-distance (1.7-km) expulsion of the intruding male lynx by the first male. These observations add to the limited information available on the social ecology of lynx during the breeding season.

Ontogeny of scent marking behaviours in an apex carnivore

Puma (Puma concolor) communication with conspecifics is via indirect scent marking behaviours that are important for individuals to advertise their territory and reproductive status, but little is known about how the behaviours develop with age. To examine the development of scent marking behaviours, we monitored the behaviours of adult pumas and dependent kittens. Based on video recordings, we found that the frequency of puma communication behaviours significantly changed over time. Kittens exhibited olfactory investigation more frequently as they aged, but kittens generally did not exhibit scent marking behaviours. Kittens travel with their mothers until they disperse, so there is no need to establish territories or advertise availability to mate, but kittens are at risk of injury or mortality from other pumas. It is possible that there is no functional need for dependent kittens to scent mark until they mature, but there is a need for frequent use of investigative behaviours.

Chinese red panda (Ailurus styani) has stable individual-level laterality of anogenital rubbing

Behavioural laterality was widely discovered in both vertebrates and invertebrates. However, reports of behavioural laterality in scent-marking are scarce and focused on limb preference during scent-marking. In this study, we observed another scent-marking behaviour, anogenital rubbing, which involved whole-body movement, in zoo-housed Chinese red pandas. We recorded the moving direction of the buttocks when initiating anogenital rubbing. Our results showed that three of our subjects were explicitly left-biased when initiating anogenital rubbing and the other one showed more left initiation although there was no statistical significance. Besides, the laterality was consistent across the whole observational period. This is the first report of laterality in anogenital rubbing, perhaps indicating hemispheric specialization for chemical communication in the Chinese red panda.

Males are more sensitive to their audience than females when scent-marking in the redfronted lemur

Audience effects, i.e. changes in behaviour caused by the presence of conspecifics, have rarely been studied in the context of olfactory communication, even though they may provide important insights into the functions of olfactory signals. Functional sex differences in scent-marking behaviours are common and influenced by the social system. To date, patterns of functional sex differences in scent-marking behaviours remain unknown in species without overt dominance relationships. We investigated sex differences in intra-group audience effects on anogenital scent-marking in a wild population of redfronted lemurs (Eulemur rufifrons) by performing focal scent-marking observations. With a combination of generalised linear mixed models and exponential random graph models, we found different audience effects in both sexes. Males were overall more sensitive than females to their audience. Only males seemed to be sensitive to the presence of both members of the opposite sex and same-sex conspecifics in the audience. Females were only moderately sensitive to the presence of other females in the audience. This study offers a potential behavioural pattern associated with anogenital scent-marking that seem to differ from those described for species exhibiting female dominance, supporting the notion that the social systems co-varies with scent-marking behaviours and scent-complexity in strepsirrhines.

Social behaviour and vocalizations of the tent-roosting Honduran white bat

Bats are highly gregarious animals, displaying a large spectrum of social systems with different organizational structures. One important factor shaping sociality is group stability. To maintain group cohesion and stability, bats often rely on vocal communication. The Honduran white bat, Ectophylla alba, exhibits an unusual social structure compared to other tent-roosting species. This small white-furred bat lives in perennial stable mixed-sex groups. Tent construction requires several individuals and, as the only tent roosting species so far, involves both sexes. The bats´ social system and ecology render this species an interesting candidate to study social behaviour and vocal communication. In our study, we investigated the social behaviour and vocalizations of E. alba in the tent by observing two stable groups, including pups, in the wild. We documented 16 different behaviours, among others play and fur chewing, a behaviour presumably used for scent-marking. Moreover, we found 10 distinct social call types in addition to echolocation calls, and for seven call types we were able to identify the corresponding broad behavioural context. Most of the social call types were affiliative, including two types of contact calls, maternal directive calls, pup isolation calls and a call type related to the fur-chewing behaviour. In sum, this study entails an ethogram and describes the social vocalizations of a tent-roosting phyllostomid bat, providing the basis for further in-depth studies about the sociality and vocal communication in E. alba.