Differences in the reactivity of 2 mouse genotypes to zoo-social signals in the partition test

The reaction was studied of male mice of CBA and C57BL/6J lines to zoosocial signals coming from another individual. "Partition" test was used, in which two males of one line were placed in a common cage divided into two sections by a transparent partition with holes; this partition divided the animals but allowed them to see and sniff each other. The number of approaches to partition, summary and average time of staying near it during one approach were recorded. Mice of both lines reacted to presence of unknown partner behind the partition by an increase of activity near the partition; in CBA mice all recorded parameters were greater than in C57BL/6J mice. A greater sensitivity is suggested of CBA animals to perception of pheromonal signals. "Partition" test may be used for estimation of mice reaction to zoosocial signals.     

Characteristics of the reaction of submissive mice to distant zoosocial stimuli

In aggressive and submissive mice well-experienced in victories and defeats, the reaction was studied to another male in neighbour section of "home" cage divided by transparent partition with holes. The activity of submissive mice near the partition was significantly lower than that of control animals without experience of agonist contacts or aggressive. Submissive mice did not react to the appearance of unknown smell in the neighbouring section while the animals of other studied groups sharply increased their activity near the partition. It is suggested that long experience of defeat leads to inhibition of perception of specific zoosocial (olfactory) stimuli triggering manifestation of aggressive reaction to another individual.     

Effects of familiarity on the behaviour towards intruders in captive common marmosets (Callithrix jacchus)

A study on the behaviour of a group of common marmosets (Callithrix jacchus) towards unrelated intruding conspecifics (juvenile male twins) was performed. The group members' proximity to the intruders during two consecutive study periods was analyzed. During the first period in which the experimental conditions as well as the intruders were unfamiliar, all but one group member were equally likely to stay near the intruders and usually more than three individuals were present simultaneously. During the second period the group members showed different scores of proximity towards the intruders. One individual, an adult male, was in close proximity nearly the whole time. Additionally, the number of individuals simultaneously staying near the intruders was clearly reduced. It is argued that (1) the change in behaviour of the group members was affected by the increasing familiarity and (2) intruder experiments with unfamiliar conspecifics are only of partial value for clarification of the process of immigration.     

Preference for social contact versus environmental enrichment in male laboratory mice

Due to their aggressive nature, male mice are less frequently used than female mice in biomedical research. When aggressive males are being used, individual housing is common practice. The question arises whether this is an acceptable housing for a social species. The present study was designed to gain more insight into the nature of inter-male social contact and into the potential of a form of environmental enrichment (nesting material) to compensate for the lack of social contact. In a series of tests, we analysed whether male mice of different ages preferred to spend time (1) near a familiar cage mate versus an empty cage, or (2) near to a familiar cage mate versus direct contact with nesting material (tissues). Dwelling time in each of the test cages and sleeping sites was recorded, as was the behaviour of the test mice. Results indicated that when other conditions were similar, male mice preferred to sleep in close proximity to their familiar cage mate. Furthermore, the need to engage in active social behaviour increased with age. Tissues were used to a large extent for sleeping and sleep-related behaviour. It is concluded that single housing in order to avoid aggression between male mice is a solution with evident negative consequences for the animals. When individual housing is inevitable due to excessive aggressive behaviour, the presence of nesting material could partly compensate for the deprivation of social contact.     

Fighting in NIH/S male mice: consequences for behaviour in resident-intruder tests and physiological parameters

Fighting is known to occur frequently in male mouse groups. In this study with outbred NIH/S mice, the possible impact of individual aggressiveness on fighting in groups and on the social status of animals was studied. Male mice were pre-tested in a resident-intruder (RI) test and rated as initially aggressive or non-aggressive according to their attack behaviour against an intruder. Thereafter they were randomly allocated to new social groups, with four mice per cage. Fighting in groups was increased when several initially aggressive animals were included in the group. Within the groups, animals were rated as dominants and subordinates according to their behaviour toward a strange intruder introduced into their home-cage (Group Intruder, GI) test and the occurrence of wounds. Additionally, subordinates were divided into aggressive and non-aggressive categories according to their behaviour in the second RI test, which was performed 3 weeks after grouping. The behaviour in the RI test prior to group-housing did not predict the individual social status or possibility of being wounded in the new social environment. On the other hand, the social relationships in the new group affected the behaviour in a subsequent RI test. All dominants showed aggressive behaviour during the second RI test. Those subordinates which behaved aggressively during this test received the most numerous and serious wounds, suggesting that in the new groups their interactions with the other group members were mostly aggressive. The reduced weight of epididymal adipose tissue in dominant and aggressive subordinates may indicate that they had fought continuously. Social status or levels of fighting in a group did not affect individual weight gain or the other physiological parameters measured. The wounded animals had enlarged spleens and reduced weights of epididymal adipose tissue, which were probably the results of increased activity of the immune system and reduced welfare, respectively. In conclusion, individual aggressiveness seems to be greatly affected by the demands of the social environment. Fighting in mouse groups leading to wounded animals may have effects on physiological research parameters.     

Comparative characteristics of the parameters of an aggressive reaction in 2 mouse genotypes

The parameters have been studied of the aggressive reaction of male mice of CBA/Lac and C57BL/6J lines differing by olfactory sensitivity to zoosocial pheromone stimuli. It has been shown that CBA males, characterized by a high olfactory sensitivity, have lower latency of the first attack than C57BL males with low olfactory sensitivity. A prolonged distant exposition to an unknown litter and male appearance lowers the latency of the first attack in mice of the studied lines proportionally to their meanings demonstrated after short time exposition. The number of attacks and total time of attacking is considerably higher in C57BL mice during the whole test period (15 min) than in CBA mice in which aggressivity is already sharply lowered after 5 min of agonistic interactions. The factors are discussed, influencing the parameters of mice aggressive reaction.     

繁殖期高原鼠兔的攻击行为

通过室内配对实验对高原鼠兔（Ｏｃｈｏｔｏｎａ ｃｕｒｚｏｎｉａｅ）繁殖期的攻击行为进行了研究。结果表明,雌雄动物的攻击水平相同,同性个体间的攻击性明显高于异性个体间。雌雄动物具有不同的攻击模式。雌性个体遇到陌生个体首先以攻击中的进攻和追逐为主,然后通过相互接触确定个体的性别,若为同性个体,以防御为主,若为异性个体,则有防御和亲昵两种选择;雄性动物遇到陌生个体同样首先以攻击为主,相互接触后,若为异性     

Effects of chronic buspirone treatment on female mice exposed to the long-lasting psychoemotional influence

The effects of chronic treatment (30 days) with the 5-HT1A receptor partial agonist buspirone (0.05, 1 and 10 mg/kg i.p.) on the behaviour of C57BL/6J female mice exposed to long-lasting psychoemotional influence were studied. The influence involved forced living of each female with an aggressive male separated with a perforated transparent partition in the same cage and daily female's presence during 10-min intermale confrontations behind a partition caused by introducing of another male to the aggressive male. Chronic buspirone injection (in all used doses) did not affect the behaviour of females estimated in the "partitions" and "open field" tests at the end of the drug treatment. The anxiolytic effect of buspirone only at the dose of 1 mg/kg on the female's plus-maze behaviour was revealed. In the Porsolt, test buspirone in the dose of 1 mg/kg caused a slight increase in the duration of immobility indicating a slight pro-depressive effect. Thus, chronic buspirone treatment of females exposed to the long-lasting psychoemotional impact has a different effect on their behaviour depending on the dose and test conditions.     

Anxiety in females caused by long-term psycho-emotional stress

Behaviour of female mice was studied under long-lasting psychoemotional influence. Daily presence of females during inter-male confrontations through a perforated transparent partition in the same cage and the next female placing on the male territory (sawdust) after the confrontations, were included as the influencing factors. Under these conditions, the increased level of anxiety in the females was revealed in the elevated plus-maze test. At the same time, the females demonstrated a more passive behaviour in the Porsol test. The psycho-emotional influence also affected the females' behaviour in the partition test. The females spent a significantly longer time near the partition both 5 minutes prior to and during the inter-male confrontations.     

Catatonia as an element of submissive behavior in mice during interspecies agonistic interactions

A catatonia-like state was elicited in male mice with different experience of social interactions, by pinch of scruff of the neck in a suspended state. In submissive males with long experience of defeat the total time of catatonia reaction during test is considerably greater than in aggressive individuals with a long experience of victories. The change of the social status of the individuals resulting from agonistic interactions leads to a change of the catatonia reaction: manifestation of submissive behaviour is accompanied by an increase of total time of catatonia reaction in the test, the aggressive behaviour is accompanied by its decrease.     

Use of the "partition" test in the behavioral and pharmacological experiments

Application of partition test measuring the behavioural activity of animals near the transparent perforated partition (dividing the experimental cage onto two halves) as a reaction to the partner in the neighbouring compartment of common cage, is considered. Behavioural reaction as a response to other individual differs in dependence on psychological and physiological states, social experience, strains of the animals and kinds of partner. Partition test may be productive in experiments studying mechanisms of sociability, anxiety, aggressive and sexual motivations, olfaction, as well as for screening of psychotropic drugs.     

How does a parent respond when its mate emphasizes the wrong role? A test using a monogamous fish

The convict cichlid fish, Archocentrus nigrofasciatus, is biparental: the male spends the majority of his time defending the territory and the female spends much of her time close to the offspring. Under natural conditions, this separation into sex-typical roles is somewhat blurred as males do spend some time with the offspring and females do attack intruders. Here we tested whether an individual selects a parental role based on the location (i.e. parental role) of its mate. For example, do females emphasize offspring care because the male is away from the offspring? Will males be more likely to care for the offspring when the female is away from the offspring? We manipulated the location of one parent by placing it in a transparent plastic box, either near the offspring or at the far end of the tank near a clear plastic compartment that held a conspecific male intruder. We tested both male and female parent under the following four conditions: boxed mate near offspring with no intruder present, boxed mate near offspring with intruder present, boxed mate near intruder compartment with no intruder present, and boxed mate near intruder compartment with intruder present. We found that both parents spent more time with the offspring and less time attacking the intruder when the mate was positioned near the offspring and more time away from the offspring and more time attacking the intruder when the mate was near the intruder. Males were more affected by the location of their mates than were females and we concluded that males were attracted both to their mates' location and their offspring while females were mostly attracted to their offspring. Overall, the location of the mate had little effect on the types of aggressive activities used against the intruder. We did find that males increased their aggression towards boxed females when they were positioned far from the offspring, whereas the aggressive behaviour of females towards boxed males when they were positioned near the offspring was ambiguous. We suggest that males in particular enforce the separation of sex-specific parental roles via this aggression.     

Individual and geographical variation in display behaviour of male harbour seals in Scotland

Studying variations in behaviour at the individual or population level enables insight into the reproductive strategies within a species. We examined individual and geographical variation in the vocal and dive behaviour of male harbour seals, Phoca vitulina, which is associated with aquatic mating. This display behaviour was recorded in the Moray Firth, Scotland, from July 1994 to 1997, and in Orkney, Scotland, during July 1998. One vocalization type was apparent in the Moray Firth and two in Orkney. Time parameters (total and pulse duration) varied between males in the population in the Moray Firth. We used both frequency and time parameters in a discriminant analysis, which showed that 73.2% of individual male vocalizations could be correctly classified; 94.6% of male vocalizations from the Moray Firth and Orkney could be correctly classified according to their geographical areas. Therefore, vocal variation was greater between geographical areas than between individuals. No individual variation was apparent between dive and surface interval durations. However, individuals varied significantly in the percentage of short surface intervals. Male harbour seals showed substantial variability in the parameters affecting their vocal and dive behaviour during the mating season. We suggest that these variations may be indicative of adaptations to varying environmental challenges influencing the reproductive strategies of discrete populations. Copyright 2000 The Association for the Study of Animal Behaviour.     

The effect of the S1A-receptor agonist ipsapirone on behavior types in wild and domesticated rats]

Selective agonist of 1A subtype of serotonine receptors ipsapirone inhibited manifestation of affective kinds of aggression in wild and domesticated rats. Administration of ipsapirone (10 mg/kg) decreased the number of aggressive attacks of wild and domesticated rats in the test of shock-induced aggression and blocked manifestation of defensive reaction to the experimenter in wild rats. Neophobia in wild rats decreased under the influence of ipsapirone. At the same time ipsapirone did not change mouse-killing behaviour either in wild or in domesticated rats. Probably, 5-HT1A receptors the aggressive regulate reaction, which are parts of the complex of defensive behaviour of the wild animals.     

Territorial behaviour of beaugregory damselfish (Stegastes leucostictus) in response to egg predators

To test the hypothesis that territorial male beaugregory damselfish (Stegastes leucostictus) can assess the degree of threat from egg predators, the aggressive behaviour of both males guarding eggs and males without eggs was recorded when they were presented with either one or five individuals of the wrasse egg predator Thalassoma bifasciatum. Presentations were made in a clear plastic bottle 0.5 m from artificial beaugregory breeding sites in the field. Two measures of aggressive behaviour (downhead threats and time spent within 10 cm of the presentation bottle) were significantly greater for multiple wrasse presentations than for single wrasse presentations, while a third measure (chase attempts) was not. In contrast, chase attempts were significantly greater for males guarding eggs than for males without eggs, but there was no significant difference in the level of downhead threats or bottle proximity time for this comparison. Levels of the three aggressive measures were not correlated with either the amount of eggs or the number of egg clutches present. These results indicate that territorial male beaugregories respond to an increase in the number of intruding egg predators by increasing the levels of low-cost threat behaviour, while the presence (but not the amount) of eggs results in an increase in the amount of higher cost attack behaviour. These experiments, therefore, support the hypothesis that male beaugregories can assess the degree of threat from egg predators, and indicate that they use this assessment to alter the strategies used in territorial defence.     

The effects of oestrous condition and familiarity on the sexual behaviour of polecats (Mustela putorius and M. fur × M. putorius hybrids)

The effects of two factors on the sexual behaviour of polecats ( Mustela furo and M. putorius × M. furo hybrids) were investigated, in an indoor arena of 16 m², firstly the oestrous condition of the female and secondly the familiarity of the two individuals.
The initial approaches of a male polecat are similar irrespective of the oestrous condition of the female but his subsequent behaviour is dependent upon the female's response. Whereas males copulated with oestrous females they showed a wider repertoire of social acts and a greater number of changes of behaviour towards females which were not in oestrous. Unreceptive females elicited both sexual and aggressive behaviour from males.
Unfamiliar females provide a more powerful eliciting stimulus for the male's copulatory behaviour than do familiar females.     

Parental investment of male two-spotted goby, Gobiusculus flavescens (Fabricius)

The trade-off between parental care and feeding was studied in the male two-spotted goby (Gobiusculus flavescens F.). Two temperatures, 8.5 degrees C and 13.0 degrees C, were used, with five replicates at each temperature, in order to determine whether temperature influenced parental behaviour. In each replicate, two males and four females were introduced to an aquarium, where the males chose between two nests and courted the females. In each replicate, one male spawned. After spawning, the males guarded the eggs until hatching. The guarding males' behaviour was recorded with a video camera twice a day (15 min each time), once before and once after they were fed. The male's condition (c-factor) was calculated at the start of the experiment and after egg hatching. The eggs were spawned in an artificial nest (half of a PVC tube), and attached to the nest in a single layer. The areas with eggs (representing brood size) were marked after spawning and the fry counted after hatching (which was used to calculate area hatched). Numbers of prey eaten (plankton) and number of aggressive encounters between the guarding male and the other fishes were recorded. Time spent in the nest and time used on fertilisation, fanning and cleaning were estimated and related to egg age, brood size, hatching success, temperature and food availability (no food or food).The results showed that feeding (expected to influence future reproduction) decreased and parental expenditure (current reproduction) increased, as the eggs developed (became closer to independence). Parental expenditure was significantly higher at 13.0 degrees C than at 8.5 degrees C, presumably due to higher oxygen demands by the eggs, and a greater risk of egg-infections. The c-factor of the males guarding eggs decreased over time, in contrast to the non-guarding males' c-factor. Guarding males' aggressiveness decreased as the eggs got older, but increased just before hatching. A possible explanation for this could be the decreasing intrusion by the non-guarding male and females caused by high aggressive behaviour by the guarding male early in the brood cycle. The exploitation of the nest (percentage of total nest area covered by eggs) seemed to determine the amount of parental expenditure and loss of condition, while brood size (area of eggs) had no effect.     

The effect of social isolation during juvenile period on the sexual arousal in adult rats

The effects of chronic postweaning social isolation combined with subsequent resocialization on the sexual arousal were studied in male rats with inherited stress-induced arterial hypertension (ISIAH strain) and in Wistar rats. Young males were isolated on the Day 21 of postnatal life for 6 weeks. Then they were kept in groups of 5. 4-month males underwent the partition test: a receptive female was introduced into the male's cage, but the male and the female were separated by a transparent partition. The number of approaches to the partition and total time spent near the partition during the test served as an index of sexual motivation. Hormonal component of sexual arousal was estimated by measuring plasma testosterone level. No interstrain differences in magnitude of the sexual arousal were observed. However, chronic social isolation during juvenile period caused a genotype-dependent diminution of sexual motivation in the adult male rats of both strains. The decrease of sexual motivation in ISIAH rats was more pronounced as compared to Wistar rats. Moreover, the social isolation during the juvenile period completely abolished the female-induced rise in plasma testosterone in ISIAH and Wistar male rats. Plasma corticosterone level was increased during the period of sexual arousal, but this rise of corticosterone was not affected by the social conditions during postweaning period.     

Anti-predator behaviour changes following an aggressive encounter in the lizard Tropidurus hispidus

Avoiding predators may conflict with territorial defence because a hiding territorial resident is unable to monitor its territory or defend it from conspecific intrusions. With persistent intruders, the presence of an intruder in the near past can indicate an increased probability of future intrusions. Therefore, following a conspecific-intrusion, territorial residents should minimize costs from future intrusions at the cost of higher predation risks. I conducted experiments with males of the territorial lizard Tropidurus hispidus recording approach distance (distance between predator and prey when the prey escapes) and time to re-emergence from a refuge after hiding. Past aggressive interactions affected anti-predator behaviour: lizards re-emerged sooner (compared to a control) when the predator attacked 5 min after an aggressive encounter. If the predator attacked while an aggressive encounter was ongoing, there was also a reduction in approach distance. The results are consistent with an economic hypothesis which predicts that T. hispidus incur greater predation risks to minimize future territorial intrusion; additionally they show that the effects of past and ongoing aggressive interactions are different, consistent with the minimization of present intrusion costs. These results are relevant for studies of the changes in aggressive behaviour due to changes in the social environment and for studies of the costs and (co) evolution of aggressive and anti-predator strategies.     

Effect of the D1-receptor antagonist SCH-23390 on the individual and aggressive behavior in male mice with various aggression experience

It has been shown that dopaminergic systems are involved in mechanisms of aggressive behavior. Effects of SCH 23390 (dopamine Di receptors antagonist. 0-1 mg/kg, i/p, 30 min) on aggressive and individual behaviors were studied in male C57BL/6J mice with different experience of aggression. SCH 23390 reduced aggressive attacks in animals without preliminary experience of aggression. However total time of hostile behavior (sum of the total time of attacks, aggressive grooming and diggings) didn't changed. No significant effects on behaviors were found in mice with long (20 days) repeated experience of aggression. It was supposed that long aggressive experience produces pharmacological desensitization of Di receptors as a result of enhanced dopaminergic activity shown earlier in aggressive animals.