Individual differences in young rhesus monkeys: Consistency and change

At 1 year and 2.5 years of age, rhesus monkeys were removed from the colony to a strange situation. Upon introduction, each monkey was watched for 2 hr, given a series of behavioural tests, and watched again six days after introduction. Activity increased with age, as did readiness to approach a ball. Time spent looking at a mirror decreased with age. Although test measures were reliable at each age, there was no significantly positive correlation from one age to the next. Nevertheless, with males, but not females, significant correlations occurred at each age between behaviour in the strange situation and observers’ ratings of behaviour in the colony.     

Subjective assessment of rhesus monkeys over four successive years

Using behaviourally-defined adjectives and a 7-point scale, observers rated all individuals over a year old in a colony of rhesus monkeys every November for four years. Principal component analyses of the ratings provided a basis for the following scores each year: CONFIDENT, EXCITABLE, and SOCIABLE. Two- and three-year old females had higher EXCITABLE scores than males, and adult males were more CONFIDENT than adult females. At all ages, CONFIDENT scores were stable from year to year, whereas EXCITABLE and SOCIABLE scores were not stable until adulthood. However for primiparous females, only their EXCITABLE scores were stable from the ante-natal to post-natal year. One-year males who had had adverse experience in their first eight months were more EXCITABLE, but no less CONFIDENT or SOCIABLE than control males. Finally, correlations between scores of mothers and their yearlings showed that CONFIDENT mothers had CONFIDENT infants and SOCIABLE mothers had SOCIABLE infants, but EXCITABLE mothers had infants who were not CONFIDENT. Scores of mothers and their 1-year olds were also significantly correlated with some measures of their social behaviour taken when the infants were 8, 16, and 52 weeks old.     

Sex differences in the termination of social play in cats

Sixteen measures of social play between kittens were found to decrease significantly between 12 and 16 weeks of age. Behaviour was little influenced by the presence of the mother during this time. Although males' rates of behaviour did not differ from females' rates when the sexes were compared regardless of group composition, males from all-male groups played at higher rates than females from all-female groups. Females' rates of behaviour declined as the number of male companions decreased. Males' behaviour was little influenced by the number of females in the group. Females with male companions behaved more like males than did females with no male companions, but this was not because they directed behaviour to brothers at higher rates than to sisters.     

Infanticide in male laboratory mice: Effects of social status,prior sexual experience,and basis for discrimination between related and unrelated young

Several aspects of infanticide, including effects of social status, prior sexual experience, and the basis for discrimination between related and unrelated young, were examined in Swiss-Webster laboratory mice (Mus musculus). Strange males introduced into the female's cage for 24 h on day 1 postpartum significantly reduced pup survival whereas the introduction of sires did not. Direct observations of infanticide were frequent, and the motor patterns used by males to kill pups are described. Males killed their own offspring when those young were in the nest of a strange female, whereas most males did not kill unrelated young in the nest of a familiar female. Thus, past association with the mother appears to be the single most important factor mediating male discrimination of young. Prior contact with a specific female's urine reduced a male's propensity for subsequently killing her young. The act of copulation itself also reduced infanticide. Infanticidal behaviour was correlated with the male's social status: most dominant males killed unrelated pups, whereas none of the subordinates engaged in infanticide. These results are discussed in terms of the population biology of this species.     

Influence of Litter Gender Composition on Subsequent Maternal Behaviour and Maternal Aggression in Female House Mice

It has been suggested that the sex-dependent pattern of mother-pup interaction that occurs early in infancy can affect some aspects of the animal's behaviour repertoire in adulthood. The aim of this study was to investigate the effects of litter gender composition (LGC) on subsequent maternal behaviour and aggression in the female house mouse. Albino mouse litters were reduced at birth to six pups according to two conditions: FM (3 females and 3 males) and FF (all females). At weaning (day 21), all mice were rehoused in unisexual groups. At adulthood (70–90 days) the females were mated and litters culled at birth to 6 pups (3 females and 3 males). On days 2, 4, and 6 after delivery the females were tested for maternal behaviour (10 min) and retrieval of pups. On day 6, at the end of the recording of maternal behaviour, the females were also tested for maternal aggression towards a strange adult male conspecific (5-min exposure). In absence of differences in maternal behaviour scores, FM females showed shorter latencies for retrieval of the first pup on postnatal days 2 and 4. Maternal aggression was also significantly affected by the two conditions. FM females showed higher scores of both duration and frequency of aggressive grooming, defensive upright postures, fleeing and of the number of attacks. FF females spent more time self-grooming, crouching, and on nest. These results support the hypothesis that a series of factors, such as olfactory, tactile, and acoustic stimulation provided by the pups, the variation of maternal behaviour depending upon LGC, and the qualitative and/or quantitative variation in social interaction with the opposite sex in infancy, contribute to the broad interindividual plasticity to cope in different environmental situations.     

Is Self‐Grooming by Male Prairie Voles a Predictor of Mate Choice?

Self-grooming by mammals is a form of scent dissemination in which individuals anoint themselves with salivary, anogenital, and other body odours. Self-grooming has been proposed to be a sexually selected trait favoured in reproductive competition and sexual attraction. We tested the hypothesis that females would show a mating preference for males that self-groomed more than a reproductive competitor that groomed less. In mate-choice experiments in which females had a choice of two tethered males, non pair-bonded females did not choose males based on their frequency of self-grooming. In a second experiment in which pair-bonded females in postpartum oestrus had access to their current mate and two strange males, strange males groomed significantly more than pair-bonded mates, yet attained the fewest copulations. Non pair-bonded females and pair-bonded males and females groomed significantly less often than did non pair-bonded males. Self-grooming behaviour was consistent with the sexual attraction hypothesis, but the frequency of self-grooming did not increase a male's mating success. We conclude that the frequency and time spent self grooming are not good predictors of mating success.     

The libidinous newt. An analysis of variations in the sexual behaviour of the male smooth newt, Triturus vulgaris

In an experiment designed to investigate variations in the behaviour of male newts in response to female behaviour, five males were tested for each of forty consecutive days in a standard 5-min trial in which the female's behaviour was controlled by the experimenter. In all males there was a steady decline over the 40 days in the number of spermatophores produced, i.e. the number of sexual sequences completed during the 5-min trial period. A number of scores relating to the frequency of performance of male acts and to their temporal patterning are shown to be correlated with one another and with spermatophore score. The temporal patterning of the male's behaviour in a given sequence is related both to the total number of sequences completed in a trial and to the position of the sequence in question within the trial. Principal components analysis enables a number of correlated scores for a sequence to be expressed as the ‘libido’ score for that sequence. A number of factors which may influence the temporal patterning of the male's behaviour are discussed, and it is suggested that the amount of sperm available and the need to ascend to the surface to breathe may be the most important.     

Dynamics of male residence and female oestrus during a breeding season of blue monkeys in the Kakamega Forest, Kenya

Blue monkeys (Cercopithecus mitis stuhlmanni) are seasonal breeders with a dynamic mating system in which typical one‐male social units are regularly disrupted and replaced by multi‐male ones. The number of males in the group is correlated with the number of oestrous females. We used observations of male presence and female oestrus on individual days during a 6‐month period to assess whether the presence of multiple males in a group stimulates female oestrus or whether oestrous females attract multiple males to the group. We confirmed prior observations with our finding that the number of males in a group was significantly correlated (r_s = 0.435, P < 0.0001) with the number of oestrous females across 126 observation days. A transition matrix did not show an obvious relationship between day‐to‐day changes in the numbers of oestrous females and males. However, cross‐correlation analysis provided stronger support for the idea that the number of oestrous females attracts males to a group than for the idea that the influx of strange males stimulates oestrus in female blue monkeys. Autocorrelation analysis showed that while female oestrus appeared to show a high degree of synchrony, as expected in a seasonal breeder, there was no evidence that the number of males accompanying a group of females influenced the likelihood of other males joining or leaving the group. Overall, our results confirm that female oestrous behaviour stimulates changes in male residence patterns. However, other observations suggest that changes in male residence may also stimulate female oestrus in some circumstances.     

哺乳期棕色田鼠对配偶的识别记忆

观察了分娩后哺乳雌性棕色田鼠（Microtus mandarinus）与配偶分离7d、14d、21d后对配偶与陌生雄鼠的行为反应。结果发现,在频次和持续时间上,与配偶分离7d、14d、21d的雌鼠对配偶的攻击行为显著低于陌生雄鼠（P〈0．05）;对配偶的嗅闻及友善行为显著高于陌生雄鼠（P〈0．05）。处于哺乳前、中、后期不同阶段的雌鼠对陌生雄鼠攻击水平没有显著性差异（P〉0．05）。这些结果说明,在整个哺乳期,雌鼠能够识别配偶,对配偶的记忆不因分离时间的增加而减弱,而且对陌生鼠的攻击水平不会因哺乳阶段的变化而变化,维持高水平的攻击可能与其较强的母性行为有关。     

Social stress,mortality and aggression in colonies and burrowing habitats

High mortality was found within six mixed-sex groups of Long-Evans rats living in burrowing habitats with 58% of subordinate males dying within 4 mo. of group formation. By contrast, no subordinate deaths occured during this time in six identical adult groups(3 males and 3 females) housed in similar (1 m square) colony cages without burrows. Although aggression against intruders was also much greater in habitats than colonies --through 400 days postformation--subordinate deaths did not appear to result from direct physical injury. It seems that mimicing key features of the rat's environment enhances intermale conflict and social stress, even while providing partial protection from biting attack. Behav. Proc.:     

The Effect of Mixing Entire Male Pigs Prior to Transport to Slaughter on Behaviour,Welfare and Carcass Lesions

Research is needed to validate lesions recorded at meat inspection as indicators of pig welfare on farm. The aims were to determine the influence of mixing pigs on carcass lesions and to establish whether such lesions correlate with pig behaviour and lesions scored on farm. Aggressive and mounting behaviour of pigs in three single sex pens was recorded on Day −5, −2, and −1 relative to slaughter (Day 0). On Day 0 pigs were randomly allocated to 3 treatments (n = 20/group) over 5 replicates: males mixed with females (MF), males mixed with males (MM), and males unmixed (MUM). Aggressive and mounting behaviours were recorded on Day 0 at holding on farm and lairage. Skin/tail lesions were scored according to severity at the farm (Day −1), lairage, and on the carcass (Day 0). Effect of treatment and time on behaviour and lesions were analysed by mixed models. Spearman rank correlations between behaviour and lesion scores and between scores recorded at different stages were determined. In general, MM performed more aggressive behaviour (50.4 ± 10.72) than MUM (20.3 ± 9.55, P < 0.05) and more mounting (30.9 ± 9.99) than MF (11.4 ± 3.76) and MUM (9.8 ± 3.74, P < 0.05). Skin lesion scores increased between farm (Day −1) and lairage (P < 0.001), but this tended to be significant only for MF and MM (P = 0.08). There was no effect of treatment on carcass lesions and no associations were found with fighting/mounting. Mixing entire males prior to slaughter stimulated mounting and aggressive behaviour but did not influence carcass lesion scores. Carcass skin/tail lesions scores were correlated with scores recorded on farm (r_skin = 0.21 and r_tail = 0.18, P < 0.01) suggesting that information recorded at meat inspection could be used as indicators of pig welfare on farm.     

Male dominance status,female choice and mating success in the brown lemming, Lemmus trimucronatus

The objective of this study was to determine whether female brown lemmings would selectively mate with dominant conspecific males. In dyadic encounters, oestrous females paired with dominant males engaged in more frequent lordosis and contact social behaviours than those paired with subordinate males. However, the mount and thrust scores of dominant and subordinate males did not differ significantly. When females had simultaneous access to tethered dominant and subordinate males, they spent more time in close proximity to dominant males and avoided contact with subordinate males. Copulation scores were higher with dominant males. In triadic encounters with free-moving dominant and subordinate males, oestrous females spent more time near, and engaged in more sexual behaviour with, dominant males. Intermale agonistic interactions resulted in ‘privileged access’ to females by dominant males. Sexual behaviour scores were lower and there was a 10-fold increase in intermale aggression in triadic encounters between females and unfamiliar dominant and subordinate males. Both intermale agonistic interactions and female ‘choice’ behaviour accounted for the differential copulatory success of dominant males.     

Effects of long-acting testosterone treatment on freeliving pied flycatchers, Ficedula hypoleuca, during the breeding period

Breeding behaviour and spermatogenesis of all males in a population of pied flycatchers, Ficedula hypoleuca, were experimentally prolonged by long-acting testosterone. The behaviour of these birds was compared with that of birds from an untreated population and a population where the males were given the vehicle only. The testosterone treatment prolonged territorial behaviour, and a higher percentage of nests without a feeding male during the nestling period was found in the experimental area. The proportion of polygamous males did not however differ between the experimental and control areas. The feeding activity of those testosterone-treated males returning to their home territories was markedly depressed. The female of such a pair did not compensate for the male's low feeding activity, but fed the nestlings as she would have done with a normal untreated male at the nest. On the other hand, females without a male present during the nestling period compensated for their mates' absence by increasing their own feeding frequency. It was also shown that the song of the male pied flycatcher is dependent upon androgens. The testosterone-treated males produced fewer fledglings than the control males.     

Influence of gonadal hormones on the behaviour of pair-living Mongolian gerbils (Meriones Unguiculatus) towards the cagemate versus a non-cagemate in a social choice test

Laboratory, semi-natural and field observations indicate that the Mongolian gerbil may naturally live in pairs or family groups. Endocrine influence on behaviour towards cagemates and non-cagemates was investigated. The males tested were intact or castrated. The hormonal condition of the females was controlled by gonadectomy and oestrogen and progesterone replacement treatment. The duration and number of visits to the incentive animals were recorded in a choice test, which allowed restricted contact between the experimental and incentive animals. Anoestrous females approached the intact cagemates more than the non-cagemates, while the intact males approached the non-cagemates more often. A comparison of the female behaviour under the different female endocrine conditions tested showed that females significantly increased their response in oestrus towards the strange intact males but not towards their cagemates. Experimental intact males analogously increased their response towards the strange oestrus female but not towards the cagemate. In tests which involved castrated males either as experimentals or incentives, no behavioural change was seen relative to the endocrine condition of the female. The hormonal effects seen were thus connected with the social relationship, as the hormone-induced changes were seen only in behaviour towards a strange animal.     

Dynamics of mate-searching behaviour in a hilltopping butterfly, Lasiommata megera (L.): the effects of weather and male density

By studying a hilltopping population of the satyrine Lasiommata megera in southern Sweden, the effects of density and meteorological conditions on mate-searching behaviour were investigated. Lasiommata megera males switched between stationary and vagrant behaviour, and the behaviour adopted was correlated to meteorological conditions; more males were stationary at low temperatures, low irradiation levels and high wind speeds than vice versa. Body temperature measurements indicated that these factors were important in deciding the body temperature and thereby the flight activity of males. Male density did not significantly influence mate-locating behaviour. The tendency of males to hilltop and their distribution around the hill were strongly influenced by weather. The hilltopping behaviour of this species did not adhere to an all-or-none pattern, but instead males, as well as the stations they used, were found at increasingly higher elevations on the hill with increasing temperatures and decreasing wind speeds. Moreover, males tended to use the lee side and sun-exposed side of the hill. Females, of which the majority were already mated, also showed this distribution around the hill, but preferred lower elevations than males. Release experiments did not reveal any propensity of mated females to fly uphill. Such a propensity was shown by released virgin females.     

The influence of urine from asymptotic laboratory populations on sexual maturation in prairie deermice

Male and female prairie deermice housed singly from weaning (21 days) until 40 days of age had urine from one of the following sources applied daily to their nostrils: sexually mature laboratory population males or females, and sexually mature breeder males or females from our laboratory colony. Other males and females were treated with water. Records were obtained of the weights of the tests, seminal vesicles and bacula of males and the ovaries and uteri of females at 40 days of age. The major results of this study were as follow: Female urine from sexually mature and inhibited population or isolated mice stimulated the development of the male reproductive organs significantly more than water or male urine. Male urine applied to young males did not differentially affect the weights of their reproductive organs compared with water and thus showed no inhibition effects. The reproductive organs of females treated with male urine did not differ significantly in weight from those of females treated with female urine. Females treated with water developed significantly larger uteri than those treated with urine from sexually mature population females (P≤0.02), inhibited population females (P<0.001) and inhibited population males (P<0.007).     

Breeding adaptations of Franklin's gull (larus pipixcan) to a marsh habitat

The behaviour and ecology of Franklin's gull were studied at Agassiz National Wildlife Refuge in northwestern Minnesota to determine the adaptations of the species for nesting in marshes. Two factors seemed to be important in colony site selection: cattail dispersion pattern and cattail density. Franklin's gulls prefer to nest in cattail areas closest to open water. The number of nests per unit area decreased as cattail density increased. Nest site selection is dependent on aggression and visibility. Visibility from nest level is the result of cattail placement and height. The distance between nests was directly correlated with visibility. Aggression by gulls on nests was lowered experimentally by decreasing visibility and raised by increasing visibility. Nest platforms were constructed of cattail material, and were attached to cattail stems. Nest material was added to the nests throughout the incubation and brooding period. Material was usually added following nest relief. The egg laying period was from 6 to 28 May. There was more synchrony of egg laying in sub-areas of the colony than in the colony as a whole. Successive eggs in clutches were laid at 24- to 48-hr intervals. The distance between nests decreased during the season as pairs filled in areas that were not defended. Territorial pairs defended an area up to 10 m from their stations prior to egg laying, but defended only the area within 3 m of their nests during incubation. Both members of pairs incubated the eggs and cared for the young. The incubation period was 24 days. The primary predators on adults and young were marsh hawk, great horned owl and mink. Franklin's gulls do not eat eggs or young of gulls. Adults fed on earthworms, insects and grain. Most marked adults fed within 16 km of the colony. Chicks were fed primarily on earthworms. The hatching period was from 30 May to 21 June. Chicks of all ages tested on a visual cliff apparatus were able to perceive the drop. Chicks tested on a 30-degree incline apparatus walked up it when 6 days old and younger, and walked down at 12 days of age and older. Brood mobility was less than in ground nesting species of gulls. In an undisturbed colony the chicks remained on the nest platforms until they were 25 to 30 days old although they were capable of swimming shortly after hatching. Individual recognition between parents and chicks appeared later in this species than in ground-nesting gulls. Adults accepted alien chicks (experimentally exchanged) that were younger than about 14 days old until their own chicks were over that age. Adults accepted larger and older broods than their own, as well as broods of mixed ages. Chicks began to react differently to strange adults at about 16 days of age. The breeding chronology of Franklin's gull is compressed when compared to that of other gulls. Possible selection pressures affecting this synchrony are discussed. The behaviour of the marsh-nesting Franklin's gull is compared with that of typical ground-and cliffnesting gulls; the possibility that the ancestral gull may have been a marsh nester is discussed.     

Haematocrit values of breeding Red-billed queleas Quelea quelea (Aves: Ploceidae) in relation to body condition and thymus activity

In a Red-billed quelea colony in north-eastern Nigeria that was later abandoned as a result of the poor nutritional condition of the adults, laying females showed low haematocrit values compared with normal pre-breeding haematocrit levels but nestbuilding males did not. In females the low haematocrits were correlated with extremely low levels of reserve lipid and labile protein but males in equally poor condition did not have such low haematocrits. This difference must result in some way from the additional nutritional burden for females of mobilizing sufficient protein to form eggs. Earlier observations of massive red blood cell production in the thymus of queleas during incubation suggest that low haematocrits, indicating anaemia, may be a normal occurrence in queleas during breeding, and were not peculiar to this abnormal abandoned colony.     

Seasonal Sexual Segregation by Monomorphic Sooty Shearwaters Puffinus griseus Reflects Different Reproductive Roles during the Pre-Laying Period

Tracking technology has revolutionized knowledge of seabird movements; yet, few studies have examined sex differences in distribution and behavior of small to medium-sized, sexually-monomorphic seabirds. Application of bird-borne geolocation-immersion loggers revealed seasonal segregation in the sexually-monomorphic Sooty Shearwater Puffinus griseus, mainly in the pre-laying period, when there were clear differences in reproductive roles. Shearwaters first returned to the Falkland Islands on 27 Sept±8 d; males, on average, 8 d earlier than females. Prior to egg-laying, distribution at sea, colony attendance and behaviour depended on sex. Males foraged locally over the southern Patagonian Shelf and Burdwood Bank, spending mainly single days at sea and intervening nights in the burrow. Females, who flew for more of the day during this time, foraged in more distant areas of the northern Patagonian Shelf and Argentine Basin that were deeper, warmer and relatively more productive. Attendance of females at the colony was also more variable than that of males and, overall, males were present for significantly more of the pre-laying period (38 vs. 19% of time). Sex differences were reduced following egg-laying, with males and females using similar foraging areas and making trips of similar mean duration in incubation (7.6±2.7 d) and chick-rearing (1.4±1.3 d). Congruence continued into the non-breeding period, with both sexes showing similar patterns of activity and areas of occupancy in the NW Atlantic. Thus, seasonal changes in reproductive roles influenced patterns of sexual segregation; this occurred only early in the season, when male Sooty Shearwaters foraged locally, returning regularly to the colony to defend (or maintain) the burrow or the mate, while females concentrated on building resources for egg development in distant and relatively more productive waters.     

Responses to oral gland scents from different males in Columbian ground squirrels

Acrylic cubes carrying oral gland scents from strange, neighbouring, and resident male Columbian ground squirrels (Spermophilus columbianus), plus a cube with no scent, were presented near the home burrows of squirrels in the field. Adult males and adult females sniffed scented cubes longer than unscented cubes, sniffed cubes with scent from other (strange and neighbouring) males longer than cubes with the resident male's own scent, and sniffed cubes with scent from strange males longer than cubes with scent from neighbouring males. Males also scent-marked the cubes on a number of occasions; differences in the frequency with which the cubes were marked followed the same pattern. It thus appears that adult Columbian ground squirrels can recognize familiar as opposed to unfamiliar males, and may also be able to determine individual identity, through oral gland scent. An ability to distinguish familiar from unfamiliar males by scent could be advantageous in facilitating differential treatment of wandering strange males versus established neighbours.