Non-oestrous Females Research Articles

Temporal Variation of White Rhino Dung Odours.

In order for an olfactory signal to be effective, it must persist in the environment for an extended period. White rhino dung odours transmit information about sex, age, territorial and oestrous states. As these odours relay important information, temporal changes in the odour emission rate and/or composition may be critical in order for other individuals to obtain this information. Here, we examine how the dung odours of adult white rhinos (male: territorial and non-territorial; female: oestrous and non-oestrous) change over the short (hours) and long (seasons) term using headspace extraction. Additionally, we measure seasonal midden visitation and defecation frequency to link behaviours to seasonal changes in odour longevity. We found that during the dry season, territorial male dung odours persisted for 48 hours, while the odours of all other adults persisted for >48 hours. The high temperature and humidity of the wet season did not affect odour longevity of oestrous females, but decreased dung odour longevity (i.e. increased emission) of territorial males, non-territorial males, and non-oestrous females. Despite this reduction, neither males nor females adjusted their seasonal visitation or defecation frequency. With regard to a temporal indicator, 3,7-dimethly-1,6-octadiene signalled dung age during the wet season, while acetophenone signalled dung age during the dry season. Ultimately, our results provide the first detailed account of temporal changes of dung VOCs, and highlight the limitations of dung as a signalling medium.

Will Trespassers Be Prosecuted or Assessed According to Their Merits? A Consilient Interpretation of Territoriality in a Group-Living Carnivore, the European Badger (Meles meles).

Socio-spatial interactions of Carnivores have traditionally been described using the vocabulary of territoriality and aggression, with scent marks interpreted as ‘scent fences’. Here, we investigate the role of olfactory signals in assumed territorial marking of group-living solitary foragers using European badgers Meles meles as a model. We presented anal gland secretions (n = 351) from known individuals to identifiable recipients (n = 187), to assess response-variation according to familiarity (own-group, neighbours, strangers) and spatial context (in-context: at a shared border; out-of-context: at an unshared border/ the main sett). Sniffing and over-marking (with subcaudal gland secretion) responses were strongest to anal gland secretions from strangers, intermediate to neighbouring-group and weakest to own-group members. Secretions from both, strangers and neighbours, were sniffed for longer than were own-group samples, although neighbour-secretion presented out-of-context evoked no greater interest than in-context. On an individual level, responses were further moderated by the relevance of individual-specific donor information encoded in the secretion, as it related to the physiological state of the responder. There was a trend bordering on significance for males to sniff for longer than did females, but without sex-related differences in the frequency of subcaudal over-marking responses, and males over-marked oestrous female secretions more than non-oestrous females. There were no age-class related differences in sniff-duration or in over-marking. Evaluating these results in the context of the Familiarity hypothesis, the Threat-level hypothesis, and the Individual advertisement hypothesis evidences that interpretations of territorial scent-marks depicting rigid and potentially agonistic discrimination between own- and foreign-group conspecifics are overly simplistic. We use our findings to advance conceptual understanding of badger socio-spatial ecology, and the general context of territoriality and group-range dynamics.

Singing, allogrooming, and allomarking behaviour during inter- and intra-sexual encounters in the Neotropical short-tailed singing mouse (Scotinomys teguina)

AbstractIn this study we determine whether brief interactions with unfamiliar conspecifics stimulate audible singing behaviour in the Neotropical short-tailed singing mouse (Scotinomys teguina). Specifically, we examine whether intra- or inter-sexual interactions elicit singing in males in a neutral-arena design. We conducted two experiments. In experiment 1, we recorded singing behaviour of male subjects both before and after a brief exposure to a female mouse. Males significantly increased their singing behaviour after the exposure to the female, as compared to prior to the exposure. In experiment 2, we compared the singing behaviour of male test subjects after a brief exposure with one of three different treatment animals: a male, a non-oestrous female and an oestrous female. We found that males are most likely to sing after an interaction with a female, regardless of her reproductive condition. Male subjects sang significantly less following an interaction with another male. Although spontaneous singing is known to occur in males and females, opposite sex elicited-singing behaviour was found to be sexually dimorphic. An interaction with a male was not effective in eliciting singing in females. In experiment 2, we also recorded incidences of allogrooming and allomarking by males during the interactions with males, non-oestrous females, and oestrous females. Male allogrooming and allomarking behaviours using the mid-ventral sebaceous gland tend to occur more frequently during interactions with females as compared to males, but were significantly different only in the case of allogrooming. Thus, this study clearly suggests sex differences in singing, allogrooming and allomarking, and a likely relationship between these behaviours and courtship in this Neotropical rodent.

Use of genital inspection and female urine tests to detect oestrus in captive Asian elephants

Captive Asian elephant ( Elephas maximus) populations are decreasing due to low birth rates compared to wild elephants. Improving oestrous detection in female elephants is required to ensure successful mating in captive and semi-captive herds. Responsive behaviours of eight semi-captive bull elephants to the uro-genital area (genital inspection test) or urinary pheromones (urine test) of 14 female elephants throughout the oestrous cycle were evaluated. Weekly blood samples were collected for 27 consecutive months (14 months for the genital inspection test and 13 months for the urine test) from female elephants to characterize the patterns of circulating progestagen. Responsive behaviours of bulls were compared between females in the follicular versus the luteal phase of the cycle. The sensitivity and specificity of the genital inspection test were 65% and 68%, while those of the urine test were 52% and 61%, respectively. The bulls showed significantly higher “genital inspection”, “flehmen from genital area” and “trunk on back” behaviours during the genital inspection test, and “flehmen” behaviours during the urine test in oestrous than in non-oestrous females. In sum, this study showed that monitoring sexual behaviours of Asian elephant bulls towards females or their urine can be used to detect the oestrous period. Although the sensitivity and specificity of both tests were not as high as expected, still, these methods appear to be more efficient at detecting oestrous than traditional methods based on mahout estimations of female receptivity. The use of genital inspection and urine tests may lead to more successful matings and thus to creating self-sustaining populations of captive elephants in range countries.

The effects of reducing population density on contact rates between brushtail possums: implications for transmission of bovine tuberculosis

1 Interactions during mating are thought to be an important mechanism for transmission of tuberculosis (Tb) Mycobacterium bovis in the brushtail possum Trichosurus vulpecula . However, little information is available on the frequency of contacts between males and females in oestrus during the breeding season, and the relationship between mating contacts and population density. 2 We used radio-telemetry to record contacts between male and oestrous and non-oestrous female possums, and determined paternity of offspring using DNA analysis. This was repeated following the removal of c . 70% of the resident possums to determine the effect of reducing density on the contact rate. 3 We could not detect any significant differences in the contact rate between oestrous and non-oestrous females and males, either before or after the density reduction, even when paternity was positively identified from DNA analysis. This suggests that actual mating contacts could not be distinguished from other agonistic or affiliative contact behaviours. 4 Despite this, the relationships between male–female and male–male contact rates and population density were non-linear convex-up, implying that the contact rate during the breeding season did not decrease in proportion to reductions in density. This appeared to be driven by the enlargement of male ranges and a corresponding increase in male overlap of female ranges following the density reduction. 5 The form of the contact rate function will influence predictions of disease spread in epidemiological models for Tb in wildlife. This has major implications for the development of tactical approaches to disease management based on such models.

The effects of sex, reproductive condition and context on discrimination of conspecific odours by giant pandas

To elucidate some of the functions of chemical communication in giant pandas, Ailuropoda melanoleuca, we systematically exposed captive males, oestrous and nonoestrous females to each others' odours by providing access to one another's temporarily unoccupied enclosures. In comparison with control observations, pandas from all reproductive categories displayed a dramatic increase in several measures of chemosensory responsiveness, both when visiting another panda's enclosure and when encountering scent deposited in their home enclosure. Evidence for discrimination between odours encountered as a resident versus a visitor was minimal, but male pandas' response patterns were suggestive of a territorial function. We also found evidence for discrimination of sex and reproductive condition via chemical cues. Males showed a marked preference for female odours, investigating, licking, scent marking and vocalizing more in response to female than male odours. Males also vocalized more in response to oestrous than nonoestrous female odours. Nonoestrous females licked more and oestrous females vocalized more when encountering male than female odours. Our data on vocalizations suggest a potential role for odours in the activation of sexual motivation. We argue that the low reproductive success observed in captivity may be attributed in part to failure to provide sufficient opportunities for chemical communication, and encourage the judicious management of social odours to promote natural mating (e.g. using intersexual odour exposure to increase libido and decrease aggressiveness prior to mating introductions).

Evidence for an important social role of allogrooming in a platyrrhine primate

Allogrooming behaviour was analysed in a wild group of tufted capuchin monkeys,Cebus apellain Iguazú National Park, Argentina. Evidence is provided that allogrooming in this platyrrhine species serves an important social function, as has been demonstrated for catarrhine primates. Using ad libitum sampling, 654 grooming sessions were recorded during 740 contact hours with one group. Seasonal variation was found in daily time allocation to allogrooming and the mean duration and reciprocity of sessions. Individual dominance rank was an important determinant of grooming relationships. The dominant male and female were the most actively involved in grooming. Among adults, dominant individuals were involved in more sessions than were subordinate individuals. The females maintained strong grooming relationships with each other and tended to reciprocate more within sessions than did males. Oestrous females engaged in more grooming bouts with adult males than did non-oestrous females. Females with newborn infants were attractive social partners for the remaining members of the group. A social function for allogrooming inCebusis indicated by the close relationship between allogrooming, the social system and coalition formation, and by the changes in quantity and direction of grooming in response to oestrous behaviour and to the birth of infants.

Sandbathing to establish familiarity in the Merriam's kangaroo rat, Dipodomys merriami

The hypothesis that olfactory signals deposited at sandbathing sites could function in neighbour and mate recognition was tested in Merriam's kangaroo rats, Dipodomys merriami. Habituation-discrimination tests revealed that both males and females could discriminate between the body oils of familiar and unfamiliar male donors. Only females, however, responded to sebum from the androgen-dependent dorsal gland of males. Oestrous and non-oestrous females preferred the dorsal gland scent of familiar males to that of unfamiliar males; males did not show a preference. In the field, many males sandbathed in the home area of oestrous females on night before and during mating. Taken together, laboratory studies and field observations show that scent deposited at sandbathing sites could convey the identity of the sandbather to conspecifics. Olfactory signals at sandbathing sites could promote familiarity among neighbours and enable males to become familiar to potential female mates.

The effect of relatedness on reproductive success and mate choice in the white-footed mouse, peromyscus leucopus

Genetic similarity between mates has a significant effect on the reproductive success of whitefooted mice. Pairs of mice bred over a range of degrees of relatedness demonstrated a significant inbreeding depression in litter size at weaning and offspring weight at weaning. If juveniles that are lighter at weaning are less likely to be recruited into the breeding population, these experiments also demonstrated a mild outbreeding depression. However, this cost does not appear to be due to the traditional mechanisms of outbreeding depression. Kin recognition appears to affect mate choice in white-footed mice and to act as a mechanism for reducing the costs of inbreeding and outbreeding. In an arena, oestrous females presented with either male odours or actual males showed a preference for males on an intermediate degree of relatedness. Non-oestrous females showed no such preferences.

Sandbathing as a territorial scent-mark in the bannertail kangaroo rat, Dipodomys spectabilis

Sandbathing by the bannertail kangaroo rat, Dipodomys spectabilis, was studied in the laboratory and field to determine its possible function as a territorial scent-mark. Rats were tested for their responses to body oil and dorsal gland scents from familiar and unfamiliar rats and to the sandbathing sites of rats in different hormonal conditions. Field evidence showed that adult and juvenile rats of both sexes sandbathed at similar rates in their territories. Rats recognized scents of different conspecifics from body oils and dorsal gland secretions. The sandbathing marks of intact males, castrated males, oestrous females and non-oestrous females were equally attractive to rats in reproductive and non-reproductive conditions. Sandbathing scents apparently do not communicate information on reproductive status in this species. Rats sandbathe to scent-mark their territories and may use the scents to distinguish familiar neighbours from unfamiliar conspecifics. Neighbour recognition is probably important in maintaining the territorial social organization of D. spectabilis.

Sexual experience, androgens and female choice of a mate in laboratory rats.

Sexual experience produces long-lasting changes in both the behaviour and reproductive system of a male rat. The response of the female rat to an area that had recently housed a previously mated male was investigated in three experiments. In experiments 1 and 2 females preferentially urine marked in an area vacated by a sexually experienced (SE) male relative to areas vacated by a sexually inexperienced (SI) or castrated (C) male. The density of female marks were ranked SE greater than SI greater than C greater than empty area. In experiment 3 female preference of an SE male with varied and multiple mating experiences was magnified when compared with an SI male. There was the suggestion that the multiple SE male was even preferred to a male with only a single mating experience. A fourth experiment demonstrated an acute increase in circulating testosterone in multiple SE males exposed to oestrous or non-oestrous females, and the increase was observable for up to 7 days after exposure to an oestrous female. The conclusion is that chronic changes in androgen-dependent urinary by-products released by the SE male mediate the discrimination and choice of a mate by the female rat.

Pre-Copulatory and Copulatory Behaviour in Relation To Stages of the Oestrous Cycle in the Female Mongolian Gerbil

1. Most previous studies of sexual behaviour in female rodents have concentrated on lordosis, and there have been few attempts to quantify pre-copulatory behaviour of the female. Conditions of testing commonly used in previous research into rodent sexual behaviour particularly seem to have focussed attention on copulatory behaviour of the female, leading to the neglect of female pre-copulatory behaviour. 2. The present study aimed to investigate both pre-copulatory and copulatory behaviour in the female Mongolian gerbil in relation to different stages of the oestrous cycle. 3. The experimental design of the present study was intended to provide an increased opportunity for females to display pre-copulatory behaviour. Daily observations were made of the behaviour of ten male/female pairs of Mongolian gerbils which were living together continuously over the four days of the oestrous cycle. Each female was paired with a test male on the day following the day of behavioural oestrus and the pair remained together until the end of the next day of behavioural oestrous. Experimental females and test males were all sexually experienced before use as subjects. 4. Under these conditions, females displayed a number of pre-copulatory behaviour patterns (piloerection posture, present posture, darting and foot-stomping) on the day of oestrus which did not appear on other days of the cycle. On the day of oestrus, females also showed pre-copulatory increases in rates of allogrooming initiated by the female and in rates of olfactory investigation of the male's head and anogenital regions compared to other days of the cycle. Oestrus females also approached and left the male more frequently than non-oestrous females. 5. Unlike behaviour, sequences of female pre-copulatory behaviour involving darting and the present or piloerection postures did not depend on tactile stimuli associated with male mounting. Sequences of female pre-copulatory behaviour always preceded instances of male pre-copulatory following and mounting. 6. During copulation, male sexual behaviour was organised into ejaculatory series of mounts and intromissions, separated by post-ejaculatory intervals. All males initiated a final incomplete series of mounts and intromissions which did not culminate in ejaculation. Female receptivity, as measured by the lordosis ratio, remained high until the end of mating, and declined only in the final series of mounts and intromissions following the last ejaculation. However, the display of female proceptive behaviour patterns (darting, foot-stomping, present posture and piloerection posture) declined over successive ejaculatory series. 7. Sequence analysis showed that each mount or intromission was preceded by one of seven types of behaviour sequence, the most common sequence, Type O, consisting of female darting, male follow, female present and male moult without intromission or male mount with intromission. At the beginning of mating, most Type O sequences were preceded by female behaviour patterns (approaching the male, investigating the male and foot-stomping). As mating proceeded, an increasing percentage of these sequences was preceded by male behaviour patterns (approaching the female and investigating the female's head). 8. It is concluded that, in the present study, oestrous female gerbils played an active role in the performance of sexual behaviour. Pre-copulatory activities of the female seemed to have a stimulatory effect on male sexual behaviour and probably made an important contribution to the initiation of mating. During copulation, females actively participated in the initiation of mounts and intromissions, and, in the earliest stages of mating, played an important role in the patterning of copulatory behaviour. In the later stages of mating, the male played an increasingly important role in the initiation of mounts and intromissions.

Social behaviour between adult male and female new zealand fur seals, Arctocephalus forsteri (Lesson) during the breeding season.

Observations on social relations between territorial adult male and adult female A. forsteri were made on the Open Bay Islands, Westland, New Zealand, during the breeding season 1970-71. Threats comprised about 80% of all social encounters between males and females. Attempted and successful olfactory investigations of females by males, herding of females by males, and 'peace-keeping' by males accounted for about 18% of all encounters, and such interactions usually had agonistic overtones. Less than 2% of all encounters were not agonistic from their inception. Herding responses of males were vigorous and frequent, and are interpreted as serving two functions: containment of females and communication of certain of the herding males' characteristics to the females. Because herding occurs throughout the Otariidae, and is rarely effective in containing females, the second function is probably more important. Males showed much individual variation in their herding tendencies. The frequency of herding behaviour was depressed at warm temperatures. Olfactory investigations of facial and perineal regions of females were common and were not restricted to peri-oestrous females. Only oestrous females were sexually receptive to and showed little aggression toward territorial males, and males detected their physiological state mainly through olfaction. A few oestrous females solicited males with mock threats or by rubbing against them. Precopulatory and early copulatory behaviour was characterized by a moderate amount of mutual contact-seeking behaviour, multiple mounts by the male, and 'activation' of the female by the male biting her. Copulations appeared to be terminated through physical resistance by the female, which resulted in ejaculation and subsequent dismounting by the male. At the time of female resistance, the male commonly had to physically control her. The sudden return to aggressive behaviour typical of non-oestrous females may be mediated through a neural inhibitory process resulting from cervico-vaginal stimulation, as has been proposed for the guinea pig.

The olfactory response of mice to urine and effects of gonadectomy.

SUMMARY Using a standard arena technique, the reactions of groups of albino mice were noted in response to traps baited with urine. The response was measured in terms of latency, duration of investigatory visit, total investigation time and number of visits. Because of a high level of variability between individuals, many of the results were not significant, but it was demonstrated that urine contained olfactory attractants and there was a suggestion that it might also contain repellents. Animals showed a positive response to traps baited with urine from the opposite sex and where there was a difference in response to urine produced during the night and urine produced during the day, 'night' urine generally elicited a stronger response than 'day' urine. Males reacted negatively to male urine, whereas females were more strongly attracted to female urine than to male urine. The attractiveness of female urine to male mice, as measured by duration of investigatory visit, was increased twofold during pregnancy and threefold during oestrus. Oestrous urine tended to be more effective than dioestrous urine. Female urine stored at −10 °C was more attractive to male mice than fresh female urine. After prepubertal castration, males showed no preference for oestrous urine over dioestrous urine. Both normal and prepubertally castrated males, however, spent less time sniffing urine from spayed females than urine from females in oestrus or from non-oestrous females. There was evidence that intact male mice spent more time investigating female urine odours than did castrated mice, but this did not apply to dioestrous urine.

The effect of parachlorophenylalanine on the behaviour of cats.

1. Male and female kittens and adult cats were given p-chlorophenylalanine orally.2. After treatment, some of the male cats showed mounting behaviour and the kittens and non-oestrous females showed an increase in treading and rubbing which was similar to one aspect of pro-oestrus behaviour.3. The treated animals also appeared to suffer from skin irritation and showed increased restlessness which accompanied sleep deprivation.4. Injection of 5-hydroxytryptophan stopped abnormal sexual activity and restored normal sleep for about 5 hours.5. It is concluded that 5-hydroxytryptamine-containing neurones inhibit sexual behaviour in cats and that this role can be seen in male and, to some extent, also in female animals.