Olfactory Contact Research Articles

Length of Estrous Cycle and Gestation in the Arabian Oryx (Oryx leucoryx) and the Importance of the Male Presence for Induction of Postpartum Estrus

The reproduction of the Arabian oryx (Oryx leucoryx) has been studied in a breeding center in Taif (Saudi Arabia). In the first experiment, three groups of females were assigned to groups immediately after calving. In group 1, from the day of calving the females had visual and olfactory but not physical contact with a male. The calves were removed on the day of birth and each female was placed with a male on Day 45. In group 2, females and their calves were placed individually with a male the day after calving. In group 3, females and their calves were kept with neither visual nor olfactory contact with a male and then placed with a male on Day 90. The estrous cycle was deduced from assays of plasma progesterone up to Day 120 after calving. All females exhibited a postpartum estrus a few days after parturition but the occurrence of the estrus was significantly delayed in females of group 3. The length of the estrous cycle was 23.7 ± 1.3 days and the gestation length was 255.2 ± 1.5 days. In the second experiment, a group of adult females was formed in 1987 and the intervals between calving recorded over a period of 5 years. The mean interval between calving was 285 ± 2 days (n= 99 gestations). However, 66.6% of these intervals averaged 276 days whereas 19.2% had averaged 294 and 13% averaged 321 days.

Evidence that primer pheromones do not cause social suppression of reproduction in male and female naked mole-rats (Heterocephalus glaber)

The role of chemical cues in mediating the reproductive suppression of nonbreeding males and females in colonies of naked mole-rats (Heterocephalus glaber) was examined by comparing reproductive activation in isolated nonbreeders with that of isolated nonbreeders maintained in olfactory and gustatory contact with their parent colony. Animals were either removed from their colony and paired directly with a member of the opposite sex from the same colony, or were removed, housed singly for 40 days, and then paired with a member of the opposite sex from the same parent colony that had also been housed singly for 40 days. Approximately half of these separated animals received a daily transfer of soiled bedding and litter from their parent colony. In females, there was no significant difference between the control and bedding transfer group, in the time taken from separation to the first sustained increase of urinary progesterone above 2 ng mg-1 Cr indicative of the luteal phase of an ovarian cycle (7.8 +/- 2.6 versus 9.4 +/- 2.0 days, respectively). In both control and bedding transfer groups, singly-housed females commenced ovarian cyclicity, revealing that the presence of a male was not required for reproductive activation and ovulation. In males, concentrations of both urinary testosterone and plasma LH increased after separation from their parent colonies in both control and bedding transfer groups, to reach values equivalent to those of breeding males.(ABSTRACT TRUNCATED AT 250 WORDS)

Do simple rules apply in honey-bee nestmate discrimination?

How do honey-bees integrate cues in nestmate recognition? Honey-bees are able to discriminate nestmates from non-nestmates using olfactory cues or contact chemoreception. Nestmates may differ from non-nestmates in either cues produced by the individuals, which have a genetic basis, or in cues that are acquired from the hive environment. Recognitive cues are learned by worker bees early in adult life; the learned cue profile serves as a template for comparison and determination of the colonial membership of bees that are encountered. We report here the response of bees to two cues: hexadecane and methyl docosonoate.

Hormonal responses to fighting in hamsters: Separation of physical and psychological causes

Male Syrian hamsters were paired and allowed to interact with a conspecific for 15 min a day for 4 days. On the fifth day, the animals were again paired, but they were kept physically separated by a mesh partition that allowed visual, olfactory, and auditory contact between the animals. Controls were placed with conspecifics on each of the 5 testing days, but the partition between them was never removed. Hamsters that were submissive on days 1–4 exhibited elevated plasma adrenocorticotropin-like immunoreactivity (ACTH-LI), beta-endorphin-like immunoreactivity (B-EP-LI), and cortisol on day 5 even though no fighting occurred on that day. Dominant hamsters did not differ from controls. These data support the hypothesis that there is an important psychological component to the pituitary-adrenocortical response in defeated hamsters.

The stimulatory effect of males on the initiation but not the maintenance of ovarian cycling in cotton-top tamarins (Saguinus oedipus).

Prior studies have shown that female cotton-top tamarins usually do not ovulate while living with natal groups, and most females do not ovulate until they are paired with an unfamiliar adult male. To examine the role of unfamiliar adult males on stimulating ovarian function, four cotton-top females were studied during three conditions: females living with their natal group for six weeks, living alone but exposed to a single unfamiliar adult male located 15 cm away from the female's cage for four weeks, and living with an unfamiliar adult male for six weeks. Behavior and urinary hormonal concentrations were measured during the three conditions. Exposure to the male consisted of visual, auditory, and airborne olfactory contact. First ovulation occurred during exposure to the unfamiliar male in three of the four females indicating that direct physical or sexual contact with the male is not required for onset of ovarian cycling. The fourth female did not ovulate even during six weeks of direct contact with the unfamiliar adult male. In addition, four parous females in either family groups (3) or singly caged (1) were examined for ovarian function 4-6 months after the death or removal of their mates. All femals continued to cycle in the absence of the male indicating that the male was not needed to continue ovarian cycling. In fact, two of the females were pregnant at the time their males died and both delivered normal infants and resumed cycling. The results of this study indicate that an unfamiliar adult male may facilitate the onset of ovarian cycling without being in direct contact with the female and visual, auditory, or airborne olfactory cues may be involved. Once repeated ovarian cycling occurs the male is not required to maintain ovarian function.

Repeated restraint and isolation stress in lambs increases pituitary-adrenal secretions and reduces cell-mediated immunity.

Rambouillet crossbred ewe lambs were used to evaluate the effect of repeated restraint and isolation stress (RIS) on endocrinological and immunological functions. Lambs were blocked by weight and assigned to either RIS (n = 6) or to control (CON; n = 6) treatments. All lambs were tethered in environmentally controlled rooms at 22 degrees C with constant light and, at this time (d 0), were given 1 mg of ovalbumin in adjuvant. On d 12, catheters were placed nonsurgically into the jugular vein of all lambs, and they were reimmunized with .5 mg of ovalbumin in incomplete adjuvant. Each lamb in the RIS treatment group was removed from its home stanchion, isolated from visual and tactile (but not auditory and olfactory) contact with other lambs, and restrained for 6 h on d 14, 15, and 16. Lambs in CON treatment remained undisturbed in their home stanchions. Lymphocyte blastogenic function and production of interleukin-2 (IL-2) were assessed in samples of blood collected before and at the conclusion (0 and 6 h) of each of the three stress bouts. In addition, ACTH and cortisol secretion in response to RIS was evaluated in samples of plasma and serum collected at .5-h intervals on the first and last days of stress (d 14 and 16). Finally, antibody production in response to immunization against ovalbumin was assessed in samples of serum obtained 14 d after reimmunization on d 12 of the study. Polynomial curves fit to the ACTH and cortisol data differed (P less than .005) on both d 14 and 16 between RIS and CON treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Variation in aggressive behavior and anatomo-physiological correlates generated by crowding without physical contact in the house mouse

Behavioral, physiological (i.e., endocrine), and anatomical consequences of crowding in mice were studied in a situation where animals were in auditory, visual, olfactory, and tactile contact but restrained from full physical interactions, to prevent overt aggression. Males that cohabited with females undisturbed by neighboring conspecifics showed greater propensity to attack same-sex intruders and had higher plasma testosterone levels than did their “crowded” counterparts, that is, males cohabiting with females and housed adjacent to other male/female pairs. In this respect, the latter animals resembled submissive males. However, a significant increase in weight of androgen-dependent target organs (i.e., seminal vesicles and preputial glands) was found in crowded males. These data indicate that despite the observed inhibition of social aggression these males are not physiologically comparable (homologous) to male mice that experienced defeat and the stress of submission during fighting. The intriguing possibility that different conversion pathway of testosterone are accelerated, as a result of social communication, in males living in these two environments and the behavioral implications of these possibilities are discussed. Finally, the parental behavior of crowded animals, although not freely interacting with each other, was disrupted, causing a marked decrease in reproductive success. In this situation a high incidence of infanticide of their offspring by both parents was observed, whereas this behavior was virtually absent in non-crowded male/female pairs.

An analysis of sex stimuli enhancing ovarian growth in pubertal African catfish, Clarias gariepinus

Ovarian growth in pubertal African catfish was followed during a 100-day period. Different combinations of male sensory stimuli resulted in three distinct levels of ovarian development. A basic level (ovarian weight 5.3–7.5 g; GSI 1.9–2.7%) was reached in controls (no contact with males) and in females having visual and auditory contact with males. An intermediate level (ovarian weight 11 g; GSI 4%) was reached if olfactory contact with males was possible. A maximum level (ovarian weight nearly 20 g; GSI 7.3%) resulted from unlimited contact between the two sexes. The question is discussed whether the difference between maximum and intermediate levels of ovarian growth should be ascribed to a better water quality due to experimental conditions rather than to the presence of male tactile stimuli. The possible existence of male primer pheromones responsible for the observed stimulation of ovarian growth in pubertal African catfish by enhancing vitellogenesis is also discussed.

Assessment of fighting ability or simple habituation: What causes young pigs (Sus scrofa) to stop fighting?

To determine how pigs assess their relative fighting ability, I observed paired contests between young pigs that were either of similar weight or of different weight. On the first day the incidence of fighting was high, but this was not affected by the size of the weight difference. Fights between pigs of different weight were shorter than those between pigs of similar weight. When the pigs were of different weight, the eventual winner bit more frequently and spent more time attacking than did the eventual loser. This difference was not apparent when the pigs were of similar weight. On the first day, winners and losers were equally likely to initiate fights. The incidence of fighting was lower on the second day, although this was unaffected by the weight difference. Losers were less likely to initiate fights on the second day, and fights were shorter than on the first day. However, for the time that they did fight, the losers fought as vigorously (based on the rate of biting) on the second day as on the first. Seventy-two hours of visual and olfactory contact before the fight had no effect on the incidence of fighting and minimal effect on its duration. I suggest a young pig cannot assess its chance of success prior to the first encounter but only during the course of the fight. This assessment is reduced by attacks from the opponent until it drops below a critical threshold, whereupon the pig stops fighting. As a result of a previous defeat, a pig will lower its assessment and will be less likely to fight or to initiate fights on subsequent encounters. It is this change in assessment rather than habituation alone that makes pigs less likely to fight as they become acquainted.

Vocal interactions between squirrel monkeys out of visual, tactile and olfactory contact

Squirrel monkeys, when out of visual, tactile and olfactory (VTO) contact, produce calls at different frequencies of occurrence than under conditions of VTO contact. This difference is not mainly caused by an increase of calls associated with contact-distance behaviour. When squirrel monkeys communicate acoustically under restricted conditions, they attend to the same rules of communication they obey under nonrestricted conditions. They produce call rates depending on the partner's rate of vocalization. Their acoustical ‘reaction’ depends on the conspecific's preceding vocalization in both situations. Hence it follows that squirrel monkeys differentiate between conspecifics solely via acoustic cues and that they are able to ‘converse’ in ‘dialogues’ (not only in relation to contact calls) when out of sight of each other.

Linguistic strategies to detect frequency modulation patterns relevant to primate vocal communication

Introduction Frequency modulation components in non-human primate calls have been shown to contain information essential to the conspecific (e.g. Snowdon and Hodun, 1981; Green, 1975; Masataka, 1983, 1986; Dittus, 1984; Masataka and Symmes, 1986). In Maurus et al. (1985) all calls of the squirrel monkey’s repertoire with at least one component showing a clear frequency modulation (at least 500 Hz difference between highest and lowest frequency) or with a fundamental frequency of more than 3kHz (referred to as z calls in the following; see Fig. 1) were found to be functionally different from all other calls (x calls). This was shown also for vocalizing partners out of visual, olfactory and tactile contact (Maurus et al., 1987, in press).

Fostering in sheep. IV. Use of restraint

Fostering an additional lamb on to a ewe with a single lamb of her own was attempted in Dorset, Corriedale and Merino ewes restrained by the neck in pens for up to 12 days. Fostering occurred more rapidly in Dorsets than in Merinos, and success rates tended to be higher in Dorsets (81%) than the other breeds (73% in Corriedales and 69% in Merinos). The use of screens at the level of the ewe's neck to limit her olfactory examination of the lambs was more successful than when full olfactory contact was allowed. The prevention of any close olfactory contact resulted in an intermediate rate of acceptance, even though acceptance was apparently based on olfaction, as shown by universal rejection of strange alien lambs. Acceptance tests done within a few minutes of release from restraint were found not to reflect accurately the final level of acceptance, since some lambs came to be accepted within a day of being released. Further acceptances, that developed several days after release into a flock of ewes and lambs, emphasize an important role of the lamb in maintaining contact with the ewe. With few exceptions, lambs accepted when released from the pens were still accepted after a week or so in the flock. Dorset ewes given one or two foster lambs in the absence of their own lamb accepted the fosters within 9 days. Restraint fostering had no apparent harmful effects on the ewes or lambs, but had the disadvantages of being laborious and of soiling the ewes' wool. It has the advantage of providing lambs with an assured milk supply, and could prove useful for ewes that have failed to accept lambs under other methods.

An Observation of Inter- and Intra-Specific Aggression Involving Brown Bear, Black Bear, and Moose in Southcentral Alaska

An Observation of Inter- and Intra-Specific Aggression Involving Brown Bear, Black Bear, and Moose in Southcentral Alaska

Reproduction in the gilt. 5. The effect of the presence of the mature male during rearing on puberty attainment

ABSTRACTForty Landrace × (Landrace × Large White) gilts were randomly assigned at 70 days of age to each of two rearing treatments. The two treatments were: (1) gilts reared with gilts but kept in complete isolation from other pigs, and (2) gilts reared with visual, aural, olfactory and limited tactile contact with a mature boar. At 160 days of age, all gilts were subjected to a pen change and housed adjacent to either a mature boar for the first time, or to a different mature boar from that with which they had contact during the rearing phase. In addition, gilts were exposed to a mature, vasectomized boar for 30 min each day. They were served twice at second oestrus and the reproductive tracts were examined at slaughter 21 days later to determine ovulation rate and embryo survival. The presence of a mature male during the rearing phase had no effect on the attainment of puberty. There were no significant differences between treatments 1 and 2 for age at puberty (168·1 and 166·9 days respectively), weight at puberty (74·0 and 75·7 kg respectively) and the interval from movement and boar introduction to puberty (8·3 and 7·4 days respectively). The rearing treatments also had no effect on ovulation rate or embryo survival.

Social interactions of juvenile Collared peccaries, Tayassu tajacu (Mammalia: Artiodactyla)

Is there a predictable relationship between species‐typical behavioural development and social organization in mammals? Earlier work on canids and rodents suggested that adult sociality is associated with a developmental schedule in which juveniles showed, among themselves: (1) frequent social play; (2) frequent amicable contact; (3) frequent olfactory contact; (4) a delay in the emergence of agonistic behaviour. In the highly social Collared peccary (Tayassu tajacu) the behaviour of juveniles conformed only partially to this scheme. Juveniles engaged in social play with each other at an early age, but showed no other observable amicable or olfactory contact until eight to twelve weeks of age and showed no delay in the emergence of agonistic behaviour among themselves. Adults, in contrast, were conspicuously tolerant of juveniles, and 86% of juvenile social interactions in the first year took place with adults.

Olfactory recognition between mother and calf in reindeer ( Rangifer t. tarandus L.)

Olfactory contacts between reindeer mothers and their calves are most frequent in nursing situations. Mothers and calves are able to identify each other by naso-nasal contacts, which usually precede nursing. During nursing, the mother frequently checks the identity of the calf by sniffing its tail. Olfactory contact before sucking attempts lead to a high frequency of successful nursing. Naso-nasal contacts and sniffing of the calf's tail prevails in contacts with other individuals. Olfactory contacts between reindeer mothers and strange calves are frequently followed by agonistic acts from the cow. The rejected calf often made olfactory contact with its own mother.

Field studies of the sensory basis of homing and orientation to the home site in Ulvaria subbifurcata (Pisces: Stichaeidae)

The roles of olfaction and vision in the homing behaviour and orientation to a home site in Ulvaria subbifurcata were investigated. These were examined by studying the home-site fidelity and the homing performance of normal, blind, and anosmic fish and the orientation to the home site of normal and sensory-impaired fish. The orientation and homing experiments indicated that olfactory contact with the home site is involved in the steering mechanism in homing. The home-site fidelity of anosmic fish, and the fact that some anosmic fish homed, indicated that vision may also be involved in the recognition of a restricted area around the home site.

Olfactory and visual cues in social interactions of Lemur catta.

The relationship between visual and olfactory cues and their relative importance in interactions between pairs of adult male ring-tailed lemurs was determined. Visual and olfactory contact was controlled. When visualcontact was prevented. little behavior occurred. When visual contact was permitted, olfactory cues altered behavior.

Further observations on the influence of the social environment on ovulation in the vole, Microtus agrestis.

The influence of the social environment on ovulation was studied in voles. Female subjects were placed in 2 environments; 1 allowed auditory and olfactory contact with males with and without visual contact while the other allowed olfactory contact only through housing in male-soiled bedding. The experimental design excluded tactile contact. 1 of 15 animals ovulated in response to visual auditory and olfactory contact and 2 of 15 females ovualted in response to auditory and olfactory contact. Since 1 of 13 females ovulated in response ot the soiled-bedding environment it is possible that male pheromones may be involved in mediating the ovulatory response. Olfactory stimuli alone were relatively ineffective in mediating the induction of ovulation which suggests that tactile-dependent pheromones may be involved in the noncoital induction of ovulation.

Studies on the antennal sensilla of selected blackflies (Diptera: Simuliidae).

The types, numbers, and distribution of the antennal sensilla of male and female Simulium rugglesi and S. baffinense, and female S. venustum and S. euryadminiculum have been determined. Seven sensillar types, including olfactory receptors, contact chemoreceptors, and mechanoreceptors, were distinguished on all specimens examined. The results are discussed with regard to the feeding habits of the various species.