Noncycling Females Research Articles

Adiposity, reproductive and metabolic health, and activity levels in zoo Asian elephant (Elephas maximus).

Many captive Asian elephant populations are not self-sustaining, possibly due in part to obesity-related health and reproductive issues. This study investigated relationships between estimated body composition and metabolic function, inflammatory markers, ovarian activity (females only) and physical activity levels in 44 Asian elephants (n=35 females, n=9 males). Deuterium dilution was used to measure total body water from which fat mass (FM) and fat-free mass (FFM) could be derived to estimate body composition. Serum was analyzed for progestagens and estradiol (females only), deuterium, glucose, insulin and amyloid A. Physical activity was assessed by an accelerometer placed on the elephant's front leg for at least 2 days. Relative fat mass (RFM) - the amount of fat relative to body mass - was calculated to take differences in body size between elephants into consideration. Body fat percentage ranged from 2.01% to 24.59%. Male elephants were heavier (P=0.043), with more FFM (P=0.049), but not FM (P>0.999), than females. For all elephants, estimated RFM (r=0.45, P=0.004) was positively correlated with insulin. Distance walked was negatively correlated with age (r=-0.46, P=0.007). When adjusted for FFM and age (P<0.001), non-cycling females had less fat compared with cycling females, such that for every 100 kg increase in FM, the odds of cycling were 3 times higher (P<0.001). More work is needed to determine what an unhealthy amount of fat is for elephants; however, our results suggest higher adiposity may contribute to metabolic perturbations.

An overview on the women in the prehistoric skill

According to current Darwinian theories, female processes drove the most punctual representative behavior. Female conceptional weight increased as mind sizes increased in Homo heidelbergensis and the rapid predecessors of Homo sapiens (exactly the time period from 500 to 130, 000 b.p.). Transformative biology foresees a battle between the sexes over the pursuit of posterity. Feminine draining became the lone big indicator of approaching richnessss whenever ovulation was covered in the human ancestry. However, although covered ovulation keeps track of which females are fertile at any one moment, the conspicuous character of the feminine sign counteracts this effect, distinguishing inexorably ripe individuals from pregnant or lactating ones. To combat male separation among cycling and non-cycling females, late antiquated/early modern Homo sapiens ladies formed partnerships and began aesthetically manipulating feminine indications on a monthly cycle. The widespread, deceptive, and increased use of red hues as body paint muddled information available to males regarding women's conceptional state and effectively molded a preadaptation to custom. This model indicates that a cosmetics business swamped by red hues would demonstrate the most punctual craftsmanship. Further expectations are set by the model, which are similar to the stone workmanship record. I'll focus on (a) the importance of paying attention to women' regeneration signals; (b) the importance of alliances; (c) the link between ladies and game animals; and (d) the one-of-a-kind mark of custom force.

Reproductive monitoring of collared peccary females (Pecari tajacu) by analysis of fecal progesterone metabolites

The measurement of fecal progesterone metabolites (fPM) by enzyme immunoassay analysis is a non-invasive technique that permits gathering reproductive information from wildlife without the stress associated with restraint. In the collared peccary (Pecari tajacu), a high correlation between serum progesterone and fPM levels (r2 = 0.783) suggests that fPM can be used to monitor their reproductive function. We monitored fPM during the estrous cycle of 15 collared peccary females. Estrous cycles averaged 27.9 ± 4.5 days (n = 28), ranging from 21 to 36 days. The luteal phase was 22.2 ± 4.8 days and the inter-luteal phase was 4.3 ± 1.4 days. Mean concentration of fPM across pregnancy were not different from those found during the luteal phase (1230 ± 718 and 1265 ± 584 ng/100 mg dried feces, respectively), however, significant differences were found when luteal phase concentrations were compared only against fPM concentrations during late pregnancy. In addition, late pregnancy fPM concentrations (1893 ± 551 ng/100 mg) were also significantly higher than those in the early (639 ± 339 ng/100 mg) and mid (1134 ± 449 ng/100 mg) pregnancy. For females during the early post-partum period, fPM concentrations were significantly increased (243 ± 118 ng/100 mg) than those of non-cycling females (103 ± 89 ng/100 mg). The analysis of fPM is a simple, non-invasive methodology to detect the ovarian activity in the collared peccary; moreover, it provides a husbandry tool, which may be used to help understand how social structure may impact reproduction.

Abstract 559: AMP-Activated Protein Kinase And Estrogen-Dependent Mechanisms Underlying Increased Susceptibility To Cardiovascular Disease During Menopause

According to the CDC (2017), more women than men have died from heart disease over the last 20-25 years. Yet, premenopausal women are protected against heart and cardiovascular disease (CVD) compared to age-matched men. The cellular and molecular mechanisms underlying the transition from premenopause/perimenopause (CVD-resistance) to postmenopause (CVD-susceptible) in women is unknown and is the focus of this project. The critical barrier impeding translational progress is the lack of appropriate models to study menopause. Most studies have used surgical removal of ovaries (ovariectomy) as a model of menopause; yet this technique poorly recapitulates the natural, physiological transition to menopause that 90% of women experience. We overcome this barrier with administration of the chemical, 4-vinylcyclohexene diepoxide (VCD), where we can mirror progressive ovarian failure and preserve the critical “perimenopause” transitional period, identical to humans. Using this model, we demonstrate that perimenopausal , like cycling (premenopausal) females, are protected from pathological angiotensin II (Ang II)-induced cardiac remodeling, while menopausal females are not. Our novel finding that perimenopausal females remain protected, despite irregular cycling (prior to complete loss of estrogen), underscores the importance of studying the role of estrogen in CVD, across the transition from perimenopause to menopause. Multiple molecular, genetic and cellular mechanisms have been suggested to underlie protection against CVD in non-cycling females, many of which put estrogen as the key mediator. We discovered that one of these pathways, the adenosine monophosphate-activated kinase (AMPK) signaling axis, is activated by estrogen through direct binding of estrogen receptors to the α-catalytic subunit of AMPK. Taken together with our published and preliminary data, we hypothesis that loss of AMPK signaling is responsible for the exacerbated pathological cardiac remodeling in menopause (see Fig.). To date, there are no studies that have tested the ability of AMPK activation to mitigate menopausal susceptibility to CVD. Aim: Determine if AMPK is necessary and/or sufficient to impart protection against pathological cardiac remodeling in menopausal females. Rationale: We discovered that AMPK signaling is severely disabled during menopause where females are more susceptible to CVD. Using the VCD mouse model of menopause, we will determine if protection against Ang II-induced cardiac remodeling during menopause is AMPK-dependent. Summary: We plan to determine the cellular and molecular mechanisms in premenopausal and perimenopausal females that prevent associated cardiovascular morbidities; and determine the underlying shift that gives rise to increased susceptibility to CVD in menopausal females.

Variations in Phase and Amplitude of Rhythmic Clock Gene Expression across Prefrontal Cortex, Hippocampus, Amygdala, and Hypothalamic Paraventricular and Suprachiasmatic Nuclei of Male and Female Rats.

The molecular circadian clock is a self-regulating transcription/translation cycle of positive (Bmal1, Clock/Npas2) and negative (Per1,2,3, Cry1,2) regulatory components. While the molecular clock has been well characterized in the body's master circadian pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), only a few studies have examined both the positive and negative clock components in extra-SCN brain tissue. Furthermore, there has yet to be a direct comparison of male and female clock gene expression in the brain. This comparison is warranted, as there are sex differences in circadian functioning and disorders associated with disrupted clock gene expression. This study examined basal clock gene expression (Per1, Per2, Bmal1 mRNA) in the SCN, prefrontal cortex (PFC), rostral agranular insula, hypothalamic paraventricular nucleus (PVN), amygdala, and hippocampus of male and female rats at 4-h intervals throughout a 12:12 h light:dark cycle. There was a significant rhythm of Per1, Per2, and Bmal1 in the SCN, PFC, insula, PVN, subregions of the hippocampus, and amygdala with a 24-h period, suggesting the importance of an oscillating molecular clock in extra-SCN brain regions. There were 3 distinct clock gene expression profiles across the brain regions, indicative of diversity among brain clocks. Although, generally, the clock gene expression profiles were similar between male and female rats, there were some sex differences in the robustness of clock gene expression (e.g., females had fewer robust rhythms in the medial PFC, more robust rhythms in the hippocampus, and a greater mesor in the medial amygdala). Furthermore, females with a regular estrous cycle had attenuated aggregate rhythms in clock gene expression in the PFC compared with noncycling females. This suggests that gonadal hormones may modulate the expression of the molecular clock.

Ovarian acyclicity in zoo African elephants (Loxodonta africana) is associated with high body condition scores and elevated serum insulin and leptin.

The purpose of the present study was to determine whether excessive body fat and altered metabolic hormone concentrations in the circulation were associated with ovarian acyclicity in the world's largest land mammal, the African elephant. We compared body condition, glucose, insulin and leptin concentrations and the glucose-to-insulin ratio (G:I) between cycling (n=23; normal 14-16 week cycles based on serum progestagens for at least 2 years) and non-cycling (n=23; consistent baseline progestagen concentrations for at least 2 years) females. A validated body condition score (BCS) index (five-point scale; 1=thinnest, 5=fattest) was used to assess the degree of fatness of the study elephants. The mean BCS of non-cycling elephants was higher than that of their cycling counterparts. There were differences in concentrations of serum metabolic biomarkers, with non-cycling elephants in the BCS 5 category having higher leptin and insulin concentrations and a lower G:I ratio than cycling BCS 5 females. Using 'non-cycling' as the outcome variable in regression models, high BCS was a strong predictor of a non-cycling status. This study provides the first evidence that ovarian acyclicity in zoo African elephants is associated with body condition indicative of obesity, as well as elevated, perturbed biomarkers of metabolic status.

Cognitive and motor aging in female chimpanzees

We present the first longitudinal data on cognitive and motor aging in the chimpanzee (Pan troglodytes). Thirty-eight adult female chimpanzees (10–54 years old) were studied. The apes were tested longitudinally for 3 years in a modified Primate Cognition Test Battery, which comprised 12 tests of physical and social cognition. The chimpanzees were also administered a fine motor task requiring them to remove a steel nut from rods of various complexity. There was little evidence for an age-related decline in tasks of Physical Cognition: for most tasks, performance was either stable or improved with repeated testing across age groups. An exception was Spatial Memory, for which 4 individuals more than 50 years old experienced a significant performance decline across the 3 years of testing. Poorer performance with age was found in 2 tasks of Social Cognition, an attention-getting task and a gaze-following task. A slight motor impairment was also observed, with old chimpanzees improving less than younger animals with repeated testing on the simplest rod. Hormonal status effects were restricted to spatial memory, with non-cycling females outperforming cycling females independently of age. Unexpectedly, older chimpanzees were better than younger individuals in understanding causality relationships based on sound.

Hyperprolactinemia is not associated with hyperestrogenism in noncycling African elephants (Loxodonta africana)

African elephants in US zoos are not reproducing at replacement levels. This is in part due to physiological problems, one of which is abnormal ovarian cyclicity that has been linked to increased prolactin secretion (hyperprolactinemia). A relationship between increased estrogen production (hyperestrogenism) and hyperprolactinemia has been found in other species. Therefore, the objective of this study was to determine if elevated prolactin was associated with increased estrogen concentrations in non-cycling African elephants. In cycling elephants (n=12), prolactin secretion followed a normal cyclic pattern, with higher concentrations observed during the follicular phase; overall mean concentration was ∼18ng/ml and baseline prolactin was ∼6ng/ml. Non-cycling females (n=18) were categorized into three groups: (1) low prolactin (<15ng/ml; n=3); (2) moderate hyperprolactinemia (16–30ng/ml; n=7); and marked hyperprolactinemia (>31ng/ml; n=8). Mean urinary estrogen conjugate concentrations ranged from 5.4 to 41.4ng/mg Crt, and were similar between normal cycling (15.4±1.5ng/mg Crt) and non-cycling, low prolactin elephants (18.4±7.3ng/mg Crt), but were lower in moderate (9.4±1.3ng/mg Crt) and marked hyperprolactinemic (9.8±1.1ng/mg Crt) groups (P<0.05). In conclusion, African elephants appear to be sensitive to alterations in prolactin production, with both low (e.g., a non-cycling pattern) and high prolactin secretion being associated with abnormal ovarian activity. However, hyperestrogenism was not related to hyperprolactinemia in the non-cycling females.

Results of the third reproductive assessment survey of north American Asian (Elephas maximus) and African (Loxodonta africana) female elephants

A written survey assessed reproductive status of female Asian and African elephants in AZA/SSP facilities in 2008, and data were compared to surveys conducted in 2002 and 2005. Results showed that ovarian acyclicity rates across the surveys remained unchanged for Asian (13.3, 10.9 and 11.1%) and African (22.1, 31.2 and 30.5%) elephants, respectively (P > 0.05), but were higher overall for African compared to Asian elephants (P < 0.05). In 2008, the percentages of Asian and African elephants with irregular cycles (14.3 and 15.8%) and irregular + no cycles (25.4 and 46.4%) was similar to 2005 (7.6 and 11.8%; 18.5 and 43.0%), but were increased compared to 2002 (2.6 and 5.2%; 16.0 and 27.3%), respectively (P < 0.05). For both species, ovarian acyclicity increased with age (P < 0.05). Reproductive tract pathologies did not account for the majority of acyclicity, although rates were higher in noncycling females (P < 0.05). Bull presence was associated with increased cyclicity rates (P < 0.05) for Asian (92.5 vs. 58.3%) and African (64.9 vs. 57.8%) elephants compared to females at facilities with no male, respectively. Cyclicity rates were higher for Asian (86.8 vs. 65.2%) and African (67.9 vs. 56.7%) elephants managed in free compared to protected contact programs (P < 0.05), respectively. Geographical facility location had no effect on cyclicity (P > 0.05). In summary, incidence of ovarian cycle problems continues to predominantly affect African elephants. Although percentages of acyclicity did not increase between 2005 and 2008, 42.2% Asian and 30.2% African females were no longer being hormonally monitored; thus, reproductive cycle abnormalities could be worse than current data suggest.

Can male white-faced saki monkeys (Pithecia pithecia) detect female reproductive state?

Abstract For mammalian males, copulating with females during ovulation is critical to reproductive success. However male knowledge of ovulation may not always be advantageous for females, as it could hinder mate choice or promote harassment. White-faced saki monkeys live in variably monogamous and polygamous social groups and hence females may have multiple motivations to conceal ovulatory timing. White-faced sakis further show no obvious physical or behavioral signs of ovulation, although they do use scent in a variety of contexts, including sexual behavior. We collected data on three wild groups of white-faced sakis at Brownsberg Naturepark, Suriname in order to assess whether male copulations are coordinated with female ovulatory timing. We recorded all occurrences of copulations and genital inspections, and collected fecal samples from females which were radioimmunoassayed to obtain estradiol and progesterone levels. We found that males copulated throughout the female reproductive cycle, although the association between copulation and reproductive state varied between dyads. Only one male–female dyad showed significantly more copulations than expected during ovulation. However four of five dyads copulated less than expected with pregnant females, suggesting that males may be able to differentiate cycling from non-cycling females. While genital inspections were distributed randomly with regard to female reproductive state, the decision to copulate was not: males were more likely to mate with both ovulating and cycling females than with non-cycling females after genital inspection. Regardless, males were not more likely to copulate with an ovulating vs. a cycling (non-ovulating) female. These data indicate that while males may receive olfactory information on female hormonal status, they do not make entirely accurate decisions with regard to copulation timing. This inaccuracy may be due to males' inability to detect ovulation, or alternately a lack of motivation to limit copulations solely to conceptive periods. Pair familiarity and sexual experience may also play a role in copulation accuracy.

The effect of pregnant and oestrous females on male testosterone and behaviour in the tammar wallaby

Tammar wallaby females ( Macropus eugenii) are seasonally breeding marsupials with a post-partum oestrus after a highly synchronised birth period when testosterone concentrations rise in males. Chemical communication appears to be important for mating, as males show checking behaviour, sniffing the urogenital opening (UGO) and the pouch of females. This study investigates whether the presence of pregnant and oestrous females directly influences testosterone in males and if oestrous odours or secretion from the pouch or UGO are attractive. Concentrations of plasma testosterone were measured in males housed with pregnant and oestrous females during two consecutive cycles in the breeding season, and an artificially induced cycle in the non-breeding season. Males were also tested for their interest in swabs taken from the urogenital opening (UGO) or pouch of oestrous females. Testosterone increased sharply in males in the presence of pregnant and oestrous females during all cycles in both seasons, but there was no change when males were exposed to non-cycling females in lactational or seasonal diapause. Males had no preference for either oestrous or non-oestrous samples taken from the pouch or from the UGO from oestrous females. This study confirms that the increase in plasma testosterone in tammar males can be induced through the presence of pregnant and oestrous females, regardless of season and that the increase began when the females were in late-pregnancy. This confirms that the male's reproductive state is dependent on a signal from females and is not blocked through seasonal effects.

Investigating the impact of rank and ovarian activity on the social behavior of captive female African elephants

Over a third of captive female African elephants in North America fail to exhibit normal estrous cycles based on long-term serum progestagen analyses. Why acyclicity occurs is unknown; however, the majority of noncycling females are ranked by keepers as the dominant individual within the group. To investigate the relationship between ovarian cyclicity status and keeper-determined social rank, observations were conducted on 33 female African elephants (18 cycling, 15 noncycling). Based on keeper evaluations, five cycling elephants were ranked dominant, seven in the middle and six as subordinate. In contrast, 10 noncycling elephants were ranked as dominate and five as subordinate with none ranked as middle. When comparing the behavior of the elephants by their keeper-determined rank, the dominant females dominant were significantly more likely to approach, displace and push. Similarly, keeper-determined subordinate females more frequently presented their hind end and held their ears erect. Behaviors initiated by one elephant toward another did not vary between cycling and noncycling females, except when the interaction with social rank was tested. Dominant, noncycling females initiated a higher percentage of "approach" and "displace" behaviors than both cycling and noncycling, subordinate elephants. Subordinate, noncycling elephants displayed the highest percentage of "ears erect." Social rank drives the interactions of ex situ female African elephants more than ovarian cyclicity status. Thus, behavioral interactions cannot be used to predict which cycling elephants are most likely to become acyclic.

Prolactin Secretion and Ovarian Function in Cycling and Non-Cycling African Female Elephants (Loxodonta africana)

Reproduction of captive elephants in zoos has shown a low fecundity and requires improvement. One of the reasons for low fecundity is ovarian dysfunction in many female elephants. To investigate whether prolactin has a correlation with ovarian function in female elephants, the serum concentrations of prolactin, progesterone and estradiol-17beta in four African female elephants (one cycling female and three non-cycling female elephants) were measured. Cyclic patterns of prolactin and estradiol-17beta were observed in the cycling female elephant, which tended to be high during the follicular phase and low during the luteal phase. On the other hand, a cyclic pattern of prolactin was not observed in the non-cycling female elephants. One of the three non-cycling females (Mako) had developed breasts and showed significantly higher average levels of prolactin than the other female elephants. These results suggested that high concentrations of circulating estradiol-17beta during the follicular phase stimulated prolactin secretion. They also suggested that hyperprolactinemia in Mako was one of the causes of the developed mammary glands and ovarian dysfunction.

35 FERTILITY AFTER FIXED-TIME AI OR INSEMINATION AT DETECTED ESTRUS FOLLOWING CIDR SYNCHRONIZATION PROTOCOLS IN FRENCH DAIRY AND BEEF CATTLE

The CIDR synchronization protocol was introduced in France since 2008, as a 7-day intravaginal progesterone treatment (1.38 g of progesterone) coupled with AI at detected estrus. The objective of this study was to compare the synchronization, ovulation, and conception rates following fixed-timed AI (FTAI) and AI on observed heat (HAI) following a CIDR synchronization program in dairy and beef cattle under on-farm conditions. A total of 466 females from Holstein, Limousin, and Charolais breeds were synchronized from October 2008 to March 2009, and inseminated by AI technicians from 4 French cooperatives (Amélis, CECNA, COOPELSO, Groupe Altitude) with the following inclusion criteria : heifers from 14 to 28 months old, cows with 1 to 5 calvings, interval from calving from 50 to 150 days, first breeding following calving without any complication. The CIDR device was left for a 7-day period and combined with a PGF2α injection 1 day before CIDR removal and an eCG injection at the time of CIDR removal. Cows within each herd were allocated to 2 insemination groups. In the FTAI group, a single insemination was performed 56 h after CIDR removal, whereas the females from the HAI group were inseminated once from 6 to 18 h after detected estrus. For each female, cyclicity was assessed before CIDR insertion with 2 progesterone measurements assayed 10 days apart. The CIDR device was lost in 25 females during treatment. In the remaining females, estrus synchronization was estimated from a progesterone measurement 56 h after CIDR removal. Ovulation rate following CIDR programs was determined by progesterone measurements 14 days after AI. Pregnancy was diagnosed by ultrasonography on Day 35 after AI in 417 females (24 missing values). From results of cycling females prior to treatment (n = 369), synchronization rates averaged 95.6% and 94.3% in HAI and FTAI groups, respectively. Ovulation rate, calculated from 399 synchronized or noncycling females, averaged 93.4% and 91.6% in HAI and FTAI groups, respectively. Conception rate at first AI averaged 51.9% (HAI: 52.6% v. FTAI: 47.4%; P &gt; 0.05), and conception rate following induced estrus (i.e. calculated from ovulated females only) averaged 55% (HAI: 55.3% v. FTAI: 52.2%; P &gt; 0.05). Conception rate was mainly influenced by breed and parity, ranging from 34% in Holstein cows to 58.7% in Holstein heifers (Table 1). To conclude, fixed-time insemination can be coupled to CIDR synchronization protocols in beef and dairy cattle and can be used to as a substitute for heat detection under on-farm conditions. Table 1.Conception rates depending on breed and parity

Control of the estrous cycle to improve fertility for fixed-time artificial insemination in beef cattle: A review1

Early estrus-synchronization protocols focused on regressing the corpus luteum (CL) with an injection of PGF(2alpha) followed by detection of estrus or involved the use of exogenous progestins that prevent estrus from occurring. Later, protocols combining the use of PGF(2alpha) and exogenous progestins were developed. Gonadotropin-releasing hormone was utilized to control follicular waves, synchronize ovulation, or to luteinize large dominant follicles. Our research aimed to develop reliable protocols that 1) relied solely on fixed-timed AI (TAI); 2) required a maximum of 3 animal handlings, and 3) were successful in estrous-cycling and noncycling females. In cows, insertion of an intravaginal progesterone insert during the 7-d interval between the initial GnRH and PGF(2alpha) injections enhanced pregnancy rates by 9 to 10%. In a multi-location study, a TAI protocol yielded pregnancy rates similar to a protocol involving detection of estrus plus a fixed-time clean-up AI for females not detected in estrus (54 vs. 58%, respectively, for cows and 53 vs. 57%, respectively, for heifers). Initiation of estrous cycles in noncycling cows is likely the primary manner in which beef producers may improve fertility in response to estrus synchronization and TAI protocols. Treatment of noncycling females with progesterone and GnRH increases the percentage of cycling females and improves fertility to a TAI, but inducing cyclicity with hCG failed to enhance fertility in TAI protocols. Supplementing progesterone after TAI failed to increase pregnancy rates in beef cattle. In contrast, administration of hCG 7 d after TAI induced an accessory CL, increased progesterone, and tended to enhance pregnancy rates. Development of TAI protocols that reduce the hassle factors associated with ovulation synchronization and AI provide cattle producers efficient and effective tools for capturing selective genetic traits of economic consequences. Location variables, however, which may include differences in pasture and diet, breed composition, body condition, postpartum interval, climate, and geographic location, affect the success of TAI protocols.

Social and hormonal mechanisms underlying male reproductive strategies in black howler monkeys (Alouatta pigra)

We investigated the social and hormonal mechanisms underlying male reproductive strategies in two multimale–multifemale groups of black howler monkeys (Alouatta pigra) during a 14-month study in Palenque National Park, Mexico. Fecal glucocorticoid (fGC) and androgen (fA) levels were analyzed for 343 fecal samples collected from 14 males during their presence in the study groups. Neither immigrating males nor resident males that remained in the group had elevated fGC and fA levels during 11 observed male migration events, suggesting that competition over group membership was not associated with variation in the fecal hormonal levels of males. Instead, fGC and fA levels were significantly higher in males who maintained a central position in the group and had almost exclusive access to fertile females than in other resident males. These “central” males were responsible for maintaining close spatial associations and cultivating strong affiliative relationships with cycling, sexually active females but not with noncycling, sexually inactive females. “Noncentral” males did not form strong social relationships with either cycling or noncycling females and had no or very few mating opportunities. Our findings suggest that male black howler monkeys compete nonaggressively by fostering relationships with cycling females and that the elevated fGC levels of central males may be indicative of the social challenges involved in their indirect competition.

What role do olfactory cues play in chacma baboon mating?

The probability of ovulation in a number of primate species is associated with both visual and auditory cues. We use 18-month behavioral data from two chacma baboon troops to provide the first systematic assessment of the possibility that olfactory cues are also involved. Using variance in the rate of olfactory inspection by males as a proxy for changes in the intensity of female vaginal odor, we found that rates of inspection were broadly correlated with changes in female fertility. Males inspected cycling females significantly more than anovulatory, noncycling females and swelling females significantly more than nonswollen cycling females. Rates of inspection peaked around the time at which males first started guarding females and were sustained until the detumescence of the female's sexual skin. We conclude, therefore, that olfactory cues represent one component of a multimodal signal of ovulation in chacma baboons. The possible reasons for such a multimodal signal are discussed.

Diet and reproductive function in wild female chimpanzees (Pan troglodytes schweinfurthii) at Kibale National Park, Uganda

Human female reproductive function is highly sensitive to current energetic condition, indicating adaptation to modulate reproductive effort in accordance with changing ecological conditions that might favor or disfavor the production of offspring. Here, we test the hypothesis that reproductive capacity in female chimpanzees is likewise limited by current energetic condition. We used 12 years of data on wild chimpanzees (Pan troglodytes schweinfurthii) in the Kanyawara community of Kibale National Park, Uganda, to examine the relationship of dietary quality, as assessed by fruit components of the diet, to the occurrence of sexually receptive females, concentrations of ovarian steroid hormones, and timing of conception. We found that the frequency of females having sexual swellings was positively related to the consumption of drupe fruits. Estrogen levels of both cycling and noncycling females increased during seasonal peaks in the consumption of drupe fruits. When average fruit consumption remained high across months, females conceived more quickly. These results support the hypothesis that cycling and conception in chimpanzees are contingent upon high energy balance, and they indicate that the availability of fruit is a key variable limiting reproductive performance in chimpanzees. Chimpanzees appear to share with humans a reproductive system that is primed to respond to proximate levels of energy acquisition.

Habituation of Wild Chimpanzees (Pan troglodytes) of the South Group at Taï Forest, Côte d’Ivoire: Empirical Measure of Progress

The last part of the chimpanzee (Pan troglodytes) habituation process of the Taï South Group was monitored over 2 years (1994–1996), during which all males and most of the females became habituated to observation by humans. The time needed (5–7 years) to habituate the community was similar to that recorded for the Taï North Group and is comparable to other populations studied in Africa. Variation emerged in habituation rate: males were habituated earlier than females, and among females, sexually cycling individuals were habituated faster than non-cycling females. Such differences may be a function of both the methods used to find the chimpanzees and the sex of the individual. Reproductive status and individuality may also have influenced habituation rates by affecting the number of contacts required to habituate a chimpanzee to neutral humans.

Novel role of the anorexigenic peptide neuromedin U in the control of LH secretion and its regulation by gonadal hormones and photoperiod

Neuromedin U (NMU) is a widely spread neuropeptide, with predominant expression at the gastrointestinal tract and brain, putatively involved in the regulation of a diversity of biological functions, including food intake, energy balance and circadian rhythms; all closely related to reproduction. Yet, the implication of NMU in the control of the gonadotropic axis remains scarcely studied. We report herein analyses on the hypothalamic expression and function of NMU in different physiological and experimental states of the rat reproductive system. Expression of NMU mRNA at the hypothalamus was persistently detected along female postnatal development, with maximum levels in adulthood that fluctuated across the cycle and were modulated by ovarian steroids. Acute central administration of NMU evoked increases of serum LH levels in pubertal female rats, while repeated injection of NMU tended to advance vaginal opening. Likewise, central injection of NMU increased serum LH concentrations in cycling female rats, with peak responses in estrus. In contrast, NMU significantly inhibited preelevated LH secretion in gonadectomized and kisspeptin-treated rats. Finally, in noncycling females due to photoperiodic manipulation (constant light), hypothalamic NMU mRNA levels were markedly depressed, but relative LH responses to exogenous NMU were significantly augmented. All together, our present data support a predominant stimulatory role of NMU in the control of the female gonadotropic axis, which appears under the influence of developmental, hormonal, and photoperiodic cues, and might contribute to the joint regulation of energy balance, biological rhythms, and reproduction.