Body Temperature and Physical Activity Correlates of the Menstrual Cycle in Chacma Baboons (Papio hamadryas ursinus)

Increase of body temperature immediately after ovulation in mares

To successfully inseminate mares, precise detection of ovulation time is crucial, especially when using frozen-thawed semen. Monitoring body temperature, as has been described in women, could be a non-invasive way to detect ovulation. The objective of this study was to investigate the relationship between the time of ovulation and the variation of body temperature in mares based on automatic continuous measurements during estrus. The experimental group included 21 mares for 70 analyzed estrous cycles. When the mares showed estrous behavior, they were administered intramuscular deslorelin acetate (2.25 mg) in the evening. At the same time, monitoring of body temperature using a sensor device fixed at the left lateral thorax was started and continued for over 60 h. In 2-hour intervals, transrectal ultrasonography was performed to detect ovulation. Estimated body temperature in the 6 h following ovulation detection was on average 0.06°C +/- 0.05°C (mean +/- SD) significantly higher when compared with body temperature at the same time on the preceding day (p=0.01). In addition, a significant effect of PGF_2α administration for estrus induction on the body temperature was found, being significantly higher until 6 h before ovulation compared to that of uninduced cycles (p=0.005). In conclusion, changes in body temperature during estrus in mares were related to ovulation. The increase in body temperature immediately after ovulation might be used in the future to establish automatized and non-invasive systems to detect ovulation. However, the identified temperature rise is relatively small on average and hardly identifiable in the individual mares.

Egg-laying increases body temperature to an annual maximum in a wild bird

Most birds, unlike reptiles, lay eggs successively to form a full clutch. During egg-laying, birds are highly secretive and prone to disturbance and predation. Using multisensor data loggers, we show that average daily body temperature during egg-laying is significantly increased (1 °C) in wild eider ducks (Somateria mollissima). Strikingly, this increase corresponds to the annual maximum body temperature (40.7 °C), representing a severe annual thermogenic challenge. This egg-laying-induced rise in body temperature may prove to be a common feature of wild birds and could be caused by habitat-related thermoregulatory adjustments and hormonal modulation of reproduction. We conclude our findings with new perspectives of the benefits of high body temperature associated with egg-laying of birds and the potential effect of heat stress that may occur with the future advent of heatwaves.

Temperature regulation in women: Effects of the menstrual cycle

Core body temperature changes across the ovulatory menstrual cycle, such that it is 0.3°C to 0.7°C higher in the post-ovulatory luteal phase when progesterone is high compared with the pre-ovulatory follicular phase. This temperature difference, which is most evident during sleep or immediately upon waking before any activity, is used by women as a retrospective indicator of an ovulatory cycle. Here, we review both historical and current literature aimed at characterizing changes in core body temperature across the menstrual cycle, considering the assessment of the circadian rhythm of core body temperature and thermoregulatory responses to challenges, including heat and cold exposure, exercise, and fever. We discuss potential mechanisms for the thermogenic effect of progesterone and the temperature-lowering effect of estrogen, and discuss effects on body temperature of exogenous formulations of these hormones as contained in oral contraceptives. We review new wearable temperature sensors aimed at tracking daily temperature changes of women across multiple menstrual cycles and highlight the need for future research on the validity and reliability of these devices. Despite the change in core body temperature across the menstrual cycle being so well identified, there remain gaps in our current understanding, particularly about the underlying mechanisms and microcircuitry involved in the temperature changes.

Explaining sex differences in lifespan in terms of optimal energy allocation in the baboon

We provide a quantitative test of the hypothesis that sex role specialization may account for sex differences in lifespan in baboons if such specialization causes the dependency of fitness upon longevity, and consequently the optimal resolution to an energetic trade-off between somatic maintenance and other physiological functions, to differ between males and females. We present a model in which females provide all offspring care and males compete for access to reproductive females and in which the partitioning of available energy between the competing fitness-enhancing functions of growth, maintenance, and reproduction is modeled as a dynamic behavioral game, with the optimal decision for each individual depending upon his/her state and the behavior of other members of the population. Our model replicates the sexual dimorphism in body size and sex differences in longevity and reproductive scheduling seen in natural populations of baboons. We show that this outcome is generally robust to perturbations in model parameters, an important finding given that the same behavior is seen across multiple populations and species in the wild. This supports the idea that sex differences in longevity result from differences in the value of somatic maintenance relative to other fitness-enhancing functions in keeping with the disposable soma theory.

Estimating activity of Japanese macaques (Macaca fuscata) using accelerometers

Accelerometers have been used to study both terrestrial and aquatic wildlife, mainly for mammal and bird species. In terrestrial mammals, there is a bias toward ungulates and carnivores, with fewer studies on nonhuman primates. In this study, we tested the use of accelerometers for studying the activity of Japanese macaques (Macaca fuscata). We modeled the activity of a male and a female subject by matching continuous focal observations from video recordings to sensor parameters derived from collar-mounted accelerometers. Models achieved classification performance (AUC) of greater than 90% for both subjects, with similar results when subjects were cross-validated. Accelerometer-based estimates of activity had comparable accuracies to estimates from instantaneous sampling at 1 min and 5 min intervals. We further demonstrated the use of model estimates for analyzing circadian rhythm and night time activity of M. fuscata. Our results add support to the feasibility of using accelerometers for studying activity of nonhuman primates. We discussed the limitations, benefits and potential applications of remote-sensing technology like accelerometers for advancing primalotogical studies.

Comparison of abdominal skin temperature between fertile and infertile women by infrared thermography: A diagnostic approach

This retrospective study aimed to evaluate the differences in abdominal temperature (AT) between fertile (n=206; age) and infertile (n=250) women between the ages of 30 and 39 years. We evaluated the differences in two distinctive skin temperatures by thermography: ΔT₁ (CV8 index) - difference in temperature between the mid-abdomen (CV8 acupuncture area) and ventral upper arm (VUA) and ΔT₂ (CV4 index) - difference in temperature between the lower abdomen (CV4 acupuncture area) and VUA. The results indicated that the ΔT₁ and ΔT₂ of infertile women were significantly lower (by 1.05°C and 0.79°C, respectively; p<0.001, both) compared to those of fertile women. Additionally, the area under the curve of ΔT₁ (0.78) was greater compared to that of ΔT₂ (0.736), and its threshold was set at 0.675°C, by which, the sensitivity and specificity of ΔT₁ for determination of fertility were found to be 80.8% and 68.4%, respectively. In conclusion, infertility is associated with lower AT. The decrease in AT in infertile women might be due to poor blood perfusion to the core muscles and tissues of the body. These findings provide a basis for further research for evaluation of clinical feasibility of thermography for analysis of infertility in women. Further evaluation of the influence of AT on fertility outcomes is required to determine the causal relationship between AT and infertility.

Morningness-Eveningness and Physical Activity in Adolescent Girls: Menarche as a Transition Point

This study identified trajectories of morningness-eveningness (M-E) and physical activity when chronological (i.e., time since birth) versus gynecological (i.e., time since menarche) age is used to indicate maturation. Piecewise models were fit for girls (N = 262, ages 11-19) using chronological or gynecological age as the time metric. Girls stayed up later (i.e., eveningness) as they approach menarche. After menarche no change in M-E was observed. In contrast, no change in M-E was detected with chronological age. No change in physical activity was observed before menarche, and physical activity declined after menarche. With chronological age, physical activity declined as girls got older. Gynecological age may be more appropriate than chronological age as a metric for understanding changes in M-E and physical activity.

Influence of menstrual cycle on the expression of clock genes in peripheral blood mononuclear cells in Macaca fascicularis

OBJECTIVE

To investigate whether the expression patterns of periphery clock genes were influenced by menstrual cycle in a monkey model.

STUDY DESIGN

In this preliminary study, the expression patterns of four clock genes (Bmal1, Clock, Cry1 and Per2) in peripheral blood mononuclear cells (PBMCs) from 6 female Macaca fascicularis in menstrual, late follicular and mid luteal phases of menstrual cycle were determined by qrt-PCR.

RESULTS

Bmal1 and Per2 mRNA levels were found to exhibit significant diurnal rhythms in all phases of the menstrual cycle. The expression of Cry1 mRNA was statistically rhythmic in late follicular and mid luteal phases. A main effect of menstrual cycle existed on the rhythms of Bmal1, Cry1 and Per2 expression, but not Clock expression. No significant differences were detected between menstrual phase and late follicular phase in all clock genes. Significant differences were found on the expression of Bmal1, Cry1 or Per2 mRNA between late follicular phase and mid luteal phase, when no difference existed in estrogen level, indicating the role of progesterone on biological clock gene expression. Furthermore, the peak of Bmal1 mRNA level slightly advanced in mid luteal phase compared with that in menstrual and late follicular phases.

CONCLUSION

The expression patterns of clock genes in PBMCs were influenced by menstrual cycle, potentially by the change of progesterone levels, and this effect maybe correlated with early pregnancy.

Core body temperature is not a reliable parameter to follow the reproductive cycle in female marmoset monkey (<i>Callithrix jacchus</i>)

Abstract. Marmosets represent an attractive and widely used animal species in biomedical research, and the routine monitoring of female reproductive cycles is often mandatory in the fields of reproductive biology and stem cell research. Today, the established method for the reliable detection of ovulation is the determination of progesterone concentrations from blood samples. This method is based on relatively frequent handling and blood collections; therefore, less invasive alternatives would help to reduce stress on the animals. Here, we investigated whether the core body temperature of marmosets would show a correlation with cycle-dependent hormonal fluctuations, as has been described for humans and other primate species. In particular, the objective was to investigate whether the telemetric recording of core body temperature could replace progesterone measurements as a reliable, less invasive method for the detection of ovulation in these animals. Here we show that the core body temperature parameters in female marmosets were characterized by frequent variations, but they were not related to particular days or phases during the reproductive cycle. Therefore, the recording of core body temperature in our controlled standard experimental setting is not an appropriate method to monitor the reproductive cycle in female marmosets, and cannot replace serum progesterone measurement as a state-of-the-art method.

Body temperature and thermal environment in a generalized arboreal anthropoid, wild mantled howling monkeys (Alouatta palliata)

Free-ranging primates are confronted with the challenge of maintaining an optimal range of body temperatures within a thermally dynamic environment that changes daily, seasonally, and annually. While many laboratory studies have been conducted on primate thermoregulation, we know comparatively little about the thermal pressures primates face in their natural, evolutionarily relevant environment. Such knowledge is critical to understanding the evolution of thermal adaptations in primates and for comparative evaluation of humans' unique thermal adaptations. We examined temperature and thermal environment in free-ranging, mantled howling monkeys (Alouatta palliata) in a tropical dry forest in Guanacaste, Costa Rica. We recorded subcutaneous (Tsc ) and near-animal ambient temperatures (Ta ) from 11 animals over 1586.5 sample hours during wet and dry seasons. Howlers displayed considerable variation in Tsc , which was largely attributable to circadian effects. Despite significant seasonal changes in the ambient thermal environment, howlers showed relatively little evidence for seasonal changes in Tsc . Howlers experienced warm thermal conditions which led to body cooling relative to the environment, and plateaus in Tsc at increasingly warm Ta . They also frequently faced cool thermal conditions (Ta  < Tsc ) in which Tsc was markedly elevated compared with Ta . These data add to a growing body of evidence that non-human primates have more labile body temperatures than humans. Our data additionally support a hypothesis that, despite inhabiting a dry tropical environment, howling monkeys experience both warm and cool thermal pressures. This suggests that thermal challenges may be more prevalent for primates than previously thought, even for species living in nonextreme thermal environments.