How evolutionary biology can explain why human and a few marine mammal females are the only ones that are menopausal

Dalton, Dave

doi:10.1016/j.jtbi.2022.111123

Cited by 3 publications

(2 citation statements)

References 41 publications

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“…The ‘social brain’ hypothesis posits that the effect of the social environment on brain size is stronger than that of the physical environment and explains the very large degree of encephalisation seen in primates, cetaceans and hominids in particular (Dunbar & Shultz, 2007; Fox et al., 2017). Indeed, it has been suggested that a high Encephalization Quotient (EQ), the ratio between observed and expected brain mass (with values above 1 suggesting that the species has a larger brain than expected for its body size; Jerison, 1975), could be a prerequisite for determining whether individuals possess a PRLS (Dalton, 2022). The very high energetic costs associated with large brains may be very important in the development of a PRLS and we develop this idea further in Section A speculative synthesis.…”

Section: Adaptive Hypothesesmentioning

confidence: 99%

No time to die: Evolution of a post‐reproductive life stage

Monaghan

Ivimey‐Cook

2023

Journal of Zoology

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In some species, permanent curtailment of reproduction part‐way through the lifespan of adult females is a feature of their evolved life history. The existence of such a post‐reproductive life stage is apparently rare; reasonably robust evidence for this is confined to only six species (humans, Asian elephants and four whales). That it occurs at all appears to contradict our view of natural selection operating to maximize fitness and special circumstances must exist to explain its occurrence. We evaluate the main hypotheses posited to explain the evolution of this life stage, why it occurs in a restricted group of animals, and why only in females. We bring together literature from multiple biological disciplines and levels of enquiry, ranging through evolutionary ecology, developmental biology, physiology, neuroscience, molecular biology, and human medicine. We conclude that while time‐limited fertility is not in itself adaptive, the duration of subsequent survival is likely to be linked to inclusive fitness benefits. We present a new hypothesis which posits that the duration of female fertility in certain long‐lived, highly encephalised species, with no post‐natal oogenesis, is limited by the need for intense screening of oocyte mitochondria. This is required to support endothermy coupled with the very high energy requirement for the development and maintenance of the exceptionally large brain size required for complex social living. This limits the number and shelf‐life of oocytes, creating an antagonistically pleotropic effect that is beneficial to the production of high performing offspring but carries the later life cost of time‐limited female fertility. But the end of the fertile period is no time to die. Inclusive fitness benefits arising from protracted parental care of offspring, overlapping generations, and kin group structures means that continued survival of post‐reproductive females is favoured by selection. We suggest further lines of research to test these ideas.

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Section: Adaptive Hypothesesmentioning

confidence: 99%

No time to die: Evolution of a post‐reproductive life stage

Monaghan

Ivimey‐Cook

2023

Journal of Zoology

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“…Менопауза -це біологічний процес, визначається як постійне припинення менструальних циклів. Фізіологічно вона пов'язана зі зменшенням кількості фолікулів, припиненням вироблення яєчниками естрогенів і прогестерону, а також відсутністю здатності яєчників реагувати на гормони гіпофіза [8,36]. Менопауза пов'язана не лише з дефіцитом статевих стероїдів, а й зі зниженням секреції мелатоніну.…”

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The features of optimal nonhormonal therapy of vegetative disorders among women with postmenopause

Konkov

Таран

Rud

et al. 2022

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Objectives: to evaluate the clinical effectiveness of the Vitae-Melatonin in the complex treatment of vegetative disorders in postmenopausal women.Materials and methods. The 64 postmenopausal women who complained of vegetative disorders were included in our prospective study. Patients were divided into clinical groups. The first group consisted of 31 women who were prescribed a herbal preparation of Cimicifuga racemosa extract – 30 mg/day for 3 months. The second group included 33 patients who received in addition to the herbal medicine Vitae-Melatonin 3 mg/day every evening 2 hours before bedtime for 1 month. The clinical effectiveness of the therapy was assessed 1, 2 and 3 months after the start of treatment based on the dynamics of psychological disorders, somatic symptoms, vasomotor and sexual disorders, sleep problems and satisfaction with the therapy.Results. The use of herbal medicine containing Cimicifuga rhizome extract alone or in combination with Vitae-Melatonin in postmenopausal women significantly reduced the manifestations of vegetative disorders, including psychological and dyssomnia in a month from the start of therapy. After 3 months from the start of therapy, the advantage of combined therapy involving Vitae-Melatonin compared to the monotherapy of Cimicifuga rhizome was marked by a significant reduction of psychological disorders, somatic symptoms, vasomotor disorders and sleep problems (р = 0.003, р = 0.01, р = 0.02 and p = 0.015, respectively). Patient satisfaction with the combined therapy of vegetative disorders during the menopause compared to monophytotherapy was probably higher (risk ratio 1.63, 95% confidence interval 1.09–2.44, p = 0.018). There was no significant difference between the two research groups regarding side effects during and after the use of the drugs (p > 0.05).Conclusions. The use of Vitae-Melatonin at a dose of 3 mg/day in addition to phytotherapy in postmenopausal women had a clear clinical effect, which was a significant reduction of vegetative disorders, both compared to the initial indicators and in comparison with monophytotherapy. Results of the study showed the safety of melatonin, as well as the willingness of participants to continue using melatonin after 3 months of the treatment.

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Sexual Behaviors of Odontocetes in Managed Care

Manitzas Hill,

Dudzinski,

Lilley

et al. 2023

Sex in Cetaceans

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A number of odontocete species have been cared for by humans for multiple decades, including but not limited to pilot whales, killer whales, Commerson’s dolphins, bottlenose dolphins (Indo-Pacific and common), and beluga whales (or white whales). Because many of these were breeding, numerous reproductive behaviors have been observed, documented, and investigated in detail. Similarly, sociosexual behaviors exchanged between nonreproductive partners have been examined. This chapter summarizes what has been learned regarding the role of hormones in sexual behavior, seasonality of sexual behavior, reproductive courtship behavior and displays, copulation, non-conceptive sexual behavior, development, social bonds, same-sex interactions, and interspecies interactions. We provide insight to the behavioral systems involved with both reproduction and social bonding for odontocetes. This chapter concludes with areas of future research that have been informed and should continue to be informed by knowledge of odontocete sexual behavior gained from managed care facilities.

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How evolutionary biology can explain why human and a few marine mammal females are the only ones that are menopausal

Cited by 3 publications

References 41 publications

No time to die: Evolution of a post‐reproductive life stage

No time to die: Evolution of a post‐reproductive life stage

The features of optimal nonhormonal therapy of vegetative disorders among women with postmenopause

Sexual Behaviors of Odontocetes in Managed Care

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