Maternal investment in mountain gorillas (Gorilla Beringei Beringei)

Investigating maternal investment (Ml) and mother-offspring relationships during the period of infant dependency is critically important to furthering the understanding of female reproductive strategies in primates. Infant primates are completely dependent upon their mothers. The way in which a mother allocates her resources therefore is crucial for infant survival, but is balanced Against her need to invest in subsequent offspring. One approach to examining how mothers might invest in their offspring stems from the Trivers & Willard hypothesis (TWH, 1973), which predicts that mothers in good condition should bias their investment towards sons and whereas mothers in poorer condition should bias investment toward daughters. Long-term demographic records on birth sex ratio and inter-birth interval suggest that female mountain gorillas (Gorilla beringei beringei) do not bias investment prenatally, but they may adjust postnatal Ml according to the TWH. This study investigated Ml and mother-offspring relationships in wild mountain gorillas, using behavioural correlates of Ml, including suckling, weaned age, physical contact, "transport, and grooming to redress the lack of understanding about Ml in this species. The appropriateness of TWH was investigated, integrating different indicators of maternal condition. Important determinants of Ml and mother-offspring relationships were considered, such as offspring age, parity, presence of siblings and maternal relatives, group size and lastly, personality, which has been largely neglected in nonhuman primates. The extent, to which the offspring influenced Ml patterns, was examined using the parent-offspring conflict theory (Trivers, 1972) as a theoretical framework. During 2006-2007, 38 mother-offspring dyads were observed in the Virunga massif, resulting in 1210 hours of direct behavioural observation. Additional field data from the previous four decades were integrated into the dataset for the analysis of suckling and weaned age. Gorilla personality was assessed through the Hominoid Personality Questionnaire. Findings relating to suckling frequency, weaned age, and maternal feeding activities were consistent with the TWH: sons suckled more often than daughters when they had mothers in good condition, whereas the reverse sex-pattern occurred in offspring with mothers in poorer condition. In addition, daughters were weaned at an earlier age than sons when mothers were in better condition, although this sex-difference reduced in older mothers that were categorised as being in good condition. Maternal feeding time and feeding efficiency revealed that mothers in poorer condition spent more time ingesting food when they had daughters, whereas mothers in better .condition spent more time ingesting food when they had sons. Furthermore, group size affected lactation duration with offspring in small groups being weaned earlier than offspring in large groups. Behavioural conflicts over Ml showed that the mother and offspring influenced Ml patterns during the period of dependency. Finally, six personality dimensions were identified, of which five revealed effects maternal behaviour, such as maternal retrieval, responsiveness and rejection, although their relative importance varied between those behaviours. In general, mother and offspring personality effects were complex due to their interactions with the developmental stage of offspring. In conclusion, my thesis research has made several novel contributions to furthering the understanding of female reproductive strategies in the highly endangered mountain gorilla. I presented the first evidence using behavioural data that females bias their postnatal investment towards the sex with the greatest fitness return as predicted by the TWH. My findings are discussed in the light of alternative Ml strategies, such as the local resource competition and enhancement model. My research has highlighted the importance of integrating anthropometric and physiological measures and demographic long-term data into future Ml studies to assess direct costs and benefits of Ml. The examination of mother-offspring behavioural conflicts showed that offspring have a strong impact on the level of Ml they receive. I have also examined the personality of a wild mountain gorilla population for the first time. My findings demonstrate that personality-parenting links are evident in several respects and I have demonstrated the great potential of personality as a determinant of maternal behaviour and mother-offspring relationships.Gladstone fellowship from the University of Chester

Female age and reproductive stage influence copulation patterns in mountain gorillas’ variable mating system

Variation in mating systems and in individuals’ copulation patterns can have important consequences for the genetic structure of a population and ultimately its evolution. Whilst most gorilla sub-species form single-male, polygynous reproductive groups, mountain gorillas have both single-male and multimale reproductive groups. Considerable research has investigated the mating patterns of males in these multimale groups, but comparatively little is known about females. We investigated the copulation patterns of 71 female mountain gorillas over 13 years. We found that most sexually active, fecundable females in multimale groups had multiple mating partners. Females’ copulation patterns varied based on their reproductive stage, mating most often and with the greatest number of partners when they were pregnant, and least often when they had young dependent offspring. Females copulated throughout pregnancy, with pregnant females copulating more frequently in single-male groups than in multimale groups. Mating also varied with age, with older females mating less often and with fewer partners. Our findings confirm that when females transfer between single-male and multimale groups, they predominantly switch from copulating with one male to copulating with multiple males, and that females are also flexibly adjusting their copulation patterns across their lifetimes. This highlights the considerable variability of the mountain gorillas mating system, particularly from the female perspective, and the importance of accounting for within-species variation in copulation patterns. Significance statement Patterns of mating can vary both between individuals of the same species and within individuals across their lives. These patterns influence the genetic structure of a population. By examining copulation patterns in female mountain gorillas, we demonstrate that whilst females in single-male groups have only one mating partner, females in multi-male groups predominantly have multiple partners across a year. They also alter their copulation patterns across their lifetimes, copulating less often and with fewer partners as they age, and copulating most when pregnant. Our results highlight the flexibility with which female mountain gorillas can adjust their copulation patterns across their lifetimes, as the costs and benefits of copulation shift

Personality dimensions and their behavioral correlates in wild virunga mountain gorillas (Gorilla beringei beringei)

This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.Studies of animal personality improve our understanding of individual variation in measures of life-history and fitness, such as health and reproductive success. Using a 54 trait personality questionnaire developed for studying great apes and other nonhuman primates, we obtained ratings on 116 wild mountain gorillas (Gorilla beringei beringei) monitored by the Dian Fossey Gorilla Fund’s Karisoke Research Center in Rwanda. There were eight raters who each had more than 1.5 years of working experience with the subjects. Principal component analyses identified four personality dimensions with high inter-rater reliabilities --- Dominance, Openness, Sociability, and Proto-Agreeableness --- that reflected personality features unique to gorillas and personality features shared with other hominoids. We next examined the associations of these dimensions with independently collected behavioral measures derived from long-term records. Predicted correlations were found between the personality dimensions and corresponding behaviors. For example, Dominance, Openness, Sociability, and Proto-Agreeableness were related to gorilla dominance strength, time spent playing, rates of approaches and rates of interventions in intra-group conflicts, respectively. These findings enrich the comparative-evolutionary study of personality and provide insights into how species differences in personality are related to ecology, social systems, and life history

African queens find mates when males are rare

This is the final version. Available from Wiley via the DOI in this record. DATA AVAILABILITY STATEMENT: Sex ratio, spermatophore numbers and Rcode: Figshare doi:10.6084/ m9.figshare.21947729.In butterflies and moths, male-killing endosymbionts are transmitted from infected females via their eggs, and the male progeny then perish. This means that successful transmission of the parasite relies on the successful mating of the host. Paradoxically, at the population level, parasite transmission also reduces the number of adult males present in the final population for infected females to mate with. Here we investigate if successful female mating when males are rare is indeed a likely rate-limiting step in the transmission of male-killing Spiroplasma in the African Monarch, Danaus chrysippus. In Lepidoptera, successful pairings are hallmarked by the transfer of a sperm-containing spermatophore from the male to the female during copulation. Conveniently, this spermatophore remains detectable within the female upon dissection, and thus, spermatophore counts can be used to assess the frequency of successful mating in the field. We used such spermatophore counts to examine if altered sex ratios in the D. chrysippus do indeed affect female mating success. We examined two different field sites in East Africa where males were often rare. Surprisingly, mated females carried an average of 1.5 spermatophores each, regardless of male frequency, and importantly, only 10-20% remained unmated. This suggests that infected females will still be able to mate in the face of either Spiroplasma-mediated male killing and/or fluctuations in adult sex ratio over the wet-dry season cycle. These observations may begin to explain how the male-killing mollicute can still be successfully transmitted in a population where males are rare.National Geographic SocietyRoyal Societ

Weaned age variation in the Virunga mountain gorillas (Gorilla beringei beringei)

The final publication is available at Springer via http://dx.doi.org/10.1007/s00265-016-2066-6Weaning marks an important milestone during life history in mammals indicating nutritional independence from the mother. Age at weaning is a key measure of maternal investment and care, affecting female reproductive rates, offspring survival and ultimately the viability of a population. Factors explaining weaned age variation in the endangered mountain gorilla are not yet well understood. This study investigated the impact of group size, group type (one-male versus multi-male), offspring sex, as well as maternal age, rank, and parity on weaned age variation in the Virunga mountain gorilla population. The status of nutritional independence was established in 69 offspring using long-term suckling observations. A Cox-regression with mixed effects was applied to model weaned age and its relationship with covariates. Findings indicate that offspring in one-male groups are more likely to be weaned earlier than offspring in multi-male groups, which may reflect a female reproductive strategy to reduce higher risk of infanticide in one-male groups. Inferior milk production capacity and conflicting resource allocation between their own and offspring growth may explain later weaning in primiparous mothers compared to multiparous mothers. Sex-biased weaned age related to maternal condition defined by parity, rank, and maternal age will be discussed in the light of the Trivers-Willard hypothesis. Long-term demographic records revealed no disadvantage of early weaning for mother or offspring. Population growth and two peaks in weaned age within the Virunga population encourage future studies on the potential impact of bamboo shoots as a weaning food and other environmental factors on weaning

Early diagnosis and better rhythm management to improve outcomes in patients with atrial fibrillation: the 8th AFNET/EHRA consensus conference

Aims Despite marked progress in the management of atrial fibrillation (AF), detecting AF remains difficult and AF-related complications cause unacceptable morbidity and mortality even on optimal current therapy.Methods and results This document summarizes the key outcomes of the 8th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA). Eighty-three international experts met in Hamburg for 2 days in October 2021. Results of the interdisciplinary, hybrid discussions in breakout groups and the plenary based on recently published and unpublished observations are summarized in this consensus paper to support improved care for patients with AF by guiding prevention, individualized management, and research strategies. The main outcomes are (i) new evidence supports a simple, scalable, and pragmatic population-based AF screening pathway; (ii) rhythm management is evolving from therapy aimed at improving symptoms to an integrated domain in the prevention of AF-related outcomes, especially in patients with recently diagnosed AF; (iii) improved characterization of atrial cardiomyopathy may help to identify patients in need for therapy; (iv) standardized assessment of cognitive function in patients with AF could lead to improvement in patient outcomes; and (v) artificial intelligence (AI) can support all of the above aims, but requires advanced interdisciplinary knowledge and collaboration as well as a better medico-legal framework.Conclusions Implementation of new evidence-based approaches to AF screening and rhythm management can improve outcomes in patients with AF. Additional benefits are possible with further efforts to identify and target atrial cardiomyopathy and cognitive impairment, which can be facilitated by AI.</p

Cooperation and competition in two forest monkeys

Putty-nosed monkeys, Cercopithecus nictitans stampflii, occur at various sites in West Africa, particularly in the transition zone between rainforest and savannah. The species is sometimes seen in primary rainforest, although at a curiously low density compared with that of other monkey species. We conducted a 24-month field study in the tropical rainforest of Taï National Park, Ivory Coast, and found that putty-nosed monkeys require an ecological niche almost identical to that of the Diana monkeys, Cercopithecus diana diana. Moreover, the niche breadth of putty-nosed monkeys was significantly decreased in the presence of Diana monkeys, suggesting that feeding competition with Diana monkeys kept putty-nosed monkeys from successfully colonizing a rainforest habitat. However, contrary to the interspecies competition hypothesis, groups of both species almost completely overlapped in home ranges and formed near-permanent mixed-species associations, rather than avoiding each other. We hypothesized that Diana monkeys tolerated immigrating putty-nosed monkeys and formed mixed-species groups with them, despite high levels of competition, because of their merit in predation defense. Direct observations and a series of field experiments confirmed that male putty-nosed monkeys play a vital role in defense against crowned eagles, suggesting that putty-nosed monkeys obtain access to feeding trees by offering antipredation benefits to Diana monkeys. We discuss these findings in light of biological market theory. Copyright 2004.alarm calls; biological markets; feeding ecology; mutualism; niche overlap; predation; semantic

Maternal investment in mountain gorillas (Gorilla beringei beringei)

Investigating maternal investment (Ml) and mother-offspring relationships during the period of infant dependency is critically important to furthering the understanding of female reproductive strategies in primates. Infant primates are completely dependent upon their mothers. The way in which a mother allocates her resources therefore is crucial for infant survival, but is balanced Against her need to invest in subsequent offspring. One approach to examining how mothers might invest in their offspring stems from the Trivers &amp; Willard hypothesis (TWH, 1973), which predicts that mothers in good condition should bias their investment towards sons and whereas mothers in poorer condition should bias investment toward daughters. Long-term demographic records on birth sex ratio and inter-birth interval suggest that female mountain gorillas (Gorilla beringei beringei) do not bias investment prenatally, but they may adjust postnatal Ml according to the TWH. This study investigated Ml and mother-offspring relationships in wild mountain gorillas, using behavioural correlates of Ml, including suckling, weaned age, physical contact, &quot;transport, and grooming to redress the lack of understanding about Ml in this species. The appropriateness of TWH was investigated, integrating different indicators of maternal condition. Important determinants of Ml and mother-offspring relationships were considered, such as offspring age, parity, presence of siblings and maternal relatives, group size and lastly, personality, which has been largely neglected in nonhuman primates. The extent, to which the offspring influenced Ml patterns, was examined using the parent-offspring conflict theory (Trivers, 1972) as a theoretical framework. During 2006-2007, 38 mother-offspring dyads were observed in the Virunga massif, resulting in 1210 hours of direct behavioural observation. Additional field data from the previous four decades were integrated into the dataset for the analysis of suckling and weaned age. Gorilla personality was assessed through the Hominoid Personality Questionnaire. Findings relating to suckling frequency, weaned age, and maternal feeding activities were consistent with the TWH: sons suckled more often than daughters when they had mothers in good condition, whereas the reverse sex-pattern occurred in offspring with mothers in poorer condition. In addition, daughters were weaned at an earlier age than sons when mothers were in better condition, although this sex-difference reduced in older mothers that were categorised as being in good condition. Maternal feeding time and feeding efficiency revealed that mothers in poorer condition spent more time ingesting food when they had daughters, whereas mothers in better .condition spent more time ingesting food when they had sons. Furthermore, group size affected lactation duration with offspring in small groups being weaned earlier than offspring in large groups. Behavioural conflicts over Ml showed that the mother and offspring influenced Ml patterns during the period of dependency. Finally, six personality dimensions were identified, of which five revealed effects maternal behaviour, such as maternal retrieval, responsiveness and rejection, although their relative importance varied between those behaviours. In general, mother and offspring personality effects were complex due to their interactions with the developmental stage of offspring. In conclusion, my thesis research has made several novel contributions to furthering the understanding of female reproductive strategies in the highly endangered mountain gorilla. I presented the first evidence using behavioural data that females bias their postnatal investment towards the sex with the greatest fitness return as predicted by the TWH. My findings are discussed in the light of alternative Ml strategies, such as the local resource competition and enhancement model. My research has highlighted the importance of integrating anthropometric and physiological measures and demographic long-term data into future Ml studies to assess direct costs and benefits of Ml. The examination of mother-offspring behavioural conflicts showed that offspring have a strong impact on the level of Ml they receive. I have also examined the personality of a wild mountain gorilla population for the first time. My findings demonstrate that personality-parenting links are evident in several respects and I have demonstrated the great potential of personality as a determinant of maternal behaviour and mother-offspring relationships.EThOS - Electronic Theses Online ServiceUniversity of ChesterGBUnited Kingdo