141 research outputs found

    Maternal Condition Does Not Influence Birth Sex Ratios in Anubis Baboons (Papio anubis)

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    Trivers and Willard predicted that when parental condition has differential effects on the fitness of male and female offspring, parents who are in good condition will bias investment toward the sex that benefits most from additional investment. Efforts to test predictions derived from Trivers and Willard's model have had mixed results, perhaps because most studies have relied on proxy measures of parental condition, such as dominance rank. Here, we examine the effects of female baboons condition on birth sex ratios and post-natal investment, based on visual assessments of maternal body condition. We find that local environmental conditions have significant effects on female condition, but maternal condition at conception has no consistent relationship with birth sex ratios. Mothers who are in poorer condition at the time of conception resume cycling significantly later than females who are in better condition, but the sex of their infants has no effect on the time to resumption of cycling. Thus, our findings provide strong evidence that maternal condition influences females' ability to reproduce, but females do not facultatively adjust the sex ratio of their offspring in relation to their dominance rank or current condition

    A Severe Lack of Evidence Limits Effective Conservation of the World's Primates

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    Threats to biodiversity are well documented. However, to effectively conserve species and their habitats, we need to know which conservation interventions do (or do not) work. Evidence-based conservation evaluates interventions within a scientific framework. The Conservation Evidence project has summarized thousands of studies testing conservation interventions and compiled these as synopses for various habitats and taxa. In the present article, we analyzed the interventions assessed in the primate synopsis and compared these with other taxa. We found that despite intensive efforts to study primates and the extensive threats they face, less than 1% of primate studies evaluated conservation effectiveness. The studies often lacked quantitative data, failed to undertake postimplementation monitoring of populations or individuals, or implemented several interventions at once. Furthermore, the studies were biased toward specific taxa, geographic regions, and interventions. We describe barriers for testing primate conservation interventions and propose actions to improve the conservation evidence base to protect this endangered and globally important taxon

    Post-translational regulation contributes to the loss of LKB1 expression through SIRT1 deacetylase in osteosarcomas

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    background: The most prevalent form of bone cancer is osteosarcoma (OS), which is associated with poor prognosis in case of metastases formation. Mice harbouring liver kinase B1 (LKB1+/−) develop osteoblastoma-like tumours. Therefore, we asked whether loss of LKB1 gene has a role in the pathogenesis of human OS. methods: Osteosarcomas (n=259) were screened for LKB1 and sirtuin 1 (SIRT1) protein expression using immunohistochemistry and western blot. Those cases were also screened for LKB1 genetic alterations by next-generation sequencing, Sanger sequencing, restriction fragment length polymorphism and fluorescence in situ hybridisation approaches. We studied LKB1 protein degradation through SIRT1 expression. MicroRNA expression investigations were also conducted to identify the microRNAs involved in the SIRT1/LKB1 pathway. results: Forty-one per cent (106 out of 259) OS had lost LKB1 protein expression with no evident genetic anomalies. We obtained evidence that SIRT1 impairs LKB1 protein stability, and that SIRT1 depletion leads to accumulation of LKB1 in OS cell lines resulting in growth arrest. Further investigations revealed the role of miR-204 in the regulation of SIRT1 expression, which impairs LKB1 stability. conclusions: We demonstrated the involvement of sequential regulation of miR-204/SIRT1/LKB1 in OS cases and showed a mechanism for the loss of expression of LKB1 tumour suppressor in this malignancy

    The Influence of Life History Milestones and Association Networks on Crop-Raiding Behavior in Male African Elephants

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    Factors that influence learning and the spread of behavior in wild animal populations are important for understanding species responses to changing environments and for species conservation. In populations of wildlife species that come into conflict with humans by raiding cultivated crops, simple models of exposure of individual animals to crops do not entirely explain the prevalence of crop raiding behavior. We investigated the influence of life history milestones using age and association patterns on the probability of being a crop raider among wild free ranging male African elephants; we focused on males because female elephants are not known to raid crops in our study population. We examined several features of an elephant association network; network density, community structure and association based on age similarity since they are known to influence the spread of behaviors in a population. We found that older males were more likely to be raiders than younger males, that males were more likely to be raiders when their closest associates were also raiders, and that males were more likely to be raiders when their second closest associates were raiders older than them. The male association network had sparse associations, a tendency for individuals similar in age and raiding status to associate, and a strong community structure. However, raiders were randomly distributed between communities. These features of the elephant association network may limit the spread of raiding behavior and likely determine the prevalence of raiding behavior in elephant populations. Our results suggest that social learning has a major influence on the acquisition of raiding behavior in younger males whereas life history factors are important drivers of raiding behavior in older males. Further, both life-history and network patterns may influence the acquisition and spread of complex behaviors in animal populations and provide insight on managing human-wildlife conflict

    Patterns of infant handling and relatedness in Barbary macaques (Macaca sylvanus) on Gibraltar

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    Among papionin primates, the Barbary macaque (Macaca sylvanus) shows the most extensive interactions between infants and group members other than the mother. Two different types of interactions occur: (1) long-lasting dyadic interactions between a handler and an infant, and (2) brief triadic interactions between two handlers involving an infant. Previous investigations showed that infant handling by males is best explained as use of infants to manage relationships with other males. In contrast, no adaptive explanation for infant handling by females emerged. Here, we compared the infant-handling pattern between subadult/adult males and subadult/adult females in a free-ranging group of 46 Barbary macaques on Gibraltar to test whether the relationship management hypothesis also applies to female handlers. We further investigated the infant-handling pattern of juveniles and used microsatellite markers to estimate relatedness between infant handlers and the infant’s mother. We found that males, females and juveniles all participated extensively in triadic interactions using infants of above-average related females. In contrast, only males and juveniles were highly involved in dyadic interactions with infants of related females, while females rarely handled infants otherthan their own. The pattern of infant handling was entirely compatible with the predictions of the relationship management hypothesis for males and mostly so for females. Moreover, our genetic analysis revealed that males and females differ in their partner choice: while females preferred to interact with related females, males had no significant preference to interact with related males. We further discuss the observed above-average relatedness values between infant handlers and the infant’s mother in the light of kin-selection theory
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