At a time when seasonal cycles are increasingly disrupted, the ecology and evolution of reproductive seasonality in tropical vertebrates remains poorly understood. In order to predict how changes in seasonality might affect these animals, it is important to understand which aspects of their diverse patterns of reproductive phenology are linked to either the equally diverse patterns of rainfall seasonality (within-year variations) or instead the marked climatic unpredictability (year-to-year variations) occurring across the intertropical belt. Here, we gather birth and climatic seasonality data from 21 populations of 11 Africa-dwelling primate species from the papionin tribe, occupying a wide range of environments, including equatorial, tropical, temperate and arid climates. We investigate (1) the environmental variations that influence the intensity of reproductive seasonality, and (2) the reproductive stage that is synchronized with increased resource availability. Our results demonstrate wide variation in the intensity of birth seasonality between and within species. Across multiple measures of climatic variation, we found rainfall unpredictability to be the only clear predictor of the intensity of reproductive seasonality across populations, i.e., greater year-to-year variation in the amount of rainfall was associated with lower to no reproductive seasonality. Finally, we identified diverse patterns of reproductive phenology, with the most seasonal breeders generally aligning lactation with the peak in resource availability while other populations show more diverse patterns, where conception, lactation or weaning can all be synchronized with maximal food availability. This study sheds new light on the extent and ecological drivers of flexible reproductive phenology in long-lived tropical mammals, and may even contribute to our understanding of why humans give birth year-round.
The evolution of social monogamy has intrigued biologists for over a century. Here, we show that the ancestral condition for all mammalian groups is of solitary individuals and that social monogamy is derived almost exclusively from this social system. The evolution of social monogamy does not appear to have been associated with a high risk of male infanticide, and paternal care is a consequence rather than a cause of social monogamy. Social monogamy has evolved in nonhuman mammals where breeding females are intolerant of each other and female density is low, suggesting that it represents a mating strategy that has developed where males are unable to defend access to multiple females.
ABSTRACT A survey was conducted in 2001 with the purpose of determining the status and nature of personal libraries of Lithuanian Americans who, in the aftermath of World War II, settled in the United States. This was the first such study of Lithuanian American bibliophiles and their libraries. The survey results were analyzed with a primary focus on this question: what books were most valued and collected by those living outside of Lithuania? KEYWORDS: Bibliophilesprivate librariesLithuanian Americans
Abstract In most social mammals, some females disperse from their natal group while others remain and breed there throughout their lives but, in a few, females typically disperse after adolescence and few individuals remain and breed in their natal group. These contrasts in philopatry and dispersal have an important consequence on the kinship structure of groups which, in turn, affects forms of social relationships between females. As yet, there is still widespread disagreement over the reasons for the evolution of habitual female dispersal, partly as a result of contrasting definitions of dispersal. This paper reviews variation in the frequency with which females leave their natal group or range (social dispersal) and argues that both the avoidance of local competition for resources and breeding opportunities and the need to find unrelated partners play an important role in contrasts between and within species.
Phylogenetic analyses increasingly take centre-stage in our understanding of the processes shaping patterns of cultural diversity and cultural evolution over time. Just as biologists explain the origins and maintenance of trait differences among organisms using phylogenetic methods, so anthropologists studying cultural macroevolutionary processes use phylogenetic methods to uncover the history of human populations and the dynamics of culturally transmitted traits. In this paper, we revisit concerns with the validity of these methods. Specifically, we use simulations to reveal how properties of the sample (size, missing data), properties of the tree (shape) and properties of the traits (rate of change, number of variants, transmission mode) might influence the inferences that can be drawn about trait distributions across a given phylogeny and the power to discern alternative histories. Our approach shows that in two example datasets specific combinations of properties of the sample, of the tree and of the trait can lead to potentially high rates of Type I and Type II errors. We offer this simulation tool to help assess the potential impact of this list of persistent perils in future cultural macroevolutionary work. This article is part of the theme issue 'Foundations of cultural evolution'.
Influence of smoking on the survival rate of various dental implant systems an 18year report Purpose: This inquiry was done to reveal possible negative effects of smoking on the probability of survival of implants. Patients and Methods: The influence of smoking on the success of dental implants was studied using 934 implant patients who had been treated with various implant systems. 712 patients (76.1%) identified themselves as non-smokers, 223 (23.9%) as smokers. A total of 1776 implants including Bonefit (212), Branemark system (42), Frialit-2 (555), IMZ (179), TPS (21), ITI (1) and Tubingen (761) types were placed in these 934 patients. 1379 implants (77.7%) were placed in non-smokers, 379 (22.3%) in smokers. Results: The smokers showed higher failure rates and significantly reduced implant survival rates (Kaplan-Meier). The negative consequences of smoking were evident even at a very low rate of tobacco consumption per day. The degree of influence resulting from smoking depended on the location of the implant. This was most clearly noticed with a reduction of the implant prognosis in the maxilla. Conclusions: The particularly marked reduction in the probability of success in the maxilla over the entire survival period of the implant led to the hypothesis that the primary causes for the reduced implant prognosis was long-term local effects. These effects seemed to be the result of two causes: the toxic chemical effect of components of tobacco smoke on the peri-implant tissue and the damage caused by forces below the threshold of perception which affect the implants. The forces result from soft tissue movements, which are increased by smoking.
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