Mother of all bonds: Influences on spatial association across the lifespan in capuchins.

In humans, being more socially integrated is associated with better physical and mental health and/or with lower mortality. This link between sociality and health may have ancient roots: sociality also predicts survival or reproduction in other mammals, such as rats, dolphins, and non-human primates. A key question, therefore, is which factors influence the degree of sociality over the life course. Longitudinal data can provide valuable insight into how environmental variability drives individual differences in sociality and associated outcomes. The first year of life-when long-lived mammals are the most reliant on others for nourishment and protection-is likely to play an important role in how individuals learn to integrate into groups. Using behavioral, demographic, and pedigree information on 376 wild capuchin monkeys (Cebus imitator) across 20 years, we address how changes in group composition influence spatial association. We further try to determine the extent to which early maternal social environments have downstream effects on sociality across the juvenile and (sub)adult stages. We find a positive effect of early maternal spatial association, where female infants whose mothers spent more time around others also later spent more time around others as juveniles and subadults. Our results also highlight the importance of kin availability and other aspects of group composition (e.g., group size) in dynamically influencing spatial association across developmental stages. We bring attention to the importance of-and difficulty in-determining the social versus genetic influences that parents have on offspring phenotypes. RESEARCH HIGHLIGHTS: Having more maternal kin (mother and siblings) is associated with spending more time near others across developmental stages in both male and female capuchins. Having more offspring as a subadult or adult female is additionally associated with spending more time near others. A mother's average sociality (time near others) is predictive of how social her daughters (but not sons) become as juveniles and subadults (a between-mother effect). Additional variation within sibling sets in this same maternal phenotype is not predictive of how social they become later relative to each other (no within-mother effect).

Genetic, maternal, and environmental influences on sociality in a pedigreed primate population.

Various aspects of sociality in mammals (e.g., dyadic connectedness) are linked with measures of biological fitness (e.g., longevity). How within- and between-individual variation in relevant social traits arises in uncontrolled wild populations is challenging to determine but is crucial for understanding constraints on the evolution of sociality. We use an advanced statistical method, known as the 'animal model', which incorporates pedigree information, to look at social, genetic, and environmental influences on sociality in a long-lived wild primate. We leverage a longitudinal database spanning 20 years of observation on individually recognized white-faced capuchin monkeys (Cebus capucinus imitator), with a multi-generational pedigree. We analyze two measures of spatial association, using repeat sampling of 376 individuals (mean: 53.5 months per subject, range: 6-185 months per subject). Conditioned on the effects of age, sex, group size, seasonality, and El Niño-Southern Oscillation phases, we show low to moderate long-term repeatability (across years) of the proportion of time spent social (posterior mode [95% Highest Posterior Density interval]: 0.207 [0.169, 0.265]) and of average number of partners (0.144 [0.113, 0.181]) (latent scale). Most of this long-term repeatability could be explained by modest heritability (h2social: 0.152 [0.094, 0.207]; h2partners: 0.113 [0.076, 0.149]) with small long-term maternal effects (m2social: 0.000 [0.000, 0.045]; m2partners: 0.000 [0.000, 0.041]). Our models capture the majority of variance in our behavioral traits, with much of the variance explained by temporally changing factors, such as group of residence, highlighting potential limits to the evolvability of our trait due to social and environmental constraints.

Using an on-site laboratory for fecal steroid analysis in wild white-faced capuchins.

Hormone laboratories located "on-site" where field studies are being conducted have a number of advantages. On-site laboratories allow hormone analyses to proceed in near-real-time, minimize logistics of sample permits/shipping, contribute to in-country capacity-building, and (our focus here) facilitate cross-site collaboration through shared methods and a shared laboratory. Here we provide proof-of-concept that an on-site hormone laboratory (the Taboga Field Laboratory, located in the Taboga Forest Reserve, Costa Rica) can successfully run endocrine analyses in a remote location. Using fecal samples from wild white-faced capuchins (Cebus imitator) from three Costa Rican forests, we validate the extraction and analysis of four steroid hormones (glucocorticoids, testosterone, estradiol, progesterone) across six assays (DetectX® and ISWE, all from Arbor Assays). Additionally, as the first collaboration across three long-term, wild capuchin field sites (Lomas Barbudal, Santa Rosa, Taboga) involving local Costa Rican collaborators, this laboratory can serve as a future hub for collaborative exchange.

Older, sociable capuchins (Cebus capucinus) invent more social behaviors, but younger monkeys innovate more in other contexts.

An important extension to our understanding of evolutionary processes has been the discovery of the roles that individual and social learning play in creating recurring phenotypes on which selection can act. Cultural change occurs chiefly through invention of new behavioral variants combined with social transmission of the novel behaviors to new practitioners. Therefore, understanding what makes some individuals more likely to innovate and/or transmit new behaviors is critical for creating realistic models of culture change. The difficulty in identifying what behaviors qualify as new in wild animal populations has inhibited researchers from understanding the characteristics of behavioral innovations and innovators. Here, we present the findings of a long-term, systematic study of innovation (10 y, 10 groups, and 234 individuals) in wild capuchin monkeys (Cebus capucinus) in Lomas Barbudal, Costa Rica. Our methodology explicitly seeks novel behaviors, requiring their absence during the first 5 y of the study to qualify as novel in the second 5 y of the study. Only about 20% of 187 innovations identified were retained in innovators' individual behavioral repertoires, and 22% were subsequently seen in other group members. Older, more social monkeys were more likely to invent new forms of social interaction, whereas younger monkeys were more likely to innovate in other behavioral domains (foraging, investigative, and self-directed behaviors). Sex and rank had little effect on innovative tendencies. Relative to apes, capuchins devote more of their innovations repertoire to investigative behaviors and social bonding behaviors and less to foraging and comfort behaviors.

L1 retrotransposition occurs mainly in embryogenesis and creates somatic mosaicism.

Long Interspersed Element 1 (L1) is a retrotransposon that comprises approximately 17% of the human genome. Despite its abundance in mammalian genomes, relatively little is understood about L1 retrotransposition in vivo. To study the timing and tissue specificity of retrotransposition, we created transgenic mouse and rat models containing human or mouse L1 elements controlled by their endogenous promoters. Here, we demonstrate abundant L1 RNA in both germ cells and embryos. However, the integration events usually occur in embryogenesis rather than in germ cells and are not heritable. We further demonstrate L1 RNA in preimplantation embryos lacking the L1 transgene and L1 somatic retrotransposition events in blastocysts and adults lacking the transgene. Together, these data indicate that L1 RNA transcribed in male or female germ cells can be carried over through fertilization and integrate during embryogenesis, an interesting example of heritability of RNA independent of its encoding DNA. Thus, L1 creates somatic mosaicism during mammalian development, suggesting a role for L1 in carcinogenesis and other disease.

CLASH's life history foundations.

We recommend extending CLASH by incorporating two evolutionary accounts of the shift toward fast life histories under harsh, unpredictable conditions. These accounts, if integrated with CLASH, make different predictions about the distributions of aggression and violence within and between societies. We discuss these predictions and propose ways of testing them.

[Promoting early reading in a social exclusion district in primary care]. / Promoción de la lectura en etapas precoces desde atención primaria en una zona de exclusión social.

INTRODUCTION: Reading is a tool that stimulates brain activity, increasing its cognitive reserve and providing innumerable benefits such as the stimulation of empathy, concentration or language development. Promoting reading at a very early age helps develop reading skills correctly. However, social inequalities can result in this practice being carried out less in groups of low socioeconomic, social or cultural levels. The purpose of this study was to assess the outcomes of a promoting reading habits intervention in a primary health care center located in a social transformation district by talking to the parents, providing books to families and encouraging books to become a part of children's play preferences. MATERIALS AND METHODS: A non-random intervention study in which children born in 2015 and registered in a particular health center took part. A reading promotion intervention was carried out at the ages of 4, 6, 12 and 18 months and at 24 months their preference for reading activities was assessed in relation to other leisure activities. RESULTS: Three hundred forty-two subjects were included, 154 allocated in the intervention group and 188 in the control group. The children in the intervention group exhibited a greater preference for reading as a leisure activity as compared to those in the control group (reading ranked in last position of favourite activities in 18.8 vs. 33.9%; p=0.003). The variables found on multivariate analysis to have a greater influence on reading position in the ranking of favorite activities were not having participated in the intervention OR: 2.06 (1.19-3.58) and gipsy ethnicity, OR: 2.37 (1.38-4.09). CONCLUSIONS: Results reveal a slight improvement in the preference for reading as an activity in the children that took part in the literacy program.