The seasonal relationships between household dietary diversity and child growth in a rural Timor-Leste community.

Both child growth and dietary diversity are poor in rural Timor-Leste. The rainy season is associated with food scarcity, yet the association between seasonal scarcity, food diversity, and child growth is underdocumented. This study assesses the relationship between household dietary diversity and children's standardized growth across the 2018 food-scarce (April-May; post-rainy period) and post-harvest (October) seasons in the agricultural community of Natarbora, on the south-coastal plains of Timor-Leste. We conducted household interviews and collected anthropometric data across 98 and 93 households in the post-rainy and post-harvest periods, respectively. Consumed household foods were obtained via 24-h diet recalls and were subsequently categorized into a nine-food-group dietary diversity score (DDS; number of different food groups consumed). The DDS was related to children's standardized short-term growth (z-weight, z-body mass index [BMI] and percent change in weight over the harvest season) via linear mixed models. Across seasons, DDS increased from 3.9 (standard deviation [SD] = 1.0) to 4.3 (SD = 1.4; p < 0.05). In the post-rainy season, children in high DDS households had higher z-weight than those in low DDS households and higher z-BMI than children in medium and low DDS households. In the post-harvest period, household DDS did not predict children's z-weight but predicted z-BMI. Consumption of protein-rich foods, particularly animal-source foods and legumes, in low- and medium-DDS households may be associated with improved child growth. While consuming more animal-source foods in the post-rainy season would be ideal, promoting the consumption of locally grown legumes, such as beans and pulses, may facilitate better nutritional outcomes for more children in rural Timor-Leste.

Spatiotemporal association patterns in a supergroup of Rwenzori black-and-white colobus (Colobus angolensis ruwenzorii) are consistent with a multilevel society.

Primates display broad diversity in their social organization. The social groups of a few primate species are organized in a multilevel fashion, with large groups composed of multiple, core one-male units (OMUs). A characteristic of multilevel societies is that the higher levels can include hundreds of individuals. The Rwenzori black-and-white colobus (Colobus angolensis ruwenzorii) in the montane forests of Rwanda form supergroups and have been suspected to exhibit multilevel social organization. Here we present the first data on the "anatomy" of a supergroup numbering 500+ individuals. We identified subgroups within the supergroup based on progression data, extracting the social network structure from the time-stamped spatiotemporal distribution of passing individuals identified to age-sex class, and selecting an optimal time window for each network using the two-step approach developed by Uddin, Choudhury, Farhad, and Rahman (2017). We detail the existence of core units-multi-male units (MMUs) with a mean of 1.7 adult males and 3.1 adult females, as well as OMUs, all-female units and bachelor units composed of adult and sub-adult males. More than two-thirds of units are MMUs. These grouping patterns conform to a multilevel society with predominantly multi-male core units, a social system that has recently also been described for a population of the same taxon in Uganda. Individual identification will be required to corroborate these interpretations.

Determinants of objectively measured physical activity in rural East Timorese children.

OBJECTIVES: The human juvenile period evolved as a period of learning and physical development in a family environment that subsidizes the costs of these processes. Children allocate energy to physical activity, maintenance, and growth. How energy is allocated has consequences for adult body size and other life-history traits. In subsistence agriculture populations, where child contributions to the household economy are common and energy availability is low, trade-offs in energy expenditure between activity and growth may help explain poor growth. METHODS: Using accelerometry, we measured physical activity over 2 years in 88 free-living children aged 5-19 years in two ecologically varying communities in rural Timor-Leste. We model characteristics related to variation in activity, and subsequently, activity is modeled against growth, illness, and aspects of household and local ecology using linear mixed models. RESULTS: Physical activity in Timorese children is characterized by high levels of moderate ( x ¯ = 8.8 h/day), no sustained vigorous, and little sedentary activity ( x ¯ = 4.6 h/day). Children in the mountainous community show a slight trade-off between activity and growth (P = .077). Males down-regulate both growth and activity relative to females. Variation in household characteristics does not predict child activity. Both activity and growth are lower in the mountainous community than in the flat, coastal community. CONCLUSIONS: Household demands on child behavior may constrain children's ability to moderate activity relative to nutritional status. Activity in this population is high relative to other subsistence populations, possibly because children face the dual pressures of contributing to household subsistence and attending school.

Growth curves and the international standard: How children's growth reflects challenging conditions in rural Timor-Leste.

OBJECTIVES: Population-specific growth references are important in understanding local growth variation, especially in developing countries where child growth is poor and the need for effective health interventions is high. In this article, we use mixed longitudinal data to calculate the first growth curves for rural East Timorese children to identify where, during development, deviation from the international standards occurs. MATERIALS AND METHODS: Over an eight-year period, 1,245 children from two ecologically distinct rural areas of Timor-Leste were measured a total of 4,904 times. We compared growth to the World Health Organization (WHO) standards using z-scores, and modeled height and weight velocity using the SuperImposition by Translation And Rotation (SITAR) method. Using the Generalized Additive Model for Location, Scale and Shape (GAMLSS) method, we created the first growth curves for rural Timorese children for height, weight and body mass index (BMI). RESULTS: Relative to the WHO standards, children show early-life growth faltering, and stunting throughout childhood and adolescence. The median height and weight for this population tracks below the WHO fifth centile. Males have poorer growth than females in both z-BMI (p = .001) and z-height-for-age (p = .018) and, unlike females, continue to grow into adulthood. DISCUSSION: This is the most comprehensive investigation to date of rural Timorese children's growth, and the growth curves created may potentially be used to identify future secular trends in growth as the country develops. We show significant deviation from the international standard that becomes most pronounced at adolescence, similar to the growth of other Asian populations. Males and females show different growth responses to challenging conditions in this population.

Household resources and seasonal patterns of child growth in rural Timor-Leste.

OBJECTIVES: This study aimed to determine through detailed contextual investigation the effects of seasonal resource shortages, and household and individual level differences, on child growth in rural Timor-Leste. We compared trends in growth across two rural Timorese villages with different ecologies. METHODS: Heads of 104 households in Natarbora, Timor-Leste, were interviewed and resource levels assessed during the food shortage season. In these households, 337 children were measured for height, weight, and mid-upper arm circumference. World Health Organization standardized measures were calculated and compared with dry season measurements. Using hierarchical linear models, child growth was related to household resource levels. Results were then compared to data from rural mountainous Ossu, Timor-Leste. RESULTS: z BMI declined over the wet season when food resources were scarce compared with the dry season (P < .001). Both age and sex were strong predictors of child growth, with older children having worse z height-for-age (P = .001) and z weight-for-age (P < .001) and boys shorter for age than girls (P = .049). Children were taller in households with modern flushable toilets (P = .005). Agricultural strategies such as crop diversity and land cultivation were linked to child growth. Results parallel findings from Ossu on the effects of season, child age and sex, but not household level socioeconomic differences. CONCLUSIONS: Results highlight the importance of subsistence-based resource stabilization and of early intervention to prevent growth faltering. Predicting growth using ecological models requires small-scale investigation, as variation exists among rural areas within an ecologically and culturally diverse country.

The varied path to adulthood: Plasticity in developmental timing in hylobatids.

Maturation includes physical, reproductive, and social aspects that develop asynchronously. Intra- and inter-individual variation in the relative timing of each aspect reflects context-dependent plasticity. Plasticity in developmental timing may be important for the family-living small apes (family Hylobatidae), where reproductive opportunities are monopolized by territorial breeding pairs. Data on development in hylobatids are so far limited due to their elusive arboreal niche and long lifespans. Herein, we provide the first quantitative analysis of behavioral development in 14 captive individuals of three species (Hylobates moloch, Nomascus leucogenys, and Symphalangus syndactylus), with some individuals being observed over 8 years. To establish a baseline for behavioral development, we compare the behavior of infants (0-2 years), juveniles (2-4 years), adolescents (4-6 years), and subadults (6-9 years) in their natal groups from data obtained over 250 focal observation hours. We then relate changes in behavior to measures of somatic and physiological development, and to wild populations, to identify the degree of intra- and inter-individual variation in developmental timing. We found greater concordance between behavioral and physiological markers of weaning than between different markers of later development, and the timing of later milestones varied more among individuals. Behavioral estimates from both captive and wild individuals in their natal groups indicate that puberty begins close to age 5, but physiological maturation can occur 0.5-3 years earlier in captive individuals than in wild individuals. Ages at onset of puberty, sexual, and social maturation vary in both captive and wild populations. The available evidence indicates that the social environment during development (e.g., presence of breeding female and appropriate mating partner), as well as nutrition, play a role in the timing of life history transitions in hylobatids. Am. J. Primatol. 78:610-625, 2016. © 2015 Wiley Periodicals, Inc.

Kloss gibbon (Hylobates klossii) behavior facilitates the avoidance of human predation in the Peleonan forest, Siberut Island, Indonesia.

Kloss gibbons (Hylobates klossii) are endemic to the Mentawai Islands in Indonesia and have been subject to human predation for more than 2000 years in the absence of any other significant predators. We investigate the behavior of Kloss gibbons that may be attributed to avoiding human predation. We observed Kloss gibbons in the Peleonan forest in the north of Siberut Island, the northernmost of the Mentawai island chain, over 18 months in 2007 and 2008, and collected data on their singing behavior, the number of individuals present during different conditions and their responses to humans. We examine behaviors that may reduce the risk of predation by humans during singing (the most conspicuous gibbon behavior), daily non-singing activities and encounters with humans. The individual risk of being stalked by hunters is reduced by singing in same-sex choruses and the risk of successful capture by hunters during singing is reduced by singing less often during daylight hours and by leaving the location of male pre-dawn singing before full light (reducing the visual signal to hunters). Groups in the Peleonan also fission during non-singing daily activity and rarely engage in play or grooming, enhancing the crypticity of their monochromatic black pelage in the canopy. We also observed a coordinated response to the presence of humans, wherein one adult individual acted as a "decoy" by approaching and distracting human observers, while other group members fled silently in multiple directions. "Decoy" behavior occurred on 31% of 96 encounters with unhabituated Kloss gibbons that detected our presence. "Decoy" individuals may put themselves at risk to increase the survival of related immatures (and adult females with infants) who have a greater risk of predation. We argue that, in combination, these behaviors are an evolved response to a long history of predation by humans.

Singing by male and female Kloss gibbons (Hylobates klossii) in the Peleonan Forest, Siberut Island, Indonesia.

Kloss gibbons (Hylobates klossii) are endemic to the Mentawai Islands in Indonesia and are one of only two gibbon species in which mated pairs do not sing duets. This is the first long-term study of the factors influencing the singing activity of Kloss gibbons within a northern Siberut Island population and follows two previous studies in central Siberut nearly 30 years ago. We collected data on the presence/absence of male and female singing within the study area on 198 days and within a focal group on 47 days. Rainfall during the time period in which they normally sing inhibits singing in both males and females. Our study supports the hypothesis that male and female songs function in intrasexual resource defence, as singing is associated with singing by same-sex neighbours, and same-sex choruses are more likely to occur after one or more days of silence (from that sex), suggesting there is pressure for individuals to communicate with same-sex neighbours regularly. Singing was not coordinated within a mated pair, suggesting that vocal coordination of the pair has been lost with the loss of the duet and that Kloss gibbon songs do not convey information to neighbours about the strength of the pair bond. On days when males sang predawn, females were more likely to sing after dawn and earlier in the morning. Additionally, the number of groups singing in female choruses was positively associated with the number of males that had sung in the predawn male chorus. We suggest that female songs have an intersexual territory defence as well as an intrasexual function.

A novel quantitative approach to women's reproductive strategies.

The patterned way in which individuals allocate finite resources to various components of reproduction (e.g. mating effort, reproductive timing and parental investment) is described as a reproductive strategy. As energy is limited, trade-offs between and within aspects of reproductive strategies are expected. The first aim of this study was to derive aspects of reproductive strategies using complete reproductive histories from 718 parous Western Australian women. Factor analysis using a subset of these participants resulted in six factors that represented 'short-term mating strategy', 'early onset of sexual activity', 'reproductive output', 'timing of childbearing', 'breastfeeding', and 'child spacing'. This factor structure was internally validated by replication using a second independent subset of the data. The second aim of this study examined trade-offs between aspects of reproductive strategies derived from aim one. Factor scores calculated for each woman were incorporated in generalised linear models and interaction terms were employed to examine the effect of mating behaviour on the relationships between reproductive timing, parental investment and overall reproductive success. Early sexual activity correlates with early reproductive onset for women displaying more long-term mating strategies. Women with more short-term mating strategies exhibit a trade-off between child quantity and child quality not observed in women with a long-term mating strategy. However, women with a short-term mating strategy who delay reproductive timing exhibit levels of parental investment (measured as breastfeeding duration per child) similar to that of women with long-term mating strategies. Reproductive delay has fitness costs (fewer births) for women displaying more short-term mating strategies. We provide empirical evidence that reproductive histories of contemporary women reflect aspects of reproductive strategies, and associations between these strategic elements, as predicted from life history theory.

Child size and household characteristics in rural Timor-Leste.

OBJECTIVES: The main objective was to determine those characteristics of the family and household that affects child health (as measured by child size for age) in the rural Ossu area of Timor-Leste. METHODS: Interviews of parents in 102 households assessed reproductive histories, the amount and type of resources available and family composition (number, sex, and age of members). Height, weight, and mid-upper arm circumference were measured for all children in the household. To standardize for age and sex, raw measures were transformed into WHO Z scores and compared across households. RESULTS: Children were low in both height and weight relative to international standards and older children compared with international standards more poorly than under-fives. There was no evidence of sex difference in relative growth. The number of children in a household was negatively associated with height but not weight and positively with BMI. Children living in the villages more distant from Ossu town center had significantly lower Z scores for height than children in town. No crop or livestock indices were related to growth. Fostered children did not show growth different from biological children, but biological children in households with fostered children were slightly larger for age. CONCLUSIONS: Short stature inflates BMI and harvest season measures may have captured short-term increases in children's energy balance. Social networks may increase child well-being by moving children toward resource richer households. Social and cultural factors influence resource allocations among children and their health in rural Timor-Leste.

Early life environment, life history and risk of endometrial cancer.

Endometrial cancer risk is influenced by reproductive behaviours, including parity and breastfeeding, and timing of life history events such as age at menarche and menopause. One potential mechanism by which altered reproductive strategies may influence endometrial cancer risk is through exposure to reproductive hormones. Current theory suggests that high lifetime exposure to oestrogen, unopposed by progesterone, increases endometrial cancer risk; here we suggest that progesterone deficiency itself may also play a significant role. Additionally, given that reproductive profile variables are themselves influenced by early childhood conditions, we hypothesise that endometrial cancer risk may be influenced by the childhood psychosocial environment as mediated through changes to adolescent and adult reproductive behaviours and hormone exposures. Investigating reproductive cancers, including endometrial cancer, using a life history approach may help to increase understanding of why these cancers occur and potentially help implementation of early detection and screening processes in the future.

Social dynamics modify behavioural development in captive white-cheeked (Nomascus leucogenys) and silvery (Hylobates moloch) gibbons.

Behavioural development was quantified in one family group of silvery gibbons (Hylobates moloch) and one of white-cheeked gibbons (Nomascus leucogenys) over 11 months during 2005 and 2008 at the Perth Zoo. Levels of locomotion, solo play and play solicitation peaked by 5 years of age but continued solo and social play in older immatures suggested that social development continued until at least 7 years of age. Mature offspring responded to play solicitations from younger siblings. The transition to sub-adulthood was marked by the presence of spatial peripheralisation from the parents, and coincided with aggression from the father to a sub-adult male. After the birth of a new infant, the male sub-adult stayed closer to his mother (and the infant) but not to his father; his juvenile brother was closer to both parents. Within-family observations of behaviour that is difficult to observe in the wild but can be observed in captivity contributes to our understanding of family dynamics in gibbons. Observations of these captive groups suggest that sub-adult peripheralisation may be influenced by family social dynamics as well as by local ecology, and that older offspring are responsive to the development of younger siblings.

Brothers delay menarche and the onset of sexual activity in their sisters.

The higher costs of sons compared with daughters extends to a negative effect of brothers on the lifetime reproductive success of their siblings in subsistence and preindustrial societies. In societies with fewer resource constraints, one might expect that these effects would be limited or non-existent. This study investigates the costs of brothers and sisters in a contemporary western society of adult Australians. Girls with elder brothers had a delayed age at menarche. Younger brothers were associated with delayed onset of sexual activity in sisters, but not in brothers. Neither younger nor elder brothers influenced fitness parameters (number of pregnancies, number of children, age at first pregnancy or age at first birth) in siblings of either sex. This study provides evidence that brothers negatively affect their sisters' onset of reproductive maturity and sexual activity; however, this delay is not associated with a fitness cost in contemporary Australia. We suggest this is due to the long period of independence prior to child bearing.