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Competition for food is often a cost associated with living in a group, and can occur in an indirect (scramble) or direct (contest) form. We investigated feeding competition in a supergroup of Rwenzori black-and-white colobus monkeys (Colobus angolensis ruwenzorii) in Rwanda, with the aim of establishing whether freedom from scramble competition allows these monkeys to form supergroups. We used the patch depletion method, measuring intake rate coupled with movement rate, to assess if food patches become depleted over the occupancy period. Resource depletion was evident when the colobus fed on young leaves, but not when feeding on mature leaves. Scramble competition was inferred from a negative correlation between group size and change in intake rate over patch occupancy. Between-group contest competition was inferred from displacement from patches. Although feeding competition exists for select resources, limited competition for mature leaves may enable Rwenzori colobus to live in a supergroup of hundreds of individuals in this montane forest.

When preferred foods are scarce, one strategy employed by primates is to switch to an alternative food item of lower quality or preferability, i.e., a fallback food. In the montane rainforest of Nyungwe National Park in southwestern Rwanda, Rwenzori black-and-white colobus (Colobus angolensis ruwenzorii) (hereafter Rwenzori colobus) form a supergroup comprising hundreds of individuals. Over 13 mo we investigated how this supergroup uses resources in periods of resource abundance vs. periods of resource scarcity. Based on 5603 feeding records we first identified preferred foods and then identified fallback foods as those food categories or species whose consumption increases when preferred foods, or preferred food categories, are less available. When the availability of 19 preferred food items was low, fruticose lichens (Usnea sp.) contributed >50% of the monthly diet for the Rwenzori colobus. Moreover, consumption of lichens was significantly negatively related to the availability of preferred foods. Fruticose lichens can therefore be considered a fallback food for Rwenzori colobus that sustains the supergroup during periods of reduced food availability. This result, in combination with previous findings that mature foliage in Nyungwe is of high quality and does not elicit feeding competition, points to the importance of resources in facilitating supergroup formation. However, several other montane forests in Eastern Africa also harbor fruticose lichens and yet support only small groups of Angolan colobus, suggesting that additional factors such as sufficient forest size and limited fragmentation and hunting pressure by humans are required for supergroups to form.

Subsistence and economic activities undertaken by households in the context of transition from subsistence farming to cash economies are sometimes seen as substitutable with only minimal reference to the households themselves. We use data from in-depth interviews of 190 householders in Ossu (mountains) and Natarbora (coastal plains), Timor-Leste, to query relationships of family composition, resource strategies, and their relationships to children’s growth. Principal component analyses of six household composition variables reveal “grandparent and fostered-in children”, “two generational households with numerous adults and children”, and “smaller households with few adults and fostered-out children”, explaining 72% of the variance. A similar procedure with 11 resource variables produced four components explaining 56% of resource variance. Households with grandparents have a pension income and engage in large animal husbandry, and are associated with better standardized BMI for resident children. Households with numerous members (but not grandparents) are more invested in subsistence gardening and are negatively associated with child stature. Salaried income is not associated with household composition, but children in these households are taller than their peers. Consistent differences between the two communities are partially a result of differences in socioecology, but there remain unexplained differences that may relate to cultural practices.

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.

Economic development introduces opportunities for subsistence households to diversify income sources. Timor-Leste is undergoing this transition; however, little is known about the patterns of household strategies and the effects of rural development on child wellbeing. We derive strategies from 190 households in two rural Timor-Leste communities and examine the links between resource strategies and child growth using linear mixed modeling. Children’s z-height, z-weight, and z-BMI are well below international standards. We find agriculture remains predominantly subsistence-based, with some reliance on cash flow from government pensions and salaries. Households with stable income sources are better able to accumulate wealth, and children living in salaried households have better z-height. However, child growth is best predicted by individual-level factors rather than household ecology. Substantial variation in household strategy and little association of strategy with growth indicates there is no ‘best’ strategy in this transitioning environment.

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.

Childhood under-nutrition and malnutrition are prevalent in low and middle-income countries. Where it is the primary source of food production, consumption, and cash income, agriculture has a close relationship with health and nutrition in these emerging economies. Although Timor-Leste achieved lower middle-income status in 2011, national economic growth has not delivered anticipated nutritional dividends. Seeking to redress a lack of research that clearly demonstrates how agriculture impacts on nutrition in Timor-Leste, we investigated the links between household agricultural activities and children's physical growth in two agro-ecologically varying field sites: lowland Natarbora and mountainous Ossu. Children in both sites were below World Health Organization standards in height, weight, and body mass index. Coastal children recorded better growth than upland children. Livestock production was linked to poorer growth in the upland, but not coastal communities, which may be linked to specific differences in husbandry practices. In both communities, access to a plantation was somewhat associated with children's (0–10 years) increased weight-for-age. As simple agricultural indicators do not fully explain growth outcomes, a livelihood security approach is proposed to better understand how households address food and nutritional needs in relation to broader livelihood concerns.

OBJECTIVES Infant handling describes cases in which youngsters are temporarily removed from the care of their mothers and "taken care of" (held, carried, etc.) by other conspecifics. Handlers may gain indirect fitness benefits from these actions and can practice mothering skills, thereby improving the odds of survival of their own infants. Great apes are notable for displaying little infant handling. Apart from anecdotal observations, no published data exist on infant handling in wild mountain gorillas. We tested two of the most pertinent explanations ("kin selection" and "learning to mother") in a wild population of mountain gorillas in Rwanda. We predicted that (a) nulliparous females would exhibit infant handling (i.e., carrying) more than parous females and (b) maternal kin would exhibit more infant handling than nonkin. METHODS We collated 8 years of data on infant carrying behavior collected in 13 groups monitored by the Dian Fossey Gorilla Fund's Karisoke Research Center. RESULTS Infant handling is an infrequent behavior (1,783 instances over 25,600 observation hours). A strong positive effect of relatedness and handler parity on the frequency of infant handling emerged. CONCLUSIONS While the nature of handler-infant interactions (affiliative, abusive, etc.) remains unstudied, they could constitute alloparental care and could therefore attenuate maternal energetic burden and ultimately allow increased birth rates. However, the rarity of this behavior makes it an unlikely contributor to mountain gorillas' relatively short interbirth intervals.

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.

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 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. Am. J. Primatol. 77:296–308, 2015. © 2014 Wiley Periodicals, Inc.

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.

We examine the relationship between birth order and reproductive behaviors in a sample of Australian residents, accounting for personality, personal achievements, and family structure. Using generalized linear models and survival analyses we build predictive models for each reproductive measure and test those models on an independent data subset. Compared with functional firstborns (middle-borns more than 5 years younger than their next older sibling), male middle-borns and last-born females had younger ages of first sexual intercourse, and middle-born females had a younger age at first pregnancy. There was no difference in females’ age at first birth. Male middle-borns tended to have an older average age at first birth. Controlling for age, both male and female middle-borns had fewer children. Overall, middle-borns differ more from functional firstborns than do last-borns. Given the significant but small effect sizes demonstrated in this study, we suggest that developmental characteristics that may facilitate middle-borns’ success within the natal family carry slight fitness costs during the reproductive years.

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.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.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.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.

Fertilised eggs, stage one and stage two juveniles of the smooth marron, Cherax cainii, are attached to the pleopods of the gravid female via specialised structures. The eggs are fixed to the maternal pleopods by egg stalks, whereas stage one and stage two juveniles remain attached by recurved spines on the dactyls of their fourth and fifth pereopods. Crayfish of the third juvenile stage are independent of the mother and receive no maternal care; their dactyl spines are straight and cannot grasp the mother's pleopods; the female displays agonistic behaviour toward her young commencing with stage III instars. We suggest that eggs and the first two juvenile stages attached to the mother would experience reduced levels of predation and be secured against strong river flow. We conclude by reviewing, briefly, the potential fitness costs and benefits of maternal care, to the mother and young of freshwater crayfish, from a life-history perspective.

This article proposes that longevity is not merely the result of an absence of mortality but a self-reinforcing and positively selected life-history trait in social species. It argues that a small increase in longevity is amplified as (1) reductions in mortality at young ages increase natural selection for mechanisms of maintenance and repair at all older ages as well as increasing the potential for intergenerational transfers; (2) intergenera-tional transfers of resources from old to young increase fitness (e.g., through improved health, skill, and competitive ability) of the young and thus favor the presence of older individuals in a population; and (3) the division of labor increases both efficiency and innovation at all levels, resulting in increased resources that can be reinvested. This theory is framed around the longevity-oriented question posed two decades ago by the ger-ontologist George Sacher, “Why do we live as long as we do?,” rather than the more prevalent question today, “Why do we grow old?” The article describes the foundational principles and the main phases of a model for the evolution of longevity mediated through social organization, and applies the concept specifically to human populations.

Regression analyses of primate life spans on recently revised female body and brain masses of Old World primates predict a human life span of between 72 years and 91 years-estimates that exceed the age of human menopause (and prior estimates) by well over 20 years. The life spans predicted from body and brain sizes in the early Homo suggest that postreproductive life spans predate Homo sapiens Among anthropoid primates, residual longevity after body and brain effects are controlled is greatest for Homo and for the New World monkeys of the genus Cebus. Body and brain masses predict a 25-year life span for Cebus, although recorded life spans exceed 50 years. Cebus are geographically widespread, have a female-bonded social organization convergent with Old World monkeys, and are primarily frugivorous, though the diet is heavily supplemented with vertebrate prey. Regressions of phylogenetically independent contrasts indicate that body mass and brain mass relationships to longevity remain significant when phylogeny is controlled and that brain mass is a more robust predictor than body mass. These data are new in terms of the completeness of species representation, more reliable body masses, presentation of various comparison group regressions, and control for phylogenetic independence.

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

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.

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. Refereed/Peer-reviewed

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 childrens 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.

A historical survey of the inheritance practices of farming families in North America and elsewhere indicates that resource allocations among children differed through time and space with regard to sex bias and equality. Tensions between provisioning all children and maintaining a productive economic entity (the farm) were resolved in various ways, depending on population pressures, the family’s relative resource level, and the number and sex of children. Against a backdrop of generalized son preference, parents responded to ecological circumstances by investing in offspring differentially within and between the sexes. Vesting the preponderance of family resources in one heir increased the likelihood of at least one line surviving across several generations, whereas varying degrees of parental investment in emigrating sons or out-marrying daughters might yield boom or bust harvests of grandchildren according to circumstances in more remote locales. Primogeniture (eldest son as primary heir) allowed early identification of heirs and appropriate socialization, as well as more time for parents to contribute to the heir’s reproductive success. Son bias and unigeniture decreased as numbers of children per family declined, as land became less critical to economic success, and as legal changes improved the resource-holding potential of females. We suggest that changing ecological conditions affected parental decisions regarding resource allocation among children at least as much as did changing ideologies of parent-child relations.

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.

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.

Enhanced virulence of pathogens infecting host populations, with no previous exposure thereto, is characteristic of many diseases labelled “emerging” or “resurging”. One cause of emergence characteristics can be interpreted as absence of co-evolutionary optimization of interactions between hosts and pathogens. We explore the historical and evolutionary development between Ross River virus (RRV) and its human host in Australia; a mosquito vectored pathogen causing polyarthritic symptoms. Epidemics of RRV have increased in frequency, size and range throughout European settlement. We hypothesise that human cultural evolution contributed to the emergence of RRV in humans, and argue that epidemics of RRV were unlikely to occur in Aboriginal hunter–gatherer societies in Australia’s early human history, but only occur in more recent agrarian and industrial societies. A perspective of cultural evolution, in addition to biological evolution, may help with understanding the determinants of disease emergence and resurgence, and inform ongoing development of effective public health interventions. Refereed/Peer-reviewed

A mail survey of physicians from Sacramento, California, elicited information on perceptions of consumer satisfaction, service quality for 10 types of service providers including physicians and the importance ratings of 12 choice criteria for the selection of a physician by consumers. The two most important selection criteria for physicians as perceived for consumers by physicians were ‘consumer's previous experience with provider’ and ‘reputation/recommendation’. The results are compared with an earlier consumer survey.

The singing behaviour of 3 pairs of white-cheeked gibbons (Nomascus leucogenys) held at the Perth Zoo was observed for 6 months in 2005. These groups included a family (mated pair and 2 immature offspring) and a pair without offspring. During the study, the female without offspring was exchanged for an unpaired female from New Zealand. After the new pair had been released onto the island enclosure and began to duet, the duetting rate of the white-cheeked gibbon family increased. The increased singing began after the new female had started to sing solo female great calls. These observations support the hypothesis that duets have an intergroup communication function in white-cheeked gibbons. The pair that duetted most frequently also copulated most frequently but allogroomed the least. We suggest that duetting may be more important to intergroup relations than to pair bond maintenance in this species.

Carey James R . Judge Debra S - Principes de biodémographie avec référence particulière à la longévité humaine Le présent article décrit un ensemble de « principes » biodémographiques fondamentaux se rapportant a la senescence, la mortalité et la longévité, derives en majeure partie (mais pas exclusivement) d'études à grande échelle de tables de survie de la mouche méditerranéenne des fruits, d'une base de données récente sur la longévité des vertèbres et de données sur la longévité humaine et la fécondité des femmes franco-canadiennes au XVIIe siècle La longévité humaine est ensuite replacée dans un contexte biodemographique en se référant à ces « principes » derives ainsi qu'aux concepts connexes suivants (i) la biodemographie comparative (c'est-a-dire les humains en tant que primates), (n) les determinants immédiats de la longévité, (ш) le coût de la procréation, (îv) la mortalité et les phases de croissance humaine, (v) le groupe familial et la longévité et (vi) le caractère cumulatif de l'allongement de la vie humaine L article s'achève par une brève discussion sur la complémentarité entre le domaine emergent de la biodemographie et la démographie traditionnelle, Carfy James R . JrDdE Debra S.- Principles de biodemograffa con especial referencia a la longevidad humana El présente articulo describe un conjunto de "pnncipios" biodemográficos fundamen- tales relativos a la senescencia, la mortalidad y la longevidad Estos pnncipios se denvan en gran parte (aunque no exclusivamente) de estudios a gran escala de tablas de mortalidad de la mosca de truta mediterranea, de una base de datos reciente relativa a la longevidad de los ver- tebrados y de datos sobre la longevidad humana y la tecundidad de las mujeres rranco-cana- dienses en el siglo XVII En este articulo anahzamos la longevidad desde una perspectiva biodemogratica basandonos en los "pnncipios" descntos y en una série de conceptos conexos (i) la biodemogratia comparativa (humanos en tanto que primates), (11) los déterminantes în- mediatos de la longevidad, (ni) el coste de la procreacion, (îv) la mortalidad y las fases de crecimiento humano, (v) el grupo familiar y la longevidad y (vi) el caracter cumulativo y la extension de la vida humana El articulo termina con una brève discusion sobre la complemen- tanedad entre la biodemogratia como disciplina émergente y la demogratia tradicional, Carey J.R., Judge D. S. Principes de biodémographie avec référence particulière à la longévité humaine. In: Population, 56ᵉ année, n°1-2, 2001. Perspectives biodémographiques de la longévité humaine, sous la direction de Jean-Marie Robine. pp. 13-49.

Sex differences in behavior are most interesting when they are the result of inherent differences in the operational rules motivating behavior and not merely a reflection of differing life history experiences. American men and women exhibit a few differences in testamentary patterns of property allocation that appear to be due to inherently different rules of allocation. Even when analyses control for resources and surviving kin configurations, women distribute their property among a greater number of individual beneficiaries than do men. The most striking differences in property allocation between men and women occur within the nuclear family and reflect differences in reproductive life span and the resulting reproductive conflicts between spouses that can endure beyond death.

A 21-day study of captive bonnet macaques at the California Primate Research Center during the 1973 birth season showed that females with new infants are spaced significantly closer to a central adult male than are pregnant females.

In general, “marketing” of any product addresses problems of product acceptance, pricing, distribution, and advertising (Nelson 1982). Sweetness may be associated with pricing to the extent that various levels and types of sweetener affect production costs and acceptability. Sweetness can have a role in product distribution in cases where potential, geographically distinct markets showed large differences in preferred levels of product sweetness. However, the most significant incorporation of product sweetness into marketing can be broken down into (a) the use of sweetness in increasing the market of a given product without specific reference to sweetness itself (i.e., sweetness as a tool to increase product acceptance), and (b) explicit marketing of the sweetness of the product (e.g., use of sweetness of the product as an advertising element). The first is more an element of product development but some methodological similarities with marketing are noteworthy. Naturally, for a specific product both of these elements could be involved to a greater or lesser degree.