The Roles of Sex,Mass and Individual Specialisation in Partitioning Foraging-Depth Niches of a Pursuit-Diving Predator

Intra-specific foraging niche partitioning can arise due to gender differences or individual specialisation in behaviour or prey selection. These may in turn be related to sexual size dimorphism or individual variation in body size through allometry. These variables are often inter-related and challenging to separate statistically. We present a case study in which the effects of sex, body mass and individual specialisation on the dive depths of the South Georgia shag on Bird Island, South Georgia are investigated simultaneously using a linear mixed model. The nested random effects of trip within individual explained a highly significant amount of the variance. The effects of sex and body mass were both significant independently but could not be separated statistically owing to them being strongly interrelated. Variance components analysis revealed that 45.5% of the variation occurred among individuals, 22.6% among trips and 31.8% among Dives, while R² approximations showed gender explained 31.4% and body mass 55.9% of the variation among individuals. Male dive depths were more variable than those of females at the levels of individual, trip and dive. The effect of body mass on individual dive depths was only marginally significant within sexes. The percentage of individual variation in dive depths explained by mass was trivial in males (0.8%) but substantial in females (24.1%), suggesting that differences in dive depths among males was largely due to them adopting different behavioural strategies whereas in females allometry played an additional role. Niche partitioning in the study population therefore appears to be achieved through the interactive effects of individual specialisation and gender upon vertical foraging patch selection, and has the potential to interact in complex ways with other axes of the niche hypervolume such as foraging locations, timing of foraging and diet.     

The relationship between cranial metric and nonmetric traits in the rhesus macaques from Cayo Santiago

This study addresses the relationship between cranial metric variables and nonmetric traits using the skeletal sample of rhesus macaques from Cayo Santiago. Discriminant function analysis is used to study the metric differences between macaque crania grouped according to the presence or absence of nine nonmetric traits. The computation of total structure coefficients from the discriminant function analyses provides information regarding how closely each metric variable is related to the discriminant functions derived. Total structure coefficients have not been used previously in the study of the relationship between metric and nonmetric traits. The results of the analysis are interpreted using an explicit approach to cranial morphogenesis-functional cranial analysis. It is concluded that the relationship between cranial metric and nonmetric traits is explicable in terms of a common developmental pathway shared by the two types of traits. Identification of the specific etiology of nonmetric traits depends on future anatomical studies or organisms throughout the period of nonmetric trait development.     

Genetic Structure and Kinship Patterns in a Population of Black Howler Monkeys, Alouatta pigra, at Palenque National Park, Mexico

We investigated the genetic structure and kinship patterns of black howler monkeys (Alouatta pigra) at Palenque National Park, Mexico. Fecal samples from 49 individuals residing in eight social groups were successfully genotyped for 19 polymorphic microsatellite markers known to be variable in other ateline primates. Overall, genetic diversity was low (H_o = 0.588) with an average of 4.2 alleles per loci (range = 2–8). We found that intergroup genetic variation among adults was relatively high (mean between‐group F_ST = 0.119), largely due to the genetic divergence of one study group from the others. Intragroup kinship patterns showed that in most social groups, either adult males, adult females, or individuals of both sexes resided with same‐sexed adult kin, suggesting that some black howler males and females may not disperse from their natal group or may disperse with related individuals. Of the six sampled immigrant males, two males joined established groups by themselves, and four males formed two pairs that each took over the social group they joined after evicting the resident males. Males in both these coalitions were genetically closely related, while the two solitary immigrants were not closely related to any of the resident males present in the group they joined. Am. J. Primatol. 74:948‐957, 2012. © 2012 Wiley Periodicals, Inc.     

Monogamous male mice bias behaviour towards females according to very small differences in kinship

To the extent that relatedness between mates predicts their reproductive success, individuals are expected to bias their behaviours towards opposite-sex conspecifics according to differences in kinship. Here we show that monogamous male oldfield mice, Peromyscus polionotus rhoadsi, bias their social behaviour towards unfamiliar, distantly related females according to an average 1.3% difference in their kinship to these potential mates. Males in the present study favoured less-related females. Previous empirical investigations have not demonstrated behavioural biases based on such small kinship differences. Consequently, these small differences in kinship have been considered inadequate to drive the evolution of mate choice, particularly by males. Even a small incremental difference in mate quality, however, may significantly affect male reproductive success, especially for monogamous species or those that require maternal care. This study has demonstrated that the social preferences of male oldfield mice are distributed between females according to small differences in their kinship to these potential mates. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour      

Sex differences in the Ilia of a known sex and age sample of fetal and infant Skeletons

Ilia from a known sex, race, and age sample of fetal and infant skeletons from the collections of the Smithsonian Institution were evaluated for six metric and one nonmetric characters. Three indices calculated from the measurements were analyzed. The nonmetric trait was examined for fit with known sex. The three indices failed to show significant sex differences. The nonmetric trait, Auricular Surface Elevation, proved dependable (91% accurate) for the male Fetal and Six Month age groups.     

藏族的体质特征

本文共调查藏族145人(男105人,女40人)。年龄均在20岁以上。各项测量均值与不同地区汉族和其他少数民族的聚类分析和大小距离分析的结果表明,藏族的体质特征与华北、西北地区的少数民族和汉族最接近。作者认为藏族是从西藏地区新石器时代居民发展而来,经华北古代居民的不断迁入和混杂、逐渐形成今日的藏族体质类型。     

Dispersal,kinship and inbreeding in an island population of the Great Tit

We investigated the kinship structure of an island population of the Great Tit (Parus major). Kinship of birds could be inferred by comparing their family trees. Dispersal was also studied to explain the observed pattern of kinship. On the island of Vlieland the tits breed in several wooded areas. Both males and females preferred to breed in their natal area; males did so more strongly than females. Hence gene flow between the areas is restricted. However, within the largest wooded area females showed random dispersal, while males showed a slight tendency to breed near their natal site. The degree of kinship of neighbouring birds is a suitable control group for the relatedness of partners that takes into account the effects of dispersal. In the largest wooded area, birds were on average equally related to their partner and to their neighbours. Moreover, the mean coefficient of kinship between male and female neighbours was equal to the average kinship in this part of the population. We conclude that mating is random with respect to kinship. There is no evidence for avoidance of inbreeding. It is unlikely that kin recognition plays an important role in the process of mate choice in this population of Great Tits. We suggest that ecological factors are the main causes for the observed patterns of dispersal and mating. On the island more female than male immigrants enter the population each year. Incidental data indicate an exchange of birds between the population studied and surrounding populations. Ancestries of immigrants are not known, and indeed a first analysis of all birds, including immigrants, showed that males were more closely related than females. However, differential immigration could not fully explain the observed difference in kinship. The presence of local adaptation in males is suggested as a possible additional cause.     

Latent structure of dermatoglyphics in gastric cancer patients

Gastric cancer is a very common malignant disease, which etiology is still unknown. It is believed that it is caused by a joint activity of both genetic and environmental factors. Gastric cancer between relatives in some families is almost four times higher and in connection with truncating mutations in the E-cadherin gene. The Helicobacter pylori are also established carcinogen and this infection increases the cancer risk by about 5 times. Digito-palmar dermatoglyphics have already been used for determining hereditary base of some malignant diseases (breast, lung, colorectal cancer etc.), which was the encouragement to investigate the latent structure in patients with gastric cancer (36 males and 32 females) and the control groups (50 males and 50 females). The factor analysis has shown that in both males and females with gastric cancer 5 factors were extracted and in males 77.17% and in females 78.92% of total variance was explained, and this result is different from control group where in males 5 factors and 75.97% of total variance were explained while in control females 6 factors and 82.86% of total variance were explained. The finger ridge counts are extracted on the first factor in all groups. In patients the second factor is formed by the first, fourth and fifth fingers, while in controls mostly by palmar variables. From the obtained findings it can be concluded that the results of latent structure in quantitative analysis of digito-palmar dermatoglyphics are affirming the existence of genetic differences in patients suffered with gastric cancer.     

Analysis of genetic and environmental sources of variation in serum cholesterol in Tecumseh, Michigan. I. Analysis of the frequency distribution for evidence of a genetic polymorphism.

Analyses of serum cholesterol measurements on 4,619 males and 4,730 females residing in the community of Tecumseh, Michigan, were conducted to estimate the contribution of sex, age, temporal variation, and bimodality to determining the normal variation among individuals sampled without regard to their health status. Female values had a higher mean (2.8 mg/100 ml greater) but smaller variance than males when adjusted by polynomial regression to a common age. Positive skew in the frequency distribution for both sexes was removed by natural logarithm (ln) transformation. Age variation accounted for 28.5% and 29.4% of the variance in a ln cholesterol measurement of males and females, respectively. Between 7% and 10% of the variance in a ln cholesterol value was estimated to be attributable to differences between age-adjusted replicate measurements of the same individual. The reduction in individual variability by adjustment for these contributions to variance will allow a more precise evaluation of the relative contribution of alternate genetic hypotheses as explanations for normal variation in cholesterol. Assuming bimodality, approximately one in 1,000 males and one in 1,000 females belong to a second mode of hypercholesterolemic individuals. The locus determining familial hypercholesterolemia is not a major source of normal phenotypic variation in the Tecumseh population.     

Inter-sex and intra-sex differences in quantitative digital dermatoglyphics of Sardinian-speaking groups

In this study, we analysed inter-sex differences within two linguistic groups from the Sardinian linguistic area and intra-sex differences between the two groups by means of 41 quantitative digital dermatoglyphic variables: 20 digital dermatoglyphic traits (radial and ulnar ridge counts on each of the 10 fingers), 15 digital dermatoglyphic directional asymmetry variables, total finger ridge count, bilateral summed radial and ulnar finger ridge counts, an index of asymmetry between homologous fingers, and two indices of intra-individual diversity of finger ridge counts. The comparisons between males and females within the same linguistic groups and between the males of the two groups and the females of the two groups were carried out with the Mann-Whitney test at a prefixed level of alpha = 0.05, using the Bonferroni correction for multiple comparisons. The results indicate a strong similarity of the two linguistic groups in the inter-sex differences, whereas there are no significant differences between them for either males or females. The similar pattern of sexual dimorphism and the homogeneity of the males and females of the two groups suggest a common genetic matrix of these Sardinian-speaking groups.     

Morphometrics of speciating mole rats: Adaptive differentiation in ecological speciation

The morphometrics of subterranean mole rats, Spalax ehrenbergi superspecies in Israel, were studied. A total of 42 skull and body variables of 327 adults from 44 populations across the ranges of the 4 chromosomal species (2n = 52, 54, 58 and 60) were measured. The results showed: a. in general, significantly higher morphological values in males than in females; b. significant interspecific quantitative diffferences in 15 skull variables of males, and in 3 of females; but no qualitative diagnosis of any of the species; c. an intercorrelation between most skull variables at different orgamsmal levels, and a uniform and complete correlation with weight; d. a statistical discrimination in both metric and nonmetric multivariate analyses between most species pairs; e. an indication of high morphological similarity based on the relatively small multivariate Mahalanobis distances of dissimilarity between species; f. a possible explanation for a significant part of the variance in most skull and body variables resulting from a combination of temperature variables and water availability; g. a declination in size in skull and body variables between northern and southern species; h. the order of speciation events to be 2n = (54, 52)→58→60. Based on these results we conclude: 1. no morphological breaks are associated with the speciation of the S. ehrenbergi complex, and morphological differentiation is quantitative rather than qualitative between the species: 2. morphological diversity is significantly explained by climatic selection, and is therefore adaptive and explicable on even very low selective pressures over evolutionary time: 3. the morphospecies seem unable to reliably reflect the biological species in the S. ehrenbergi complex, and morphological differentiation, at least in this superspecies, evolves in a gradual rather than a punctual way: this would conform with Neo-Darwinian evolutionary theory.     

Alloparental care and kinship in captive social groups of vervet monkeys (Cercopithecus aethiops sabaeus)

Estimates of alloparental behavior on the basis of kinship and maternal qualities of permissiveness/restrictiveness were examined in vervet mother-infant pairs. Amounts of alloparenting were examined for the subgroup categories female siblings, juvenile females, subadult nulliparous females, adult females, males, and yearlings. Analysis of the six subgroups for months 1 through 6 revealed that the most alloparenting occurred in month 1 with siblings caretaking more than any other subgroup. By month 2 subadult nulliparous females were the most frequent caretakers. Correlations between kin alloparenting and maternal permissiveness/restrictiveness indicated that kinship was a better predictor of alloparenting than maternal qualities of permissiveness. Additionally, examination of the data on maternal behaviors towards related and unrelated individuals revealed significant differences by months.     

The interaction between nonmetric and metric cranial variation.

Cranial discrete or 'epigenetic" traits have been analyzed for interrelationships with measurements of the skull in a sample of American Negro males. Univariate t and multivariate T2 tests are used. It has been the previous consensus view that nonmetric and metric characters are unrelated. Statistically significant associations between the total of 50 discrete and 23 metrical characters, however, are much more frequent than would be expected through random distribution. Multivariate analysis supplements simpler statistics by synthesizing patterns of variation within regions of the skull, identifying many interrelations of skull size and shape with discrete traits. A low but observable general influence is exerted upon nonmetric morphology by metrical variation of the human skull (or vice versa).     

Anthropology of the Late Period cemetery in the Tomb of King Horemheb at Saqqara (Egypt) (preliminary report)

Anthropological material unearthed by the excavation of the Egypt Exploration Society (London) in the Tomb of King Horemheb at Saqqara consists of original burials dated 14th cent. B.C., of a series of 18 individuals dated 13th cent. B.C. and of a large amount of material (seven burials and a lot of scattered isolated bones) from a secondary cemetery dated Late Period. In it the total number of individuals was determined as 260, divided into 37.3% immatures and 62.7% adults, which consist of 60.7% males and 39.3% females. The mean age at death was for the whole series 24.1 years, for adult males 33.3 years and for adult females 29.4 years. In all metric features a well-cut sexual dimorphism is apparent and a similarity with a contemporary nearly located series from the Mastaba of Ptahshepses at Abusir. The average stature reconstructed by the Negro equations of Trotter and Gleser equals 166.5 cm for males and 154.7 cm for females. Cranioscopic, epigenetic and osteoscopic features, however, showed many differences between the Horemheb and the Ptahshepses series. The paleopathological study revealed cases of traumatism, inflammations, degenerative osteoarthropathies, benign as well as malign tumours, anaemias, congenital anomalies, senile changes and dental diseases.     

Early growth,dominance acquisition and lifetime reproductive success in male and female cooperative meerkats

In polygynous species, variance in reproductive success is higher in males than females. There is consequently stronger selection for competitive traits in males and early growth can have a greater influence on later fitness in males than in females. As yet, little is known about sex differences in the effect of early growth on subsequent breeding success in species where variance in reproductive success is higher in females than males, and competitive traits are under stronger selection in females. Greater variance in reproductive success has been documented in several singular cooperative breeders. Here, we investigated consequences of early growth for later reproductive success in wild meerkats. We found that, despite the absence of dimorphism, females who exhibited faster growth until nutritional independence were more likely to become dominant, whereas early growth did not affect dominance acquisition in males. Among those individuals who attained dominance, there was no further influence of early growth on dominance tenure or lifetime reproductive success in males or females. These findings suggest that early growth effects on competitive abilities and fitness may reflect the intensity of intrasexual competition even in sexually monomorphic species.     

Kinship shapes affiliative social networks but not aggression in ring-tailed coatis

Animal groups typically contain individuals with varying degrees of genetic relatedness, and this variation in kinship has a major influence on patterns of aggression and affiliative behaviors. This link between kinship and social behavior underlies socioecological models which have been developed to explain how and why different types of animal societies evolve. We tested if kinship and age-sex class homophily in two groups of ring-tailed coatis (Nasua nasua) predicted the network structure of three different social behaviors: 1) association, 2) grooming, and 3) aggression. Each group was studied during two consecutive years, resulting in four group-years available for analysis (total of 65 individuals). Association patterns were heavily influenced by agonistic interactions which typically occurred during feeding competition. Grooming networks were shaped by mother-offspring bonds, female-female social relationships, and a strong social attraction to adult males. Mother-offspring pairs were more likely to associate and groom each other, but relatedness had no effect on patterns of aggressive behavior. Additionally, kinship had little to no effect on coalitionary support during agonistic interactions. Adult females commonly came to the aid of juveniles during fights with other group members, but females often supported juveniles who were not their offspring (57% of coalitionary interactions). These patterns did not conform to predictions from socioecological models.     

Hand locomotor functions, body structure, and epidermal ridge patterns: preliminary study

The purpose of this study was to determine whether any relationships exist between hand locomotor functions and dermatoglyphic characteristics and body structure. The pilot sample consisted of 71 adult normal individuals (30 males and 41 females). The locomotor function tests included a power grip and two precision grips; dermatoglyphic features were represented by finger and palmar pattern intensities and ridge counts, and body structure by 35 head, face, trunk, and limb anthropometric measurements. Univariate and multivariate correlation analyses reveal that on average half of the variance in the locomotor hand-function tests can be accounted for by a set of body and/or dermatoglyphic variables in males; this contribution is appreciably lower in females. Body longitudinal measurements and some facial measures, such as jaw length, were found to be the main correlates of either a power grip or a simple thumb-index squeeze, especially in males; head and face measurements and the size and intensity of patterns on fingers 1 and 2 were the main correlates of more complex precision tests involving complicated manipulation of objects using the thumb and index finger. These preliminary results identify some previously unknown sources of variation in dermatoglyphic patterns and contribute to a better understanding of the evolutionary aspects of the relationships between specific functional and morphologic traits in humans.     

The Influence of Kinship on Familiar Natal Migrant Rhesus Macaques (Macaca mulatta)

In most primate species, females remain in the natal group with kin while males disperse away from kin around the time of puberty. Philopatric females bias their social behavior toward familiar maternal and paternal kin in several species, but little is known about kin bias in the dispersing sex. Male dispersal is likely to be costly because males encounter an increased risk of predation and death, which might be reduced by dispersing together with kin and/or familiar males (individuals that were born and grew up in same natal group) or into a group containing kin and/or familiar males. Here we studied the influence of kinship on familiar natal migrant rhesus macaques (Macaca mulatta) on Cayo Santiago, Puerto Rico, by combining demographic, behavioral, and genetic data. Our data suggest that kinship influences spatial proximity between recent natal immigrants and males familiar to them. Immigrants were significantly nearer to more closely related familiar males than to more distantly related individuals. Within a familiar subgroup, natal migrants were significantly closer to maternal kin, followed by paternal kin, then non-kin, and finally to males related via both the maternal and paternal line. Spatial proximity between natal immigrants and familiar males did not decrease over time in the new group, suggesting that there is no decline in associations between these individuals within the first months of immigration. Overall, our results might indicate that kinship is important for the dispersing sex, at least during natal dispersal when kin are still available.     

The effectiveness of scaling procedures for comparing ground reaction forces

Various scaling methods are used when attempting to remove the influence of anthropometric differences on ground reaction forces (GRF) when comparing groups. Though commonly used, ratio scaling often results in an over-correction. Allometric scaling has previously been suggested for kinetic variables but its effectiveness in partialing out the effect of anthropometrics is unknown due to a lack of consistent application. This study examined the effectiveness of allometric scaling vertical, braking and propulsive GRF and loading rate for 84 males and 47 females while running at 4.0 m/s. Raw, unfiltered data were ratio scaled by body mass (BM), height (HT), and BM multiplied by HT (BM1HT). Gender specific exponents for allometric scaling were determined by performing a log-linear (for BM and HT individually) or log-multilinear regression (BMHT). Pearson productmoment correlations were used to assess the effectiveness of each scaling method. Ratio scaling by BM, HT, or BM1HT resulted in an over-correction of the data for most variables and left a considerable portion of the variance still attributable to anthropometrics. Allometric scaling by BM successfully removed the effect of BM and HT for all variables except for braking GRF in males and vertical GRF in females. However, allometric scaling for BMHT successfully removed the effect of BM and HT for all reactionary forces in both genders. Based on these results, allometric scaling for BMHT was the most appropriate scaling method for partialing out the effect of BM and HT on kinetic variables to allow for effective comparisons between groups or individuals.