Body mass and growth rates in captive chimpanzees (Pan troglodytes) cared for in African wildlife sanctuaries,zoological institutions,and research facilities

Captive chimpanzees (Pan troglodytes) mature earlier in body mass and have a greater growth rate compared to wild individuals. However, relatively little is known about how growth parameters compare between chimpanzees living in different captive environments. To investigate, body mass was measured in 298 African sanctuary chimpanzees and was acquired from 1030 zoological and 442 research chimpanzees, using data repositories. An analysis of covariance, adjusting for age, was performed to assess same-sex body mass differences between adult sanctuary, zoological, and research populations. Piecewise linear regression was performed to estimate sex-specific growth rates and the age at maturation, which were compared between sexes and across populations using extra-sum-of-squares F tests. Adult body mass was greater in the zoological and resarch populations compared to the sanctuary chimpanzees, in both sexes. Male and female sanctuary chimpanzees were estimated to have a slower rate of growth compared with their zoological and research counterparts. Additionally, male sanctuary chimpanzees were estimated to have an older age at maturation for body mass compared with zoological and research males, whereas the age at maturation was similar across female populations. For both the zoological and research populations, the estimated growth rate was greater in males compared to females. Together, these data contribute to current understanding of growth and maturation in this species and suggest marked differences between the growth patterns of chimpanzees living in different captive environments.     

A simplified method to estimate body growth parameters of the European eel Anguilla anguilla

A simple approach is proposed to fit a body growth model for the European eel Anguilla anguilla to data‐poor case studies. The model is a modified von Bertalanffy curve allowing for delayed sex determination and sexual dimorphism. The proposed procedure provides preliminary estimates of model parameters on the basis of average age and body length of silver eels.     

Reproductive aging in captive and wild common chimpanzees: factors influencing the rate of follicular depletion

We examine and discuss evidence of contrasting differences in fertility patterns between captive and wild female chimpanzees, Pan troglodytes, as they age; in the wild females reproduce in their 40s, but captive studies suggest that menopause occurs around that time. Thus, despite the increased longevity generally observed in captive populations reproductive life span is shortened. We outline a hypothesis to explain the apparent differential pace of reproductive decline observed between wild and captive populations. The breeding schedules of captive primates may contribute to accelerated reproductive senescence because continuous cycling in captive animals results in early depletion of the ovarian stock and premature senescence. Available evidence supports the hypothesis that women with patterns of high oocyte loss experience earlier menopause. Chimpanzees in captivity live longer, and thus, similar to humans, they may experience follicular depletion that precedes death by many years. In captivity, chimpanzees typically have an early age at menarche and first birth, shorter interbirth intervals associated with short lactational periods as young mature faster, and nursery rearing, which allows mothers to begin cycling earlier. Variables typical of wild chimpanzee populations, including late age at menarche and first birth, long interbirth intervals associated with prolonged lactational periods, and a long period of female infertility after immigration, spare ovulations and may be responsible for the later age at reproductive termination. Finally, we describe and discuss the timing of specific reproductive landmarks that occur as female chimpanzees age, distinguishing between functional menopause (age at last birth) and operational menopause (end of cycling). Am. J. Primatol. 71:271–282, 2009. © 2008 Wiley‐Liss, Inc.     

Sexual dimorphism in growth from 8 to 18 years

A mixed longitudinal study of growth and development has been conducted, centering on an analysis of differences based on sex between the ages of 8 and 18 years for a series of 12 anthropometric indicators. The sample consisted of 50 girls and 63 boys. Proceeding from the specific differences, the variables can be divided into four groups with identical structures of differences. The first group comprises measurements of body height, body mass, shoulder width and pelvic span, all of which have higher values in boys between 8 and 10 and between 14 and 18. Between the ages of 11 and 13 girls are taller, heavier, with broader shoulders and pelvises. The second group covers measurements of subcutaneous fat. which are higher for girls throughout the period under review. The third group of indicators comprises the diameters of the joints of the extremities, i.e. of elbows and knees. Throughout the period under observation, these measurements are higher in boys, with the absolute differences between the sexes being the same at the age of 8 and ten years later. The fourth group consists of circumferences measurements of the extremities. It was found that calf circumferences manifested a specific inversion of the curves between 14 and 15, with girls showing a larger calf circumference up to the age of 14, and boys from the age of 15. The effect of earlier onset of puberty in girls was found to be reflected only on the inversion of the curve flow of the variables from the first group.     

Ontogeny of facial dimorphism and patterns of individual development within one human population

Based on a longitudinal study of radiographs of the Denver Growth Study, we investigated the morphological development of individual and gender differences in the anterior neurocranium, face, and basicranium. In total, 500 X-rays of 14 males and 14 females, each with 18 landmarks and semilandmarks, were digitized and analyzed using geometric morphometric methods. Sexual dimorphism in shape and form is already present at the earliest age stage included in the analysis. However, the nature of dimorphism changes with age. Four factors apper to contribute to cranial sexual dimorphism in human postnatal development: 1) initial, possibly prenatal, differences in shape; 2) differences in the association of size and shape; 3) male hypermorphosis; and 4) some degree of difference in the direction of male and female growth trajectories. Studying changes in individuals, we find a low correlation between newborn and adult morphology, while 3-year-olds already show a high correlation with their adult form. We conclude that the adult pattern of interindividual difference in facial form in a single human population is established within the first few years of life.     

Behavior of giant pandas (Ailuropoda melanoleuca) in captive conditions: Gender differences and enclosure effects

The behavior of giant pandas (Ailuropoda melanoleuca) was studied under captive conditions. Both male and female pandas spent similar amounts of time engaged in eating and locomotion. Males performed anogenital‐marking more but rested less than females, which suggests a sexually dimorphic pattern of behavior. Furthermore, females housed in the seminatural environment spent significantly less time engaged in stereotyped behavior than did females housed in the traditional enclosure, indicating that an enclosure environment affects the behavior of giant pandas. These data illustrate the importance of careful management and facility design for captive giant pandas. Zoo Biol 22:77–82, 2003. © 2003 Wiley‐Liss, Inc.     

Morphometrics and pattern of growth in wild sifakas (Propithecus edwardsi) at ranomafana national park,madagascar

We summarize morphometric data collected over a period of 22 years from a natural population of rainforest sifakas (Propithecus edwardsi) at Ranomafana National Park, Madagascar, and we use those data to document patterns of growth and development. Individually identified, known‐age sifakas were successfully captured, measured, and released. We found that body segment lengths increased faster during growth than did body mass, with individuals attaining adult lengths earlier than adult mass. Females can begin reproducing before they are fully grown, but this may not be common. With the exception of hand length, we found no significant sex difference in any adult metric including body mass, chest, and limb circumferences, body segment lengths, and canine tooth height; however, body masses of individual females fluctuated more, independently of pregnancy, than did those of males. We found considerable interannual fluctuation in body mass with single individuals differing more within the same season in different years than from season to season in the same year. Such body mass fluctuation may be a consequence of eastern Madagascar's variable and unpredictable environment in which rainfall during any selected month varies from year to year. Am. J. Primatol. 73:155–172, 2011. © 2010 Wiley‐Liss, Inc.     

Morphometric study and sexual dimorphism analyses in an Iranian population of Scorpio maurus (Arachnida: Scorpionidae)

Natural selection and sexual selection are cardinal factors in shaping the body of animals such as scorpions. Scorpio maurus (Scorpiones: Scorpionidae) has a worldwide distribution. Sexual dimorphism has been reported from this species in a study in Egypt. Morphometry is used to determine the sexual dimorphism between the two sexes. In the current study, scorpions were collected from six locations of the southern and northern provinces of Fars, Iran. In this study, 53 morphological characters of 15 specimens of each sex of Scorpio maurus were studied based on statistical analyses; however, dimorphism was only observed in 21 morphological characters, including chelicerae and carapace length, pedipalp characters, width of the second segment of metasoma, telson and pectin length, number of left pectin teeth, and some of the leg''s segments. It means that these characters are in the control of sexual and natural selection. This study was performed for the first time on Scorpio maurus species in Iran.     

Sex matters: Otolith shape and genomic variation in deacon rockfish (Sebastes diaconus)

Little is known about intraspecific variation within the deacon rockfish (Sebastes diaconus), a recently described species found in the northeast Pacific Ocean. We investigated population structure among fish sampled from two nearshore reefs (Siletz Reef and Seal Rock) and one offshore site (Stonewall Bank) within a <50‐km² area off the Oregon coast. Fish from the three sample sites exhibited small but statistically significant differences based on genetic variation at >15,000 neutral loci, whether analyzed independently or classified into nearshore and offshore groups. Male and females were readily distinguished using genetic data and 92 outlier loci were associated with sex, potentially indicating differential selection between males and females. Morphometric results indicated that there was significant secondary sexual dimorphism in otolith shape, but further sampling is required to disentangle potential confounding influence of age. This study is the first step toward understanding intraspecific variation within the deacon rockfish and the potential management implications. Since differentiation among the three sample sites was small, we consider the results to be suggestive of a single stock. However, future studies should evaluate how the stock is affected by differences in sex, age, and gene flow between the nearshore and offshore environments.     

Pelvic growth: ontogeny of size and shape sexual dimorphism in rat pelves

The mammalian pelvis is sexually dimorphic with respect to both size and shape. Yet little is known about the differences in postnatal growth and bone remodeling that generate adult sexual dimorphism in pelvic bones. We used Sprague-Dawley laboratory rats (Rattus norvegicus), a species that exhibits gross pelvic size and shape dimorphism, as a model to quantify pelvic morphology throughout ontogeny. We employed landmark-based geometric morphometrics methodology on digitized landmarks from radiographs to test for sexual dimorphism in size and shape, and to examine differences in the rates, magnitudes, and directional patterns of shape change during growth. On the basis of statistical significance testing, the sexes became different with respect to pelvic shape by 36 days of age, earlier than the onset of size dimorphism (45 days), although visible shape differences were observed as early as at 22 days. Males achieved larger pelvic sizes by growing faster throughout ontogeny. However, the rates of shape change in the pelvis were greater in females for nearly all time intervals scrutinized. We found that trajectories of shape change were parallel in the two sexes until age of 45 days, suggesting that both sexes underwent similar bone remodeling until puberty. After 45 days, but before reproductive maturity, shape change trajectories diverged because of specific changes in the female pelvic shape, possibly due to the influence of estrogens. Pattern of male pelvic bone remodeling remained the same throughout ontogeny, suggesting that androgen effects on male pelvic morphology were constant and did not contribute to specific shape changes at puberty. These results could be used to direct additional research on the mechanisms that generate skeletal dimorphisms at different levels of biological organization.     

Telemetered electromyography of the supinators and pronators of the forearm in gibbons and chimpanzees: implications for the fundamental positional adaptation of hominoids.

Extant apes are similar to one another, and different from monkeys, in features granting them greater range of forearm rotation and greater size of the muscles that produce this motion. Although these traits may have been independently acquired by the various apes, the possibility arises that such features reflect adaptation to the stem behavior of the hominoid lineage. Anticipating that knowledge of forearm rotatory muscle recruitment during brachiation, vertical climbing, arm-hanging during feeding, and voluntary reaching might point to this stem behavior, we undertook telemetered electromyographic experiments on the supinator, pronator quadratus, ulnar head of pronator teres, and a variety of other upper limb muscles in two gibbons and four chimpanzees. The primary rotator muscles of the hominoid forearm were recruited at high levels in a variety of behaviors. As had been suspected by previous researchers, the supinator is usually active during the support phase of armswinging, but we observed numerous instances of this behavior during which the muscle was inactive. No other muscle took over its role. Kinetic analyses are required to determine how apes can execute body rotation of armswinging without active muscular effort. The one behavior that is common to most extant apes, is rare in monkeys, and which places a consistently great demand on the primary forearm rotatory muscles, is hang-feeding. The muscles of the supporting limb are essential to properly position the body; those of the free limb are essential for grasping food. Since the greater range of forearm rotation characterizing apes is also best explained by adaptation to this behavior, we join previous authors who assert that it lies at the very origin of the Hominoidea.     

Theft in an ultimatum game: chimpanzees and bonobos are insensitive to unfairness

Humans, but not chimpanzees, punish unfair offers in ultimatum games, suggesting that fairness concerns evolved sometime after the split between the lineages that gave rise to Homo and Pan. However, nothing is known about fairness concerns in the other Pan species, bonobos. Furthermore, apes do not typically offer food to others, but they do react against theft. We presented a novel game, the ultimatum theft game, to both of our closest living relatives. Bonobos and chimpanzee ‘proposers’ consistently stole food from the responders'' portions, but the responders did not reject any non-zero offer. These results support the interpretation that the human sense of fairness is a derived trait.     

Sexual dimorphism in relation to swarming and pair formation patterns in leptocerid caddisflies (Trichoptera: Leptoceridae)

North European Leptoceridae (Trichoptera) perform three types of swarming flight patterns: (1) swarming males of Athripsodesand Ceracleafly in horizontal zigzag patterns over the water surface, (2) the Mystacidesspp. perform vertical zigzag movements, and (3) the flight of males of Triaenodes unanimisMcLach. is a mixture of the horizontal and vertical zigzagging. Also three groups of pair formation behavior can be distinguished. In the first group, of Athripsodesand Ceraclea,the females fly into the male swarms, where they are grasped and carried to the riparian vegetation by the flying males with the females hanging upside-down in genitalia coupling. In the second group, a Mystacidesfemale is caught by a male, when approaching a swarm and both use their wings to fly in tandem to the shore where they copulate. In the third group, of Triaenodes bicolor(Curt.) and Oecetis lacustris(Curt.), the males fly searching for females sitting on aquatic plants and when a female is found the male lands and they copulate immediately while clinging to the plant. The different swarming and mating behaviors might have favored selection for three types of sexual dimorphism: (1) longer forewings in males than females in species which fly in copula, (2) larger eyes in males of the vertically zigzagging species, and (3) much smaller males in the group where males search for females sitting on aquatic plants. In the second group approaching females are detected by males before reaching the swarm and in the third group the female almost always mates with the male which is the first to find her. In conclusion, we suggest that females of Athripsodesand Ceracleahave a greater choice among swarming males than do females of Mystacides, T. bicolor,and O. Lacustris.     

Sex-specific plasticity of growth and maturation size in a spider: implications for sexual size dimorphism

Sex-specific plasticity in body size has been recently proposed to cause intraspecific patterns of variation in sexual size dimorphism (SSD). We reared juvenile male and female Mediterranean tarantulas (Lycosa tarantula) under two feeding regimes and monitored their growth until maturation. Selection gradients calculated across studies show how maturation size is under net stabilizing selection in females and under directional selection in males. This pattern was used to predict that body size should be more canalized in females than in males. As expected, feeding affected male but not female maturation size. The sex-specific response of maturation size was related to a dramatic divergence between subadult male and female growth pathways. These results demonstrate the existence of sex-specific canalization and resource allocation to maturation size in this species, which causes variation in SSD depending on developmental conditions consistent with the differential-plasticity hypothesis explaining Rensch's Rule.     

Sexual dimorphism and growth trade‐offs in Blue Tit Cyanistes caeruleus nestlings

The outcome of sibling competition for food is often determined by variation in body size within the brood and involves trade‐offs; traits that enhance competitive ability within the nest may be developed at the expense of traits that enable effective flight at fledging, or vice versa. We quantified growth of skeletal, body mass and feather traits in male and female Blue Tit Cyanistes caeruleus nestlings. Males were significantly heavier, had longer tarsi and tended to have greater head–bill lengths than females, whereas females were similar to males in wing flight feather growth. These differences in growth may result from sexual differences in selection of the traits. Females are likely to prioritize feather growth to facilitate synchronized fledging with the rest of the brood, and to enhance escape from predators. We suggest that males are heavier and develop longer tarsi because body size is an important determinant of male reproductive success.