Laterality of hand use pays off in foraging success for wild chimpanzees

The aim of this study was to see if behavioral lateralization in hand use benefits a lateralized organism in nature. We recorded wild chimpanzees (Pan troglodytes schweinfurthii) at Gombe, Tanzania, fishing for termites (Macrotermes spp.), an extractive foraging task using elementary technology. We compared individual apes who were completely lateralized, using only one hand or the other for the task, versus those who were incompletely lateralized, using either hand. Exclusively lateralized individuals were more efficient, that is, gathered more prey per unit effort, but were no different in success or error rate from incompletely lateralized apes. This is the first demonstration of a payoff to laterality of behavioral function in primates in conditions of ecological validity.     

Does Bipedality Predict the Group-Level Manual Laterality in Mammals?

Background

Factors determining patterns of laterality manifestation in mammals remain unclear. In primates, the upright posture favours the expression of manual laterality across species, but may have little influence within a species. Whether the bipedalism acts the same in non-primate mammals is unknown. Our recent findings in bipedal and quadrupedal marsupials suggested that differences in laterality pattern, as well as emergence of manual specialization in evolution might depend on species-specific body posture. Here, we evaluated the hypothesis that the postural characteristics are the key variable shaping the manual laterality expression across mammalian species.

Methodology/Principal Findings

We studied forelimb preferences in a most bipedal marsupial, brush-tailed bettong, Bettongia penicillata in four different types of unimanual behavior. The significant left-forelimb preference at the group level was found in all behaviours studied. In unimanual feeding on non-living food, catching live prey and nest-material collecting, all or most subjects were lateralized, and among lateralized bettongs a significant majority displayed left-forelimb bias. Only in unimanual supporting of the body in the tripedal stance the distribution of lateralized and non-lateralized individuals did not differ from chance. Individual preferences were consistent across all types of behaviour. The direction or the strength of forelimb preferences were not affected by the animals’ sex.

Conclusions/Significance

Our findings support the hypothesis that the expression of manual laterality depends on the species-typical postural habit. The interspecies comparison illustrates that in marsupials the increase of bipedality corresponds with the increase of the degree of group-level forelimb preference in a species. Thus, bipedalism can predict pronounced manual laterality at both intra- and interspecific levels in mammals. We also conclude that quadrupedal position in biped species can slightly hinder the expression of manual laterality, but the evoked biped position in quadrupedal species does not necessarily lead to the enhanced manifestation of manual laterality.     

Does the Complexity of the Task Influence Manual Laterality in De Brazza’s Monkeys (Cercopithecus neglectus)?

We assessed the manual preferences of 12 De Brazza's monkeys ( Cercopithecus neglectus ) in spontaneous feeding situations and in two different coordinated bimanual tasks that were not visually guided. We recorded the hand used by each subject for 22 spontaneous activities, hand and digits use while extracting peanut butter from a hollow tube (tube task) and the hand used to extract candies from hanging plastic balls (ball task). Spontaneous activities revealed individual manual preferences but no population-level biases. For both experimental tasks, all subjects were lateralized in their hand use. We found a left bias at the group level for the tube task, but no group-level asymmetry for the ball task. Experimental tasks induced greater strength of laterality than did spontaneous activities. Although the size of our sample did not allow us to draw any conclusions concerning manual preference at the population level, this study stresses the importance of coordinated bimanual tasks to reveal manual laterality in non-human primates.     

Problem-Solving Strategies and Hand Preferences for a Multicomponent Task by Tufted Capuchins (Cebus apella)

We examined hand preferences in 23 tufted capuchins (Cebus apella) in 2 tasks requiring the lid of a box to be lifted before taking out a peanut. The first task, Box 1, could entail either 2 or 3 problem-solving acts, with the 3-act solution involving bimanual coordination for food retrieval. The second task, Box 2, involved only the 3-act solution. The results indicated that the types of solution employed to perform the task influenced capuchin hand preferences. In the 2-act solution, capuchins exhibited a significant right-hand bias for the final one-handed reaching action, but not for the initial lid lifting action. In contrast, in the 3-act solution, no significant asymmetry emerged for any act. We noted a significant effect of subject's sex on the strength of laterality, with males being more strongly lateralized than females. We discuss results in the light of recent models of primate laterality.     

The predatory behaviour of common kestrels facing various types of prey

Nine rehabilitated adult common kestrels (Falco tinnunculus) were tested for predatory behaviour. Tests were carried out individually on four different prey: two invertebrates (grasshopper and earthworm) and two vertebrates (lizard and laboratory mouse). The birds were offered prey randomly once daily, not necessarily on subsequent days. The latency to attack was similar. In contrast to predation tests with vertebrates, kestrels preying on invertebrates landed mostly (P<0.01 for earthworm and P<0.05 for grasshopper) a few centimetres from the prey itself, grasping it after a few steps. Earthworms were gripped almost invariably with the beak, but other prey with the toes. The birds struck the prey with their beak at highly variable rates (P<0.001): vertebrates mostly with the beak, while earthworms were never struck. The latency to ingest prey varied greatly (P<0.001) between prey. Captivity had only limited importance; it did not affect the behaviour sequence on any prey, but just induced kestrels in captivity for long time to attack mice with shorter latency and to strike them more with the beak. It is then demonstrated that the common kestrel has a strong behavioural plasticity even within the predatory sequence, which is then not stereotyped, and is able to modify its behaviour patterns in relation to different prey.An erratum to this article can be found at     

Bipedal tool use strengthens chimpanzee hand preferences

The degree to which non-human primate behavior is lateralized, at either individual or population levels, remains controversial. We investigated the relationship between hand preference and posture during tool use in chimpanzees (Pan troglodytes) during bipedal tool use. We experimentally induced tool use in a supported bipedal posture, an unsupported bipedal posture, and a seated posture. Neither bipedal tool use nor these supported conditions have been previously evaluated in apes. The hypotheses tested were 1) bipedal posture will increase the strength of hand preference, and 2) a bipedal stance, without the use of one hand for support, will elicit a right hand preference. Results supported the first, but not the second hypothesis: bipedalism induced the subjects to become more lateralized, but not in any particular direction. Instead, it appears that subtle pre-existing lateral biases, to either the right or left, were emphasized with increasing postural demands. This result has interesting implications for theories of the evolution of tool use and bipedalism, as the combination of bipedalism and tool use may have helped drive extreme lateralization in modern humans, but cannot alone account for the preponderance of right-handedness.     

Prey preferences of aquatic insects: potential implications for the regulation of wetland mosquitoes

Wetlands are potential sites for mosquito breeding and are thus important in the context of public health. The use of chemical and microbial controls is constrained in wetlands in view of their potential impact on the diverse biota. Biological control using generalist aquatic insects can be effective, provided a preference for mosquito larvae is exhibited. The mosquito prey preferences of water bugs and larvae of odonate species were evaluated using chironomid larvae, fish fingerlings and tadpoles as alternative prey. Manly's selectivity (α_i) values with 95% confidence intervals (CIs) were estimated to judge prey preference patterns. Multivariate analysis of variance (manova) and standardized canonical coefficients were used to test the effects of density on prey selectivity. The α_i values indicated a significant preference (P < 0.05) in all of the insect predators tested for mosquito larvae over the alternative prey as a density‐dependent function. On a comparative scale, chironomid larvae had the highest impact as alternative prey. In a multiple‐prey experiment, predators showed a similar pattern of preference for mosquito larvae over alternative prey, reflecting a significant (P < 0.05) niche overlap. The results suggest that, in a laboratory setting, these insect predators can effectively reduce mosquito density in the presence of multiple alternative prey.     

Immunological Adjuvant Effect of a Water‐Soluble Polysaccharide,CPP, from the Roots of Codonopsis pilosula on the Immune Responses to Ovalbumin in Mice

In this study, one water‐soluble polysaccharide, CPP, was purified from the root of Codonopsis pilosula. The immunomodulatory effect and the adjuvant potential of CPP on the cellular and humoral immune response of ICR mice against ovalbumin (OVA) were investigated. CPP was shown not to be lethal in vivo for mice in doses ranging from 0.5 to 4 mg. ICR Mice were immunized subcutaneously with 0.1 mg of OVA alone or with 0.1 mg of OVA dissolved in saline‐containing aluminum hydroxide gel (Alum) (0.2 mg), QuilA (0.01 and 0.02 mg) or CPP (0.5, 1 or 2 mg) on days 1 and 15. Two weeks later (day 28), concanavalin A (ConA)‐, lipopolysaccharide (LPS)‐, and OVA‐stimulated splenocyte proliferation, and OVA‐specific serum antibodies were measured. CPP significantly enhanced the ConA‐, LPS‐, or OVA‐induced splenocyte proliferation in the OVA‐immunized mice especially at a dose of 1 mg (P<0.05 or P<0.01). The OVA‐specific IgG, IgG1, and IgG2b antibody levels in serum were also significantly enhanced by CPP compared with OVA control group (P<0.05 or P<0.01). The results suggest that CPP could be a safe efficacious adjuvant for use in vaccines against both pathogens and cancer.     

Differential prey use by male and female cougars in Washington

Male and female predators are often assumed to have the same effects on prey. Because of differences in body size and behavior, however, male and female predators may use different species, sexes, and ages of prey, which could have important implications for wildlife conservation and management. We tested for differential prey use by male and female cougars (Puma concolor) from 2003 to 2008 in Washington State. We predicted that male cougars would kill a greater proportion of larger and older prey (i.e., adult elk [Cervus elaphus]), whereas females would kill smaller and younger prey (i.e., elk calves, mule deer [Odocoileus hemionus]). We marked cougars with Global Positioning System (GPS) radio collars and investigated 436 predation sites. We located prey remains at 345 sites from 9 male and 9 female cougars. We detected 184 mule deer, 142 elk, and 17 remains from 4 other species. We used log-linear modeling to detect differences in species and age of prey killed among cougar reproductive classes. Solitary females and females with dependent offspring killed more mule deer than elk (143 vs. 83, P < 0.01), whereas males killed more elk than mule deer (59 vs. 41, P < 0.01). Proportionately, males killed 4 times more adult elk than did females (24% vs. 6% of kills) and females killed 2 times more adult mule deer than did males (26% vs. 15% of kills). Managers should consider the effects of sex of predator in conservation and management of ungulates, particularly when managing for sensitive species. © 2011 The Wildlife Society.     

Testosterone,physical activity,and somatic outcomes among Filipino males

Testosterone (T) facilitates male investment in reproduction in part through its anabolic effects on skeletal muscle. Traits like muscle and strength are energetically costly but are believed to enhance competitive ability in humans and other mammals. However, there are limited data on relationships between T and somatic outcomes in lean, non‐western populations. We evaluate relationships between waking and pre‐bed salivary T and adiposity, fat‐free mass (FFM), arm muscle area (AMA), and grip strength (GS) in a large, population‐based birth cohort of young adult Filipino males (20.8–22.6 years, n = 872). Data were collected as part of the Cebu Longitudinal Health and Nutrition Survey. Neither waking nor evening T predicted FFM, AMA, or GS. However, there were borderline or significant interactions between T and basketball playing (the most common team sport) and weight lifting as predictors of outcomes: higher waking T predicted higher FFM (activity × T interaction P < 0.01), AMA (interaction P < 0.1), and GS (interaction P < 0.02) among frequent basketball players, and GS (interaction P < 0.09) among the smaller sample of weight lifters. In contrast to clinical studies, but consistent with findings in several subsistence‐level populations, T was positively related to adiposity in these lean young males, suggesting that energy status might regulate circulating T. Our findings support a role of the prewaking rise in T as a determinant of energetic allocation to lean mass and strength in the context of repeated muscular use and support the hypothesized role of T as a mediator of investment in costly somatic traits in human males. Am J Phys Anthropol 142:590–599, 2010. © 2010 Wiley‐Liss, Inc.     

Platycodin D2 Improves Specific Cellular and Humoral Responses to Hepatitis B Surface Antigen in Mice

Platycodin D2 ( 1 ), a less hemolytic saponin from the root of Platycodon grandiflorum than platycodin D ( 2 ), was evaluated for the potential to enhance specific cellular and humoral immune responses to hepatitis B surface antigen (HBsAg) in mice. It significantly increased the concanavalin A (Con A)‐, lipopolysaccharide (LPS)‐, and HBsAg‐induced splenocyte proliferation in HBsAg‐immunized mice (P<0.05, P<0.01, and P<0.001, resp.). HBsAg‐specific IgG, IgG1, IgG2a, and IgG2b antibody titers in the serum were also markedly enhanced by 1 compared to the HBsAg control group (P<0.01 or P<0.001). Moreover, 1 significantly promoted the production of Th1 (IL‐2 and IFN‐γ) and Th2 (IL‐4 and IL‐10) cytokines from splenocytes in the HBsAg‐immunized mice (P<0.001). The adjuvant potential of 1 on splenocyte proliferation, serum HBsAg‐specific IgG2a and IgG2b antibody response, as well as Th1‐cytokine secretion from splenocytes in the HBsAg‐immunized mice was higher than that of Alum. The results suggest that 1 could improve both cellular and humoral immune responses to HBsAg in mice. Hence, 1 might be a promising adjuvant for hepatitis B vaccine with dual Th1‐ and Th2‐potentiating activity.     

Ghrelin improves disturbed myocardial energy metabolism in rats with heart failure induced by isoproterenol

To explore the effects of ghrelin on disturbed myocardial energy metabolism during chronic heart failure (CHF). Rats were subcutaneously injected with isoproterenol (ISO) for 10 days with or without ghrelin for another 10 days. Enzyme immunoassay was to measure ghrelin concentrations. Compared with the control group, ISO‐treated rats showed suppressed cardiac function with high ghrelin/GHS‐R expressions. These rats also showed the decreases in food consumption and weight. The decreased levels of plasma glucose and myocardial glucogen, but the high lactate in blood and myocardium showed myocardial metabolic disturbance. Compared with the group given ISO alone, the rats with ghrelin (20 and 100 µg/kg/day) improved cardiac dysfunction and increased food intake by 13.5 and 14.2% (both P < 0.01), and rate of weight gain by 95% (P < 0.05) and 1.71‐fold (P < 0.01), respectively. The plasma glucose were increased by 49.7 and 50.8% (both P < 0.01), and myocardial glucogen, by 40.5 and 51.7% (both P < 0.01), but blood lactate decreased by 1.56‐ and 1.96‐fold (both P < 0.01), and myocardial lactate by 32.1 and 48.7% (both P < 0.05), respectively. Their MCT1 mRNA and protein expressions increased. The myocardial ghrelin/GHS‐R pathway can be upregulated during CHF. The ghrelin can attenuate cardiac dysfunction and energy metabolic disturbance in CHF rats. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

Patterns and laterality of hand use in free-ranging aye-ayes (<Emphasis Type="Italic">Daubentonia madagascariensis</Emphasis>) and a comparison with captive studies

We observed hand use in free-ranging aye-ayes (Daubentonia madagascariensis) on an island in the Mananara River, eastern Madagascar. The results were compared with those of two conflicting studies on hand laterality in captive aye-ayes. We argue that patterns of hand preference in wild aye-ayes are comparable to those of captive animals and that discrepancies between studies are—at least partly—caused by different ways of collecting and processing data. Aye-ayes fit Level 2 of the categories of hand laterality described by McGrew and Marchant (Yearb Phys Anthropol 40:201–232, 1997), with some individuals showing significant hand preference, but with the proportion of right- to left-preferent animals being very close to 1:1. We observed hand preference to be consistent for two of the most frequent behaviors, tapping and probing with fingers. Reaching and holding objects in hands is rare in aye-ayes, and the patterns of hand use in aye-ayes are therefore not directly comparable with those of other prosimians in which laterality has been studied. We detected no effect of sex on hand preference and were unable to determine whether there is an effect of age. The posture adopted by the animals did not influence hand preference.     

Interleukin‐6 downregulation with mesenchymal stem cell differentiation results in loss of immunoprivilege

Allogeneic mesenchymal stem cell (MSC) transplantation improves cardiac function, but cellular differentiation results in loss of immunoprivilege and rejection. To explore the mechanism involved in this immune rejection, we investigated the influence of interleukin‐6 (IL‐6), a factor secreted by MSCs, on immune privilege after myogenic, endothelial and smooth muscle cell differentiation induced by 5‐azacytidine, VEGF, and transforming growth factor‐β (TGF‐β), respectively. Both RT‐PCR and ELISA showed that myogenic differentiation of MSCs was associated with significant downregulation of IL‐6 expression (P < 0.01), which was also observed following endothelial (P < 0.01) and smooth muscle cell differentiation (P < 0.05), indicating that IL‐6 downregulation was dependent on differentiation but not cell phenotype. Flow cytometry demonstrated that IL‐6 downregulation as a result of myogenic differentiation was associated with increased leucocyte‐mediated cell death in an allogeneic leucocyte co‐culture study (P < 0.01). The allogeneic reactivity associated with IL‐6 downregulation was also observed following MSC differentiation to endothelial and smooth muscle cells (P < 0.01), demonstrating that leucocyte‐mediated cytotoxicity was also dependent on differentiation but not cell phenotype. Restoration of IL‐6 partially rescued the differentiated cells from leucocyte‐mediated cell death. These findings suggest that rejection of allogeneic MSCs after implantation may be because of a reduction in cellular IL‐6 levels, and restoration of IL‐6 may be a new target to retain MSC immunoprivilege.     

TIP39 modulates effects of novelty‐induced arousal on memory

Tuberoinfundibular peptide of 39 residues (TIP39) is a neuropeptide localized to neural circuits subserving emotional processing. Recent work showed that mice with null mutation for the gene coding TIP39 (TIP39‐KO mice) display increased susceptibility to environmental provocation. Based on this stressor‐dependent phenotype, the neuroanatomical distribution of TIP39, and knowledge that novelty‐induced arousal modulates memory functions via noradrenergic activation, we hypothesized that exposure to a novel environment differently affects memory performance of mice with or without TIP39 signaling, potentially by differences in sensitivity of the noradrenergic system. We tested TIP39‐KO mice and mice with null mutation of its receptor, the parathyroid hormone 2 receptor (PTH2‐R), in tasks of short‐term declarative and social memory (object recognition and social recognition tests, respectively), and of working memory (Y‐maze test) under conditions of novelty‐induced arousal or acclimation to the test conditions. Mice lacking TIP39 signaling showed memory impairment selectively under conditions of novelty‐induced arousal. Acute administration of a PTH2‐R antagonist in wild‐type mice had a similar effect. The restoration of memory functions in TIP39‐KO mice after injection of a β‐adrenoreceptor‐blocker, propranolol, suggested involvement of the noradrenergic system. Collectively, these results suggest that the TIP39/PTH2‐R system modulates the effects of novelty exposure on memory performance, potentially by acting on noradrenergic signaling.     

Lateral bias in feeding and brachiation inHylobates

Lateralized hand use in gibbons was assessed for both food reaching and leading limb in brachiation. Sex and age effects were found in hand preference for food reaching. Adult females were all very strongly right hand preferent, whereas adult males had no across group consistent preference. Within the female group there was a strong correlation between age and strength of right handedness. When compared in terms of absolute strength of hand preference, females were found to be more strongly lateralized than males. Leading limb preference in brachiation was scored into vocal and non-vocal categories. Three subjects had a shift in preferred leading limb from the non-vocal brachiation condition to the vocal brachiation condition. This shift may be influenced by the arousal effects of species typical vocalization. The results of this study underline the importance of consideration of such factors as sex and age when interpreting behavioral lateralization data. The exploration of laterality in many different response measures is important to the achievement of a complete understanding of behavioral lateralization in primates.     

Experimental alteration of limb posture in the chicken (Gallus gallus) and its bearing on the use of birds as analogs for dinosaur locomotion

Extant birds represent the only diverse living bipeds, and can be informative for investigations into the life‐history parameters of their extinct dinosaurian relatives. However, morphological changes that occurred during early avian evolution, including the unique adoption of a nearly horizontal femoral orientation associated with a shift in center of mass (CM), suggest that caution is warranted in the use of birds as analogs for nonavian dinosaur locomotion. In this study, we fitted a group of white leghorn chickens (Gallus gallus) with a weight suspended posterior to the hip in order to examine the effects on loading and morphology. This caused a CM shift that necessitated a change in femoral posture (by 35° towards the horizontal, P < 0.001), and resulted in reorientation of the ground reaction force (GRF) vector relative to the femur (from 41° to 82°, P < 0.001). Despite similar strain magnitudes, an overall increase in torsion relative to bending (from 1.70 to 1.95 times bending, P < 0.001) was observed, which was weakly associated with a tendency for increased femoral cross‐sectional dimensions (P = 0.1). We suggest that a relative increase in torsion is consistent with a change in femoral posture towards the horizontal, since this change increases the degree to which the bone axis and the GRF vector produce mediolateral long‐axis rotation of the bone. These results support the hypothesis that a postural change during early avian evolution could underlie the allometric differences seen between bird and nonavian dinosaur femora by requiring more robust femoral dimensions in birds due to an increase in torsion. J. Morphol. 240:237–249, 1999. © 1999 Wiley‐Liss, Inc.     

Umbelliprenin shows antitumor,antiangiogenesis, antimetastatic,anti‐inflammatory,and immunostimulatory activities in 4T1 tumor‐bearing Balb/c mice

Umbelliprenin (UMB) has shown various pharmacological properties in vitro. We investigated the antineoplastic and immunostimulatory effects of UMB in 4T1 mammary‐tumor‐bearing mice. Two‐hundred microliter of UMB (12.5 mg/ml) was intraperitoneally administrated to healthy and tumor‐bearing female Balb/c mice for a period of 18 days. Data was analyzed using GraphPad Prism 5 software for Windows (version 5, La Jolla, CA). UMB caused a significant decrease in tumor size (P < 0.01). Serum interferon gamma (IFNγ) was augmented in both healthy and tumor‐bearing animals (P < 0.01), and IL‐4 declined in healthy animals (P < 0.01) treated with UMB. Expressions of Ki‐67, VEGF, CD31, MMP2, MMP9, VCAM1, and NF‐κB were significantly decreased in tumors from UMB‐treated animals (P < 0.001), whereas E‐Cadherin and TNFR1 expressions were markedly increased (P < 0.001). The rates of liver and lung metastases in UMB‐administrated animals were smaller compared to the control. UMB can potently inhibit tumor growth, angiogenesis, metastasis, and inflammation and potentiate an antitumor immune response in vivo. However, further investigations are required to evaluate the UMB mechanisms of action in cancerous cells.     

Low‐carbohydrate High‐fat Diets: Regulation of Energy Balance and Body Weight Regain in Rats

The aim of the current investigations was to examine the effects of a low‐carbohydrate high‐fat diet (LC‐HFD) on body weight, body composition, growth hormone (GH), IGF‐I, and body weight regain after stopping the dietary intervention and returning the diet back to standard laboratory chow (CH). In study one, both adolescent and mature male Wistar rats were maintained on either an isocaloric LC‐HFD or CH for 16 days before having their diet switched. In study two, mature rats were maintained on either LC‐HFD or CH for 16 days to determine the effects of the LC‐HFD on fat pad weight. LC‐HFD leads to body weight loss in mature rats (P < 0.01) and lack of body weight gain in adolescent rats (P < 0.01). Despite less body weight, increased body fat was observed in rats maintained on LC‐HFD (P < 0.05). Leptin concentrations were higher (P < 0.05), and IGF‐I (P < 0.01) concentrations were reduced in the LC‐HFD rats. When the diet was returned to CH following LC‐HFD, body weight regain was above and beyond that which was lost (P < 0.01). The LC‐HFD resulted in increased body fat and had a negative effect upon both GH and IGF‐I concentrations, which might have implications for the accretion and maintenance of lean body mass (LBM), normal growth rate and overall metabolic health. Moreover, when the LC‐HFD ceases and a high‐carbohydrate diet follows, more body weight is regained as compared to when the LC‐HFD is consumed, in the absence of increased energy intake.