Two-year-old children copy more reliably and more often than nonhuman great apes in multiple observational learning tasks

Individuals observing a proficient model can potentially benefit by copying at least one of the following three elements: motor movements (i.e., actions), goals, and results. Although several studies have investigated this issue in human infants, there are still very few studies that have systematically examined great apes’ ability to spontaneously copy each of these three elements (particularly in comparison with human infants). We tested great apes and human children with eight two-target puzzle boxes—with varying levels of difficulty—to isolate the aspects that the various species may be more prone to copying. We found first trial evidence for observational learning of actions, goals, and results in children. Some copying was found for apes as well, but only if their performance was averaged across trials.     

TB-infected deer are more closely related than non-infected deer

Identifying mechanisms of pathogen transmission is critical to controlling disease. Social organization should influence contacts among individuals and thus the distribution and spread of disease within a population. Molecular genetic markers can be used to elucidate mechanisms of disease transmission in wildlife populations without undertaking detailed observational studies to determine probable contact rates. Estimates of genealogical relationships within a bovine tuberculosis-infected white-tailed deer (Odocoileus virginianus) population indicated that infected deer were significantly more closely related than non-infected deer suggesting that contact within family groups was a significant mechanism of disease transmission. Results demonstrate that epidemiological models should incorporate aspects of host ecology likely to affect the probability of disease transmission.     

Homokaryons are more combative than heterokaryons of Hericium coralloides

The homokaryotic stage of the basidiomycete lifecycle is generally considered to be short lived, although there is little experimental evidence relating to their longevity in the field. The vast majority of studies on basidiomycete ecology have used only heterokaryons. The few investigations comparing related homokaryons and heterokaryons have revealed no overall trend in differences of extension rate, wood decay or competitive ability. For a rare species the homokaryotic phase may be of greater importance than in common species as it is likely to last longer. Hericium coralloides, a rare wood decay basidiomycete, was used to investigate differences between homokaryons and heterokaryons in terms of extension rate and combative ability. Fifteen homokaryons from three fruit bodies and five heterokaryons (obtained by fruit body tissue isolation) were compared at 5–35 °C on malt agar for extension rate, and paired against heterokaryons of 13 wood decay species to assess combative ability. Homokaryons were paired to create ten artificial heterokaryons whose extension rate at 10 and 20 °C was compared to parental rates. There were some significant differences in extension rates between homokaryons and natural heterokaryons, between homokaryons and heterokaryons created artificially from homokaryons, and between homokaryons from different fruit bodies, but no consistent trends. Homokaryons proved more combative than heterokaryons, which was assessed quantitatively as well as qualitatively using a scoring system for outcome of each pairing. Results are discussed in relation to previous findings and in an ecological context.     

A blessing in disguise: Transposable elements are more than parasites

Transposable elements (TEs) are various DNA fragments inserted throughout genomes, which are able to move or duplicate themselves. Recent advances in genomics have placed them back at the center of genome dynamics. One of the emerging observations, especially in plants, is the importance of interactions between TEs and genes to generate or to participate in relevant functions essential for development, adaptation and/or life cycle. A recent publication illustrates the influence of TEs epigenetic control on the expression of a neighboring gene crucial for reproduction. Different reports lately showed that a fundamental mechanism such as imprinting is likely to be closely linked to the dynamics of TEs epigenetic control. Here we discuss and bring together these and others recent findings, to underline that the cis-vicinity or the trans-relation between TEs and genes could bring unexpected but positive outcomes.     

Youth are more sensitive to price changes in cigarettes than adults

Virtually all smoking begins in our population's youth and remains as a habit into those smokers' elder years. If we desire to halt smoking in its infancy, we should seek to deter and induce cessation in the youth years. It has been cited that taxation is an effective means to deter smoking at all ages, particularly efficacious in the youth population. This paper explores the merits of this method of preventative medicine, and intends to investigate differences between the price elasticity of cigarette demand between various cohorts, particularly the adult versus the youth population. We use a two-variable log-log, ordinary least-squares econometric regression to determine the extent that price alterations have on participation rates and quantity smoked. Our results show that youth are quite responsive to price increases showing a decrease of 14 percent prevalence in smoking for a 10 percent increase in price; whereas, the adult population is relatively less responsive to such price changes, exhibiting nearly a 2 percent decrease in prevalence for a 10 percent increase in price. We conclude that taxation is an effective means of socially-enacted preventative medicine in deterring youth smoking.     

Cleaner wrasses Labroides dimidiatus are more cooperative in the presence of an audience

Humans may help others even in?situations where the recipient will not reciprocate [1-5]. In some cases, such behavior can be explained by the helpers increasing their image score, which will increase the probability that bystanders will help them in the future [5-7]. For other animals, the notion that many interactions take place in an environment containing an audience of eavesdropping bystanders has also been proposed to have important consequences for social behavior, including levels of cooperation [8]. However, experimental evidence is currently restricted to the demonstration that cleaner fish Labroides dimidiatus can learn to solve a foraging task [9]. The cleaners learned to feed against their preference on artificial clients if that allowed them to access additional artificial clients, which would translate into cooperatively eating ectoparasites rather than cheating by eating client mucus under natural conditions [10]. Here we show that cleaners immediately increase current levels of cooperation in the presence of?bystander client reef fish. Furthermore, we find that bystanders respond to any occurrence of cleaners cheating their current client with avoidance. In conclusion, the results demonstrate, for the first time, that image scoring by an audience indeed leads to increased levels of cooperation in a nonhuman animal.     

Metazoan evolution: some animals are more equal than others

Comparison of newly available sequence data facilitates reconstruction of the gene inventory of the Urbilateria, the last common ancestor of flies, nematodes and humans. The most surprising outcome is that human genes seem to be closer to the bilaterian roots than previously assumed.     

Sticklebacks from streams are more bold than sticklebacks from ponds

Risk-taking behaviour has important consequences for fitness. Here, we show that risk-taking behaviour in sticklebacks consistently varies according to the habitat of origin. We compared the risk-taking behaviour of individual sticklebacks from three pond and three stream populations. Specifically, we measured willingness to forage under predation risk following a simulated attack by a model heron predator. Sticklebacks from stream populations were more willing to forage under predation risk than fish from pond populations. Sticklebacks from streams resumed eating after the simulated attack faster and spent more time eating compared to sticklebacks from ponds. We discuss these findings in terms of differences in life history and predation pressure in the two habitat types.     

Hunter-gatherer males are more risk-seeking than females,even in late childhood

Observed economic and labor disparities between the sexes may, in part, result from evolved sex differences in risk preferences. Using incentivized economic games, we report on sex differences in risk preferences in the Hadza, a population of hunter-gatherers. One game played in 2010 (n = 233) found that more Hadza males than females prefer to gamble for a chance to earn more maize rather than settle for a sure, but smaller, amount. Similarly, a second game played in 2013 (n = 102) found that male Hadza gamble a greater proportion of honey for a chance to earn more compared to female Hadza. Effect sizes are small to medium. We find weak evidence that risk-taking increases in men as their mating opportunities increase. In both games, the sex difference widens throughout childhood and is greatest among adolescents; though note that child samples are small. We explore developmental trends further using observational data on food returns in children (n = 357). Our data suggest that while the mean number of calories boys bring to camp remains stable with age, the variance in their caloric returns increases. Among girls, the variance remains stable with increased age. Both the economic games and food return data are consistent with the sexual division of labor wherein boys, beginning in late childhood, begin to target riskier foods. To the extent that the Hadza allow us to make inferences about long-standing patterns of human behavior, we suggest that sex differences in risk preferences may have been present long before agriculture and the modern work environment.     

Molecules are more than markers: new directions in molecular microbial ecology

Macromolecules such as DNA, RNA, and proteins are widely used to quantify diversity in natural communities, to monitor the dispersal of organisms and their genes, and to trace phylogenetic relationships among organisms. With such widespread use of molecules as markers, it is easy to forget that they perform functions that are integral to the survival of organisms. The structural and functional properties of macromolecules have been intensively studied in genetics, biochemistry, and physiology. These fields, however, have not generally focused on the ecological significance of molecular variation, but instead have used defective variants as tools for identifying structure and function. Understanding the significance of molecular variation for organismal success or failure is a central problem in ecology, one whose solution will require the integration of diverse approaches and perspectives from ecology, molecular biology, genetics, physiology, and evolutionary biology. I review several studies of bacterial populations evolving in simple environments that have begun to integrate these approaches and perspectives in order to examine the consequences of molecular variation for ecological performance.     

Aged preparations are electrophysiologically more representative of intact tissue than are freshly excised preparations

Studies using excised tissues usually suffer from a discrepancy in the results between freshly excised preparations and aged ones (i.e. preparations which are allowed to rest and-or regenerate for about a day between excision and experimentation). This is especially true for measurements of the membrane potential (V_m) and its changes upon exposure to light in slices of extensor tissue of the laminar pulvini of Phaseolus coccineus L. Measurements of the V _m of extensor cells in situ reveal virtually identifical results to those obtained from aged excised preparations (more negative resting V _m; dramatic, light-induced transients of V _m), whereas freshly excised preparations display a small and light-insensitive V _m. It is concluded, therefore, that for the given example aged preparations are more suitable than fresh ones for investigating the properties of intact tissues.Symbol V_m membrane potential