Shallow water ray-finned marine fishes follow Bergmann’s rule

Understanding the interspecific variation in body size across macroclimatic gradients has been of paramount importance to naturalists and biogeographers. Bergmann’s rule, which describes a trend of increasing body size polewards, is arguably the best-known ecogeographical rule in terrestrial environments but remains largely unexplored in the marine realm. In this study we tested Bergmann's rule in marine ray-finned fishes (Pisces, Actinopterygii), analyzing the relationship between body size and latitude in 5662 species. To examine possible underlying mechanisms, we adopted a cross-species approach to evaluate the association of body size with four predictors: Sea Surface Temperature, Net Primary Productivity, Salinity, and Human impact. We analyzed the relationships between body size and environmental and anthropogenic variables building mixed linear models, which considered the taxonomic structure in the data. We conducted complementary analyses dividing the data into five latitudinal bands. Actinopterygii showed a clear Bergmannian pattern, with the largest species observed in temperate regions, being the first global analysis on ray-finned fishes showing a pattern consistent with Bergmann’s rule. Sea Surface Temperature and Net Primary Productivity were the best predictors, in accordance with the time to sexual maturity and resource availability hypotheses. Our analyses based on latitudinal bands showed a differential response of body size to the environment, with temperature, salinity and human impact more strongly associated with size variation at cold environments. These results agree with previous studies on Bergmann’s rule for terrestrial ectothermic, freshwater and marine fishes. Our findings suggest that temperature rise in the ocean and growing human impact may have effects on the distribution of body size, thus altering ecosystem functioning. Fundamental differences often assumed to exist between marine and terrestrial systems are not so evidently reflected in the emergence of large-scale body size gradients.     

I Should but I Won’t: Why Young Children Endorse Norms of Fair Sharing but Do Not Follow Them

Young children endorse fairness norms related to sharing, but often act in contradiction to those norms when given a chance to share. This phenomenon has rarely been explored in the context of a single study. Using a novel approach, the research presented here offers clear evidence of this discrepancy and goes on to examine possible explanations for its diminution with age. In Study 1, 3–8-year-old children readily stated that they themselves should share equally, asserted that others should as well, and predicted that others had shared equally with them. Nevertheless, children failed to engage in equal sharing until ages 7–8. In Study 2, 7–8-year-olds correctly predicted that they would share equally, and 3–6-year-olds correctly predicted that they would favor themselves, ruling out a failure-of-willpower explanation for younger children''s behavior. Similarly, a test of inhibitory control in Study 1 also failed to explain the shift with age toward adherence to the endorsed norm. The data suggest that, although 3-year-olds know the norm of equal sharing, the weight that children attach to this norm increases with age when sharing involves a cost to the self.     

Let’s Not Forget about Non-Specific Autophagy

No abstract available.     

Bergmann’s rule for Neomys fodiens in the middle of the distribution range

The body size of Palearctic Sorex shrews decreases at higher latitudes, and as such the Bergmann’s rule does not work. However, no analysis has ever been done for water shrew (Neomys fodiens) in the middle of distribution range. Analysis of available literature data showed that some body and skull measurements of N. fodiens are negatively correlated to latitude. Measurements of 158 water shrews from Estonia and Lithuania were also analyzed with respect to the short scale latitudinal pattern. We found that populations are separated (Wilk’s lambda = 0.363, p<0.0001). Differences are related to PC1 (skull size), explaining 49.80% of the variance and PC2 (body size), explaining 10.06% of the variance. Estonian shrews are smaller in their body and skull (most differences significant) and their skulls are relatively shorter and wider in the area of the brain case. Thus, the negative correlation of body and skull size to latitude in N. fodiens is applicable even over quite short latitudinal distances. Further analysis of diagnostic characters between N. fodiens and N. anomalus is required.     

Evaluating Darwin’s Naturalization Hypothesis in Experimental Plant Assemblages: Phylogenetic Relationships Do Not Determine Colonization Success

Darwin’s naturalization hypothesis (DNH) proposes that colonization is less likely when the colonizing species is related to members of the invaded community, because evolutionary closeness intensifies competition among species that share similar resources. Studies that have evaluated DNH from correlational evidence have yielded controversial results with respect to its occurrence and generality. In the present study we carried out a set of manipulative experiments in which we controlled the phylogenetic relatedness of one colonizing species (Lactuca sativa) with five assemblages of plants (the recipient communities), and evaluated the colonizing success using five indicators (germination, growth, flowering, survival, and recruitment). The evolutionary relatedness was calculated as the mean phylogenetic distance between Lactuca and the members of each assemblage (MPD) and by the mean phylogenetic distance to the nearest neighbor (MNND). The results showed that the colonization success of Lactuca was not affected by MPD or MNND values, findings that do not support DNH. These results disagree with experimental studies made with communities of microorganisms, which show an inverse relation between colonization success and phylogenetic distances. We suggest that these discrepancies may be due to the high phylogenetic distance used, since in our experiments the colonizing species (Lactuca) was a distant relative of the assemblage members, while in the other studies the colonizing taxa have been related at the congeneric and conspecific levels. We suggest that under field conditions the phylogenetic distance is a weak predictor of competition, and it has a limited role in determining colonization success, contrary to prediction of the DNH. More experimental studies are needed to establish the importance of phylogenetic distance between colonizing species and invaded community on colonization success.     

Coming to America: Acclimation in macaque body structures and Bergmann’s rule

I analyzed somatometric measurements from subsets of the Texas and Oregon transplanted troops of Japanese macaques(Macaca fuscata) to reveal secular changes in body size and shape. Body weights of the Texas population (N = 59) are lower than those of the Oregon population(N = 49) and the founding population from Arashiyama. The adult weights of the Oregon population are significantly higher than the founding population from Mihara. There are significant differences in adult circumferential measures and in skinfolds, which are correlated with the increased weight of the Oregon macaques. The adult Texas macaques have longer limb segments in comparison with the adult Oregon troop members, while the latter have significantly longer heads and trunks. Examination of the developing morphological trends through regression analyses on the complete sample suggests distinctive growth patterns for each population. Members of the Texas population start with smaller initial measurements but hold a steeper growth pattern for limb segments, while the Oregon macaques start larger in most measures and show lower growth rates. I argue that these differences in both somatometry and growth patterns are related to the differing climatic conditions under which the translocated macaques have lived. This set of analyses supports the basic arguments for Bergmann’s rule and Allen’s rule.     

Bergmann’s Rule,Adaptation, and Thermoregulation in Arctic Animals: Conflicting Perspectives from Physiology,Evolutionary Biology,and Physical Anthropology After World War II

Bergmann’s rule and Allen’s rule played important roles in mid-twentieth century discussions of adaptation, variation, and geographical distribution. Although inherited from the nineteenth-century natural history tradition these rules gained significance during the consolidation of the modern synthesis as evolutionary theorists focused attention on populations as units of evolution. For systematists, the rules provided a compelling rationale for identifying geographical races or subspecies, a function that was also picked up by some physical anthropologists. More generally, the rules provided strong evidence for adaptation by natural selection. Supporters of the rules tacitly, or often explicitly, assumed that the clines described by the rules reflected adaptations for thermoregulation. This assumption was challenged by the physiologists Laurence Irving and Per Scholander based on their arctic research conducted after World War II. Their critique spurred a controversy played out in a series of articles in Evolution, in Ernst Mayr’s Animal Species and Evolution, and in the writings of other prominent evolutionary biologists and physical anthropologists. Considering this episode highlights the complexity and ambiguity of important biological concepts such as adaptation, homeostasis, and self-regulation. It also demonstrates how different disciplinary orientations and styles of scientific research influenced evolutionary explanations, and the consequent difficulties of constructing a truly synthetic evolutionary biology in the decades immediately following World War II.     

Allometry for Sexual Size Dimorphism in Stoneflies Defies the Rensch’s Rule

The Rensch’s rule predicts that male-biased sexual size dimorphism (SSD) increases with body size, while female-biased SSD (FBSSD) decreases. In insects, many groups follow this rule, but the evidence suggests that it is taxon dependent and that the inverse of the rule can occur in species with FBSSD. Therefore, we conducted this study with Gripopterygidae stoneflies (Plecoptera) to describe their pattern of SSD and determine if they follow the Rensch’s rule. Our data suggest that stoneflies exhibit FBSSD and do not follow the rule, but a reverse pattern. Our results corroborate other studies that suggest that the Rensch’s rule is taxon based and that groups with FBSSD usually fail to obey the rule.     

It’s Not Just Conflict That Motivates Killing of Orangutans

We investigated why orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill orangutans. Those who reported having personally killed an orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons orangutans were killed was fear of orangutans or in self-defence. A similar pattern was evident among reports of orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 orangutans were killed in Kalimantan within the respondents’ active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of orangutans in Indonesian Borneo, and that effective reduction of orangutan killings is urgently needed.     

Do Hypertensive Individuals Who Are Aware of Their Disease Follow Lifestyle Recommendations Better than Those Who Are Not Aware?

Lifestyle modification is the first step in hypertension management. Our objective was to assess adherence to lifestyle recommendations by individuals who were aware of their hypertension and to identify characteristics associated with non-adherence. Using data from the Korea National Health and Nutrition Examination Survey conducted in 2010–2012, we compared the adherence to six lifestyle recommendations of hypertensive subjects aware of the status of their condition with that of those who were not aware, based on survey regression analysis. The characteristics associated with non-adherence were assessed by multiple logistic regression analysis. Of all hypertensive subjects, <20% adhered to a healthy diet and reduced salt intake and about 80% moderated alcohol consumption and did not smoke. Half of all subjects maintained normal body weight and engaged in physical activity. Most lifestyle features of aware hypertensive Koreans did not differ greatly from those of hypertensive individuals who were not aware. Reduction in salt intake was slightly more prevalent among those aware of their hypertensive status. Obesity was more prevalent among the aware hypertensive subjects, and the prevalence of obesity increased with the duration of hypertension. Male gender, younger age, residence in a rural area, low income, and the use of antihypertensive medication were associated with non-adherence to lifestyle recommendations by hypertensive individuals. Many hypertensive Koreans do not comply with lifestyle recommendations for the management of hypertension. The association between the use of antihypertensive medications and non-adherence suggested an over-reliance on medication rather than a commitment to a healthy lifestyle. Our study highlights that efforts encouraging healthy lifestyles, as the first step in hypertension management, need to be increased.     

African Vultures Don’t Follow Migratory Herds: Scavenger Habitat Use Is Not Mediated by Prey Abundance

The ongoing global decline in vulture populations raises major conservation concerns, but little is known about the factors that mediate scavenger habitat use, in particular the importance of abundance of live prey versus prey mortality. We test this using data from the Serengeti-Mara ecosystem in East Africa. The two hypotheses that prey abundance or prey mortality are the main drivers of vulture habitat use provide alternative predictions. If vultures select areas based only on prey abundance, we expect tracked vultures to remain close to herds of migratory wildebeest regardless of season. However, if vultures select areas where mortality rates are greatest then we expect vultures to select the driest regions, where animals are more likely to die of starvation, and to be attracted to migratory wildebeest only during the dry season when wildebeest mortality is greatest. We used data from GSM-GPS transmitters to assess the relationship between three vulture species and migratory wildebeest in the Mara-Serengeti ecosystem. Results indicate that vultures preferentially cluster around migratory herds only during the dry season, when herds experience their highest mortality. Additionally during the wet season, Ruppell’s and Lappet-faced vultures select relatively dry areas, based on Normalized Difference Vegetation Index, whereas White-backed vultures preferred wetter areas during the wet season. Differences in habitat use among species may mediate coexistence in this scavenger guild. In general, our results suggest that prey abundance is not the primary driver of avian scavenger habitat use. The apparent reliance of vultures on non-migratory ungulates during the wet season has important conservation implications for vultures in light of on-going declines in non-migratory ungulate species and use of poisons in unprotected areas.     

Explaining Darwin’s Corollary to Haldane’s Rule: The Role of Mitonuclear Interactions in Asymmetric Postzygotic Isolation Among Toads

We examine the basis of Darwin’s corollary to Haldane’s rule, which describes viability and fertility differences between F₁ produced from reciprocal crosses. We analyzed asymmetries in hybrid viability from >100 reciprocal crosses involving 36 toad species to test whether relatively high rates of mitochondrial vs. nuclear evolution produce dams with systematically less viable F₁ hybrid progeny. We find no such effect, suggesting a predominant role for stochastic accumulation of asymmetric epistatic incompatibilities.     

Not Beyond Reasonable Doubt: Howard Temin’s Provirus Hypothesis Revisited

During the 1960s, Howard M. Temin (1934–1994), dared to advocate a “heretical” hypothesis that appeared to be at variance with the central dogma of molecular biology, understood by many to imply that information transfer in nature occurred only from DNA to RNA. Temin’s provirus hypothesis offered a simple explanation of both virus replication and viral-induced cancer and stated that Rous sarcoma virus, an RNA virus, is replicated via a DNA intermediate. Popular accounts of this scientific episode, written after the discovery of an RNA-directed DNA polymerase in 1970, tend to describe the reaction to his proposition as ardent opposition. Typically these accounts use a ‹molecular biology’ standpoint emphasizing the central dogma’s part in its rejection. In this article, however, this episode will be examined from a joint perspective of virology and experimental cancer research. From this perspective it is clear that Temin’s work was well within the epistemological and methodological boundaries of virology and cancer research. Still, scientists did have␣reasons to doubt the provirus hypothesis, but these do not seem to be good enough to either justify an account that portrays Temin as a renegade or his ideas as heretical.