Sharp gene pool transition in a population affected by phenotype-based selective hunting

We use a microscopic model of population dynamics, a modified version of the well known Penna model, to study some aspects of microevolution. This research is motivated by recent reports on the effect of selective hunting on the gene pool of bighorn sheep living in the Ram Mountain region, in Canada. Our model finds a sharp transition in the structure of the gene pool as some threshold for the number of animals hunted is reached.Comment: 5 pages, 4 figure

JOINT DISPLACEMENTS AND PEAK ACHILLES TENDON FORCE DURING IRISH DANCING-SPECIFIC LANDING TASKS

Achilles tendinopathy is prevalent among Irish dancers, thought to be due to the high impact, stiff-style landing tasks associated with the sport. This study aimed to investigate the relationship between sagittal plane joint displacements, at the ankle, knee, hip and thorax segment, and peak Achilles tendon force during an Irish dancing ‘leap over’ landing task. Kinetic and kinematic data were collected for 12 participants performing the ‘leap over’, and used to calculate peak Achilles tendon force and joint displacements. Results of the study found a statistically significant positive correlation between ankle dorsiflexion and peak Achilles tendon force during the ‘leap over’. These findings can be used to inform future research into the effect of joint displacement on peak Achilles tendon force, and to develop strategies to help dancers reduce their risk of developing Achilles tendinopathy

Barriers and enablers to participation in physical activity among women diagnosed with ovarian cancer.

Ovarian cancer is the leading cause of death among gynecological cancers, with low survival rates and a high disease burden. Despite the known benefits, most women reduce their participation in physical activity following diagnosis. Little is known about ovarian cancer survivors' experiences of physical activity. The primary aim of this study was to explore the barriers and enablers to participation in physical activity among women diagnosed with ovarian cancer. A qualitative descriptive study design was conducted via semi-structured interviews with nine women diagnosed with ovarian cancer (stages I-IV; 40-77 years). The interviews took place at the participant's home via telephone or online video conferencing software Coviu©. An inductive thematic approach was used. The organization and coding of data were completed using NVivo computer software (Version 12.6.0, QSR International Pty Ltd.). Weekly discussions occurred among the research team to ensure that themes accurately represented participant views. The consolidated criteria for reporting qualitative studies (COREQ) 32-item checklist were followed. The main barriers to physical activity participation that emerged were (i) the lack of referral to an exercise professional within the multidisciplinary cancer team, (ii) fear of injury after surgery and during treatment, and (iii) treatment-related side effects. However, many of the participants perceived benefits of physical activity related to (i) enhanced physical and psychological health, (ii) improved cancer outcomes, and (iii) social benefits as key enablers of physical activity participation. Physical activity interventions for women with ovarian cancer should address the modifiable barriers identified in this study. A key focus should be to streamline timely referral pathways within the multidisciplinary team, including exercise professionals, dietitians, psychologists, and specialists nurses following a diagnosis of ovarian cancer. Further research and service development are needed to optimize supported self-management through (i) education about the importance of physical activity to both healthcare professionals and women alike, (ii) enhanced symptom management for women, which was identified as a barrier to participation, and (iii) the development of shared care plans and patient center goals to address any fears or concerns. People diagnosed with ovarian cancer have low participation levels of physical activity. Cancer care professionals' support could increase physical activity uptake and reduce some of the burden of an ovarian cancer diagnosis

Continental-scale patterns of pathogen prevalence: a case study on the corncrake

Pathogen infections can represent a substantial threat to wild populations, especially those already limited in size. To determine how much variation in the pathogens observed among fragmented populations is caused by ecological factors, one needs to examine systems where host genetic diversity is consistent among the populations, thus controlling for any potentially confounding genetic effects. Here, we report geographic variation in haemosporidian infection among European populations of corncrake. This species now occurs in fragmented populations, but there is little genetic structure and equally high levels of genetic diversity among these populations. We observed a longitudinal gradient of prevalence from western to Eastern Europe negatively correlated with national agricultural yield, but positively correlated with corncrake census population sizes when only the most widespread lineage is considered. This likely reveals a possible impact of local agriculture intensity, which reduced host population densities in Western Europe and, potentially, insect vector abundance, thus reducing the transmission of pathogens. We conclude that in the corncrake system, where metapopulation dynamics resulted in variations in local census population sizes, but not in the genetic impoverishment of these populations, anthropogenic activity has led to a reduction in host populations and pathogen prevalence

Host density drives viral, but not trypanosome, transmission in a key pollinator

Supplemental feeding of wildlife populations can locally increase the density of individuals, which may in turn impact disease dynamics. Flower strips are a widely used intervention in intensive agricultural systems to nutritionally support pollinators such as bees. Using a controlled experimental semi-field design, we asked how density impacts transmission of a virus and a trypanosome parasite in bumblebees. We manipulated bumblebee density by using different numbers of colonies within the same area of floral resource. In high-density compartments, slow bee paralysis virus was transmitted more quickly, resulting in higher prevalence and level of infection in bumblebee hosts. By contrast, there was no impact of density on the transmission of the trypanosome Crithidia bombi, which may reflect the ease with which this parasite is transmitted. These results suggest that agri-environment schemes such as flower strips, which are known to enhance the nutrition and survival of bumblebees, may also have negative impacts on pollinators through enhanced disease transmission. Future studies should assess how changing the design of these schemes could minimize disease transmission and thus maximise their health benefits to wild pollinators

Gas Component Transport Across the Soil-Atmosphere Interface for Gases of Different Density: Experiments and Modeling

We investigate the influence of near-surface wind conditions on subsurface gas transport and on soil-atmosphere gas exchange for gases of different density. Results of a sand tank experiment are supported by a numerical investigation with a fully coupled porous medium-free flow model, which accounts for wind turbulence. The experiment consists of a two-dimensional bench-scale soil tank containing homogeneous sand and an overlying wind tunnel. A point source was installed at the bottom of the tank. Gas concentrations were measured at multiple horizontal and vertical locations. Tested conditions include four wind velocities (0.2/1.0/2.0/2.7 m/s), three different gases (helium: light, nitrogen: neutral, and carbon dioxide: heavy), and two transport cases (1: steady-state gas supply from the point source; 2: transport under decreasing concentration gradient, subsequent to termination of gas supply). The model was used to assess flow patterns and gas fluxes across the soil surface. Results demonstrate that flow and transport in the vicinity of the surface are strongly coupled to the overlying wind field. An increase in wind velocity accelerates soil-atmosphere gas exchange. This is due to the effect of the wind profile on soil surface concentrations and due to wind-induced advection, which causes subsurface horizontal transport. The presence of gases with pronounced density difference to air adds additional complexity to the transport through the wind-affected soil layers. Wind impact differs between tested gases. Observed transport is multidimensional and shows that heavy as well as light gases cannot be treated as inert tracers, which applies to many gases in environmental studies. © 2020. The Authors

Host Patch Traits Have Scale‐Dependent Effects On Diversity In A Stickleback Parasite Metacommunity

Many metacommunities are distributed across habitat patches that are themselves aggregated into groups. Perhaps the clearest example of this nested metacommunity structure comes from multi‐species parasite assemblages, which occupy individual hosts that are aggregated into host populations. At both spatial scales, we expect parasite community diversity in a given patch (either individual host or population) to depend on patch characteristics that affect colonization rates and species sorting. But, are these patch effects consistent across spatial scales? Or, do different processes govern the distribution of parasite community diversity among individual hosts, versus among host patches? To answer these questions, we document the distribution of parasite richness among host individuals and among populations in a metapopulation of threespine stickleback Gasterosteus aculeatus. We find some host traits (host size, gape width) are associated with increased parasite richness at both spatial scales. Other patch characteristics affect parasite richness only among individuals (sex), or among populations (lake size, lake area, elevation and population mean heterozygosity). These results demonstrate that some rules governing parasite richness in this metacommunity are shared across scales, while others are scale‐specific

Indirect effects on fitness between individuals that have never met via an extended phenotype

Interactions between organisms are ubiquitous and have important consequences for phenotypes and fitness. Individuals can even influence those they never meet, if they have extended phenotypes that alter the environments others experience. North American red squirrels (Tamiasciurus hudsonicus) guard food hoards, an extended phenotype that typically outlives the individual and is usually subsequently acquired by non‐relatives. Hoarding by previous owners can, therefore, influence subsequent owners. We found that red squirrels breed earlier and had higher lifetime fitness if the previous hoard owner was a male. This was driven by hoarding behaviour, as males and mid‐aged squirrels had the largest hoards, and these effects persisted across owners, such that if the previous owner was male or died in mid‐age, subsequent occupants had larger hoards. Individuals can, therefore, influence each other’s resource‐dependent traits and fitness without ever meeting, such that the past can influence contemporary population dynamics through extended phenotypes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148423/1/ele13230.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148423/2/ele13230_am.pd

Social effects of territorial neighbours on the timing of spring breeding in North American red squirrels

Organisms can affect one another’s phenotypes when they socially interact. Indirect genetic effects occur when an individual’s phenotype is affected by genes expressed in another individual. These heritable effects can enhance or reduce adaptive potential, thereby accelerating or reversing evolutionary change. Quantifying these social effects is therefore crucial for our understanding of evolution, yet estimates of indirect genetic effects in wild animals are limited to dyadic interactions. We estimated indirect phenotypic and genetic effects, and their covariance with direct effects, for the date of spring breeding in North American red squirrels (Tamiasciurus hudsonicus) living in an array of territories of varying spatial proximity. Additionally, we estimated indirect effects and the strength of selection at low and high population densities. Social effects of neighbours on the date of spring breeding were different from zero at high population densities but not at low population densities. Indirect phenotypic effects accounted for a larger amount of variation in the date of breeding than differences attributable to the among‐individual variance, suggesting social interactions are important for determining breeding dates. The genetic component to these indirect effects was however not statistically significant. We therefore showcase a powerful and flexible method that will allow researchers working in organisms with a range of social systems to estimate indirect phenotypic and genetic effects, and demonstrate the degree to which social interactions can influence phenotypes, even in a solitary species.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149549/1/jeb13437_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149549/2/jeb13437.pd

Management of phosphorus supply to Australian floricultural species

Young plants of Sticherus, waxflower (Chamelaucium) and two Caustis cultivars were grown in a soilless potting medium. The plants were fertilised at seven rates of the soluble monocalcium phosphate (MCP) fertiliser and one rate of the slightly soluble rock phosphate (RP). One group of plants was watered by a non-leaching and a second group of plants watered by a leaching method. Both Caustis cultivars (M63, B84) grown in the potting medium under the non-leaching regime did not show deficiency symptoms at no added P, but they showed P toxicity symptoms at MCP-P application rates > 11 g m-3. The critical P concentration in the shoots associated with a 10% decrease in yield from the maximum was 0.26% for Caustis M63 and 0.33% for Caustis B84. The two Caustis cultivars did not develop P toxicity symptoms or show any decline in shoot dry weight when fertilised with RP under both non-leaching and leaching regimes. Leaching reduced but did not eliminate P toxicity in both Caustis cultivars, although shoot dry weight did not differ significantly between the two watering regimes used. Waxflower grew poorly in the potting medium under the non-leaching regime at no added P or when fertilised with RP but did not develop P toxicity symptoms at any rate of P application as MCP, including the highest rate of 352 g m-3. The waxflower plants grew less well under the leaching than when grown under the non-leaching regime. The critical NaHCO3-extractable P level required for production of 90% relative dry weight of shoots of waxflower was about 46 mg kg-1 under the non-leaching and about 69 mg kg-1 medium under the leaching regime. Under the non-leaching regime the critical NaHCO3-extractable P level for toxicity of Caustis B84 was about 13 mg kg-1 while under the leaching regime this was higher at about 22 mg kg-1. Sticherus plants did not respond significantly to P application as either MCP or RP. However, Sticherus plants grew much better when grown under the leaching than when they were grown under the non-leaching regime. Although leaching conferred some advantages in the growth of Sticherus and in the reduction of P toxicity in Caustis, it also caused a considerable loss of P