scholarly journals Social hosts evade predation but have deadlier parasites

2021 ◽  
Author(s):  
Jason Walsman ◽  
Mary J. Janecka ◽  
David R. Clark ◽  
Rachael D. Kramp ◽  
Faith Rovenolt ◽  
...  
Keyword(s):  
Social Behaviour ◽  
Evolutionary Ecology ◽  
Group Living ◽  
Common Garden ◽  
Virulence Evolution ◽  
The Common ◽  
Trinidadian Guppy ◽  
Host Parasite ◽  
Predator Defence ◽  
Insight Into

AbstractParasites exploit hosts to replicate and transmit, but overexploitation kills both host and parasite1: parasite virulence evolves to balance these costs and benefits. Predators can in theory shift this balance by consuming hosts2–4. However, the non-consumptive effects of predators may be as important as their consumptive effects5. Here, we use an eco-coevolutionary model to show that predators select for host grouping, a common anti-predator, defensive social behaviour6. Host grouping simultaneously increases parasite transmission, thus within-host parasite competition, and therefore favours more exploitative, virulent, parasites7. When parametrized with data from the guppy-Gyrodactylus spp. system, including our experimentally demonstrated trade-off between virulence and transmission, our model accurately predicted the common garden-assayed virulence of 18 parasite lines collected from four Trinidadian guppy populations under different predation regimes. The quantitative match between theory and data lends credence to the model’s insight that the non-consumptive, social behaviour pathway is entirely responsible for the observed increase in virulence with predation pressure. Our results indicate that parasites play an important, underappreciated role in guppy evolutionary ecology. Moreover, group living is a common anti-predator defence6 and our general model accommodates host-parasite interactions across taxa: its insight into the interactions among predation, sociality, and virulence evolution may apply broadly. Our results additionally suggest that social distancing, by reducing host-host contact, can select for less virulent parasites and pathogens.

Analysis of Short-term Selection Experiments: 1. Least-squares Approaches

2018 ◽  
Author(s):  
Bruce Walsh ◽  
Michael Lynch
Keyword(s):  
Least Squares ◽  
Common Garden ◽  
Selection Response ◽  
Short Term ◽  
Term Selection ◽  
Generation Means ◽  
Selection Experiments ◽  
The Common ◽  
The Mean ◽  
Insight Into

This chapter examines short-term (a few generations) selection response in the mean of a trait. Traditionally, such experiments are analyzed using least-squares (LS) approaches. While ordinary LS (OLS) is often used, genetic drift causes the residual to be both correlated and heteroscedastic, resulting in the sampling variances given by OLS being too small. This chapter details the appropriate general LS (GLS) approaches to properly account for this residual error structure. It also reviews some of the common features observed in short-term selection experiments and examines experimental designs, such as the use of a control population versus a divergence-selection approach. It concludes by discussing another linear model used mainly by plant breeders, generation-means analysis (GMA), wherein remnant seed for several generations of response are crossed and then grown in a common garden. Such an analysis can provide insight into the genetic nature of any response.

scholarly journals Immune defence, parasite evasion strategies and their relevance for ‘macroscopic phenomena’ such as virulence

2008 ◽  
Vol 364 (1513) ◽  
pp. 85-98 ◽  
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Immune Evasion ◽  
Life History Theory ◽  
Evolutionary Ecology ◽  
Parasite Clearance ◽  
Multiple Infections ◽  
Parasite Fitness ◽  
Host Parasite Interactions ◽  
Evolution Of Virulence ◽  
Host Parasite ◽  
Insight Into

The discussion of host–parasite interactions, and of parasite virulence more specifically, has so far, with a few exceptions, not focused much attention on the accumulating evidence that immune evasion by parasites is not only almost universal but also often linked to pathogenesis, i.e. the appearance of virulence. Now, the immune evasion hypothesis offers a deeper insight into the evolution of virulence than previous hypotheses. Sensitivity analysis for parasite fitness and life-history theory shows promise to generate a more general evolutionary theory of virulence by including a major element, immune evasion to prevent parasite clearance from the host. Also, the study of dose–response relationships and multiple infections should be particularly illuminating to understand the evolution of virulence. Taking into account immune evasion brings immunological processes to the core of understanding the evolution of parasite virulence and for a range of related issues such as dose, host specificity or immunopathology. The aim of this review is to highlight the mechanism underlying immune evasion and to discuss possible consequences for the evolutionary ecology analysis of host–parasite interactions.

What Can Economists Contribute to the Common Good Tradition?

2017 ◽  
Author(s):  
Andrew M. Yuengert
Keyword(s):  
Common Good ◽  
Common Pool Resources ◽  
Economic Approach ◽  
Public And Private ◽  
Private Provision ◽  
The Public ◽  
The Common Good ◽  
The Common ◽  
The Individual ◽  
Insight Into

Although most economists are skeptical of or puzzled by the Catholic concept of the common good, a rejection of the economic approach as inimical to the common good would be hasty and counterproductive. Economic analysis can enrich the common good tradition in four ways. First, economics embodies a deep respect for economic agency and for the effects of policy and institutions on individual agents. Second, economics offers a rich literature on the nature of unplanned order and how it might be shaped by policy. Third, economics offers insight into the public and private provision of various kinds of goods (private, public, common pool resources). Fourth, recent work on the development and logic of institutions and norms emphasizes sustainability rooted in the good of the individual.

Social ethology of the wolverine

2018 ◽  
Author(s):  
Jeffrey P. Copeland ◽  
Arild Landa ◽  
Kimberly Heinemeyer ◽  
Keith B. Aubry ◽  
Jiska van Dijk ◽  
...  
Keyword(s):  
Social Organization ◽  
Social Interactions ◽  
Resource Availability ◽  
Social Behaviour ◽  
Social System ◽  
Group Living ◽  
Field Studies ◽  
Ecological Framework ◽  
The Social ◽  
Living Species

Social behaviour in solitary carnivores has long been an active area of investigation but for many species remains largely founded in conjecture compared to our understanding of sociality in group-living species. The social organization of the wolverine has, until now, received little attention beyond its portrayal as a typical mustelid social system. In this chapter the authors compile observations of social interactions from multiple wolverine field studies, which are integrated into an ecological framework. An ethological model for the wolverine is proposed that reveals an intricate social organization, which is driven by variable resource availability within extremely large territories and supports social behaviour that underpins offspring development.

scholarly journals Reducing the metabolic energy of walking and running using an unpowered hip exoskeleton

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tiancheng Zhou ◽  
Caihua Xiong ◽  
Juanjuan Zhang ◽  
Di Hu ◽  
Wenbin Chen ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Design Method ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Spring Stiffness ◽  
Spatiotemporal Parameters ◽  
The Common ◽  
Hip Flexion ◽  
Optimal Stiffness ◽  
Insight Into

Abstract Background Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce the metabolic rate of walking or running. However, the combined requirements of overcoming the fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of the exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy during both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton. Methods We analyzed the metabolic rates, muscle activities and spatiotemporal parameters of 9 healthy subjects (mean ± s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at a speed of 1.5 m s−1 and running at a speed of 2.5 m s−1 with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the assistance from a spring with optimal stiffness at different speeds to demonstrate the generality of the proposed approach. Results We found that the common optimal exoskeleton spring stiffness for walking and running was 83 Nm Rad−1, corresponding to 7.2% ± 1.2% (mean ± s.e.m, paired t-test p < 0.01) and 6.8% ± 1.0% (p < 0.01) metabolic reductions compared to walking and running without exoskeleton. The metabolic energy within the tested speed range can be reduced with the assistance except for low-speed walking (1.0 m s−1). Participants showed different changes in muscle activities with the assistance of the proposed exoskeleton. Conclusions This paper first demonstrates that the metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate the metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provide new insight into human response to the same assistive principle for different gaits (walking and running).

Studies on the Toxicity of Aromatic Hydrocarbons on Chorella Vulgaris by 3D-QSAR Using CoMFA and CoMSIA Methods

2012 ◽  
Vol 610-613 ◽  
pp. 3574-3579
Author(s):  
Cui Hua Wang ◽  
Sheng Long Yang ◽  
Chao Lu ◽  
Hong Xia Yu ◽  
Lian Shen Wang ◽  
...  
Keyword(s):  
Benzene Ring ◽  
Aromatic Hydrocarbons ◽  
Common Factor ◽  
3D Qsar ◽  
The Other ◽  
Contour Maps ◽  
Substituent Group ◽  
Donor And Acceptor ◽  
The Common ◽  
Insight Into

By using CoMFA and CoMSIA methods, the new quantitative structures of 25 aromatic hydrocarbons and the 96 hr-EC50 data with C. vulgaris have been investigated to obtain more detailed insight into the relationships between molecular structure and bioactivity. Compared to CoMFA (the average Q2LOO option =0.610), CoMSIA (the average Q2LOO =0.736) has the better results with robustness and stability. CoMSIA analysis using steric, electrostatic, hydrophobic, and H-bond donor and acceptor descriptors show H-bond donor is the common factor for influencing the toxicity, the steric and electrostatic descriptors are next and the hydrophobic descriptor was last. From the contour maps, the number of benzene ring is more crucial for the compound toxicity and the compounds with more benzene ring make toxicity increased. Under the same number of benzene ring, the kind of substituent group and the formed ability of H-bond are the other parameters to influencing the aromatic hydrocarbons toxicity.

scholarly journals Evidence of between-population differences in natural selection on extra-floral nectaries of the shrub Anemopaegma album (Bignoniaceae)

Botany ◽  
2016 ◽  
Vol 94 (3) ◽  
pp. 201-213
Author(s):  
Anselmo Nogueira ◽  
Pedro J. Rey ◽  
Julio M. Alcántara ◽  
Lúcia G. Lohmann
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Evolutionary Ecology ◽  
Common Garden ◽  
Phenotypic Selection ◽  
Population Differences ◽  
Wild Populations ◽  
Neotropical Savanna ◽  
Foliar Damage ◽  
Floral Nectaries

Extra-floral nectaries (EFNs) are thought to represent protective adaptations against herbivory, but studies on the evolutionary ecology of EFNs have seldom been conducted. Here we investigate the patterns of natural selection and genetic variation in EFN traits in two wild populations of Anemopaegma album Mart. ex DC. (Bignoniaceae) that have been previously described as contrasting EFN – ant adapted localities in the Neotropical savanna (Cristália and Grão Mogol). In each population, four EFN descriptors, foliar damage, and reproductive success variables were measured per plant (100–120 plants per population). To estimate the heritability of EFN traits, we crossed reproductive plants in the field, and grew offspring plants in a common garden. The results showed that ant assemblages differed between populations, as did the range of foliar herbivory. Genetic variation and positive phenotypic selection in EFN abundance were only detected in the Cristália population, in which plants with more EFNs were more likely to reproduce. An evaluation of putative causal links conducted by path analysis corroborated the existence of phenotypic selection on EFNs, which was mediated by the herbivory process in the Cristália population. While EFNs could be currently under selection in Cristália, it is possible that past selection may have driven EFN traits to become locally adapted to the local ant assemblage in the Grão Mogol population.

scholarly journals Erythraeid larvae parasitizing dragonflies in Zambia—description of Leptus (Leptus) chingombensis sp. nov. with data on biology and ecology of host-parasite interactions

2019 ◽  
Vol 24 (5) ◽  
pp. 790
Author(s):  
Rafał Bernard ◽  
Magdalena Felska ◽  
Joanna Mąkol
Keyword(s):  
Dna Barcode ◽  
Morphological Characteristics ◽  
Parasite Load ◽  
Ventral Side ◽  
Habitat Conditions ◽  
Local Character ◽  
Host Parasite Interactions ◽  
Group Variation ◽  
The Common ◽  
Host Parasite

A survey of odonate fauna in Zambia (Central Province, Luano District) resulted in discovery of ectoparasitic larvae of Leptus (L.) chingombensis sp. nov. (Trombidiformes: Parasitengona, Erythraeidae) on four species of dragonflies (Odonata) representing four different families assigned to Zygoptera and Anisoptera. The morphological characteristics of the new species is supported with DNA barcode sequence. Despite some intra-group variation related to relatively large sample, the morphological and genetic consistence confirm the common specific identity of the material. A brief comparison of Leptus spp. hitherto known from the Afrotropic as larvae is given. Supplementary data to the descriptions of Leptus (L.) bicristatus Fain et Elsen, 1987, Leptus (L.) aldonae Haitlinger, 1987 and Leptus (L.) soddagus Haitlinger, 1990, based on examination of type material, are provided. In the case of L. (L.) chingombensis sp. nov., the parasite load reached high, previously not recorded for Odonata–terrestrial Parasitengona association values, attaining at 44 and 49 larvae. Clear topic preferences towards the ventral side of the host’s body were recorded, with an additional tendency to distal parts of synthorax and the ventral depression of the abdomen. We hypothesize that the infestation did not take place synchronously at dragonflies emergence, but consisted in repeated infestation events during the recurrent appearance of dragonflies in the contact microhabitat occupied by Leptus. The very local character of the finding along with the regular appearance of larvae parasitizing dragonflies, obviously favoured by specific habitat conditions, no doubts confirms the non-accidental nature of the phenomenon.

scholarly journals The development of a CEFR-based scale for assessing young foreign language learners’ writing skills

Linguistica ◽  
2014 ◽  
Vol 54 (1) ◽  
pp. 241-259
Author(s):  
Karmen Pižorn
Keyword(s):  
Foreign Language ◽  
Language Learners ◽  
Classroom Assessment ◽  
Writing Skills ◽  
Age Group ◽  
Young Learners ◽  
Foreign Language Learners ◽  
The Common ◽  
Literacy Research ◽  
Insight Into

The Common European Framework of Reference (CEFR) was designed with adults in mind, which is clearly reflected in the six levels encompassing a range of proficiency that represents lifelong learning. Therefore, any use of the CEFR levels as a basis for describing the ability of young learners requires adapting the content of each level, as well as identifying which levels on the scale are appropriate for children.The present article examines the contribution that feedback, in the form of an assessment scale, can make to valid classroom assessment of the writing of young learners, in the age group of 9–13 years. It shows that a scale of descriptors adapted from the CEFR can play a central role in this assessment. The article presents the AYLLIT (Assessment of Young Learner Literacy) research project, which developed a CEFR-based writing scale and guidelines for teachers, enabling them to provide their students with feedback, and to gain a clearer insight into their students’ progress. After describing the procedures followed in the project, the article examines the extent to which its outcomes may enable teachers to give feedback that could contribute to valid classroom assessment.

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