Behavioural trait assortment in a social network: Patterns and implications

This a post-print, author-produced version of an article accepted for publication in Behavioral Ecology and Sociobiology. Copyright © 2009 Springer Verlag. The definitive version is available at http://link.springer.com/article/10.1007%2Fs00265-009-0802-x#The social fine structure of a population plays a central role in ecological and evolutionary processes. Whilst many studies have investigated how morphological traits such as size affect social structure of populations, comparatively little is known about the influence of behaviours such as boldness and shyness. Using information on social interactions in a wild population of Trinidadian guppies (Poecilia reticulata), we construct a social network. For each individual in the network, we quantify its behavioural phenotype using two measures of boldness, predator inspection tendency, a repeatable and reliably measured behaviour well studied in the context of co-operation, and shoaling tendency. We observe striking heterogeneity in contact patterns, with strong ties being positively assorted and weak ties negatively assorted by our measured behavioural traits. Moreover, shy fish had more network connections than bold fish and these were on average stronger. In other words, social fine structure is strongly influenced by behavioural trait. We assert that such structure will have implications for the outcome of selection on behavioural traits and we speculate that the observed positive assortment may act as an amplifier of selection contributing to the maintenance of co-operation during predator inspection

Experimental harvesting of fish populations drives genetically based shifts in body size and maturation

Size-selective harvesting in commercial fisheries can induce rapid changes in biological traits. While experimental and wild harvested populations often exhibit clear shifts in body size and maturation associated with fishing pressure, the relative contributions of genetic and environmental factors to these shifts remain uncertain and have been much debated. To date, observations of so-called fisheries-induced evolution (FIE) have been based solely on phenotypic measures, such as size data. Genetic data are hitherto lacking. Here, we quantify genetic versus environmental change in response to size-selective harvesting for small and large body size in guppies (Poecilia reticulata) across three generations of selection. We document for the first time significant changes at individual genetic loci, some of which have previously been associated with body size. In contrast, variation at neutral microsatellite markers was unaffected by selection, providing direct genetic evidence for rapid evolution induced by size-selective harvesting. These findings demonstrate FIE in an experimental system, with major implications for the sustainability of harvested populations, as well as impacts on size-structured communities and ecosystem processes. These findings highlight the need for scientists and managers to reconsider the capacity of harvested stocks to adapt to, and recover from, harvesting and predation. © 2013 The Ecological Society of America

Evolution of non-kin cooperation: social assortment by cooperative phenotype in guppies

This is the final version. Available from The Royal Society via the DOI in this record.Data accessibility: The data used in this study are available at the Dryad Digital Repository: doi:10.5061/dryad.js446q8Cooperation among non-kin constitutes a conundrum for evolutionary biology. Theory suggests that non-kin cooperation can evolve if individuals differ consistently in their cooperative phenotypes and assort socially by these, such that cooperative individuals interact predominantly with one another. However, our knowledge of the role of cooperative phenotypes in the social structuring of real-world animal populations is minimal. In this study, we investigated cooperative phenotypes and their link to social structure in wild Trinidadian guppies (Poecilia reticulata). We first investigated whether wild guppies are repeatable in their individual levels of cooperativeness (i.e. have cooperative phenotypes) and found evidence for this in seven out of eight populations, a result which was mostly driven by females. We then examined the social network structure of one of these populations where the expected fitness impact of cooperative contexts is relatively high, and found assortment by cooperativeness, but not genetic relatedness. In contrast, in accordance with our expectations we did not find assortment by cooperativeness in a population where the expected fitness impact of cooperative contexts is lower. Our results provide empirical support for current theory and suggest that assortment by cooperativeness is important for the evolution and persistence of non-kin cooperation in real-world populations.Leverhulme TrustDanish Council for Independent Researc

Dynamic eye colour as an honest signal of aggression

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordAnimal eyes are some of the most widely recognisable structures in nature. Due to their salience to predators and prey, most research has focussed on how animals hide or camouflage their eyes [1]. However, across all vertebrate Classes many species actually express brightly coloured or conspicuous eyes, suggesting they may have also evolved a signalling function. Nevertheless, perhaps due to the difficulty with experimentally manipulating eye appearance, very few species beyond humans [2] have been experimentally shown to use eyes as signals [3]. Using staged behavioural trials we show that Trinidadian guppies (Poecilia reticulata), which can rapidly change their iris colour, predominantly express conspicuous eye colouration when performing aggressive behaviours towards smaller conspecifics. We then show, using a novel visually-realistic robotic system to create a mismatch between signal and relative competitive ability, that eye colour is used to honestly signal aggressive motivation. Specifically, robotic ‘cheats’, i.e. smaller and thus less-competitive robotic fish that displayed aggressive eye colouration when defending a food patch, attracted greater food competition from larger real fish. Our study suggests that eye colour may be an under-appreciated aspect of signalling in animals, shows the utility of our new biomimetic robotic system for investigations in animal behaviour, and provides rare experimental evidence that socially-mediated costs towards low-quality individuals may maintain the honesty of dynamic colour signals.This work was supported by a research grant from the Leverhulme Trust (RPG-2015-047) awarded to D.P.C. and S.K.D. D.P.C. and S.K.D. also acknowledge funding from the Danish Council for Independent Research (DFF – 1323-00105). We are very grateful to Rajendra Mahabir for assistance in the field, to Fiona Moultrie, Joah Madden, Sam Ellis, Ashley Ward, and John Endler for valuable discussion, and to Tom Houslay for advice on the R code to generate the plots

The Value of In Vivo Reflectance Confocal Microscopy as an Assessment Tool in Chemotherapy-Induced Peripheral Neuropathy:A Pilot Study

Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting toxicity with significant sequelae. There is a lack of standardized objective and reliable assessment tools in CIPN. In vivo reflectance confocal microscopy (RCM) imaging offers a non-invasive method to identify peripheral neuropathy markers, namely Meissner's corpuscles. This article reports on the feasibility and value of RCM in CIPN.Background There is a lack of standardized objective and reliable assessment tools for chemotherapy-induced peripheral neuropathy (CIPN). In vivo reflectance confocal microscopy (RCM) imaging offers a non-invasive method to identify peripheral neuropathy markers, namely Meissner's corpuscles (MC). This study investigated the feasibility and value of RCM in CIPN. Patients and Methods Reflectance confocal microscopy was performed on the fingertip to evaluate MC density in 45 healthy controls and 9 patients with cancer (prior, during, and post-chemotherapy). Quantification was completed by 2 reviewers (one blinded), with maximum MC count/3 x 3 mm image reported. Quantitative Sensory Testing (QST; thermal and mechanical detection thresholds), Grooved pegboard test, and patient-reported outcomes measures (PROMS) were conducted for comparison. Results In controls (25 females, 20 males; 24-81 years), females exhibited greater mean MC density compared with males (49.9 +/- 7.1 vs 30.9 +/- 4.2 MC/3 x 3 mm; P = .03). Differences existed across age by decade (P < .0001). Meissner's corpuscle density was correlated with mechanical detection (rho = -0.51), warm detection (rho = -0.47), cold pain (rho = 0.49) thresholds (P < .01); and completion time on the Grooved pegboard test in both hands (P <= .02). At baseline, patients had reduced MC density vs age and gender-matched controls (P = .03). Longitudinal assessment of MC density revealed significant relationships with QST and PROMS. Inter-rater reliability of MC count showed an intraclass correlation of 0.96 (P < .0001). Conclusions The findings support the clinical utility of RCM in CIPN as it provides meaningful markers of sensory nerve dysfunction. Novel, prospective assessment demonstrated the ability to detect subclinical deficits in patients at risk of CIPN and potential to monitor neuropathy progression

Lenin on the Agrarian and Peasant Questions

Lenin attached great importance to the processes of agricultural and rural development. This is understandable in view of the fact that tsarist Russia where he prepared a socialist revolution had all the characteristics of an agrarian peasant country. Thus it was in Russia that many theories came into being which were contrary to the Marxist interpretations of historical evolution. Using the example of agriculture and peasantry, their authors tried to prove Marxist analysis wrong. They insisted that the special features of agriculture call for different laws of development (influence of natural factors, work with living matter, land as a special means of production, etc.). Thus defined, the agrarian question raised by bourgeois and revisionist economists did not exist for Lenin. For this sphere too is penetrated by capitalism, which leads to concentration, differentiation and social contrasts. One can only speak of different forms of its emergence in agriculture and industry, while the basic features remain the same. There are numerous works in which Lenin argued with the Populists and other champions of the agrarian question. The second group of questions which Lenin was concerned with derives from attempts to determine the attitude of the proletariat towards the peasants. Like Engels and Kautsky before him, he too was in favour of a firm alliance with small and medium farmers in the preparation for and realization of the revolution and, after its victory, for a gradual inclusion of the peasants in large-scale socialist agriculture on the principle of voluntary agreement and financial interest. The third group of questions studied by Lenin refers to the systems of co- -operation and association. In voluntary large-scale association of small producers Lenin saw the only way for agricultural development in the conditions of pettv ownership. But this involved an indispensable need for the development of industry which would provide agriculture with the necessary means

Effects of near-source coagulation of biomass burning aerosols on global predictions of aerosol size distributions and implications for aerosol radiative effects

Biomass burning is a significant global source of aerosol number and mass. In fresh biomass burning plumes, aerosol coagulation reduces aerosol number and increases the median size of aerosol size distributions, impacting aerosol radiative effects. Near-source biomass burning aerosol coagulation occurs at spatial scales much smaller than the grid boxes of global and many regional models. To date, these models have ignored sub-grid coagulation and instantly mixed fresh biomass burning emissions into coarse grid boxes. A previous study found that the rate of particle growth by coagulation within an individual smoke plume can be approximated using the aerosol mass emissions rate, initial size distribution median diameter and modal width, plume mixing depth, and wind speed. In this paper, we use this parameterization of sub-grid coagulation in the GEOS-Chem–TOMAS (TwO-Moment Aerosol Sectional) global aerosol microphysics model to quantify the impacts on global aerosol size distributions, the direct radiative effect, and the cloud-albedo aerosol indirect effect. We find that inclusion of biomass burning sub-grid coagulation reduces the biomass burning impact on the number concentration of particles larger than 80&thinsp;nm (a proxy for CCN-sized particles) by 37&thinsp;% globally. This cloud condensation nuclei (CCN) reduction causes our estimated global biomass burning cloud-albedo aerosol indirect effect to decrease from −76 to −43&thinsp;mW&thinsp;m−2. Further, as sub-grid coagulation moves mass to sizes with more efficient scattering, including it increases our estimated biomass burning all-sky direct effect from −224 to −231&thinsp;mW&thinsp;m−2, with assumed external mixing of black carbon and from −188 to −197&thinsp;mW&thinsp;m−2 and with assumed internal mixing of black carbon with core-shell morphology. However, due to differences in fire and meteorological conditions across regions, the impact of sub-grid coagulation is not globally uniform. We also test the sensitivity of the impact of sub-grid coagulation to two different biomass burning emission inventories to various assumptions about the fresh biomass burning aerosol size distribution and to two different timescales of sub-grid coagulation. The impacts of sub-grid coagulation are qualitatively the same regardless of these assumptions.</p

Evolution of non-kin cooperation:social assortment by cooperative phenotype in guppies

© 2019 The Authors. Cooperation among non-kin constitutes a conundrum for evolutionary biology. Theory suggests that non-kin cooperation can evolve if individuals differ consistently in their cooperative phenotypes and assort socially by these, such that cooperative individuals interact predominantly with one another. However, our knowledge of the role of cooperative phenotypes in the social structuring of real-world animal populations is minimal. In this study, we investigated cooperative phenotypes and their link to social structure in wild Trinidadian guppies (Poecilia reticulata). We first investigated whether wild guppies are repeatable in their individual levels of cooperativeness (i.e. have cooperative phenotypes) and found evidence for this in seven out of eight populations, a result which was mostly driven by females. We then examined the social network structure of one of these populations where the expected fitness impact of cooperative contexts is relatively high, and found assortment by cooperativeness, but not by genetic relatedness. By contrast, and in accordance with our expectations, we did not find assortment by cooperativeness in a population where the expected fitness impact of cooperative contexts is lower. Our results provide empirical support for current theory and suggest that assortment by cooperativeness is important for the evolution and persistence of non-kin cooperation in real-world populations

Wall-less Flow Phantom for High-Frequency Ultrasound Applications

AbstractThere are currently very few test objects suitable for high-frequency ultrasound scanners that can be rapidly manufactured, have appropriate acoustic characteristics and are suitably robust. Here we describe techniques for the creation of a wall-less flow phantom using a physically robust konjac and carrageenan-based tissue-mimicking material. Vessel dimensions equivalent to those of mouse and rat arteries were achieved with steady flow, with the vessel at a depth of 1.0 mm. We then employed the phantom to briefly investigate velocity errors using pulsed wave Doppler with a commercial preclinical ultrasound system. This phantom will provide a useful tool for testing preclinical ultrasound imaging systems

Cyclic phosphonium ionic liquids

Ionic liquids (ILs) incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonyl)amide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners