scholarly journals Plant carbohydrate content limits performance and lipid accumulation of an outbreaking herbivore

2020 ◽  
Vol 287 (1940) ◽  
pp. 20202500
Author(s):  
Stav Talal ◽  
Arianne J. Cease ◽  
Jacob P. Youngblood ◽  
Ruth Farington ◽  
Eduardo V. Trumper ◽  
...  
Keyword(s):  
Ecological Factors ◽  
South American ◽  
Anthropogenic Influences ◽  
Artificial Diets ◽  
Lipid Contents ◽  
Structural Carbohydrate ◽  
Survival And Growth ◽  
Total Body ◽  
Local Plants ◽  
And Migration

Locusts are major intermittent threats to food security and the ecological factors determining where and when these occur remain poorly understood. For many herbivores, obtaining adequate protein from plants is a key challenge. We tested how the dietary protein : non-structural carbohydrate ratio (p : c) affects the developmental and physiological performance of 4th-5th instar nymphs of the South American locust, Schistocerca cancellata, which has recently resurged in Argentina, Bolivia and Paraguay. Field marching locusts preferred to feed on high carbohydrate foods. Field-collected juveniles transferred to the laboratory selected artificial diets or local plants with low p : c. On single artificial diets, survival rate increased as foods became more carbohydrate-biased. On single local plants, growth only occurred on the plant with the lowest p : c. Most local plants had p : c ratios substantially higher than optimal, demonstrating that field marching locusts must search for adequate carbohydrate or their survival and growth will be carbohydrate-limited. Total body lipids increased as dietary p : c decreased on both artificial and plant diets, and the low lipid contents of field-collected nymphs suggest that obtaining adequate carbohydrate may pose a strong limitation on migration for S. cancellata . Anthropogenic influences such as conversions of forests to pastures, may increase carbohydrate availability and promote outbreaks and migration of some locusts.

scholarly journals Ecological Factors Preventing Restoration of Degraded Short Tussock Landscapes in New Zealand’s Dryland Zone

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Anna P. Rodrigues ◽  
Elena Moltchanova ◽  
David A. Norton ◽  
Matthew Turnbull
Keyword(s):  
Water Availability ◽  
Ecological Factors ◽  
Woody Species ◽  
Biotic Factors ◽  
Introduced Herbivores ◽  
Physical Chemical ◽  
Native Woody Species ◽  
Dryland Ecosystems ◽  
Survival And Growth ◽  
Chemical Conditions

AbstractBiotic factors such as the presence of invasive animal and/or plant species are well known as major causes of ecological degradation and as limiting either natural or assisted (human-induced) ecological restoration. However, abiotic aspects of the landscape, such as water availability and soil physical/chemical conditions can also potentially limit restoration and should be considered. Dryland ecosystems are amongst the world’s most threatened and least protected. New Zealand’s drylands have been drastically changed, initially through burning, agricultural and grazing practices and the impacts of introduced herbivores and plants. This research aimed at identifying some of the key environmental factors preventing the reestablishment of native woody species in a New Zealand dryland ecosystem. The experiments involved a combination of shading, irrigation and grazing exclusion. The results showed that supplemental water was not beneficial for the survival and growth of the native seedlings, unless combined with shade. Fencing proved important for establishment, even though the species used are regarded in the literature as unpalatable to herbivores. The results indicated that the presence of shade was fundamental for the establishment and growth of the native seedlings likely due to improvements in the microclimate, soil aeration, and water availability to seedlings.

scholarly journals Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen

2017 ◽  
Author(s):  
Marina Pais ◽  
Kentaro Yoshida ◽  
Artemis Giannakopoulou ◽  
Mathieu A. Pel ◽  
Liliana M. Cano ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phenotypic Plasticity ◽  
South American ◽  
Nucleotide Polymorphisms ◽  
Natural Ecosystems ◽  
Asexual Lineage ◽  
Irish Famine ◽  
Eukaryotic Microbes ◽  
And Migration ◽  
Potato Famine

Outbreaks caused by asexual lineages of fungal and oomycete pathogens are an expanding threat to crops, wild animals and natural ecosystems (Fisher et al. 2012,Kupferschmidt 2012). However, the mechanisms underlying genome evolution and phenotypic plasticity in asexual eukaryotic microbes remain poorly understood (Seidl and Thomma 2014). Ever since the 19th century Irish famine, the oomycete Phytophthora infestans has caused recurrent outbreaks on potato and tomato crops that have been primarily caused by the successive rise and migration of pandemic asexual lineages (Cooke et al. 2012, Yoshida et al. 2013,Yoshida et al. 2014). Here, we reveal patterns of genomic and gene expression variation within a P. infestans asexual lineage by compared sibling strains belonging to the South American EC-1 clone that has dominated Andean populations since the 1990s (Forbes et al. 1997, Oyarzun et al. 1998, Delgado et al. 2013, Yoshida et al. 2013, Yoshida et al. 2014). We detected numerous examples of structural variation, nucleotide polymorphisms and gene conversion within the EC-1 clone. Remarkably, 17 genes are not expressed in one of the two EC-1 isolates despite apparent absence of sequence polymorphisms. Among these, silencing of an effector gene was associated with evasion of disease resistance conferred by a potato immune receptor. These results highlight the exceptional genetic and phenotypic plasticity that underpins host adaptation in a pandemic clonal lineage of a eukaryotic plant pathogen.

scholarly journals Integrating behaviour and ecology into global biodiversity conservation strategies

2019 ◽  
Vol 374 (1781) ◽  
pp. 20190012 ◽  
Author(s):  
Joseph A. Tobias ◽  
Alex L. Pigot
Keyword(s):  
Extinction Risk ◽  
Spatial Scales ◽  
Bird Species ◽  
Ecological Factors ◽  
Population Pressure ◽  
Conservation Strategies ◽  
Conservation Practice ◽  
Latent Extinction ◽  
Conservation Assessments ◽  
And Migration

Insights into animal behaviour play an increasingly central role in species-focused conservation practice. However, progress towards incorporating behaviour into regional or global conservation strategies has been more limited, not least because standardized datasets of behavioural traits are generally lacking at wider taxonomic or spatial scales. Here we make use of the recent expansion of global datasets for birds to assess the prospects for including behavioural traits in systematic conservation priority-setting and monitoring programmes. Using International Union for Conservation of Nature Red List classifications for more than 9500 bird species, we show that the incidence of threat can vary substantially across different behavioural categories, and that some types of behaviour—including particular foraging, mating and migration strategies—are significantly more threatened than others. The link between behavioural traits and extinction risk is partly driven by correlations with well-established geographical and ecological factors (e.g. range size, body mass, human population pressure), but our models also reveal that behaviour modifies the effect of these factors, helping to explain broad-scale patterns of extinction risk. Overall, these results suggest that a multi-species approach at the scale of communities, continents and ecosystems can be used to identify and monitor threatened behaviours, and to flag up cases of latent extinction risk, where threatened status may currently be underestimated. Our findings also highlight the importance of comprehensive standardized descriptive data for ecological and behavioural traits, and point the way towards deeper integration of behaviour into quantitative conservation assessments. This article is part of the theme issue ‘Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation’.

Political Socialization in the South American Middle Class

1968 ◽  
Vol 38 (3) ◽  
pp. 506-527 ◽  
Author(s):  
Arthur Stinchcombe
Keyword(s):  
Political System ◽  
Political Socialization ◽  
The Political ◽  
South American ◽  
Social Causation ◽  
Middle Classes ◽  
Political Processes ◽  
The Third ◽  
Political Events ◽  
And Migration

Political socialization may be thought of as having three aspects: the degree to which people interpret the conditions of their milieu in terms of distant political processes, the ideas of social causation with which they interpret such distant processes, and the interpretation of specific political events and structures of their country. This paper attempts to show that the first is determined mainly by men's educational and migration biography, the second mainly by men's occupational experience, and the third mainly by the history and structure of the political system men live under. The data come from a study of the contrasts between industrial bureaucrats and the traditional middle classes in steel cities in three South American countries, Chile, Argentina, and Venezuela.

scholarly journals ECOLOGICAL - PHYSIOLOGICAL CHARACTERISTICS OF FODDER PLANTS USED TO PREVENT DESERTIFICATION IN THE CHUST-PAP ADYRS OF THE FERGHANA VALLEY

2020 ◽  
Vol 5 (6(75)) ◽  
pp. 4-11
Author(s):  
Otabek Normirzoyevich Imomov ◽  
Turakhon Uzakovna Rakhimova ◽  
Saidmakhmud Mirzaev
Keyword(s):  
Scientific Basis ◽  
Anthropogenic Influences ◽  
Natural Ecosystems ◽  
North West ◽  
The Past ◽  
The North ◽  
Fodder Plants ◽  
Ferghana Valley ◽  
The Republic ◽  
Local Plants

Adyrs of Chust-Pap, located in the north-west of the Ferghana Valley of the Republic of Uzbekistan, the process of desertification due to anthropogenic influences has been observed over the past 35-40 years. This process was confirmed by scientists, and evidence was provided. The aim of this study was to analyze the threeyear data on the parameters of the water regime in the conditions of rainfed cultivation of such local plants as Salsola orientalis S. G. Gmel., Kochia prostrata (L) Schrad. subsp. grisea prat. Subsp. nov., Krascheninnikovia ewersmanniana (Stschegl. ex Losinsk.) Grubov., Artemisia sogdiana Bge., used in the restoration of plant communities. A scientific basis has been created for the propagation of species to prevent desertification, that adapted to the region and common in natural ecosystems.

Niche divergence and diversification in South American freshwater turtles of the genus Acanthochelys (Chelidae)

2019 ◽  
Vol 40 (4) ◽  
pp. 475-485
Author(s):  
Franco Souza ◽  
João Rodrigues ◽  
Miguel Olalla-Tárraga ◽  
José Diniz-Filho ◽  
Pablo Martinez ◽  
...  
Keyword(s):  
Species Distribution Models ◽  
Ecological Factors ◽  
Niche Overlap ◽  
Distribution Patterns ◽  
South American ◽  
Freshwater Turtles ◽  
Distribution Models ◽  
Niche Divergence ◽  
Species Pairs ◽  
Environmental Requirements

Abstract Species distribution models (SDMs) are increasingly used to assess how ecological factors shape species distributions and diversification. Chelid turtles represent the richest family of chelonians in South America. Given the distributional disjunction and distinct habitats of four Acanthochelys species, we explored SDMs and niche overlap metrics between species pairs to evaluate the extent to which niche divergence or conservatism may have contributed to their geographic distribution patterns. None of the species pairs presented patterns consistent with niche conservatism suggesting that these species have different environmental requirements. However, when comparing species pairs co-occurring in the same watershed, results were conflicting. Niche divergence detected among Acanthochelys species indicate an interaction between ecological niche preference and geographical barriers for allopatric speciation. This interaction implies that ecological differentiation contributed to the diversification of Acanthochelys side-necked turtles that occur in South American freshwater environments.

scholarly journals Evolution of long-term coloration trends with biochemically unstable ingredients

2016 ◽  
Vol 283 (1831) ◽  
pp. 20160403 ◽  
Author(s):  
Dawn M. Higginson ◽  
Virginia Belloni ◽  
Sarah N. Davis ◽  
Erin S. Morrison ◽  
John E. Andrews ◽  
...  
Keyword(s):  
Breeding Season ◽  
Ecological Factors ◽  
Carotenoid Pigments ◽  
Animal Coloration ◽  
Selective Expression ◽  
Carotenoid Composition ◽  
And Migration ◽  
Short Time ◽  
Repeated Samples

The evolutionarily persistent and widespread use of carotenoid pigments in animal coloration contrasts with their biochemical instability. Consequently, evolution of carotenoid-based displays should include mechanisms to accommodate or limit pigment degradation. In birds, this could involve two strategies: (i) evolution of a moult immediately prior to the mating season, enabling the use of particularly fast-degrading carotenoids and (ii) evolution of the ability to stabilize dietary carotenoids through metabolic modification or association with feather keratins. Here, we examine evolutionary lability and transitions between the two strategies across 126 species of birds. We report that species that express mostly unmodified, fast-degrading, carotenoids have pre-breeding moults, and a particularly short time between carotenoid deposition and the subsequent breeding season. Species that expressed mostly slow-degrading carotenoids in their plumage accomplished this through increased metabolic modification of dietary carotenoids, and the selective expression of these slow-degrading compounds. In these species, the timing of moult was not associated with carotenoid composition of plumage displays. Using repeated samples from individuals of one species, we found that metabolic modification of dietary carotenoids significantly slowed their degradation between moult and breeding season. Thus, the most complex and colourful ornamentation is likely the most biochemically stable in birds, and depends less on ecological factors, such as moult timing and migration tendency. We suggest that coevolution of metabolic modification, selective expression and biochemical stability of plumage carotenoids enables the use of unstable pigments in long-term evolutionary trends in plumage coloration.

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