scholarly journals Extreme environmental variation sharpens selection that drives the evolution of a mutualism

2007 ◽  
Vol 274 (1620) ◽  
pp. 1799-1805 ◽  
Author(s):  
Adam M Siepielski ◽  
Craig W Benkman
Keyword(s):  
Adaptive Evolution ◽  
Species Interactions ◽  
Evolutionary Dynamics ◽  
Phenotypic Selection ◽  
Whitebark Pine ◽  
Nucifraga Columbiana ◽  
Seed Predator ◽  
Clark's Nutcracker ◽  
Small Seed ◽  
Seed Crops

The importance of infrequent events for both adaptive evolution and the evolution of species interactions is largely unknown. We investigated how the infrequent production of large seed crops (masting) of a bird-dispersed tree (whitebark pine, Pinus albicaulis ) influenced phenotypic selection exerted by its primary avian seed predator–disperser, the Clark's nutcracker ( Nucifraga columbiana ). Selection was not evident during common years of low seed abundance, whereas it was replicated among areas and favoured traits facilitating seed dispersal during infrequent years of high seed abundance. Since nutcrackers act mostly as seed predators during small seed crops but as seed dispersers during the largest seed crops, trees experienced strong selection from nutcrackers only during infrequent years when the interaction was most strongly mutualistic. Infrequent events can thus be essential to both adaptive evolution and the evolutionary dynamics of species interactions.

Assessing Clark's nutcracker seed-caching flights using maternally inherited mitochondrial DNA of whitebark pine

2002 ◽  
Vol 32 (6) ◽  
pp. 1103-1107 ◽  
Author(s):  
Bryce A Richardson ◽  
Ned B Klopfenstein ◽  
Steven J Brunsfeld
Keyword(s):  
Mitochondrial Dna ◽  
Spatial Scales ◽  
Random Pattern ◽  
Fine Scale ◽  
Whitebark Pine ◽  
Coarse Scale ◽  
Nucifraga Columbiana ◽  
Seed Caching ◽  
Clark's Nutcracker ◽  
Haplotype Frequencies

Maternally inherited mitochondrial DNA haplotypes in whitebark pine (Pinus albicaulis Engelm.) were used to examine the maternal genetic structure at three hierarchical spatial scales: fine scale, coarse scale, and inter population. These data were used to draw inferences into Clark's nutcracker (Nucifraga columbiana Wilson) seed-caching flight distances. Statistical analyses of fine-scale and coarse-scale distribution of haplotypes showed no apparent signs of deviation from a random pattern. This suggests nutcrackers are effective in dispersal of seed within populations, which is consistent with data gathered on nutcracker seed-caching behavior. However, the lack of homogeneity in haplotype frequencies among populations indicates nutcrackers rarely disperse seeds across large gaps (>20 km) in subalpine habitat.

scholarly journals Assessing trends and vulnerabilities in the mutualism between whitebark pine (Pinus albicaulis) and Clark’s nutcracker (Nucifraga columbiana) in national parks of the Sierra-Cascade region

PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0227161
Author(s):  
Chris Ray ◽  
Regina M. Rochefort ◽  
Jason I. Ransom ◽  
Jonathan C. B. Nesmith ◽  
Sylvia A. Haultain ◽  
...  
Keyword(s):  
National Parks ◽  
Pinus Albicaulis ◽  
Whitebark Pine ◽  
Nucifraga Columbiana ◽  
Clark's Nutcracker

scholarly journals The importance of species interactions in eco-evolutionary community dynamics under climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anna Åkesson ◽  
Alva Curtsdotter ◽  
Anna Eklöf ◽  
Bo Ebenman ◽  
Jon Norberg ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Community Dynamics ◽  
Evolutionary Dynamics ◽  
Negative Impact ◽  
Trophic Levels ◽  
Temperature Dependent ◽  
Modeling Framework ◽  
Impact Of Climate Change ◽  
The Impact

AbstractEco-evolutionary dynamics are essential in shaping the biological response of communities to ongoing climate change. Here we develop a spatially explicit eco-evolutionary framework which features more detailed species interactions, integrating evolution and dispersal. We include species interactions within and between trophic levels, and additionally, we incorporate the feature that species’ interspecific competition might change due to increasing temperatures and affect the impact of climate change on ecological communities. Our modeling framework captures previously reported ecological responses to climate change, and also reveals two key results. First, interactions between trophic levels as well as temperature-dependent competition within a trophic level mitigate the negative impact of climate change on biodiversity, emphasizing the importance of understanding biotic interactions in shaping climate change impact. Second, our trait-based perspective reveals a strong positive relationship between the within-community variation in preferred temperatures and the capacity to respond to climate change. Temperature-dependent competition consistently results both in higher trait variation and more responsive communities to altered climatic conditions. Our study demonstrates the importance of species interactions in an eco-evolutionary setting, further expanding our knowledge of the interplay between ecological and evolutionary processes.

scholarly journals Increase of seeding material quality of agrarian crops by the pneumatic electric separator

2019 ◽  
Vol 132 ◽  
pp. 01016
Author(s):  
Urszula Malaga-Toboła ◽  
Stepan Kovalyshyn ◽  
Viktor Dadak ◽  
Ivan Horodetskyy
Keyword(s):  
Cereal Crops ◽  
Force Action ◽  
Separation Channel ◽  
Operating Modes ◽  
Small Seed ◽  
Pneumatic Separation ◽  
Seeding Material ◽  
High Quality Seed ◽  
Seed Crops

A detailed analysis of technical means and methods of seeds separation, as well as the research results of domestic and foreign authors, have proved that one of the perspective methods for getting of high quality seed material is the pneumatic and electric separation.The analysis of research works and the modern technical level of pneumatic separators showed that insufficient attention was paid to the study of aerodynamic separation of small-seed crops, especially, cereal grasses. By the conditions of separation in a vertical pneumatic channel the cereal crops change the area of the midlength section as to the air flow forces, and the probability was increased of getting of seeds with germs to a biologically defective seed without germs. To increase the quality of pneumatic separation one can by the selective orientation of seeds in mixture with longer axis perpendicularly to the flow of air. It is possible to achieve these conditions by the additional force action on seeds (as particles). The response of this force action could be different for a healthy seeds (with germs) and for a non-viable (without embryo) or a weed seed. Such a force effect on the particles of small-seed crop mixtures can be realized by creating of a homogeneous electric field in a separation channel. This requires a theoretical and experimental study of force action on particles during the process of separation, also justification of parameters and operating modes of the pneumatic electric separator. This study is the preconditions for design improvement of the pneumatic electric separator.

Yellowstone Grizzly Bear Mortality, Human Habituation, and Whitebark Pine Seed Crops

1992 ◽  
Vol 56 (3) ◽  
pp. 432 ◽  
Author(s):  
David J. Mattson ◽  
Bonnie M. Blanchard ◽  
Richard R. Knight
Keyword(s):  
Grizzly Bear ◽  
Whitebark Pine ◽  
Seed Crops

scholarly journals The evolutionary dynamics of influenza A virus adaptation to mammalian hosts

2013 ◽  
Vol 368 (1614) ◽  
pp. 20120382 ◽  
Author(s):  
S. Bhatt ◽  
T. T. Lam ◽  
S. J. Lycett ◽  
A. J. Leigh Brown ◽  
T. A. Bowden ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Adaptive Evolution ◽  
Influenza A ◽  
Evolutionary Dynamics ◽  
Adaptive Dynamics ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Viral Fitness ◽  
Influenza A Viruses ◽  
Entire Genome

Few questions on infectious disease are more important than understanding how and why avian influenza A viruses successfully emerge in mammalian populations, yet little is known about the rate and nature of the virus’ genetic adaptation in new hosts. Here, we measure, for the first time, the genomic rate of adaptive evolution of swine influenza viruses (SwIV) that originated in birds. By using a curated dataset of more than 24 000 human and swine influenza gene sequences, including 41 newly characterized genomes, we reconstructed the adaptive dynamics of three major SwIV lineages (Eurasian, EA; classical swine, CS; triple reassortant, TR). We found that, following the transfer of the EA lineage from birds to swine in the late 1970s, EA virus genes have undergone substantially faster adaptive evolution than those of the CS lineage, which had circulated among swine for decades. Further, the adaptation rates of the EA lineage antigenic haemagglutinin and neuraminidase genes were unexpectedly high and similar to those observed in human influenza A. We show that the successful establishment of avian influenza viruses in swine is associated with raised adaptive evolution across the entire genome for many years after zoonosis, reflecting the contribution of multiple mutations to the coordinated optimization of viral fitness in a new environment. This dynamics is replicated independently in the polymerase genes of the TR lineage, which established in swine following separate transmission from non-swine hosts.

scholarly journals Epigenetically Inherited Mutation Rates Predicted to Maximize Adaptation Rates

2021 ◽  
Author(s):  
Yoav Ram ◽  
Yitzhak Tzachi Pilpel ◽  
Gabriela Aleksandra Lobinska
Keyword(s):  
Mutation Rate ◽  
Adaptive Evolution ◽  
Evolutionary Dynamics ◽  
Epigenetic Inheritance ◽  
Fitness Landscapes ◽  
Mutation Rates ◽  
Switching Rate ◽  
Asexual Population ◽  
Parental Phenotype ◽  
Rugged Fitness Landscapes

The mutation rate is an important determinant of evolutionary dynamics. Because the mutation rate determines the rate of appearance of beneficial and deleterious mutations, it is subject to second-order selection. The mutation rate varies between and within species and populations, increases under stress, and is genetically controlled by mutator alleles. The mutation rate may also vary among genetically identical individuals: empirical evidence from bacteria suggests that the mutation rate may be affected by translation errors and expression noise in various proteins (1). Importantly, this non-genetic variation may be heritable via transgenerational epigenetic inheritance. Here we investigate how the inheritance mode of the mutation rate affects the rate of adaptive evolution on rugged fitness landscapes. We model an asexual population with two mutation rate phenotypes, non-mutator and mutator. An offspring may switch from its parental phenotype to the other phenotype. The rate of switching between the mutation rate phenotypes is allowed to span a range of values. Thus, the mutation rate can be interpreted as a genetically inherited trait when the switching rate is low, as an epigenetically inherited trait when the switching rate is intermediate, or as a randomly determined trait when the switching rate is high. We find that epigenetically inherited mutation rates result in the highest rates of adaptation on rugged fitness landscapes for most realistic parameter sets. This is because an intermediate switching rate can maintain the association between a mutator phenotype and pre-existing mutations, which facilitates the crossing of fitness valleys. Our results provide a rationale for the evolution of epigenetic inheritance of the mutation rate, suggesting that it could have been selected because it facilitates adaptive evolution.

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