scholarly journals Intraspecific niche partition without speciation: individual level web polymorphism within a single island spider population

2021 ◽  
Vol 288 (1945) ◽  
pp. 20203138
Author(s):  
Darko D. Cotoras ◽  
Miyuki Suenaga ◽  
Alexander S. Mikheyev
Keyword(s):  
Cryptic Species ◽  
Sampling Site ◽  
Behavioural Plasticity ◽  
Small Islands ◽  
Ecological Specialization ◽  
Individual Level ◽  
Island Populations ◽  
Web Architecture ◽  
Translocation Experiments ◽  
Adaptive Radiations

Early in the process of adaptive radiation, allopatric disruption of gene flow followed by ecological specialization is key for speciation; but, do adaptive radiations occur on small islands without internal geographical barriers? Island populations sometimes harbour polymorphism in ecological specializations, but its significance remains unclear. On one hand, morphs may correspond to ‘cryptic’ species. Alternatively, they could result from population, developmental or behavioural plasticity. The spider Wendilgarda galapagensis (Araneae, Theridiosomatidae) is endemic to the small Isla del Coco and unique in spinning three different web types, each corresponding to a different microhabitat. We tested whether this variation is associated with ‘cryptic’ species or intraspecific behavioural plasticity. Despite analysing 36 803 loci across 142 individuals, we found no relationship between web type and population structure, which was only weakly geographically differentiated. The same pattern holds when looking within a sampling site or considering only F st outliers. In line with genetic data, translocation experiments showed that web architecture is plastic within an individual. However, not all transitions between web types are equally probable, indicating the existence of individual preferences. Our data supports the idea that diversification on small islands might occur mainly at the behavioural level producing an intraspecific niche partition without speciation.

scholarly journals Ecological specialization, variability in activity patterns and response to environmental change

2018 ◽  
Vol 14 (6) ◽  
pp. 20180115 ◽  
Author(s):  
Talisin T. Hammond ◽  
Rupert Palme ◽  
Eileen A. Lacey
Keyword(s):  
Environmental Change ◽  
Environmental Conditions ◽  
Phenotypic Variability ◽  
Activity Patterns ◽  
Temporal Patterns ◽  
Past Century ◽  
Ambient Conditions ◽  
Ecological Specialization ◽  
Sympatric Populations ◽  
Individual Level

Differences in temporal patterns of activity can modulate the ambient conditions to which organisms are exposed, providing an important mechanism for responding to environmental change. Such differences may be particularly relevant to ecological generalists, which are expected to encounter a wider range of environmental conditions. Here, we compare temporal patterns of activity for partially sympatric populations of a generalist (the lodgepole chipmunk, Tamias speciosus ) and a more specialized congener (the alpine chipmunk, Tamias alpinus ) that have displayed divergent responses to the past century of environmental change. Although mean activity budgets were similar between species, analyses of individual-level variation in locomotion revealed that T. alpinus exhibited a narrower range of activity patterns than T . speciosus . Further analyses revealed that T. alpinus was more active earlier in the day, when temperatures were cooler, and that activity patterns for both species changed with increased interspecific co-occurrence. These results are consistent with the greater responsiveness of T. alpinus to changes in environmental conditions. In addition to highlighting the utility of accelerometers for collecting behavioural data, our findings add to a growing body of evidence, suggesting that the greater phenotypic variability displayed by ecological generalists may be critical to in situ responses to environmental change.

scholarly journals Genomic associations with poxvirus across divergent island populations in Berthelot's pipit

2021 ◽  
Author(s):  
Eleanor Sheppard ◽  
Claudia Martin ◽  
Claire Armstrong ◽  
Catalina González-Quevedo ◽  
Juan Carlos Illera ◽  
...  
Keyword(s):  
Viral Infection ◽  
Population Level ◽  
Genomic Variation ◽  
Nucleotide Polymorphisms ◽  
Individual Level ◽  
Island Populations ◽  
Bird Populations ◽  
Animal Populations ◽  
Infection Pressure ◽  
Avian Pox

Understanding the mechanisms and genes that enable animal populations to adapt to pathogens is important from an evolutionary, health and conservation perspective. Berthelot’s pipit (Anthus berthelotii) experiences extensive and consistent spatial heterogeneity in avian pox infection pressure across its range of island populations, thus providing an excellent system with which to examine how pathogen-mediated selection drives spatial variation in immunogenetic diversity. Here we test for evidence of genetic variation associated with avian pox at both an individual and population-level. At the individual level, we find no evidence that variation in MHC class I and TLR4 (both known to be important in recognising viral infection) was associated with pox infection within two separate populations. However, using genotype-environment association (Bayenv) in conjunction with genome-wide (ddRAD-seq) data, we detected strong associations between population-level avian pox prevalence and allele frequencies of single nucleotide polymorphisms (SNPs) at a number of sites across the genome. These sites were located within genes involved in cellular stress signalling and immune responses, many of which have previously been associated with responses to viral infection in humans and other animals. Consequently, our analyses provide evidence that pathogen-mediated selection has shaped genomic variation among relatively recently colonised island bird populations, and highlights the utility of genotype-environment associations for identifying candidate genes involved in adaption to local pathogen pressures.

scholarly journals Stability versus diversity of the dentition during evolutionary radiation in cyprinine fish

2014 ◽  
Vol 281 (1780) ◽  
pp. 20132688 ◽  
Author(s):  
Emmanuel Pasco-Viel ◽  
Lei Yang ◽  
Monette Veran ◽  
Vincent Balter ◽  
Richard L. Mayden ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Cichlid Fish ◽  
Ecological Specialization ◽  
Evolutionary Radiation ◽  
Adaptive Radiations ◽  
Phylogenetic Framework ◽  
Evolutionary Radiations ◽  
Dental Patterns ◽  
The Difference ◽  
The One

Evolutionary radiations, especially adaptive radiations, have been widely studied but mainly for recent events such as in cichlid fish or Anolis lizards. Here, we investigate the radiation of the subfamily Cyprininae, which includes more than 1300 species and is estimated to have originated from Southeast Asia around 55 Ma. In order to decipher a potential adaptive radiation, within a solid phylogenetic framework, we investigated the trophic apparatus, and especially the pharyngeal dentition, as teeth have proved to be important markers of ecological specialization. We compared two tribes within Cyprininae, Poropuntiini and Labeonini, displaying divergent dental patterns, as well as other characters related to their trophic apparatus. Our results suggest that the anatomy of the trophic apparatus and diet are clearly correlated and this explains the difference in dental patterns observed between these two tribes. Our results illustrate the diversity of mechanisms that account for species diversity in this very diverse clade: diversification of dental characters from an ancestral pattern on the one hand, conservation of a basal synapomorphy leading to ecological specialization on the other hand. By integrating morphological, ecological and phylogenetic analyses, it becomes possible to investigate ancient radiation events that have shaped the present diversity of species.

scholarly journals Behavioural plasticity of social trematodes depends upon social context

2013 ◽  
Vol 9 (1) ◽  
pp. 20121027 ◽  
Author(s):  
T. Kamiya ◽  
R. Poulin
Keyword(s):  
Social Context ◽  
Reproductive Output ◽  
Behavioural Plasticity ◽  
Short Term ◽  
Individual Level ◽  
Additional Production ◽  
The Individual ◽  
The Cost ◽  
Trematode Parasites

Members of some social insects adjust their behaviours depending upon social context. Such plasticity allows colonies to sustain efficiency of the whole without the cost of additional production of individuals or delayed responses to perturbations. Using the recently discovered social clonal stage of trematode parasites, we investigated whether members of the reproductive caste adjust their defensive behaviour according to the local availability of non-reproductive defensive specialists, and if so whether the plasticity affects the short-term reproductive success of reproductive morphs. In vitro experiments demonstrated plasticity in competitive interactions of the reproductive morphs depending on the number of non-reproductive defensive specialists present nearby, which lead to differences in reproductive output at the individual level. This study provides support for the benefit of maintaining non-reproductive morphs in competitive situations, arising through socially mediated behavioural plasticity.

scholarly journals Daily sampling of early SARS-CoV-2 infection reveals substantial heterogeneity in infectiousness

2021 ◽  
Author(s):  
Ruian Ke ◽  
Pamela P Martinez ◽  
Rebecca L Smith ◽  
Laura L Gibson ◽  
Agha Mirza ◽  
...  
Keyword(s):  
Infectious Virus ◽  
Acute Infection ◽  
Sampling Site ◽  
Virus Shedding ◽  
Individual Level ◽  
Viral Loads ◽  
Infection Dynamics ◽  
Daily Sampling ◽  
Clearance Kinetics ◽  
Longitudinal Sampling

The dynamics of SARS-CoV-2 replication and shedding in humans remain poorly understood. We captured the dynamics of infectious virus and viral RNA shedding during acute infection through daily longitudinal sampling of 60 individuals for up to 14 days. By fitting mechanistic models, we directly estimate viral reproduction and clearance rates, and overall infectiousness for each individual. Significant person-to-person variation in infectious virus shedding suggests that individual-level heterogeneity in viral dynamics contributes to superspreading. Viral genome load often peaked days earlier in saliva than in nasal swabs, indicating strong compartmentalization and suggesting that saliva may serve as a superior sampling site for early detection of infection. Viral loads and clearance kinetics of B.1.1.7 and non-B.1.1.7 viruses were indistinguishable, however B.1.1.7 exhibited a significantly slower pre-peak growth rate in saliva. These results provide a high-resolution portrait of SARS-CoV-2 infection dynamics and implicate individual-level heterogeneity in infectiousness in superspreading.

scholarly journals How past exposure to predation affects personality and behavioural plasticity?

2019 ◽  
Author(s):  
Juliette Tariel ◽  
Sandrine Plénet ◽  
Émilien Luquet
Keyword(s):  
Individual Difference ◽  
Population Level ◽  
Induced Response ◽  
Behavioural Plasticity ◽  
Developmental Exposure ◽  
Predator Cues ◽  
Individual Level ◽  
Two Generations ◽  
Carry Over ◽  
The Individual

AbstractWhen behaviour is observed multiple times on animals from the same population, between-individual difference in mean behaviour (personality) and in behavioural plasticity are often reported. While the developmental environment might explain such an individual difference, the effect of parental environment is still unexplored -a surprising observation as parental carry-over effect are now well-known to influence the average phenotype and plastic responses of offspring-.We tested whether parental and developmental exposure to predator cues impacted the immediate behavioural predator-induced response in the snail Physa acuta at both mean level (average response) and individual level (between-individual variation). Two generations of snails were reared in laboratory without or with exposure to predator cues. Then, escape behaviour was repeatedly assessed on adult snails in the presence or absence of predator cues.Both parental and developmental exposure to predator cues acted additively towards a lower average behavioural plasticity. At the individual level, developmental exposure induced higher differentiation in personality trait but not in behavioural plasticity while parental environment did not influence the between-individual differences.These results highlight that past environments can strongly influence behaviour at the population level and that they should be taken into consideration when investigating why individuals differ in behaviour.

scholarly journals Variation and constraints in hybrid genome formation

2017 ◽  
Author(s):  
Anna Runemark ◽  
Cassandra N. Trier ◽  
Fabrice Eroukhmanoff ◽  
Jo S. Hermansen ◽  
Michael Matschiner ◽  
...  
Keyword(s):  
Dna Repair ◽  
Nuclear Genes ◽  
Species Boundaries ◽  
Z Chromosome ◽  
Parent Species ◽  
Island Populations ◽  
Hybrid Genome ◽  
Adaptive Radiations ◽  
Homoploid Hybrid ◽  
Genomic Regions

SummaryRecent genomic investigations have revealed hybridization to be an important source of variation, the working material of natural selection1,2. Hybridization can spur adaptive radiations3, transfer adaptive variation across species boundaries4, and generate species with novel niches5. Yet, the limits to viable hybrid genome formation are poorly understood. Here we investigated to what extent hybrid genomes are free to evolve or whether they are restricted to a specific combination of parental alleles by sequencing the genomes of four isolated island populations of the homoploid hybrid Italian sparrow Passer italiae6,7. Based on 61 Italian sparrow genomes from Crete, Corsica, Sicily and Malta, and 10 genomes of each of the parent species P. domesticus and P. hispaniolensis, we report that a variety of novel and fully functional hybrid genomic combinations have arisen on the different islands, with differentiation in candidate genes for beak shape and plumage colour. There are limits to successful genome fusion, however, as certain genomic regions are invariably inherited from the same parent species. These regions are overrepresented on the Z-chromosome and harbour candidate incompatibility loci, including DNA-repair and mito-nuclear genes; loci that may drive the general reduction of introgression on sex chromosomes8. Our findings demonstrate that hybridization is a potent process for generating novel variation, but variation is limited by DNA-repair and mito-nuclear genes, which play an important role in reproductive isolation and thus contribute to speciation.

DNA Barcoding of Red Sea Fishes from Saudi Arabia – The first approach

DNA Barcodes ◽  
2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Subrata Trivedi ◽  
Raafat Affan ◽  
Abdulrahman Hirab A Alessa ◽  
Abid A Ansari ◽  
Bishal Dhar ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Cryptic Species ◽  
Dna Barcoding ◽  
Red Sea ◽  
Coastal Waters ◽  
Large Scale ◽  
Sampling Site ◽  
Fish Samples ◽  
Preliminary Study ◽  
High Possibility

AbstractDNA barcoding is a worldwide initiative. Although there is a campaign to barcode all fishes, there is no information on the DNA barcoding of Red Sea fishes. With the aim of strengthening the BOLD/barcode database with the sequences of Red sea fishes this preliminary study was conducted with six different fish species collected from coastal waters of Tabuk in Saudi Arabia. Among the six fish samples collected from the same sampling site, two sequences were novel. So, it is necessary to carry out large scale sampling covering a bigger area of Red Sea because there is high possibility to detect new/cryptic species from the unexplored biodiversity rich Red Sea.

Variability in the motion behaviour of intertidal gastropods: ecological and evolutionary perspectives

2010 ◽  
Vol 91 (1) ◽  
pp. 237-244 ◽  
Author(s):  
Coraline Chapperon ◽  
Laurent Seuront
Keyword(s):  
Environmental Conditions ◽  
Movement Patterns ◽  
Adaptive Strategy ◽  
Individual Variability ◽  
Foraging Strategies ◽  
Behavioural Plasticity ◽  
Environmental Fluctuation ◽  
Individual Level ◽  
Interspecific Differences ◽  
The Individual

The variability in motion behaviour properties was investigated for three species of intertidal gastropods at the inter-specific, inter-individual and individual levels in the absence of abiotic and biotic cues. Interspecific differences in movement patterns were reminiscent of the optimal searching behaviours expected for Austrocochlea porcata, Nerita atramentosa and Bembicium melanostomum in their natural environment. Specifically, N. atramentosa, A. porcata and B. melanostomum respectively displayed extensive and intensive foraging strategies consistent with their feeding ecology. The related inter-individual variability within each species highlights the potential ability of species to adapt their movement patterns to new environmental conditions and to persist over long-term changes. Finally, the strong variability observed in the speed and turning angle of individuals of the three species and the resulting behavioural plasticity may be an adaptive strategy to optimize energy expenditure and to react to an environmental fluctuation. Specifically, it is suggested that the lack of significant differences in individual behavioural variability between the three species indicates that despite clear inter-specific differences in motion behaviour, at the individual level A. porcata, N. atramentosa and B. melanostomum have similar abilities to face environmental fluctuations. This work stresses that individual variability in the motion behaviour of intertidal gastropods constitutes a fundamental evolutionary advantage when facing heterogeneous environmental conditions.

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