Species‐specific habitat preferences do not shape the structure of a crested newt hybrid zone (
            Triturus cristatus
             x 
            T. carnifex
            )

SummaryEnvironmental DNA (eDNA) analysis is a rapid, cost-effective, non-invasive biodiversity monitoring tool which utilises DNA left behind in the environment by organisms for species detection. The method is used as a species specific survey tool for rare or invasive species across a broad range of ecosystems. Recently, eDNA and ‘metabarcoding’ have been combined to describe whole communities rather than focusing on single target species. However, whether metabarcoding is as sensitive as targeted approaches for rare species detection remains to be evaluated. The great crested newt Triturus cristatus is a flagship pond species of international conservation concern and the first UK species to be routinely monitored using eDNA. We evaluate whether eDNA metabarcoding has comparable sensitivity to targeted real-time quantitative PCR (qPCR) for T. cristatus detection. Extracted eDNA samples (N = 532) were screened for T. cristatus by qPCR and analysed for all vertebrate species using High-Throughput Sequencing technology. With qPCR and a detection threshold of 1/12 positive qPCR replicates, newts were detected in 50% of ponds. Detection decreased to 32% when the threshold was increased to 4/12 positive qPCR replicates. With metabarcoding, newts were detected in 34% of ponds without a detection threshold, and in 28% of ponds when a threshold (0.028%) was applied. Therefore, qPCR provided greater detection than metabarcoding but metabarcoding detection with no threshold was equivalent to qPCR with a stringent detection threshold. The proportion of T. cristatus sequences in each sample was positively associated with the number of positive qPCR replicates (qPCR score) suggesting eDNA metabarcoding may be indicative of eDNA concentration. eDNA metabarcoding holds enormous potential for holistic biodiversity assessment and routine freshwater monitoring. We advocate this community approach to freshwater monitoring to guide management and conservation, whereby entire communities can be initially surveyed to best inform use of funding and time for species-specific surveys.

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RELATIVE ABUNDANCE AND THE SPECIES-SPECIFIC REINFORCEMENT OF MALE MATING PREFERENCE IN THE CHRYSOCHUS (COLEOPTERA: CHRYSOMELIDAE) HYBRID ZONE

Evolution ◽

10.1554/05-120.1 ◽

2005 ◽

Vol 59 (12) ◽

pp. 2639 ◽

Cited By ~ 1

Author(s):

Merrill A. Peterson ◽

Barbara M. Honchak ◽

Stefanie E. Locke ◽

Timothy E. Beeman ◽

Jessica Mendoza ◽

...

Keyword(s):

Relative Abundance ◽

Hybrid Zone ◽

Mating Preference ◽

Male Mating ◽

Species Specific

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Migratory orientation in a narrow avian hybrid zone

PeerJ ◽

10.7717/peerj.3201 ◽

2017 ◽

Vol 5 ◽

pp. e3201 ◽

Cited By ~ 3

Author(s):

David P.L. Toews ◽

Kira E. Delmore ◽

Matthew M. Osmond ◽

Philip D. Taylor ◽

Darren E. Irwin

Keyword(s):

Hybrid Zone ◽

Genetic Background ◽

Migratory Restlessness ◽

Long Distance ◽

Mountain Valley ◽

Migratory Orientation ◽

Isotopic Studies ◽

Migratory Routes ◽

Species Specific ◽

Migratory Divide

Background Zones of contact between closely related taxa with divergent migratory routes, termed migratory divides, have been suggested as areas where hybrid offspring may have intermediate and inferior migratory routes, resulting in low fitness of hybrids and thereby promoting speciation. In the Rocky Mountains of Canada there is a narrow hybrid zone between Audubon’s and myrtle warblers that is likely maintained by selection against hybrids. Band recoveries and isotopic studies indicate that this hybrid zone broadly corresponds to the location of a possible migratory divide, with Audubon’s warblers migrating south-southwest and myrtle warblers migrating southeast. We tested a key prediction of the migratory divide hypothesis: that genetic background would be predictive of migratory orientation among warblers in the center of the hybrid zone. Methods We recorded fall migratory orientation of wild-caught migrating warblers in the center of the hybrid zone as measured by video-based monitoring of migratory restlessness in circular orientation chambers. We then tested whether there was a relationship between migratory orientation and genetic background, as measured using a set of species-specific diagnostic genetic markers. Results We did not detect a significant association between orientation and genetic background. There was large variation among individuals in orientation direction. Mean orientation was towards the NE, surprising for birds on fall migration, but aligned with the mountain valley in which the study took place. Conclusions Only one other study has directly analyzed migratory orientation among naturally-produced hybrids in a migratory divide. While the other study showed an association between genetic background and orientation, we did not observe such an association in yellow-rumped warblers. We discuss possible reasons, including the possibility of a lack of a strong migratory divide in this hybrid zone and/or methodological limitations that may have prevented accurate measurements of long-distance migratory orientation.

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The Role of Plasticity and Adaptation in the Incipient Speciation of a Fire Salamander Population

Genes ◽

10.3390/genes10110875 ◽

2019 ◽

Vol 10 (11) ◽

pp. 875

Author(s):

Joana Sabino-Pinto ◽

Daniel J. Goedbloed ◽

Eugenia Sanchez ◽

Till Czypionka ◽

Arne W. Nolte ◽

...

Keyword(s):

Gene Expression ◽

Phenotypic Plasticity ◽

Local Adaptation ◽

Habitat Preferences ◽

Genetic Change ◽

Incipient Speciation ◽

Expression Of Genes ◽

Species Specific ◽

Reciprocal Transfer ◽

High Degree

Phenotypic plasticity and local adaptation via genetic change are two major mechanisms of response to dynamic environmental conditions. These mechanisms are not mutually exclusive, since genetic change can establish similar phenotypes to plasticity. This connection between both mechanisms raises the question of how much of the variation observed between species or populations is plastic and how much of it is genetic. In this study, we used a structured population of fire salamanders (Salamandra salamandra), in which two subpopulations differ in terms of physiology, genetics, mate-, and habitat preferences. Our goal was to identify candidate genes for differential habitat adaptation in this system, and to explore the degree of plasticity compared to local adaptation. We therefore performed a reciprocal transfer experiment of stream- and pond-originated salamander larvae and analyzed changes in morphology and transcriptomic profile (using species-specific microarrays). We observed that stream- and pond-originated individuals diverge in morphology and gene expression. For instance, pond-originated larvae have larger gills, likely to cope with oxygen-poor ponds. When transferred to streams, pond-originated larvae showed a high degree of plasticity, resembling the morphology and gene expression of stream-originated larvae (reversion); however the same was not found for stream-originated larvae when transferred to ponds, where the expression of genes related to reduction-oxidation processes was increased, possibly to cope with environmental stress. The lack of symmetrical responses between transplanted animals highlights the fact that the adaptations are not fully plastic and that some level of local adaptation has already occurred in this population. This study illuminates the process by which phenotypic plasticity allows local adaptation to new environments and its potential role in the pathway of incipient speciation.

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Geographic variation and taxonomy of crested newts (Triturus cristatus superspecies): morphological and mitochondrial DNA data

Contributions to Zoology ◽

10.1163/18759866-06803004 ◽

1999 ◽

Vol 68 (3) ◽

pp. 181-203 ◽

Cited By ~ 43

Author(s):

J.W. Arntzen ◽

Graham P. Wallis

Keyword(s):

Geographic Variation ◽

Species Interactions ◽

Hybrid Zones ◽

Confounding Factors ◽

Direct Count ◽

Triturus Cristatus ◽

Trunk Length ◽

Crested Newt ◽

Haplotype Data ◽

Mtdna Haplotype

Within the newt genus Triturus, the large-bodied species in the T. cristatus (crested newt) superspecies show an unusual degree of variation in relative trunk length as a result of among-taxon variation in interlimb vertebral count. Here we examine the systematic value of this feature as assessed by both exterior measurement (Wolterstorff Index) and direct radiographic count of rib-bearing vertebrae, with particular reference to a number of confounding factors (sex differences, hybridisation, geographic variation, allometry, preservation effects). Using our mtDNA haplotype data, which are largely concordant with geographic distribution of species, we find that direct count ofthe rib-bearing vertebrae performs more reliably (14% misclassification) than external measurement (31% misclassification) as a species identifier. We therefore recommend this feature as a taxonomic tool, although (like external measurement) it breaks down near hybrid zones. To account for the observed biogeographicalpattern and phenotype-genotype discrepancies, a scenario is presented that combines the movement of the contact zone between taxa with asymmetric hybridisation. This scenario applies to species interactions in eastern Yugoslavia and western France.

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