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Unique mating behaviours in knife livebearers of the genus Alfaro (Poeciliidae): New observations from Alfaro huberiNARA Subscribed
Poeciliid fishes show diverse courtship displays. Building on recent work in Alfaro cultratus , we document mating behaviours in its only congener, Alfaro huberi . In both species, males adopt a unique posture above females and initiate physical contact. A. cultratus males rub the tops of females' heads with their pelvic fins, whereas A. huberi males touch females' chins with the gonopodium, a modified anal fin used in copulat...
Host‐Microbiome Associations in Livebearing Fishes Adapted to Toxic Environments Rich in Hydrogen SulfideNARA Subscribed
Organisms inhabiting extreme environments must tolerate a variety of physiochemical stressors. In some cases, host‐associated microbial communities facilitate the survival of their hosts in extreme environments, but extremophile symbioses have not been identified in vertebrates. We used 16S rRNA amplicon sequencing to investigate commonalities and differences in the gut bacterial communities of livebearing fishes ( Poecilia me...
Why Is It Too Cold? Towards a Mechanistic Understanding of Cold‐Water Pollution Effects on Recruitment of an Imperiled Warmwater FishNARA Subscribed
Environmental temperature shapes the ontogeny of ectotherms by influencing rates of growth and development which can be key determinants of survival. Whereas the escalating impacts of water management on freshwater ecosystems is well documented, the effects of cold‐water releases from dams—which can alter downstream temperatures—remains relatively underexplored but may present novel challenges to endemic ectotherms. Specifical...
Selection on standing genetic variation mediates convergent evolution in extremophile fishNARA Subscribed
Hydrogen sulfide is a toxic gas that disrupts numerous biological processes, including energy production in the mitochondria, yet fish in the Poecilia mexicana species complex have independently evolved sulfide tolerance several times. Despite clear evidence for convergence at the phenotypic level in these fishes, it is unclear if the repeated evolution of hydrogen sulfide tolerance is the result of similar genomic changes. To...
Research on telomeres in the fields of ecology and evolution has been rapidly expanding over the last two decades. This has resulted in the formulation of a multitude of, often name‐given, hypotheses related to the associations between telomeres and life‐history traits or fitness‐facilitating processes (and the mechanisms underlying them). However, the differences (or similarities) between the various hypotheses, which can ori...
Impacts of heavy metal pollution on the ionomes and transcriptomes of Western mosquitofish ( Gambusia affinis )NARA Subscribed
Our understanding of the mechanisms mediating the resilience of organisms to environmental change remains lacking. Heavy metals negatively affect processes at all biological scales, yet organisms inhabiting contaminated environments must maintain homeostasis to survive. Tar Creek in Oklahoma, USA, contains high concentrations of heavy metals and an abundance of Western mosquitofish ( Gambusia affinis ), though several fish spe...
Parallel shifts of visual sensitivity and body coloration in replicate populations of extremophile fishNARA Subscribed
Visual sensitivity and body pigmentation are often shaped by both natural selection from the environment and sexual selection from mate choice. One way of quantifying the impact of the environment is by measuring how traits have changed after colonization of a novel habitat. To do this, we studied Poecilia mexicana populations that have repeatedly adapted to extreme sulphidic (H 2 S‐containing) environments. We measured visual...
Intensive slurry management and climate change promote nitrogen mining from organic matter-rich montane grassland soilsNARA Subscribed
Aims Consequences of climate change and land use intensification on the nitrogen (N) cycle of organic-matter rich grassland soils in the alpine region remain poorly understood. We aimed to identify fates of fertilizer N and to determine the overall N balance of an organic-matter rich grassland in the European alpine region as influenced by intensified management and warming. Methods We combined 15 N cattle slurry labelling wit...
Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyon...
Extreme environments and the origins of biodiversity: Adaptation and speciation in sulphide spring fishesNARA Subscribed
Organisms adapted to physiochemical stressors provide ideal systems to study evolutionary mechanisms that drive adaptation and speciation. This review study focuses on livebearing fishes of the Poecilia mexicana species complex (Poeciliidae), members of which have repeatedly colonized hydrogen sulphide (H 2 S)‐rich springs. H 2 S is a potent respiratory toxicant that creates extreme environmental conditions in aquatic ecosyste...
The roles of plasticity and evolutionary change in shaping gene expression variation in natural populations of extremophile fishNARA Subscribed
The notorious plasticity of gene expression responses and the complexity of environmental gradients complicate the identification of adaptive differences in gene regulation among populations. We combined transcriptome analyses in nature with common‐garden and exposure experiments to establish cause–effect relationships between the presence of a physiochemical stressor and expression differences, as well as to test how evolutio...
Genome‐scale data reveal that endemic Poecilia populations from small sulphidic springs display no evidence of inbreedingNARA Subscribed
Populations with limited ranges can be highly vulnerable to changes in their environment and are, thus, of high conservation concern. Populations that experience human‐induced range reductions are often highly inbred and lack genetic diversity, but it is unknown whether this is also the case for populations with naturally small ranges. The fishes Poecilia sulphuraria (listed as critically endangered) and Poecilia thermalis , w...
Complexities of gene expression patterns in natural populations of an extremophile fish ( Poecilia mexicana , Poeciliidae)NARA Subscribed
Variation in gene expression can provide insights into organismal responses to environmental stress and physiological mechanisms mediating adaptation to habitats with contrasting environmental conditions. We performed an RNA ‐sequencing experiment to quantify gene expression patterns in fish adapted to habitats with different combinations of environmental stressors, including the presence of toxic hydrogen sulphide (H 2 S) and...
From richer to poorer: successful invasion by freshwater fishes depends on species richness of donor and recipient basinsNARA Subscribed
Evidence for the theory of biotic resistance is equivocal, with experiments often finding a negative relationship between invasion success and native species richness, and large‐scale comparative studies finding a positive relationship. Biotic resistance derives from local species interactions, yet global and regional studies often analyze data at coarse spatial grains. In addition, differences in competitive environments acro...
Colonisation of toxic environments drives predictable life‐history evolution in livebearing fishes (Poeciliidae)NARA Subscribed
New World livebearing fishes (family Poeciliidae) have repeatedly colonised toxic, hydrogen sulphide‐rich waters across their natural distribution. Physiological considerations and life‐history theory predict that these adverse conditions should favour the evolution of larger offspring. Here, we examined nine poeciliid species that independently colonised toxic environments, and show that these fishes have indeed repeatedly ev...