Adaptive Divergence of Trophic Phenotype among Freshwater Populations of the Threespine Stickleback (Gasterosteus aculeatus)

1986 ◽  
Vol 43 (12) ◽  
pp. 2455-2463 ◽  
Author(s):  
P. A. Lavin ◽  
J. D. McPhail
Keyword(s):  
Water Column ◽  
Gasterosteus Aculeatus ◽  
Drainage System ◽  
Stomach Contents ◽  
Open Water ◽  
Threespine Stickleback ◽  
Adaptive Divergence ◽  
Population Divergence ◽  
Foraging Success ◽  
Trophic Resources

We investigated differences in the morphological and behavioural contributions to foraging success among three morphotypes (open-water, littoral, and intermediate) of the threespine stickleback (Gasterosteus aculeatus) from a single drainage system on Vancouver Island. Stomach contents from wild samples showed diet to be dependent on morphotype. Interpopulation differences in trophic morphology were associated with differences in foraging success on given prey types. The longer jaw of the bottom-browsing littoral morphotype allowed it to ingest significantly larger prey then either the intermediate or open-water populations. In addition, the littoral type spent less time manipulating benthic prey then either the open-water or intermediate morphotype. The latter observation is independent of interpopulation differences in jaw length. Both the planktivorous open-water morphotype and intermediate morphotypes were superior foragers in experiments on water column prey. The differences in water column foraging success are associated with interpopulation differences in gill raker morphology. Our results support the conclusion that inter population divergence in trophic phenotype is an adaptive response to differences in the primary trophic resources available in lakes of different morphometry.

scholarly journals Environmental determinants of threespine stickleback species pair evolution and persistence

2011 ◽  
Vol 68 (11) ◽  
pp. 1983-1997 ◽  
Author(s):  
Chad I. Ormond ◽  
Jordan S. Rosenfeld ◽  
Eric B. Taylor
Keyword(s):  
Gasterosteus Aculeatus ◽  
Character Displacement ◽  
Threespine Stickleback ◽  
Physical Habitat ◽  
Species Pair ◽  
Trophic Resources ◽  
Species Pairs ◽  
Resource Requirements ◽  
Abiotic And Biotic Factors ◽  
Species At Risk Act

Threespine stickleback ( Gasterosteus aculeatus ) species pairs are found in four watersheds in southwestern British Columbia, Canada, and are listed as Endangered under the federal Species at Risk Act. Their origin is thought to be through a double-invasion process followed by character displacement; however, this hypothesis does not consider whether speciation is dependent on unique environmental factors necessary to support two species with separate habitat and resource requirements, which may be essential both for their evolution and persistence. To test whether species pair lakes have unique attributes, we compared abiotic and biotic factors of species pair lakes to lakes with only a single population of stickleback. There were no clear environmental differences between species pair and non-species pair lakes, but species pairs were only present in lakes with low fish species diversity, suggesting that evolution and persistence of species pairs requires a simplified fish community. Our study suggests that colonization history rather than unique lake attributes (related to either physical habitat or trophic resources) facilitated the evolution of stickleback species pairs and that the fish assemblage in lakes may affect resource availability and speciation potential as strongly as the limnological attributes of the lakes themselves.

scholarly journals Regulatory architecture of gene expression variation in the threespine stickleback, Gasterosteus aculeatus

2016 ◽  
Author(s):  
Victoria L. Pritchard ◽  
Heidi M. Viitaniemi ◽  
R.J. Scott McCairns ◽  
Juha Merilä ◽  
Mikko Nikinmaa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Regulatory Networks ◽  
Gasterosteus Aculeatus ◽  
Genotyping By Sequencing ◽  
Interval Mapping ◽  
Threespine Stickleback ◽  
Adaptive Divergence ◽  
Gene Expression Variation ◽  
Expression Variation ◽  
Regulatory Architecture

Much adaptive evolutionary change is underlain by mutational variation in regions of the genome that regulate gene expression rather than in the coding regions of the genes themselves. An understanding of the role of gene expression variation in facilitating local adaptation will be aided by an understanding of underlying regulatory networks. Here, we characterize the genetic architecture of gene expression variation in the threespine stickleback (Gasterosteus aculeatus), an important model in the study of adaptive evolution. We collected transcriptomic and genomic data from 60 half-sib families using an expression microarray and genotyping-by-sequencing, and located QTL underlying the variation in gene expression (eQTL) in liver tissue using an interval mapping approach. We identified eQTL for several thousand expression traits. Expression was influenced by polymorphism in both cis and trans regulatory regions. Trans eQTL clustered into hotspots. We did not identify master transcriptional regulators in hotspot locations: rather, the presence of hotspots may be driven by complex interactions between multiple transcription factors. One observed hotspot co-located with a QTL recently found to underlie salinity tolerance in the threespine stickleback. However, most other observed hotspots did not co-locate with regions of the genome known to be involved in adaptive divergence between marine and freshwater habitats.

scholarly journals Geographical variation in colour of female threespine stickleback (Gasterosteus aculeatus)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4807
Author(s):  
Connor M. French ◽  
Travis Ingram ◽  
Daniel I. Bolnick
Keyword(s):  
Geographical Variation ◽  
Gasterosteus Aculeatus ◽  
Social Roles ◽  
Threespine Stickleback ◽  
Future Research ◽  
Population Divergence ◽  
Body Colour ◽  
Selective Pressures ◽  
Lake Size ◽  
Lateral Area

The ecological multifunctionality of colour often results in multiple selective pressures operating on a single trait. Most research on colour evolution focuses on males because they are the most conspicuous sex in most species. This bias can limit inferences about the ecological drivers of colour evolution. For example, little is known about population divergence in colour of female threespine stickleback (Gasterosteus aculeatus), which is among the most intensively-studied model vertebrates in evolution, ecology, and behaviour. In contrast, the evolution and ecology of colour in male stickleback has received considerable attention. One aspect of female colouration that is lacking previous research is non-ornamental body colour. Non-ornamental colour can play defensive and social roles, and indicate other aspects of female stickleback ecology. To remedy this knowledge gap, we measured the colour and brightness of one dorsal and one ventral lateral area on female stickleback from nine lake populations on Vancouver Island. We found that lake populations varied in overall colour brightness and dorso-ventral contrast. In addition, we found that female brightness increased with lake size, indicating potential ecological drivers of these colour differences. Our results demonstrate that there is substantial scope for future research on female colour diversification, which has been overlooked because past researchers focused on dramatic male nuptial colours.

Morphological Divergence and the Organization of Trophic Characters Among Lacustrine Populations of the Threespine Stickleback (Gasterosteus aculeatus)

1987 ◽  
Vol 44 (11) ◽  
pp. 1820-1829 ◽  
Author(s):  
Patrick A. Lavin ◽  
J. D. McPhail
Keyword(s):  
Gasterosteus Aculeatus ◽  
Genetic Correlations ◽  
Open Water ◽  
Threespine Stickleback ◽  
Selection Gradients ◽  
Structure Selection ◽  
Trophic Morphology ◽  
Local Selection ◽  
Food Size ◽  
Gill Raker

A multivariate solution for dealing with patterns of character covariance, when character genotypic covariances are known, has been applied to the organization of trophic morphology among lacustrine populations of the threespine stickleback (Gasterosteus aculeatus). The quantitative genetics governing eight trophic characters were investigated using representative populations from each of three known trophic ecotypes (open-water, littoral, and intermediate) which occur in the same drainage. Character heritabilities (0.19–0.84) were all significant. Estimates of character genetic correlations (−0.65 < rG < 0.85) were obtained and their standard errors were calculated by bootstrapping. Cluster analyses of the genetic correlation matrices defined two character suites, head shape and gill raker structure. Selection gradients between trophic ecotypes indicated that directional selection had operated most strongly on characters related to food size (upper jaw length and gill raker number). These results support the hypothesis that interpopulation variability in trophic morphology is organized as an adaptive response to local selection pressures.

scholarly journals Adaptive divergence and the evolution of hybrid phenotypes in threespine stickleback

2020 ◽  
Author(s):  
Avneet K. Chhina ◽  
Ken A. Thompson ◽  
Dolph Schluter
Keyword(s):  
Reproductive Isolation ◽  
Phenotypic Variation ◽  
Gasterosteus Aculeatus ◽  
Threespine Stickleback ◽  
Adaptive Divergence ◽  
Phenotypic Traits ◽  
Ancestral State ◽  
Ecological Divergence ◽  
Critical Determinant ◽  
Phenotypic Distance

AbstractThe fitness of hybrids is a critical determinant of gene flow between hybridizing populations. If hybrid phenotypes change predictably as parental populations become increasingly divergent, this could provide insight into general mechanisms linking ecological divergence with reproductive isolation. In this study, we used threespine stickleback fish (Gasterosteus aculeatus L.) to examine how phenotypic divergence between populations drives the evolution of dominance, phenotypic variation, and trait ‘mismatch’ in hybrids. We generated F1 and F2 hybrids between 12 freshwater populations—which ranged from highly planktivorous to highly benthic-feeding—and an anadromous population that is highly planktivorous and resembles the ancestral state of derived freshwater populations. We measured 16 phenotypic traits in hybrids and pure parental individuals raised under common conditions. We found that dominance varied markedly among traits. By contrast, dominance for a given trait was typically consistent among populations except for two traits where dominance was predicted by the phenotype of the freshwater parent. We find that multivariate phenotypic variation is greater in hybrids between more divergent parents. Finally, we demonstrate that the extent to which parental traits are ‘mismatched’ in both F1 and F2 hybrids increases with the phenotypic distance between the parent populations. Critically, this relationship was clearer in F1 hybrids than in F2s—largely due to traits having different dominance coefficients and F1s having relatively little phenotypic variation. Our results demonstrate that some aspects of hybrid phenotypes evolve predictably as parental populations diverge. We also find evidence for a possible general mechanistic link between ecological divergence and reproductive isolation—that more divergent parent populations tend to produce hybrids with novel and potentially deleterious multivariate phenotypes.

scholarly journals Recent evolution of extreme cestode growth suppression by a vertebrate host

2016 ◽  
Author(s):  
Jesse N. Weber ◽  
Natalie C. Steinel ◽  
Kum Chuan Shim ◽  
Daniel I. Bolnick
Keyword(s):  
Natural Selection ◽  
Gasterosteus Aculeatus ◽  
Growth Suppression ◽  
Threespine Stickleback ◽  
Vertebrate Host ◽  
Population Divergence ◽  
Infection Prevalence ◽  
Heritable Variation ◽  
F1 Hybrid ◽  
Schistocephalus Solidus

AbstractParasites can be a major cause of natural selection on hosts, which consequently evolve a variety of strategies to avoid, eliminate, or tolerate infection. When ecologically similar host populations present disparate infection loads, this natural variation can reveal immunological strategies underlying adaptation to infection and population divergence. For instance, the tapeworm Schistocephalus solidus persistently infects between 0% to 80% of threespine stickleback (Gasterosteus aculeatus) in lakes on Vancouver Island. To test whether these heterogeneous infection rates are due to evolved differences in immunity, we experimentally exposed lab-reared fish from high-and low-infection populations, which are not known to differ in natural exposure risk, to controlled doses of Schistocephalus. We observed heritable between-population differences in several immune traits: fish from the naturally uninfected population initiated a stronger granulocyte response to Schistocephalus infection, and their granulocytes constitutively generated threefold more reactive oxygen species (ROS). Despite these immunological differences, Schistocephalus was equally successful at establishing initial infections in both host populations. However, the low-infection fish dramatically suppressed tapeworm growth relative to high-infection fish, and parasite size was intermediate in F1 hybrid hosts. Our results show that stickleback recently evolved heritable variation in their capacity to suppress helminth growth. Comparative data from many from natural populations indicate that growth suppression is widespread but not universal and, when present, is associated with reduced infection prevalence. Host suppression of helminth somatic growth may be an important immune strategy that aids in parasite clearance, or in mitigating the fitness costs of persistent infection.SignificanceLarge parasites remain a persistent source of morbidity and mortality in humans, domesticated animals, and wildlife. Hosts are subject to strong natural selection to eliminate or tolerate these parasite infections. Here, we document the recent evolution of a striking form of resistance by a vertebrate host (threespine stickleback) against its cestode parasite (Schistocephalus solidus). After Pleistocene glacial retreat, marine stickleback colonized freshwater lakes, encountered Schistocephalus, and evolved varying levels of resistance to it. We show that a heavily-and a rarely-infected population of stickleback have similar resistance to Schistocephalus colonization, but rarely-infected fish suppress parasite growth by orders of magnitude. These populations represent ends of a natural continuum of cestode growth suppression, which is associated with reduced infection prevalence.

Subglacial brine flow and wind-induced internal waves in Lake Bonney, Antarctica

2020 ◽  
Vol 32 (3) ◽  
pp. 223-237
Author(s):  
Jade P. Lawrence ◽  
Peter T. Doran ◽  
Luke A. Winslow ◽  
John C. Priscu
Keyword(s):  
Water Column ◽  
Internal Waves ◽  
Open Water ◽  
Surface Discharge ◽  
Katabatic Wind ◽  
Neutral Buoyancy ◽  
Cold Temperatures ◽  
Glacier Terminus ◽  
Wind Events ◽  
Taylor Glacier

AbstractBrine beneath Taylor Glacier has been proposed to enter the proglacial west lobe of Lake Bonney (WLB) as well as from Blood Falls, a surface discharge point at the Taylor Glacier terminus. The brine strongly influences the geochemistry of the water column of WLB. Year-round measurements from this study are the first to definitively identify brine intrusions from a subglacial entry point into WLB. Furthermore, we excluded input from Blood Falls by focusing on winter dynamics when the absence of an open water moat prevents surface brine entry. Due to the extremely high salinities below the chemocline in WLB, density stratification is dominated by salinity, and temperature can be used as a passive tracer. Cold brine intrusions enter WLB at the glacier face and intrude into the water column at the depth of neutral buoyancy, where they can be identified by anomalously cold temperatures at that depth. High-resolution measurements also reveal under-ice internal waves associated with katabatic wind events, a novel finding that challenges long-held assumptions about the stability of the WLB water column.

scholarly journals Diversity and sexual dimorphism in the head lateral line system in North Sea populations of threespine sticklebacks, Gasterosteus aculeatus (Teleostei: Gasterosteidae)

Zoomorphology ◽  
2020 ◽  
Author(s):  
Harald Ahnelt ◽  
David Ramler ◽  
Maria Ø. Madsen ◽  
Lasse F. Jensen ◽  
Sonja Windhager
Keyword(s):  
Sexual Dimorphism ◽  
North Sea ◽  
Lateral Line ◽  
Gasterosteus Aculeatus ◽  
Sensory System ◽  
Threespine Stickleback ◽  
Lateral Line System ◽  
Line System ◽  
Marine Population ◽  
Threespine Sticklebacks

AbstractThe mechanosensory lateral line of fishes is a flow sensing system and supports a number of behaviors, e.g. prey detection, schooling or position holding in water currents. Differences in the neuromast pattern of this sensory system reflect adaptation to divergent ecological constraints. The threespine stickleback, Gasterosteus aculeatus, is known for its ecological plasticity resulting in three major ecotypes, a marine type, a migrating anadromous type and a resident freshwater type. We provide the first comparative study of the pattern of the head lateral line system of North Sea populations representing these three ecotypes including a brackish spawning population. We found no distinct difference in the pattern of the head lateral line system between the three ecotypes but significant differences in neuromast numbers. The anadromous and the brackish populations had distinctly less neuromasts than their freshwater and marine conspecifics. This difference in neuromast number between marine and anadromous threespine stickleback points to differences in swimming behavior. We also found sexual dimorphism in neuromast number with males having more neuromasts than females in the anadromous, brackish and the freshwater populations. But no such dimorphism occurred in the marine population. Our results suggest that the head lateral line of the three ecotypes is under divergent hydrodynamic constraints. Additionally, sexual dimorphism points to divergent niche partitioning of males and females in the anadromous and freshwater but not in the marine populations. Our findings imply careful sampling as an important prerequisite to discern especially between anadromous and marine threespine sticklebacks.

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