scholarly journals Elevated temperatures drive the evolution of armor loss in the threespine stickleback Gasterosteus aculeatus

2020 ◽  
Author(s):  
Carl Smith ◽  
Grzegorz Zięba ◽  
Mirosław Przybylski

AbstractWhile there is evidence of genetic and phenotypic responses to climate change, few studies have demonstrated change in functional traits with a known genetic basis. Here we present evidence for an evolutionary adaptive response to elevated temperatures in freshwater populations of the threespine stickleback (Gasterosteus aculeatus). Using a unique set of historical data and museum specimens, in combination with contemporary samples, we fitted a Bayesian spatial model to identify a population-level decline in the number of lateral bony plates, comprising anti-predator armor, in multiple populations of sticklebacks over the last 90 years in Poland. Armor loss was predicted by elevated temperatures and is proposed to be a correlated response to selection for reduced body size. This study demonstrates a change in a functional trait of known genetic basis in response to elevated temperature, and illustrates the utility of the threespine stickleback as a model for measuring the evolutionary and ecological impacts of environmental change across the northern hemisphere.

1999 ◽  
Vol 77 (12) ◽  
pp. 1967-1974 ◽  
Author(s):  
David C Heins ◽  
Scarlet S Singer ◽  
John A Baker

We investigated the relationship between reproduction in the threespine stickleback (Gasterosteus aculeatus) and parasitism by plerocercoids of the cestode Schistocephalus solidus in Walby Lake, Alaska, by quantifying stickleback reproduction and parasite infection using 1655 fish from four samples collected in 1990-1996. Stickleback in Walby Lake largely spawned during May and June as 2-year-olds in the second spring-summer after hatching, as was the case with other stickleback populations we studied in south-central Alaska. Contrary to an earlier hypothesis that S. solidus has been selected to delay its deleterious effects on threespine stickleback, i.e., limit its infection levels, until after the stickleback have reproduced, substantial levels of parasitic infection co-occurred with the stickleback reproductive period. Chi-squared analyses of individual samples suggested that in May, infected females were as capable of producing clutches of eggs as uninfected females but in June, S. solidus inhibited clutch production. An overall analysis, however, failed to support the hypothesis that the effect of S. solidus on clutch production differed between early and late periods of the spawning season. We concluded that S. solidus inhibits the ability of female stickleback in Walby Lake to produce a clutch, and that there was no differential effect on clutch production with season. Nonetheless, 77% of all infected females produced clutches. These results contrast with those of one study in which it was found only 9% of infected females became gravid (ripe) and another report that 23% of infected females were able to mature. We offer hypotheses for the co-occurrence of stickleback reproduction and substantial parasitism at the population level and for the ability of a large proportion of infected females to produce clutches. Our results suggest that the host-parasite relationship is more complex than was previously realized.


2021 ◽  
Vol 8 ◽  
Author(s):  
Cameron M. Hudson ◽  
Kay Lucek ◽  
David A. Marques ◽  
Timothy J. Alexander ◽  
Marvin Moosmann ◽  
...  

Invasive species can be powerful models for studying contemporary evolution in natural environments. As invading organisms often encounter new habitats during colonization, they will experience novel selection pressures. Threespine stickleback (Gasterosteus aculeatus complex) have recently colonized large parts of Switzerland and are invasive in Lake Constance. Introduced to several watersheds roughly 150 years ago, they spread across the Swiss Plateau (400–800 m a.s.l.), bringing three divergent hitherto allopatric lineages into secondary contact. As stickleback have colonized a variety of different habitat types during this recent range expansion, the Swiss system is a useful model for studying contemporary evolution with and without secondary contact. For example, in the Lake Constance region there has been rapid phenotypic and genetic divergence between a lake population and some stream populations. There is considerable phenotypic variation within the lake population, with individuals foraging in and occupying littoral, offshore pelagic, and profundal waters, the latter of which is a very unusual habitat for stickleback. Furthermore, adults from the lake population can reach up to three times the size of adults from the surrounding stream populations, and are large by comparison to populations globally. Here, we review the historical origins of the threespine stickleback in Switzerland, and the ecomorphological variation and genomic basis of its invasion in Lake Constance. We also outline the potential ecological impacts of this invasion, and highlight the interest for contemporary evolution studies.


Author(s):  
N. P. Planidin ◽  
T. E. Reimchen

Behavioural asymmetry, typically referred to as laterality, is widespread among bilaterians and is often associated with asymmetry in brain structure. However, the influence of sensory receptor asymmetry on laterality has undergone limited investigation. Here we use threespine stickleback (Gasterosteus aculeatus) to investigate the influence of lateral line asymmetry on laterality during lab simulations of three mechanosensation-dependent behaviours: predator evasion, prey localization and rheotaxis. We recorded the response of stickleback to impacts at the water surface and water flow in photic conditions and low-frequency oscillations in the dark, across four repeat trials. We then compared individuals’ laterality to asymmetry in the number of neuromasts on either side of their body. Stickleback hovered with their right side against the arena wall 57% of the time (P<0.001) in illuminated surface impact trials and 56% of the time in (P=0.085) dark low-frequency stimulation trials. Light regime modulated the effect of neuromast count on laterality, as fish with more neuromasts were more likely to hover with the wall on their right during illumination (P=0.007) but were less likely to do so in darkness (P=0.025). Population level laterality diminished in later trials across multiple behaviours and individuals did not show a consistent side bias in any behaviours. Our results demonstrate a complex relationship between sensory structure asymmetry and laterality, suggesting that laterality is modulated multiple sensory modalities and temporally dynamic.


Zoomorphology ◽  
2020 ◽  
Author(s):  
Harald Ahnelt ◽  
David Ramler ◽  
Maria Ø. Madsen ◽  
Lasse F. Jensen ◽  
Sonja Windhager

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.


Author(s):  
L. Leveelahti ◽  
P. Leskinen ◽  
E.H. Leder ◽  
W. Waser ◽  
M. Nikinmaa

Genetics ◽  
2021 ◽  
Vol 217 (1) ◽  
Author(s):  
Juntao Hu ◽  
Sara J S Wuitchik ◽  
Tegan N Barry ◽  
Heather A Jamniczky ◽  
Sean M Rogers ◽  
...  

Abstract Epigenetic mechanisms underlying phenotypic change are hypothesized to contribute to population persistence and adaptation in the face of environmental change. To date, few studies have explored the heritability of intergenerationally stable methylation levels in natural populations, and little is known about the relative contribution of cis- and trans-regulatory changes to methylation variation. Here, we explore the heritability of DNA methylation, and conduct methylation quantitative trait loci (meQTLs) analysis to investigate the genetic architecture underlying methylation variation between marine and freshwater ecotypes of threespine stickleback (Gasterosteus aculeatus). We quantitatively measured genome-wide DNA methylation in fin tissue using reduced representation bisulfite sequencing of F1 and F2 crosses, and their marine and freshwater source populations. We identified cytosines (CpG sites) that exhibited stable methylation levels across generations. We found that additive genetic variance explained an average of 24–35% of the methylation variance, with a number of CpG sites possibly autonomous from genetic control. We also detected both cis- and trans-meQTLs, with only trans-meQTLs overlapping with previously identified genomic regions of high differentiation between marine and freshwater ecotypes. Finally, we identified the genetic architecture underlying two key CpG sites that were differentially methylated between ecotypes. These findings demonstrate a potential role for DNA methylation in facilitating adaptation to divergent environments and improve our understanding of the heritable basis of population epigenomic variation.


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