Genetically based differences in foraging behaviour among sympatric morphs of arctic charr (Pisces: Salmonidae)

Skúlason, Skúli; Snorrason, Sigurður S.; Ota, Damijana; Noakes, David L. G.

doi:10.1006/anbe.1993.1140

Cited by 139 publications

(116 citation statements)

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“…Consistent with this hypothesis, differences in maximum body size and growth patterns between morphs are maintained in common garden experiments, indicating a large genetic component (Skúlason et al, 1989b(Skúlason et al, , 1993(Skúlason et al, , 1996Eiríksson et al, 1999).…”

Section: Muscle Growth In Arctic Charrsupporting

confidence: 52%

“…Local origin of morphs is supported by several studies on other lakes containing polymorphic charr (Gíslason et al, 1999;Wilson et al, 2004). Common garden rearing experiments indicate that the differences in morphology, growth and behaviour between the morphs have a strong genetic component (Skúlason et al, 1989b(Skúlason et al, , 1993(Skúlason et al, , 1996Eiríksson et al, 1999).…”

Section: Introductionmentioning

confidence: 79%

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Rapid evolution of muscle fibre number in post-glacial populations of Arctic charrSalvelinus alpinus

Johnston

Abercromby

Vieira

et al. 2004

Journal of Experimental Biology

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SUMMARY Thingvallavatn, the largest and one of the oldest lakes in Iceland,contains four morphs of Arctic charr Salvelinus alpinus. Dwarf benthic (DB), large benthic (LB), planktivorous (PL) and piscivorous (PI)morphs can be distinguished and differ markedly in head morphology,colouration and maximum fork length (FLmax), reflecting their different resource specialisations within the lake. The four morphs in Thingvallavatn are thought to have been isolated for approximately 10 000 years, since shortly after the end of the last Ice Age. We tested the null hypothesis that the pattern of muscle fibre recruitment was the same in all morphs, reflecting their recent diversification. The cross-sectional areas of fast and slow muscle fibres were measured at 0.7 FL in 46 DB morphs, 23 LB morphs, 24 PL morphs and 22 PI morphs, and the ages of the charr were estimated using sacculus otoliths. In fish larger than 10 g, the maximum fibre diameter scaled with body mass(Mb)0.18 for both fibre types in all morphs. The number of myonuclei per cm fibre length increased with fibre diameter, but was similar between morphs. On average, at 60 μm diameter, there were 2264 nuclei cm–1 in slow fibres and 1126 nuclei cm–1 in fast fibres. The absence of fibres of diameter 4–10 μm was used to determine the FL at which muscle fibre recruitment stopped. Slow fibre number increased with body length in all morphs, scaling with Mb0.45. In contrast, the recruitment of fast muscle fibres continued until a clearly identifiable FL, corresponding to 18–19 cm in the dwarf morph, 24–26 cm in the pelagic morph, 32–33 cm in the large benthic morph and 34–35 cm in the piscivorous morph. The maximum fast fibre number(FNmax) in the dwarf morph (6.97×104) was 56.5% of that found in the LB and PI morphs combined(1.23×105) (P<0.001). Muscle fibre recruitment continued until a threshold body size and occurred at a range of ages,starting at 4+ years in the DB morph and 7+ years in the LB and PI morphs. Our null hypothesis was therefore rejected for fast muscle and it was concluded that the dwarf condition was associated with a reduction in fibre number. We then investigated whether variations in development temperature associated with different spawning sites and periods were responsible for the observed differences in muscle cellularity between morphs. Embryos from the DB, LB and PL morphs were incubated at temperature regimes simulating cold subterranean spring-fed sites (2.2–3.2°C) and the general lakebed(4–7°C). Myogenic progenitor cells (MPCs) were identified using specific antibodies to Paired box protein 7 (Pax 7), Forkhead box protein K1-α (FoxK1-α), MyoD and Myf-5. The progeny showed no evidence of developmental plasticity in the numbers of either MPCs or muscle fibres. Juveniles and adult stages of the DB and LB morphs coexist and have a similar diet. We therefore conclude that the reduction in FNmax in the dwarf morph probably has a genetic basis and that gene networks regulating myotube production are under high selection pressure. To explain these findings we propose that there is an optimal fibre size, and hence number,which varies with maximum body size and reflects a trade-off between diffusional constraints on fibre diameter and the energy costs of maintaining ionic gradients. The predictions of the optimal fibre size hypothesis and its consequences for the adaptive evolution of muscle architecture in fishes are briefly discussed.

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Section: Muscle Growth In Arctic Charrsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 79%

Rapid evolution of muscle fibre number in post-glacial populations of Arctic charrSalvelinus alpinus

Johnston

Abercromby

Vieira

et al. 2004

Journal of Experimental Biology

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“…For example, pumpkinseed and bluegill sunfish occupy distinct ecological niches where they co-occur; however, where only the pumpkinseed occurs, it has differentiated into two morphs (128). In whitefish the presence of competition may be inferred from morphology (76) 148,152,153,167). Similarly, typical and cannibal morphs of tiger salamanders occur primarily where resource competitors and potential predators (fish) are relatively few (22).…”

Section: Open Niches Habitat Variability and The Relaxation Of Intermentioning

confidence: 99%

“…For example, variability in early behavior in the Atlantic salmon influences foraging and thus growth and later life history (88, 178); varying levels of flexibility in foraging behavior have been identified as key features in some polymorphic systems (7, 28, 29, 43, 47, 79, 84, 89, 90, 153,197).…”

Section: The Role Of Specializationmentioning

confidence: 99%

“…The relative contribution varies among lakes in arctic charr (58,106,149,151,153,171) and, based on rearing experiments, among forms in whitefish and Mexican Ilyodon (179). In contrast, morphological differences in species pairs of threespine sticklebacks in British Columbia have a strong genetic component (85, 86), but environmentally induced effects on morphology may accentuate their segregation.…”

Section: Phenotypic Plasticity Induction and Genetic Basismentioning

confidence: 99%

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Evolutionary Significance of Resource Polymorphisms in Fishes, Amphibians, and Birds

Smith

Skúlason

1996

Annu. Rev. Ecol. Syst.

611

687

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Resource polymorphism in vertebrates is generally underappreciated as a diversifying force and is probably more common than is currently recognized. Research across diverse taxa suggest they may play important roles in population divergence and speciation. They may involve various kinds of traits, including morphological and behavioral traits and those related to life history. Many of the evolutionary, ecological, and genetic mechanisms producing and maintaining resource polymorphisms are similar among phylogenetically distinct species. Although further studies are needed, the genetic basis may be simple, in some cases under the control of a single locus, with phenotypic plasticity playing a proximate role in some taxa. Divergent selection including either directional, disruptive, or frequencydependent selection is important in their evolution. Generally, the invasion of "open" niches or underutilized resources requiring unique trophic characters and decreased interspecific competition have promoted the evolution of resource polymorphisms. Further investigations centered on their role in speciation, especially adaptive radiation, are likely to be fruitful.

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Feeding Ecology of Piscivorous Fishes

Juanes¹,

Buckel²,

Scharf³

Handbook of Fish Biology and Fisheries, Volume 1

108

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Genetically based differences in foraging behaviour among sympatric morphs of arctic charr (Pisces: Salmonidae)

Cited by 139 publications

References 0 publications

Rapid evolution of muscle fibre number in post-glacial populations of Arctic charrSalvelinus alpinus

Rapid evolution of muscle fibre number in post-glacial populations of Arctic charrSalvelinus alpinus

Evolutionary Significance of Resource Polymorphisms in Fishes, Amphibians, and Birds

Feeding Ecology of Piscivorous Fishes

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