Locomotory capacity of Baltic Sea and freshwater populations of the threespine stickleback (Gasterosteus aculeatus)

SUMMARYNon-migratory, stream-resident populations of threespine stickleback, Gasterosteus aculeatus, have a lower maximum oxygen consumption (M O2,max ) than ancestral migratory marine populations. Here, we examined laboratory-bred stream-resident and marine crosses from two locations (West and Bonsall Creeks) to determine which steps in the oxygen transport and utilization cascade evolved in conjunction with, and thus have the potential to contribute to, these differences in M O2,max . We found that West Creek stream-resident fish have larger muscle fibres (not measured in Bonsall fish), Bonsall Creek stream-resident fish have smaller ventricles, and both stream-resident populations have evolved smaller pectoral adductor and abductor muscles. However, many steps of the oxygen cascade did not evolve in stream-resident populations (gill surface area, hematocrit, mean cellular hemoglobin content and the activities of mitochondrial enzymes per gram ventricle and pectoral muscle), arguing against symmorphosis. We also studied F1 hybrids to determine which traits in the oxygen cascade have a genetic architecture similar to that of M O2,max . In West Creek, M O2,max , abductor and adductor size all showed dominance of marine alleles, whereas in Bonsall Creek, M O2,max and ventricle mass showed dominance of stream-resident alleles. We also found genetically based differences among marine populations in hematocrit, ventricle mass, pectoral muscle mass and pectoral muscle pyruvate kinase activity. Overall, reductions in pectoral muscle mass evolved in conjunction with reductions in M O2,max in both stream-resident populations, but the specific steps in the oxygen cascade that have a genetic basis similar to that of M O2,max , and are thus predicted to have the largest impact on M O2,max , differ among populations. Supplementary material available online at

Section: Traits Associated With Reductions In M O2max : Stream-residmentioning

confidence: 64%

Section: Traits Associated With Reductions In M O2max : Stream-residmentioning

confidence: 70%

Mechanisms underlying parallel reductions in aerobic capacity in non-migratory threespine stickleback (Gasterosteus aculeatus) populations

Dalziel

Schulte

2012

“…We pre-incubated the sample for 3 min at 25°C and initiated the reaction by adding 0.1 ml oxaloacetate. The progress and products of the reaction were monitored for 1 min and analyzed using a temperature-controlled spectrophotometer (Beckman DU 640, Fullerton, CA, USA) (HouleLeroy et al, 2000;Schaarschmidt and Jürss, 2003) at extinction of 412 nm. All enzyme assays were run in duplicate.…”

Section: Food Consumption Digestibility and Morphometricsmentioning

confidence: 99%

“…an increase of hydration) rather than changes in mass-specific metabolic capacity (Starck, 1999b). Therefore, we also quantified the activity of citrate synthase (CS), a mitochondrial enzyme, which is a good indicator of the aerobic metabolic activity of tissues (Choi et al, 1993;Houle-Leroy et al, 2000;Janssens et al, 2000;Schaarschmidt and Jürss, 2003;Tripathi and Verma, 2004).…”

Section: Introductionmentioning

confidence: 99%

Phenotypic flexibility of traits related to energy acquisition in mice divergently selected for basal metabolic rate (BMR)

Książek

Czerniecki

Konarzewski

2009

SUMMARYTheoretical considerations suggest that one of the main factors determining phenotypic flexibility of the digestive system is the size (mass) of internal organs. To test this, we used mice from two lines selected for high and low levels of basal metabolic rate (BMR). Mice with higher BMRs also have larger internal organs and higher daily food consumption (C) under non-stressful conditions. We exposed animals from both lines to a sudden cold exposure by transferring them (without prior acclimation) from an ambient temperature of 23°C to 5°C. Cold exposure elicited a twofold increase in C and a 25% reduction of apparent digestive efficiency. For the same body mass-corrected C, small intestine, kidneys, heart and liver of cold-exposed low-BMR mice were smaller than those of the high-BMR line. Therefore, the internal organs of low-BMR animals were burdened with substantially higher metabolic loads (defined as C or digestible food intake per total mass of a particular organ). The mass-specific activity of citrate synthase (CS) in the liver and kidneys (but not heart) was also lower in the low-BMR mice. The magnitude of phenotypic flexibility of internal organ size and CS activity was strictly proportional to the organ mass (in the case of kidneys and liver, also mass-specific CS activity) prior to an increased energy demand. Thus, phenotypic flexibility had additive rather than multiplicative dynamics. Our results also suggest that variation in BMR positively correlates with the magnitude of an immediate spare capacity that fuels the initial response of internal organs to a sudden metabolic stress.

“…On the northern Pacific Coast of North America, marine fish established a number of freshwater populations when these habitats were uncovered after the Cordilleran Ice Sheet receded, approximately 10,000 to 12,000years ago (McPhail, 1994). We have previously shown that differences in prolonged swimming capacity between wild stream-resident and anadromous marine (hereafter referred to as 'marine') stickleback populations (Schaarschmidt and Jürss, 2003;Tudorache et al, 2007) are genetically based (Dalziel et al, 2012a). In addition, we have found that a number of morphological, physiological and biochemical traits predicted to impact prolonged swimming have evolved in conjunction with differences in performance in stream-resident threespine stickleback populations (Dalziel et al, 2012a;Dalziel et al, 2012b).…”

Section: Introductionmentioning

confidence: 99%

Correlates of prolonged swimming performance in F2 hybrids of migratory and non-migratory threespine stickleback ecotypes

Dalziel

Schulte

2012

SUMMARYDetermining which underlying traits contribute to differences in whole-animal performance can be difficult when many traits differ between individuals with high and low capacities. We have previously found that migratory (anadromous marine) and nonmigratory (stream-resident) threespine stickleback (Gasterosteus aculeatus) populations have genetically based differences in prolonged swimming performance (U crit ) that are associated with divergence of a number of candidate morphological and physiological traits (pectoral fin size and shape, body shape, pectoral muscle and heart size, and pectoral muscle metabolic enzyme activities). Here, we use F2 hybrid crosses to determine which traits are correlated with U crit when expressed in a largely randomized genetic background and a range of trait values for other divergent traits. We found that four of our 12 candidate traits were positively correlated with U crit in F2 hybrids and that the combined effects of ventricle mass, pectoral adductor mass and adductor citrate synthase activity accounted for 17.9% of the variation in U crit . These data provide additional support for a causal role of muscle and heart size in mediating intraspecific differences in U crit , but indicate that many candidate morphological and biochemical traits do not have a strong effect on U crit when disassociated from other divergent traits. However, the limited variation in U crit in our F2 hybrid families may have decreased our ability to detect correlations among these candidate traits and U crit . These data suggest that many traits, interactions among traits and traits not measured in this study affect prolonged swimming performance in threespine stickleback. Supplementary material available online at