The evolution of freshwater diversity in the threespine stickleback (Gasterosteus aculeatus): site-specific differentiation of trophic morphology

1985 ◽  
Vol 63 (11) ◽  
pp. 2632-2638 ◽  
Author(s):  
P. A. Lavin ◽  
J. D. Mcphail

To assess interpopulation levels of morphological variability populations of Gasterosteus aculeatus were sampled from lakes within the upper Cowichan River system (Vancouver Island, British Columbia). Phenotypic divergence between populations is assumed to be a postglacial event. Nine characters were scored; eight were related to feeding and the ninth character was lateral plate number. All populations were the low plate morph; however, populations of Gasterosteus in lakes lacking piscivorous fish had significantly fewer lateral plates than populations in lakes with predatory fish species. Two distinct trophic "morphotypes" were identified, each one associated with a specific lake environment. Populations inhabiting benthic-dominated environments were found to possess reduced gill raker number and reduced gill raker length but increased upper jaw length relative to populations from limnetic environments. We propose that the interpopulation variability in trophic morphology is a response to trophic resource differences between lakes.

1972 ◽  
Vol 50 (6) ◽  
pp. 721-732 ◽  
Author(s):  
G. E. E. Moodie

In Mayer Lake Black sticklebacks shared an exposed environment with several predatory fish, whereas leiurus, the typical freshwater form of Gasterosteus aculeatus, was the only fish inhabiting the vegetation-choked margins of the inlet streams and stream mouths. Black sticklebacks and, to a lesser extent, leiurus were seldom collected outside their respective habitats. Breeding Black males were probably at least 2 years old. They preferred to nest near vegetation, on sandy, gently sloping substrates. The length of the breeding season and the number of breeding cycles in the season were similar to those of other populations. Males of different phenotypes appeared to nest in habitats differing in water depth and proximity to shelter. Some differences in habitat of the nest site were seemingly correlated with breeding success. Black sticklebacks are distinguished from leiurus by their large size and pelvic spines; high gill raker, vertebral and lateral plate counts; streamlined shape; melanism and drab breeding colors. Black sticklebacks probably meet the requirements of a biologically defined species.


1995 ◽  
Vol 73 (5) ◽  
pp. 898-906 ◽  
Author(s):  
Tom Klepaker

Norwegian freshwater stickleback populations were founded after the last glacial period, and the progressive uplift of the land has produced an age range (1000 – 13 000 years) of the stickleback habitats. Most of the freshwater populations of today have probably been formed by isolation of marine sticklebacks in the process of land uplift. The freshwater threespine stickleback is known for its great morphological variability. Three distinct morphs ("low," "partial," and "complete") are recognized on the basis of variation in the lateral row of plates. Among the Norwegian populations, all three morphs were found, but the low morph was by far the most common and occurred mostly in monomorphic populations. The presence of the complete and partial morphs was mostly restricted to young lakes near the sea. It is likely that the plate polymorphism in this region is a transitionary evolutionary stage from a founding population dominated by complete to a monomorphic low population. The hypothesis of a polytypic origin of the low morph is discussed, and an alternative hypothesis is proposed. Within each plate morph, the number of plates also varied, and populations with exceptionally low plate numbers were mostly confined to three different areas. Within these areas, populations with plateless specimens also occurred. These plateless specimens tended to inhabit old lakes. The low plate number and plateless populations were found in parts of Norway that were deglaciated early. The advanced plate reduction can therefore be a result of a longer period of isolation and freshwater evolution. Other populations may be on their way towards extreme plate reduction, but have not yet reached the level of platelessness.


2019 ◽  
Vol 97 (11) ◽  
pp. 988-996 ◽  
Author(s):  
N.P. Planidin ◽  
T.E. Reimchen

Lateral lines, a major sensory modality in fishes, are diverse among taxa, but their intraspecific variation has received limited attention. We examined numbers of superficial neuromasts on the buttressing lateral plates (LP) of 1910 threespine stickleback (Gasterosteus aculeatus Linnaeus, 1758) from 26 ecologically and morphologically diverse populations on the Haida Gwaii archipelago, western Canada. Extending from previous studies, we predicted that (i) highly stained dystrophic localities would have threespine stickleback with elevated numbers of neuromasts per plate due to a greater reliance on non-visual sensory modalities and (ii) that LP count and neuromast numbers per plate would functionally covary with predatory assemblage. We found that there were no differences in neuromast count across major habitats (marine, lake, stream), but clear-water populations and those with predatory fish had significantly more neuromasts per plate than most populations in highly stained dystrophic lakes, the effects being accentuated on the first buttressing plate (LP4). We also report the first evidence that neuromast counts per plate are sexually dimorphic, with males having a greater density of neuromasts in most populations. Two transplant experiments between ecologically opposite habitats indicate that within 12 generations, neuromast counts per plate can rapidly shift in response to a change in habitat.


1992 ◽  
Vol 70 (6) ◽  
pp. 1140-1148 ◽  
Author(s):  
Jeffrey V. Baumgartner

Differentiation with respect to two functional components of morphology, the defensive complex and overall body form, was studied in a population of threespine sticklebacks (Gasterosteus aculeatus) from the Brush Creek drainage, a small coastal system in northern California with high- and low-gradient habitats. The vast majority of body-shape differences among localities was accounted for by size-related allometric variation, the differences being closely related to overall growth trends. Relative to general body size, small individuals had long spines and fins whereas larger individuals tended to be deep bodied and have shorter fins and shorter spines. Significant size-independent differentiation with respect to the defensive complex and overall body form was also observed. The spatial pattern of differentiation in the components of the defensive complex changed dramatically over the period of study, possibly in response to natural selection. Stable stepped clines for overall body form and lateral-plate morph ratio were observed. Both clines were centered on the ecotone between high- and low-gradient habitats, and were apparently maintained by differential selection in alternative stream-gradient habitats despite gene flow across the ecotone. Sticklebacks from the high-gradient habitat had a continuous row of lateral plates, were elongate, and had long fins, whereas those from the low-gradient or standing-water habitat tended to have only abdominal plates, were more robust through the midbody, and had shorter fins. The results of this study and previous work suggest that various aspects of stickleback morphology may respond independently and rapidly to different evolutionary forces and be functionally related to hydrodynamics.


Behaviour ◽  
2000 ◽  
Vol 137 (7-8) ◽  
pp. 1097-1112 ◽  
Author(s):  
◽  

AbstractFluctuating asymmetry (FA) has been used as a measure of developmental stability across many taxa, with asymmetric individuals presumed to have reduced fitness. FA has also been suggested for use in conservation biology as a measure of the health of populations. Here we assess the suitability of these uses of FA by using a novel measure of asymmetry in the bony lateral plates of threespine stickleback (Gasterosteus aculeatus) from 60 insular and endemic freshwater populations from the Queen Charlotte Islands. The frequency of asymmetric G. aculeatus individuals among populations varied from 1% to 76% with a mean of 42%. Extreme variation in the frequency of asymmetries among lateral plate positions within samples was also observed. Plates important to the structural integrity of predator defences were least asymmetric, either due to selection against asymmetry at these positions or to variation in the temporal development of the plates. These results emphasize the need for caution when interpreting differential levels of FA among traits in individuals and populations, as the differences may be due to variation in the strength or direction of selection for symmetry, and not exclusively to differences in fitness.


2006 ◽  
Vol 84 (5) ◽  
pp. 643-654 ◽  
Author(s):  
T.E. Reimchen ◽  
P. Nosil

We investigated defence and trophic morphology of 40 freshwater stickleback (Gasterosteus aculeatus L., 1758) populations from the Banks–Estevan archipelago for comparison with the isolated stickleback populations from the nearby Haida Gwaii archipelago. Using 14 size-standardized metric traits and 11 meristic or categorical traits from 1706 individuals (14–54/site), we found that the first principal component (PC1) defined a defence apparatus characterized by high loadings for pelvic spine length, number of forks on the ascending process, number of lateral plates, and overlap between lateral and basal plates. The second component (PC2) defined a trophic apparatus characterized by high loadings for gape length, eye diameter, and body depth. Populations with loss of spines, loss of plates, increased gape, increased body depth, and low gill raker number were most prevalent in ponds and shallow lakes with low conductivity. Most traits were sexually dimorphic, with males exhibiting greater armature and increased benthic trophic adaptations. We observed substantially less morphological variability among Banks–Estevan stickleback populations than among the Haida Gwaii populations and one instance of common ancestry or convergence to the giant black stickleback of Haida Gwaii.


1974 ◽  
Vol 31 (6) ◽  
pp. 1155-1157 ◽  
Author(s):  
Brian W. Coad ◽  
G. Power

Samples of threespine sticklebacks, Gasterosteus aculeatus, from two lakes and a river in the Matamek River system, Québec were analyzed for five meristic characters. Mean vertebral number differed for each area (range 32.00–32.85) but mean soft fin ray number showed little variation (dorsal rays 11.52–11.79, anal rays 8.68–8.76). Gill raker number was higher in the lake samples (21.25 and 21.80) than in the river sample (20.76). In Matamek Lake only semiarmatus plate morphs were found; in Bill Lake, semiarmatus and trachurus morphs in a ratio of 4:1 with about 10% intermediate; and in the lower Matamek River, semiarmatus and, at a low frequency, leiurus morphs.


1984 ◽  
Vol 62 (3) ◽  
pp. 368-376 ◽  
Author(s):  
R. Craig Sargent ◽  
Michael A. Bell ◽  
William H. Krueger ◽  
Jeffrey V. Baumgartner

We examined samples of Gasterosteus wheatlandi collected in coastal marine waters from northern Maine to southern New York. Gasterosteus wheatlandi exhibited remarkable variation in lateral plate number, including phenotypes similar to the low, partial, and complete morphs described in Gasterosteus aculeatus. Partials and completes, however, seemed to represent a continuum, thus we could only recognize two discreet phenotypes, low and partial–complete. The low phenotype predominated strongly north of Cape Cod and was rare or absent south of it. Within both phenotypes mean plate number increased toward the southern end of the range; thus, both lateral plate number and lateral plate phenotype exhibited a pronounced step-cline. We found significant sexual dimorphism among localities for total lateral plates and for a suite of other morphological characters. Both sexes had higher mean vertebral counts north of Cape Cod, a trend which ran counter to the cline in lateral plates. The pervasive sexual dimorphism in G. wheatlandi, and the fact that latitudinal variation in lateral plates ran counter to the trend in G. aculeatus, suggest that different processes may be responsible for maintaining the geographical variation in these two species.


1969 ◽  
Vol 26 (2) ◽  
pp. 405-412 ◽  
Author(s):  
David W. Narver

Four phenotypes of the threespine stickleback, Gasterosteus aculeatus Linnaeus, were identified from the two Chignik lakes, Alaska: unplated (2–6 anterior plates); half-plated (7–15 anterior plates); fully plated (18–22 plates) lacustrine; and fully plated (18–22) estuarine. Distinctions lie in number and size of lateral plates and extent of lateral keel development on the caudal peduncle. Composition of the three lacustrine phenotypes in either lake population was similar among the years 1962–64 for both age I and age II in Black Lake but dissimilar in Chignik Lake. The Black Lake population contained a higher proportion of the unplated and half-plated phenotypes but fewer of the fully plated phenotypes than the Chignik Lake population. The life history of the estuarine phenotype is outlined. The mechanisms responsible for the maintenance of the four phenotypes in the Chignik River system have not been determined.


2002 ◽  
Vol 80 (2) ◽  
pp. 207-213 ◽  
Author(s):  
C A Bergstrom

Threespine stickleback (Gasterosteus aculeatus) have colonized freshwater habitats in circumboreal coastal regions, resulting in populations with variable but generally reduced lateral plate numbers compared with marine ancestors. Several abiotic and ecological factors associated with variation in lateral plate number among freshwater populations of G. aculeatus have been found, including large-scale climatic effects, variation in water-flow rates and levels of dissolved calcium, and the presence or absence of predatory fish. In addition, it has been proposed that plate reduction might be an adaptation for evading predator pursuit that enhances fast-start performance. If this hypothesis is correct, one would predict that fast-start performance would improve as lateral plate numbers decrease. I tested this prediction by comparing fast-start performance among stickleback with different numbers of lateral plates within two freshwater populations. Fast-starts of individual stickleback were video-recorded at 60 Hz and maximum velocity, maximum acceleration, displacement, and body curvature were calculated for each fish. Lateral plate number was significantly negatively correlated with velocity and displacement but not with acceleration or curvature. These results suggest that reduction in lateral plate number has the potential to be advantageous in some predation regimes because of its association with enhanced fast-start performance.


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