Ecology of the fourspine stickleback, Apeltes quadracus, with respect to a polymorphism for dorsal spine number

1981 ◽  
Vol 59 (9) ◽  
pp. 1677-1692 ◽  
Author(s):  
D. M. Blouw ◽  
D. W. Hagen
Keyword(s):  
Generation Time ◽  
Ecological Genetics ◽  
Dorsal Spine ◽  
Frequency Distributions ◽  
Time Period ◽  
Present Information ◽  
Apeltes Quadracus ◽  
Ecological Patterns ◽  
Fourspine Stickleback ◽  
Spine Number

The subject of our research is the ecological genetics of a polymorphism for dorsal spine number in Apeltes quadracus. Here we present information on its ecology and on dorsal spine variation, as background for subsequent publications.Estimating age from otoliths is subject to several serious errors, and spine sections are questionable. We have estimated generation time at about 1 year using length frequency distributions. Dorsal spine number varies from one to seven, but the four-and five-spined morphs predominate. The polymorphism is ubiquitous; where samples are available for comparisons over time, morph frequencies have remained relatively constant for at least 50 years. Sex ratio is highly variable among sites and among samples at particular sites. However, morph frequencies are independent of sex and age. Morph frequencies are homogeneous among samples taken at differing times of day, tide levels, months within a year, and among years. They are also homogeneous among microhabitats we sampled in an estuary. The relevance of these results to our subsequent publications is the following: (1) we take 1 year as the generation time, (2) sexes and ages can be pooled to estimate morph frequencies, and (3) since morph frequencies remain relatively constant, at least within the time period of our survey, comparisons of morph frequencies among sites to detect geographical and ecological patterns of variation seems valid.

The adaptive significance of dorsal spine variation in the fourspine stickleback, Apeltes quadracus. II. Phenotype–environment correlations

1984 ◽  
Vol 62 (7) ◽  
pp. 1340-1350 ◽  
Author(s):  
D. M. Blouw ◽  
D. W. Hagen
Keyword(s):  
Physical Environment ◽  
Adaptive Significance ◽  
Dorsal Spine ◽  
Geographic Differentiation ◽  
Environmental Correlates ◽  
Selective Agents ◽  
Apeltes Quadracus ◽  
Geographical Position ◽  
Fourspine Stickleback ◽  
Spine Number

The fourspine stickleback (Apeltes quadracus) is polymorphic for dorsal spine number, the variation is heritable, and morph frequencies are highly differentiated geographically. Our purpose here is to determine how spines vary in relation to environment. Dorsal spine number is significantly correlated (P < 0.001) with environmental differences among sites; the environmental correlates include predators, potential competitors, vegetation, physical environment, habitat, and geographical position. Based on these correlations we hypothesize that selection by predators favours the higher spined morphs and that selection by competitors favours the lower spined morphs. The correlations with other environmental variables probably reflect interactions with predation and (or) competition, but they may be concomitants of independent and unidentified selective agents. The observed patterns of geographic variation in spine number are in agreement with those expected if predators and competitors are selective agents. We conclude that selection acts on this polymorphism; the geographic differentiation in spine number is adaptive.

The adaptive significance of dorsal spine variation in the fourspine stickleback, Apeltes quadracus, I. Geographic variation in spine number

1984 ◽  
Vol 62 (7) ◽  
pp. 1329-1339 ◽  
Author(s):  
D. M. Blouw ◽  
D. W. Hagen
Keyword(s):  
Genetic Differentiation ◽  
Geographic Variation ◽  
Adaptive Significance ◽  
Maritime Provinces ◽  
Selective Agents ◽  
Apeltes Quadracus ◽  
Remarkable Result ◽  
Fourspine Stickleback ◽  
Very High Frequencies ◽  
Spine Number

The goal of our research is to investigate the adaptive significance of a polymorphism for the number of dorsal spines in Apeltes quadracus, the fourspine stickleback. One approach we take is to search for correlations between phenotypes and environments. To this end we collected Apeltes and scored environments at 570 sites in the Maritime Provinces of Canada. In this paper we describe geographic variation in spine number and evaluate how reliably it reflects genetic differentiation among sites. Morph frequencies are highly differentiated geographically. We describe four kinds of variation: relatively constant frequencies, gentle clines, steep clines, and remarkably abrupt changes (called "intrusions") where frequencies at some sites differ greatly from those at a larger number of surrounding sites. Most of the variation among sites is due to differences in the frequencies of the four- and five-spined morphs. However, a remarkable result is that the three-spined morph, which is rare or absent elsewhere in the range, reaches very high frequencies in Bras D'Or Lake. Our evidence suggests this variation among sites reflects substantial genetic differentiation. The differentiation is favorable for detecting selective agents, if indeed selection is responsible.

The adaptive significance of dorsal spine variation in the fourspine stickleback, Apeltes quadracus. V. Temporal variation

1987 ◽  
Vol 65 (11) ◽  
pp. 2651-2657 ◽  
Author(s):  
D. M. Blouw ◽  
D. W. Hagen
Keyword(s):  
Temporal Variation ◽  
Geographic Variation ◽  
Local Equilibrium ◽  
Adaptive Significance ◽  
Pungitius Pungitius ◽  
Maritime Provinces ◽  
Ninespine Stickleback ◽  
Apeltes Quadracus ◽  
Fourspine Stickleback ◽  
Spine Number

We investigated temporal variation in polymorphisms for the number of dorsal spines in the fourspine stickleback, Apeltes quadracus, and in the ninespine stickleback, Pungitius pungitius, to complement studies based on geographic variation. The changes in spine number that occurred over a 10-year period at Daigle Inlet, New Brunswick, are small relative to geographic variation among sites in the Maritime Provinces. However, some statistically significant changes occur in both species: they take place at or near reproduction; there is no evidence that they are related to selection by predators or any other environmental factor that we measured; and they tend to be followed by reversals that damp the net change. Contrary to expectation, based on spatial relationships, spine numbers in A. quadracus and P. pungitius do not covary predictably over time. The results show that events at or near reproduction play a role in determining local morph frequencies. Our main finding is that spine number is surprisingly stable for both species, and we conclude that it is constrained to local equilibrium values.

Growth of four species of juvenile fish associated with the Seagrass Zostera capricorni, in Botany Bay, NSW

1992 ◽  
Vol 43 (5) ◽  
pp. 1189 ◽  
Author(s):  
DG Worthington ◽  
DJ Ferrell ◽  
SE NcNeill ◽  
JD Bell
Keyword(s):  
Sea Water ◽  
New South ◽  
Juvenile Fish ◽  
Natural Populations ◽  
Length Frequency ◽  
Frequency Distributions ◽  
South Wales ◽  
Time Period ◽  
Flow Through ◽  
Sampling Programme

Populations of four species of juvenile fish- Rhabdosargus sarba, Acanthopagrus australis, Achoerodus viridis and Girella tricuspidata-were sampled from a seagrass bed in Botany Bay, New South Wales. Fish were collected eight times between 22 March 1990 and 22 February 1991, using a small seine-net. Growth rates were calculated from the progression of cohorts in length-frequency distributions. Cohorts of R. sarba, A. australis and A. viridis grew most slowly during winter (0.02, 0.04 and 0.21 mm day-1, respectively); growth then increased, peaking just prior to the loss of the cohort from the habitat (0.3 1, 0.24 and 0.39 mm day-1). Populations of R. sarba, A. australis and A. viridis were comprised of one or two cohorts that remained in the habitat for at least 3-4 months. Conversely, up to seven cohorts of G. tricuspidata were found between October and February, and most cohorts did not remain in the habitat for more than 2 months. As a result, there were only two confident estimates of growth for G. tricuspidata: 0.23 mm day-1 between October and November, and 0.34 mm day-1 between January and February. Individuals of each species were also kept in a flow-through 4000-L tank of sea water. Growth of cohorts of fish kept in the tank was very similar to that found in natural populations during the same time period. The rates of recruitment and loss of cohorts from seagrass can be rapid and these factors must be considered in designing a sampling programme to assess growth by analysis of length-frequency distributions.

scholarly journals Never-buyers of consumer non-durables

1984 ◽  
Vol 15 (3) ◽  
pp. 155-161
Author(s):  
C. Firer
Keyword(s):  
Graduate School ◽  
Negative Binomial ◽  
Toilet Soap ◽  
Traditional Theory ◽  
Data Sets ◽  
Data Set ◽  
Frequency Distributions ◽  
Unpublished Work ◽  
Time Period ◽  
Zero Cell

In this article the concept of never-buyers of consumer non-durables is discussed. The traditional Negative Binomial Distribution approach of Ehrenberg to the question is presented. Previously unpublished work carried out at the Graduate School of Business Administration, University of the Witwatersrand, is reviewed and hypotheses are put forward that the observed large zero cell in the purchase frequency distributions may be caused by the existence of a group of never-buyers of the product, or by the superimposition of at least two distinct buying populations, previously identified as brand-loyal and multibrand/brand-switching households. The results of the research aimed at testing the first hypothesis are presented here. Two carefully monitored data sets were modelled using zero-augmented Negative Binomial and Sichel distributions. The data were previously shown to exhibit the necessary mean households purchase/consumption stationarity. Individual brands in one data set (purchases of toilet soap) were shown to follow the predictions of the traditional theory - the proportion of non-buyers decreasing with time. In the second data set (consumption of packaged soup) the proportion of non-consumers of the brands fell towards zero as the length of the time period studied was increased, but at a rate faster than that predicted by the theory. The hypothesis of the existence of never-buyers/users of individual brands in these two product classes was therefore rejected.

Helminth parasites of the fourspine stickleback (Apeltes quadracus (Mitchill)) in Newfoundland

1970 ◽  
Vol 48 (2) ◽  
pp. 404-406 ◽  
Author(s):  
George Hanek ◽  
William Threlfall
Keyword(s):  
Helminth Parasites ◽  
Digenetic Trematodes ◽  
Apeltes Quadracus ◽  
Cystidicola Farionis ◽  
Fourspine Stickleback

Fifteen specimens of the fourspine stickleback, Apeltes quadracus (Mitchill), caught in Salmonier Arm, near Mitchells Brook, St. Mary's Bay, Newfoundland, were examined for helminth parasites. Three species of monogenetic trematodes (Gyrodactylus avalonia Hanek and Threlfall, 1969; Gyrodactylus cameroni n. sp.; Gyrodactylus canadensis Hanek and Threlfall, 1969), one of digenetic trematodes (Podocotyle atomon (Rudolphi, 1802)), one of Cestoda (Proteocephalus sp.), and one of Nematoda (Cystidicola farionis Fischer, 1798) were recovered.

Abundance and Life History of Mysis relicta in the St. Lawrence Great Lakes

1974 ◽  
Vol 31 (3) ◽  
pp. 319-325 ◽  
Author(s):  
G. F. Carpenter ◽  
E. L. Mansey ◽  
N. H. F. Watson
Keyword(s):  
Life History ◽  
Generation Time ◽  
Lake Superior ◽  
Life Cycles ◽  
Lake Huron ◽  
Summer Period ◽  
Mysis Relicta ◽  
Frequency Distributions ◽  
History Of ◽  
Major Period

In sampling on lakes Ontario, Erie, and Superior during three cruises from spring to fall, and on Lake Huron during eight cruises, Mysis relicta was generally not taken or not abundant in waters less than 25 m in depth. Its abundance appeared to increase with depth at least up to 200 m. Populations appeared to be concentrated in waters 125–200 m deep during summer and more dispersed during spring and fall. Highest numbers were found in Lake Superior, followed by lakes Ontario and Huron. A small localized population was found in the deep eastern part of Lake Erie.Size-frequency distributions from the various cruises on lakes Superior, Huron, and Ontario indicated differences in life cycles of the mysid in the three lakes. In Lake Superior there was one major period of recruitment, from February to July, and the generation time appeared to be 2 yr. In lakes Huron and Ontario recruitment appeared to occur from February to August and to be separated into a winter and a summer period; each of the generations appeared to mature in 18 mo.

scholarly journals Heritability of dorsal spines in the fourspine stickleback (Apeltes quadracus)

Heredity ◽  
1983 ◽  
Vol 50 (3) ◽  
pp. 275-281 ◽  
Author(s):  
D W Hagen ◽  
D M Blouw
Keyword(s):  
Apeltes Quadracus ◽  
Fourspine Stickleback
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