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.

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.

Helminth parasite communities of kangaroos and wallabies (Macropus spp. and Wallabia bicolor) from north and central Queensland

1998 ◽  
Vol 46 (5) ◽  
pp. 473 ◽  
Author(s):  
I. Beveridge ◽  
N. B. Chilton ◽  
P. M. Johnson ◽  
L. R. Smales ◽  
R. Speare ◽  
...  
Keyword(s):  
Host Species ◽  
Helminth Species ◽  
Helminth Parasites ◽  
Parasite Communities ◽  
Gastrointestinal Helminth ◽  
Helminth Communities ◽  
Digenetic Trematodes ◽  
Single Host ◽  
Wallabia Bicolor ◽  
High Level

The occurrence of gastrointestinal helminth parasites in 40 Macropus agilis, 12 M. antilopinus, 39 M. dorsalis, 28 M. giganteus, 29 M. parryi, 30 M. robustus and 26 Wallabia bicolor from north and central Queensland was examined. A total of 124 morphologically defined species of helminth was encountered, comprising 103 species of strongyloid nematodes, 6 species of trichostrongyloid nematodes, 2 species of spiruroid nematodes, 4 species of oxyuroid nematodes, 7 species of anoplocephalid cestodes and 2 species of digenetic trematodes. Helminth communities in each macropodid host species exhibited a high level of diversity, and were dominated numerically by strongyloid nematodes. A high proportion of the helminth species was restricted to a single host species and there was a low level of similarity between helminth communities in different host species. Similarities that did occur were not apparently related to the phylogenetic relationships between hosts and are best explained by host switching between hosts sharing overlapping habitats and feeding preferences. There was poor separation of the helminth species into ‘core’, ‘secondary’ and ‘satellite’ members of communities.

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.

On Some Nematodes from the Freshwater Fishes of Ghana with the Description of a New Species, Spironoura petrei n.sp

1970 ◽  
Vol 44 (1) ◽  
pp. 63-68 ◽  
Author(s):  
L. F. Khalil
Keyword(s):  
New Species ◽  
Freshwater Fishes ◽  
Helminth Parasites ◽  
Research Project ◽  
Previous Record ◽  
Volta Basin ◽  
Digenetic Trematodes ◽  
The University ◽  
University Of Ghana ◽  
A New Species

Mr. T Petre of the Volta Basin Research Project of the University of Ghana kindly entrusted the writer with some nematodes collected from the freshwater fishes of Ghana. As far as can be found from published literature there is no previous record of nematodes from the freshwater fishes of Ghana. In fact, the helminth parasites of the freshwater fishes of this country are inadequately known and only monogeneans, digenetic trematodes and a single acanthocephalan have so far been reported. This collection represents 3 different species of nematodes from various hosts, one of which is new to science and is named after Mr. Petre to whom I am most grateful

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. 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.

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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