Raiding shoal size and a distraction display in male sticklebacks (Gasterosteus)

1988 ◽  
Vol 66 (1) ◽  
pp. 201-205 ◽  
Author(s):  
Mark S. Ridgway ◽  
J. D. McPhail

In threespine sticklebacks (Gasterosteus aculeatus), shoals of foraging conspecifics attack the nests of parental males and consume the offspring. This type of nest predation also occurs in lakes with sympatric species pairs of sticklebacks (Gasterosteus sp.) in which benthic stickleback shoals attack the nests of parental limnetic males. We manipulated shoal size of benthic sticklebacks in Paxton and Enos lakes to determine if there is a minimum shoal size necessary before parental limnetic males will perform the spasmodic swim display, a behaviour used by parental males to lure foraging shoals away from their nest and offspring. Males showed a significant increase in display frequency beginning with shoals of eight fish. The display occurred only when there were offspring in the nest and not when the nest was empty. We interpret the display to be a foraging deception in which parental males manipulate raiding shoals into giving up their search for a food source, causing them to leave the area of the male's nest site. This distraction display appears to be widespread within the threespine stickleback species complex.

2008 ◽  
Vol 86 (6) ◽  
pp. 564-571 ◽  
Author(s):  
J. L. Gow ◽  
S. M. Rogers ◽  
M. Jackson ◽  
D. Schluter

Sympatric species pairs of benthic and limnetic threespine stickleback ( Gasterosteus aculeatus L., 1758 complex) are an important example of the role of ecology in speciation in nature. Four endemic pairs are known and each appears to have diverged independently as a consequence of adaptation to alternative environments. Using specific ecological and physical attributes hypothesized to be important to their evolution, we focused a search for further species pairs. Now, two decades after the last discovery, we describe another benthic–limnetic species pair from Little Quarry Lake on Nelson Island, British Columbia, Canada. Bimodality of genetic admixture values provides evidence of strong reproductive isolation between two morphological and genetic clusters, supporting the existence of a sympatric species pair within this lake. Close correspondence in shape to extant benthic and limnetic species pairs confirm their status as such. The remarkable similarity between them and other benthic and limnetic species pairs in levels of morphological differentiation, as well as extent of admixture and hybridization, points to similar processes underlying their origin. This discovery serves as an important reminder of the specificity of ecological factors that promote and maintain biodiversity, as well as the value of habitat conservation.


Zoomorphology ◽  
2020 ◽  
Author(s):  
Harald Ahnelt ◽  
David Ramler ◽  
Maria Ø. Madsen ◽  
Lasse F. Jensen ◽  
Sonja Windhager

AbstractThe mechanosensory lateral line of fishes is a flow sensing system and supports a number of behaviors, e.g. prey detection, schooling or position holding in water currents. Differences in the neuromast pattern of this sensory system reflect adaptation to divergent ecological constraints. The threespine stickleback, Gasterosteus aculeatus, is known for its ecological plasticity resulting in three major ecotypes, a marine type, a migrating anadromous type and a resident freshwater type. We provide the first comparative study of the pattern of the head lateral line system of North Sea populations representing these three ecotypes including a brackish spawning population. We found no distinct difference in the pattern of the head lateral line system between the three ecotypes but significant differences in neuromast numbers. The anadromous and the brackish populations had distinctly less neuromasts than their freshwater and marine conspecifics. This difference in neuromast number between marine and anadromous threespine stickleback points to differences in swimming behavior. We also found sexual dimorphism in neuromast number with males having more neuromasts than females in the anadromous, brackish and the freshwater populations. But no such dimorphism occurred in the marine population. Our results suggest that the head lateral line of the three ecotypes is under divergent hydrodynamic constraints. Additionally, sexual dimorphism points to divergent niche partitioning of males and females in the anadromous and freshwater but not in the marine populations. Our findings imply careful sampling as an important prerequisite to discern especially between anadromous and marine threespine sticklebacks.


2019 ◽  
Vol 93 (9) ◽  
Author(s):  
Megan A. Hahn ◽  
Nolwenn M. Dheilly

ABSTRACT The complete genome sequence of an RNA virus was assembled from RNA sequencing of virus particles purified from threespine stickleback intestine tissue samples. This new virus is most closely related to the Eel picornavirus and can be assigned to the genus Potamipivirus in the family Picornaviridae. Its unique genetic properties are enough to establish a new species, dubbed the Threespine Stickleback picornavirus (TSPV). Due to their broad geographic distribution throughout the Northern Hemisphere and parallel adaptation to freshwater, threespine sticklebacks have become a model in evolutionary ecology. Further analysis using diagnostic PCRs revealed that TSPV is highly prevalent in both anadromous and freshwater populations of threespine sticklebacks, infects almost all fish tissues, and is transmitted vertically to offspring obtained from in vitro fertilization in laboratory settings. Finally, TSPV was found in Sequence Reads Archives of transcriptome of Gasterosteus aculeatus, further demonstrating its wide distribution and unsought prevalence in samples. It is thus necessary to test the impact of TSPV on the biology of threespine sticklebacks, as this widespread virus could interfere with the behavioral, physiological, or immunological studies that employ this fish as a model system. IMPORTANCE The threespine stickleback species complex is an important model system in ecological and evolutionary studies because of the large number of isolated divergent populations that are experimentally tractable. For similar reasons, its coevolution with the cestode parasite Schistocephalus solidus, its interaction with gut microbes, and the evolution of its immune system are of growing interest. Herein we describe the discovery of an RNA virus that infects both freshwater and anadromous populations of sticklebacks. We show that the virus is transmitted vertically in laboratory settings and found it in Sequence Reads Archives, suggesting that experiments using sticklebacks were conducted in the presence of the virus. This discovery can serve as a reminder that the presence of viruses in wild-caught animals is possible, even when animals appear healthy. Regarding threespine sticklebacks, the impact of Threespine Stickleback picornavirus (TSPV) on the fish biology should be investigated further to ensure that it does not interfere with experimental results.


1973 ◽  
Vol 51 (5) ◽  
pp. 547-551 ◽  
Author(s):  
E. T. Garside ◽  
T. Hamor

Samples of threespine stickleback, Gasterosteus aculeatus L., collected from several areas of Newfoundland and Nova Scotia, and single sites from Iles de la Madeleine, Quebec, and eastern Lake Ontario, were analyzed for variation in numbers of anterior lateral plates and vertebrae. Counts of vertebrae varied from 28 to 35 and mean counts from 30.3 to 33.4, without being related to any obvious geographic gradients. Trunk and caudal segments of the vertebral column had about the same degree of variation. Counts of lateral plates exclusive of ossicles of the caudal keel ranged from 0 to 31 with a range of means from 1.6 to 24.7. Incomplete development of potential plate number and absence of caudal keels were observed in 1st-year individuals. These results are discussed in relation to information about this species complex from populations of Pacific North America and Europe.


1970 ◽  
Vol 48 (6) ◽  
pp. 1341-1344 ◽  
Author(s):  
John F. Leatherland

The activity of pituitary homotransplants in the anadromous form (trachurus) of the threespine stickleback, Gasterosteus aculeatus L. was investigated by examining the structure of the thyroid, interrenal, gonad, and in situ pituitary; the melanophore index was also measured.The thyroid gland was markedly more active and the in situ thyrotrophs more granulated in the recipient fish when compared with the sham-operated animals. Similarly, the interrenal nuclear index was slightly (but significantly) larger in the recipient fish and there was a concomitant partial regression of the in situ pituitary corticotrophs.There was no difference between the structure of the gonads in the two groups although the in situ gonadotrophs were apparently smaller and less well granulated in the recipient fish.The melanophore index was significantly lower in recipient sticklebacks.In situ prolactin-secreting cells, somatotrophs, and neurointermediate lobes were similar in recipient and sham-operated animals.


2011 ◽  
Vol 68 (11) ◽  
pp. 1983-1997 ◽  
Author(s):  
Chad I. Ormond ◽  
Jordan S. Rosenfeld ◽  
Eric B. Taylor

Threespine stickleback ( Gasterosteus aculeatus ) species pairs are found in four watersheds in southwestern British Columbia, Canada, and are listed as Endangered under the federal Species at Risk Act. Their origin is thought to be through a double-invasion process followed by character displacement; however, this hypothesis does not consider whether speciation is dependent on unique environmental factors necessary to support two species with separate habitat and resource requirements, which may be essential both for their evolution and persistence. To test whether species pair lakes have unique attributes, we compared abiotic and biotic factors of species pair lakes to lakes with only a single population of stickleback. There were no clear environmental differences between species pair and non-species pair lakes, but species pairs were only present in lakes with low fish species diversity, suggesting that evolution and persistence of species pairs requires a simplified fish community. Our study suggests that colonization history rather than unique lake attributes (related to either physical habitat or trophic resources) facilitated the evolution of stickleback species pairs and that the fish assemblage in lakes may affect resource availability and speciation potential as strongly as the limnological attributes of the lakes themselves.


1985 ◽  
Vol 63 (8) ◽  
pp. 1991-1994 ◽  
Author(s):  
F. G. Whoriskey ◽  
G. J. FitzGerald

In a field population of Gasterosteus aculeatus, analysis of the patterns of nest destruction following removal of males indicated that nest site variables per se offered little protection against egg predation in the absence of paternal defense. These experiments also indicated that male breeding densities were not limited by a lack of space for territories. We suggest that site quality and male quality, which is determined in part by the quality of parental defense, interact to determine the number of eggs a male can hatch.


1975 ◽  
Vol 53 (4) ◽  
pp. 441-450 ◽  
Author(s):  
D. E. Hay ◽  
J. D. McPhail

Earlier studies suggest that the freshwater form of the threespine stickleback (Gasterosteus aculeatus) may be reproductively isolated from the anadromous form. In this study, assortative mating is examined as a possible isolating mechanism between the two forms. Mate selection tests were conducted in which (1) courting males were simultaneously exposed to receptive females of both forms, and (2) receptive females were simultaneously exposed to both forms of courting males. The results demonstrate clearly that in choice situations matings between similar phenotypes are more likely than matings between dissimilar phenotypes.


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.


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