scholarly journals Sympatric Speciation in Threespine Stickleback: Why Not?

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Daniel I. Bolnick
Keyword(s):  
Sexual Dimorphism ◽  
Assortative Mating ◽  
Intraspecific Competition ◽  
Gasterosteus Aculeatus ◽  
Theoretical Models ◽  
Sympatric Speciation ◽  
Threespine Stickleback ◽  
Disruptive Selection ◽  
Evolutionary Diversification ◽  
Trait Variance

Numerous theoretical models suggest that sympatric speciation is possible when frequency-dependent interactions such as intraspecific competition drive disruptive selection on a trait that is also subject to assortative mating. Here, I review recent evidence that both conditions are met in lake populations of threespine stickleback (Gasterosteus aculeatus). Nonetheless, sympatric speciation appears to be rare or absent in stickleback. If stickleback qualitatively fit the theoretical requirements for sympatric speciation, why do they not undergo sympatric speciation? I present simulations showing that disruptive selection and assortative mating in stickleback, though present, are too weak to drive speciation. Furthermore, I summarize empirical evidence that disruptive selection in stickleback drives other forms of evolutionary diversification (plasticity, increased trait variance, and sexual dimorphism) instead of speciation. In conclusion, core assumptions of sympatric speciation theory seem to be qualitatively reasonable for stickleback, but speciation may nevertheless fail because of (i) quantitative mismatches with theory and (ii) alternative evolutionary outcomes.

scholarly journals Positive assortative mating between recently described sympatric morphs of Icelandic sticklebacks

2006 ◽  
Vol 2 (2) ◽  
pp. 250-252 ◽  
Author(s):  
Gudbjörg Á Ólafsdóttir ◽  
Michael G Ritchie ◽  
Sigurdur S Snorrason
Keyword(s):  
Mate Choice ◽  
Reproductive Isolation ◽  
Assortative Mating ◽  
Gasterosteus Aculeatus ◽  
Sympatric Speciation ◽  
Threespine Stickleback ◽  
Positive Assortative Mating ◽  
Important Character ◽  
Nest Type ◽  
Sympatric Morphs

Recently, models of sympatric speciation have suggested that assortative mating can develop between sympatric morphs due to divergence in an ecologically important character. For example, in sympatric pairs of threespine stickleback ( Gasterosteus aculeatus L.) size-assortative mating seems to be instrumental in reproductive isolation. Here, we examine courtship behaviour and assortative mating of newly described sympatric stickleback morphs in Lake Thingvallavatn, Iceland. We find that the two morphs show strong positive assortative mating. However, the mechanism involved in mate choice does not seem to be as straightforward as in other similar systems of sympatric stickleback morphs and may involve variation in nest type.

scholarly journals Diversity and sexual dimorphism in the head lateral line system in North Sea populations of threespine sticklebacks, Gasterosteus aculeatus (Teleostei: Gasterosteidae)

Zoomorphology ◽  
2020 ◽  
Author(s):  
Harald Ahnelt ◽  
David Ramler ◽  
Maria Ø. Madsen ◽  
Lasse F. Jensen ◽  
Sonja Windhager
Keyword(s):  
Sexual Dimorphism ◽  
North Sea ◽  
Lateral Line ◽  
Gasterosteus Aculeatus ◽  
Sensory System ◽  
Threespine Stickleback ◽  
Lateral Line System ◽  
Line System ◽  
Marine Population ◽  
Threespine Sticklebacks

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.

scholarly journals Acoustic discrimination of sympatric morphs in Darwin's finches: a behavioural mechanism for assortative mating?

2010 ◽  
Vol 365 (1543) ◽  
pp. 1031-1039 ◽  
Author(s):  
Jeffrey Podos
Keyword(s):  
Assortative Mating ◽  
Disruptive Selection ◽  
Evolutionary Divergence ◽  
Santa Cruz Island ◽  
Evolutionary Diversification ◽  
Acoustic Discrimination ◽  
Behavioural Types ◽  
Geospiza Fortis ◽  
Beak Size ◽  
Behavioural Mechanism

Populations with multiple morphological or behavioural types provide unique opportunities for studying the causes and consequences of evolutionary diversification. A population of the medium ground finch ( Geospiza fortis ) at El Garrapatero on Santa Cruz Island, Galápagos, features two beak size morphs. These morphs produce acoustically distinctive songs, are subject to disruptive selection and mate assortatively by morph. The main goal of the present study was to assess whether finches from this population are able to use song as a cue for morph discrimination. A secondary goal of this study was to evaluate whether birds from this population discriminate songs of their own locality versus another St Cruz locality, Borrero Bay, approximately 24 km to the NW. I presented territorial males with playback of songs of their own morph, of the other morph, and of males from Borrero Bay. Males responded more strongly to same-morph than to other-morph playbacks, showing significantly shorter latencies to flight, higher flight rates and closer approaches to the playback speaker. By contrast, I found only minor effects of locality on responsiveness. Evidence for morph discrimination via acoustic cues supports the hypothesis that song can serve as a behavioural mechanism for assortative mating and sympatric evolutionary divergence.

Differences in male courtship in freshwater and marine sticklebacks (Gasterosteus aculeatus)

1983 ◽  
Vol 61 (2) ◽  
pp. 292-297 ◽  
Author(s):  
J. D. McPhail ◽  
D. E. Hay
Keyword(s):  
British Columbia ◽  
Assortative Mating ◽  
Gasterosteus Aculeatus ◽  
Threespine Stickleback ◽  
Male Courtship ◽  
First Response ◽  
Positive Assortative Mating ◽  
First Contact

Earlier studies indicated that the freshwater and marine forms of threespine stickleback (Gasterosteus aculeatus) in the Little Campbell River are genetically differentiated and that they do not mate randomly. In this study, we examine the possible contribution of male courtship to this positive assortative mating. Marine and freshwater sticklebacks were obtained from the Little Campbell River, southwestern British Columbia. Males were allowed to build nests in large aquaria and court females. The following courtship behaviours were recorded: zigzag bouts per minute, bites per minute, fanning bouts per minute, glueing, creeping through, and the male's first response. Freshwater males zigzag more, bite less, and glue more than marine males. The intensity of courtship in freshwater males depends on the form of female courted, whereas marine males do not alter their courtship with different forms of females. Freshwater males typically zigzag on first contact with a female, and marine males usually bite. This difference in male first response is independent of the type of female courted. Differences in male courtship provide a basis for positive assortative mating between the two forms of sticklebacks. We argue that selection should favour a male first response that signals genotype.

scholarly journals Sexual dimorphism patterns of the White Sea threespine stickleback (Gasterosteus aculeatus)

2021 ◽  
Vol 66 (3) ◽  
Author(s):  
Ahmed Dorgham ◽  
Ulrika Candolin ◽  
Tatiana Ivanova ◽  
Mikhail Ivanov ◽  
Ekaterina Nadtochii ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Gasterosteus Aculeatus ◽  
White Sea ◽  
Threespine Stickleback ◽  
Ecological Niches ◽  
Body Parts ◽  
The White Sea ◽  
Spawning Period ◽  
Biased Sex Ratio ◽  
Anterior Body

Sexual dimorphism (SD) in the threespine stickleback Gasterosteus aculeatus reflects the different roles of the sexes in reproduction and their adaptations to different ecological niches. We quantified SD in one population of marine stickleback from the White Sea, collected during the spawning period from three spawning grounds, each at a distance of 5 km or less from the others. We used a landmark-based approach to quantify variation in 44 morphometric linear traits. In total, 749 females and 693 males were analyzed. In males, anterior body parts are larger — the base of the caudal fin and armor structures such as the first and second dorsal spines and the pelvic spine. Females have larger posterior bodies — the abdomen, pelvic girdle and the third dorsal spine. The SD of caudal body parts exhibits complex patterns. In White Sea threespine stickleback, SD patterns are generally similar to other populations of the species, but more often show male-biased patterns. Female-biased size SD may be associated with the female biased sex ratio of White Sea stickleback.

Mate selection in threespine sticklebacks (Gasterosteus)

1975 ◽  
Vol 53 (4) ◽  
pp. 441-450 ◽  
Author(s):  
D. E. Hay ◽  
J. D. McPhail
Keyword(s):  
Assortative Mating ◽  
Mate Selection ◽  
Gasterosteus Aculeatus ◽  
Threespine Stickleback ◽  
Threespine Sticklebacks ◽  
Anadromous Form ◽  
Isolating Mechanism

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.

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