scholarly journals Parasites contribute to ecologically dependent postmating isolation in the adaptive radiation of three-spined stickleback

2016 ◽  
Vol 283 (1836) ◽  
pp. 20160691 ◽  
Author(s):  
Aliya El Nagar ◽  
Andrew D. C. MacColl
Keyword(s):  
Reproductive Isolation ◽  
Adaptive Radiation ◽  
Strong Evidence ◽  
Parasite Species ◽  
Ecological Speciation ◽  
Population Divergence ◽  
Parasitic Infections ◽  
Wild Populations ◽  
Postmating Isolation ◽  
Theory And Model

Spatial variation in parasitic infections is common, and has the potential to drive population divergence and the reproductive isolation of hosts. However, despite support from theory and model laboratory systems, little strong evidence has been forthcoming from the wild. Here, we show that parasites are likely to cause reproductive isolation in the adaptive radiation of three-spined stickleback. Adjacent wild populations on the Scottish island of North Uist differ greatly and consistently in the occurrence of different parasites that have substantial effects on fitness. Laboratory-reared fish are more resistant to experimental infection by parasite species from their own population. Furthermore, hybrid backcrosses between the host populations are more resistant to parasites from the parental population to which they are more closely related. These patterns provide strong evidence that parasites can cause ecological speciation, by contributing to selection against migrants and ecologically dependent postmating isolation.

scholarly journals “And if you gaze long into an abyss, the abyss gazes also into thee”: four morphs of Arctic charr adapting to a depth-gradient in Lake Tinnsjøen

2019 ◽  
Author(s):  
Kjartan Østbye ◽  
Marius Hagen Hassve ◽  
Ana-Maria Tamayo Peris ◽  
Mari Hagenlund ◽  
Thomas Vogler ◽  
...  
Keyword(s):  
Life History ◽  
Reproductive Isolation ◽  
Adaptive Radiation ◽  
Arctic Charr ◽  
River System ◽  
Ecological Speciation ◽  
The Arctic ◽  
Life History Trait ◽  
Life History Variation ◽  
Microsatellite Variation

AbstractBackgroundThe origin of species is a central topic in biology aiming at understanding mechanisms, level and rate of diversification. Ecological speciation is an important driver in adaptive radiation during post-glacial intra-lacustrine niche diversification in fishes. The Arctic charr Salvelinus alpinus L. species complex in the Northern hemisphere freshwater systems display huge morphological and life history divergence in lakes with one or several morphs present, thus offering a unique opportunity to address ongoing speciation mechanisms.We studied Arctic charr in Lake Tinnsjøen by fishing in four nominal lake habitats (pelagial, littoral, shallow-moderate profundal, and deep-profundal habitats) down to 350 meters depth. Research topics addressed were; (1) to illuminate Holarctic phylogeography and lineages colonizing Lake Tinnsjøen, (2) to estimate reproductive isolation of morphs or fish using unbiased methods, and (3) to document eco-morphological and life history trait divergence. Also, we compared Lake Tinnsjøen with four Norwegian outgroup populations of Arctic charr.ResultsFour field-assigned morphs were identified in Lake Tinnsjøen; the planktivore morph in all habitats except deep-profundal, the dwarf morph in shallow-moderate profundal, the piscivore morph in shallow-moderate profundal (less in littoral and deep-profundal), and an undescribed new morph – the abyssal morph in the deep-profundal only. The morphs displayed extensive life history variation based on age and size patterns. A moderate to high concordance was observed between field-assigned morphs and four unbiased genetic clusters obtained from microsatellite variation. MtDNA suggested the occurrence of two minor endemic clades in Lake Tinnsjøen likely originating from one widespread colonizing clade in the Holarctic. All morphs were genetically differentiated at microsatellites (FST: 0.12-0.20; with some ongoing gene flow among morphs, and for most mtDNA comparisons (FST: 0.04-0.38). Analyses of Norwegian outgroup lakes implied colonization from a river system below Lake Tinnsjøen.ConclusionOur findings suggest post-glacial adaptive radiation of one colonizing mtDNA lineage with divergent niche specialization along a depth-temperature-productivity-pressure gradient. Concordance between reproductive isolation and the realized habitat of the morphs imply that ecological speciation may be the mechanism of divergence. Particularly novel is the extensive morph diversification with depth into the often unexplored deep-water profundal habitat, suggesting we may have systematically underestimated biodiversity present in lakes.

scholarly journals The Role of Parasitism in Adaptive Radiations—When Might Parasites Promote and When Might They Constrain Ecological Speciation?

2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Anssi Karvonen ◽  
Ole Seehausen
Keyword(s):  
Reproductive Isolation ◽  
Parasite Species ◽  
Ecological Speciation ◽  
Divergent Selection ◽  
Divergent Evolution ◽  
Selective Agents ◽  
Adaptive Radiations ◽  
Recurrent Patterns ◽  
Single Versus

Research on speciation and adaptive radiation has flourished during the past decades, yet factors underlying initiation of reproductive isolation often remain unknown. Parasites represent important selective agents and have received renewed attention in speciation research. We review the literature on parasite-mediated divergent selection in context of ecological speciation and present empirical evidence for three nonexclusive mechanisms by which parasites might facilitate speciation: reduced viability or fecundity of immigrants and hybrids, assortative mating as a pleiotropic by-product of host adaptation, and ecologically-based sexual selection. We emphasise the lack of research on speciation continuums, which is why no study has yet made a convincing case for parasite driven divergent evolution to initiate the emergence of reproductive isolation. We also point interest towards selection imposed by single versus multiple parasite species, conceptually linking this to strength and multifariousness of selection. Moreover, we discuss how parasites, by manipulating behaviour or impairing sensory abilities of hosts, may change the form of selection that underlies speciation. We conclude that future studies should consider host populations at variable stages of the speciation process, and explore recurrent patterns of parasitism and resistance that could pinpoint the role of parasites in imposing the divergent selection that initiates ecological speciation.

scholarly journals Cultural traditions and the evolution of reproductive isolation: ecological speciation in killer whales?

2012 ◽  
Vol 106 (1) ◽  
pp. 1-17 ◽  
Author(s):  
RÜDIGER RIESCH ◽  
LANCE G. BARRETT-LENNARD ◽  
GRAEME M. ELLIS ◽  
JOHN K. B. FORD ◽  
VOLKER B. DEECKE
Keyword(s):  
Reproductive Isolation ◽  
Ecological Speciation ◽  
Killer Whales ◽  
Cultural Traditions

scholarly journals Ecological Divergence and the Origins of Intrinsic Postmating Isolation with Gene Flow

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Aneil F. Agrawal ◽  
Jeffrey L. Feder ◽  
Patrik Nosil
Keyword(s):  
Linkage Disequilibrium ◽  
Gene Flow ◽  
Natural Selection ◽  
Theoretical Models ◽  
Ecological Speciation ◽  
Divergent Selection ◽  
Postmating Isolation ◽  
Divergent Natural Selection ◽  
Mathematical Exploration ◽  
Neutral Gene

The evolution of intrinsic postmating isolation has received much attention, both historically and in recent studies of speciation genes. Intrinsic isolation often stems from between-locus genetic incompatibilities, where alleles that function well within species are incompatible with one another when brought together in the genome of a hybrid. It can be difficult for such incompatibilities to originate when populations diverge with gene flow, because deleterious genotypic combinations will be created and then purged by selection. However, it has been argued that if genes underlying incompatibilities are themselves subject to divergent selection, then they might overcome gene flow to diverge between populations, resulting in the origin of incompatibilities. Nonetheless, there has been little explicit mathematical exploration of such scenarios for the origin of intrinsic incompatibilities during ecological speciation with gene flow. Here we explore theoretical models for the origin of intrinsic isolation where genes subject to divergent natural selection also affect intrinsic isolation, either directly or via linkage disequilibrium with other loci. Such genes indeed overcome gene flow, diverge between populations, and thus result in the evolution of intrinsic isolation. We also examine barriers to neutral gene flow. Surprisingly, we find that intrinsic isolation sometimes weakens this barrier, by impeding differentiation via ecologically based divergent selection.

scholarly journals The health impact of polyparasitism in humans: are we under-estimating the burden of parasitic diseases?

Parasitology ◽  
2008 ◽  
Vol 135 (7) ◽  
pp. 783-794 ◽  
Author(s):  
R. PULLAN ◽  
S. BROOKER
Keyword(s):  
Disease Burden ◽  
Parasite Species ◽  
Health Impact ◽  
Multiple Infections ◽  
Parasitic Infections ◽  
Parasitic Diseases ◽  
Human Parasite ◽  
Health Significance ◽  
The Tropics ◽  
International Strategies

SUMMARYParasitic infections are widespread throughout the tropics and sub-tropics, and infection with multiple parasite species is the norm rather than the exception. Despite the ubiquity of polyparasitism, its public health significance has been inadequately studied. Here we review available studies investigating the nutritional and pathological consequences of multiple infections with Plasmodium and helminth infection and, in doing so, encourage a reassessment of the disease burden caused by polyparasitism. The available evidence is conspicuously sparse but is suggestive that multiple human parasite species may have an additive and/or multiplicative impact on nutrition and organ pathology. Existing studies suffer from a number of methodological limitations and adequately designed studies are clearly necessary. Current methods of estimating the potential global morbidity due to parasitic diseases underestimate the health impact of polyparasitism, and possible reasons for this are presented. As international strategies to control multiple parasite species are rolled-out, there is a number of options to investigate the complexity of polyparasitism, and it is hoped that that the parasitological resarch community will grasp the opportunity to understand better the health of polyparasitism in humans.

Reproductive isolation between two closely related species of the Queensland fruit fly Dracus tryoni (Frogg) and D. neohumeralis Hardy (Diptera : Tephritidae) I. Variation in humeral callus pattern and the occurrence of intermediate colour forms in the wild

1967 ◽  
Vol 15 (3) ◽  
pp. 501 ◽  
Author(s):  
H Wolda
Keyword(s):  
Reproductive Isolation ◽  
Related Species ◽  
Fruit Fly ◽  
Abundant Species ◽  
Colour Pattern ◽  
Wild Populations ◽  
Closely Related Species ◽  
Similar Variation ◽  
In The Wild

A number of samples from wild populations of the Queensland fruit fly, Dacus tryoni and D. neohumeralis, were studied. There is a considerable variation in the colour pattern on the humeral callus. This variation is continuous so that any criterion for distinguishing between "intermediates" and "good species" is purely arbitrary. It was found in areas where D. neohumeralis does not occur as well as in localities where it is very abundant. By whatever criterion one defines intermediates, there appears to be no relation between the frequency of such forms and the presence or absence of D. neohumeralis or with the relative proportions of the two species in the population. However, flies with only a very small yellow area on an otherwise brown humeral callus were found only in Cairns where D. neohumeralis is usually the most abundant species. A similar variation in humeral callus pattern was found in other related species, such as D. kraussi and D. halfordiae. It is concluded that the intermediate colour forms may not be hybrids between D. tryoni and D. neohumeralis but variants of D. tryoni and, possibly the darker forms from Cairns, of D. neohumeralis.

scholarly journals Adaptive zones shape the magnitude of premating reproductive isolation in Timema stick insects

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190541 ◽  
Author(s):  
Moritz Muschick ◽  
Víctor Soria-Carrasco ◽  
Jeffrey L. Feder ◽  
Zach Gompert ◽  
Patrik Nosil
Keyword(s):  
Species Diversity ◽  
Reproductive Isolation ◽  
Fossil Record ◽  
Distinct Species ◽  
Flowering Plants ◽  
Population Divergence ◽  
Host Use ◽  
Theme Issue ◽  
Stick Insects ◽  
Ecological Shifts

Simpson's fossil-record inspired model of ‘adaptive zones’ proposes that evolution is dominated by small fluctuations within adaptive zones, occasionally punctuated by larger shifts between zones. This model can help explain why the process of population divergence often results in weak or moderate reproductive isolation (RI), rather than strong RI and distinct species. Applied to the speciation process, the adaptive zones hypothesis makes two inter-related predictions: (i) large shifts between zones are relatively rare, (ii) when large shifts do occur they generate stronger RI than shifts within zones. Here, we use ecological, phylogenetic and behavioural data to test these predictions in Timema stick insects. We show that host use in Timema is dominated by moderate shifts within the systematic divisions of flowering plants and conifers, with only a few extreme shifts between these divisions. However, when extreme shifts occur, they generate greater RI than do more moderate shifts. Our results support the adaptive zones model, and suggest that the net contribution of ecological shifts to diversification is dependent on both their magnitude and frequency. We discuss the generality of our findings in the light of emerging evidence from diverse taxa that the evolution of RI is not always the only factor determining the origin of species diversity. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.

scholarly journals Parasitic infections in tambaqui from eight fish farms in Northern Brazil

2015 ◽  
Vol 67 (4) ◽  
pp. 1070-1076 ◽  
Author(s):  
M.K.R. Dias ◽  
L.R. Neves ◽  
R.G.B. Marinho ◽  
M. Tavares-Dias
Keyword(s):  
Water Quality ◽  
Parasite Species ◽  
Parasitic Infection ◽  
Parasitic Infections ◽  
Ichthyophthirius Multifiliis ◽  
Fish Farms ◽  
Colossoma Macropomum ◽  
Northern Brazil

The aim of this study was to evaluate the parasites and parasite-host relationship in Colossoma macropomum from eight fish farms in Amapá State, Northern Brazil. A total of 12,242,559 parasites were recovered from hosts in the eight fish farms, and 87.4% of fish were infected by one or more parasite species, such as Ichthyophthirius multifiliis, Piscinoodinium pillulare, Trichodinasp. and Tetrahymena sp. (Protozoa), Anacanthorus spathulatus, Linguadactyloides brinkmanni, Mymarothecium boegeri and Notozothecium janauachensis (Monogenoidea), Procamallanus(Spirocamallanus) inopinatus (Nematoda) and Perulernaea gamitanae and Braga patagonica (Crustacea). Ichthyophthirius multifiliis presented dominance, but the greatest levels of parasitism were caused by I. multifiliis, P. pilulare, monogenoideans species and P. gamitanae, and all these parasites had an aggregate dispersion. The eight fish farms have differences in the parasitic infection levels, management and water quality, which are further discussed here.

scholarly journals Song discrimination by male Mourning Warblers (Geothlypis philadelphia) and implications for population divergence across the breeding range

2015 ◽  
Vol 128 (4) ◽  
pp. 408
Author(s):  
Jay Pitocchelli
Keyword(s):  
Nova Scotia ◽  
Reproductive Isolation ◽  
Geographic Variation ◽  
Learning Experience ◽  
Population Divergence ◽  
Playback Experiments ◽  
Breeding Range ◽  
Song Discrimination ◽  
Song Types ◽  
Song Playback

Geographic variation in song may reduce or eliminate the ability of some populations to recognize each other as conspecifics, possibly leading to assortative mating, reproductive isolation, and speciation. Song playback experiments, used to evaluate the significance of geographic variation in song, have been particularly useful in discovering divergence among previously unknown populations of sibling species. In this study, I report the results of song playback to male Mourning Warblers (Geothlypis philadelphia) from populations throughout the breeding range and discuss the implications for population divergence. Four regions in the breeding range contain unique song types or regiolects: western, eastern, Nova Scotia, and Newfoundland. Results of reciprocal song playback experiments showed that males from the western and Newfoundland regiolects respond more aggressively to songs in their own regiolect than those in the other regiolects. Interior populations, i.e., eastern and Nova Scotia regions, showed little or no difference in aggressive response toward their own versus other regiolects. This pattern may be due to a combination of geographic proximity of populations belonging to different regiolects, song learning, experience, and contact during migration. Song discrimination by populations from the western Prairie Provinces and Newfoundland is consistent with the existence of at least partial reproductive isolation at the geographic extremes of the breeding range.

Sign in / Sign up

Export Citation Format

Share Document