Food division within two sympatric species-pairs of skates (Pisces: Rajidae)

1976 ◽  
Vol 35 (4) ◽  
pp. 301-317 ◽  
Author(s):  
J. D. McEachran ◽  
D. F. Boesch ◽  
J. A. Musick
Keyword(s):  
Sympatric Species ◽  
Species Pairs ◽  
Food Division

scholarly journals Sympatry drives colour and song evolution in wood-warblers (Parulidae)

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202804
Author(s):  
Richard K. Simpson ◽  
David R. Wilson ◽  
Allison F. Mistakidis ◽  
Daniel J. Mennill ◽  
Stéphanie M. Doucet
Keyword(s):  
Related Species ◽  
Species Recognition ◽  
Sympatric Species ◽  
Signal Evolution ◽  
Wood Warblers ◽  
Mixed Support ◽  
Species Pairs ◽  
Song Divergence ◽  
Signal Diversity ◽  
Signal Divergence

Closely related species often exhibit similarities in appearance and behaviour, yet when related species exist in sympatry, signals may diverge to enhance species recognition. Prior comparative studies provided mixed support for this hypothesis, but the relationship between sympatry and signal divergence is likely nonlinear. Constraints on signal diversity may limit signal divergence, especially when large numbers of species are sympatric. We tested the effect of sympatric overlap on plumage colour and song divergence in wood-warblers (Parulidae), a speciose group with diverse visual and vocal signals. We also tested how number of sympatric species influences signal divergence. Allopatric species pairs had overall greater plumage and song divergence compared to sympatric species pairs. However, among sympatric species pairs, plumage divergence positively related to the degree of sympatric overlap in males and females, while male song bandwidth and syllable rate divergence negatively related to sympatric overlap. In addition, as the number of species in sympatry increased, average signal divergence among sympatric species decreased, which is likely due to constraints on warbler perceptual space and signal diversity. Our findings reveal that sympatry influences signal evolution in warblers, though not always as predicted, and that number of sympatric species can limit sympatry's influence on signal evolution.

scholarly journals Genome assembly, structural variants, and genetic differentiation between Lake Whitefish young species pairs (Coregonus sp.) with long and short reads

2022 ◽  
Author(s):  
Claire M&eacuterot ◽  
Kristina S R Stenl&oslashkk ◽  
Clare Venney ◽  
Martin Laporte ◽  
Michel Moser ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Genetic Architecture ◽  
Large Fraction ◽  
Sympatric Species ◽  
Secondary Contact ◽  
Species Differentiation ◽  
Lake Whitefish ◽  
Structural Variants ◽  
Species Pairs ◽  
Long Read

The parallel evolution of nascent pairs of ecologically differentiated species offers an opportunity to get a better glimpse at the genetic architecture of speciation. Of particular interest is our recent ability to consider a wider range of genomic variants, not only single-nucleotide polymorphisms (SNPs), thanks to long-read sequencing technology. We can now identify structural variants (SVs) like insertions, deletions, and other structural rearrangements, allowing further insights into the genetic architecture of speciation and how different variants are involved in species differentiation. Here, we investigated genomic patterns of differentiation between sympatric species pairs (Dwarf and Normal) belonging to the Lake Whitefish (Coregonus clupeaformis) species complex. We assembled the first reference genomes for both Dwarf and Normal Lake Whitefish, annotated the transposable elements, and analysed the genome in the light of related coregonid species. Next, we used a combination of long-read and short-read sequencing to characterize SVs and genotype them at population-scale using genome-graph approaches, showing that SVs cover five times more of the genome than SNPs. We then integrated both SNPs and SVs to investigate the genetic architecture of species differentiation in two different lakes and highlighted an excess of shared outliers of differentiation. In particular, a large fraction of SVs differentiating the two species was driven by transposable elements (TEs), suggesting that TE accumulation during a period of allopatry predating secondary contact may have been a key process in the speciation of the Dwarf and Normal Whitefish. Altogether, our results suggest that SVs play an important role in speciation and that by combining second and third generation sequencing we now have the ability to integrate SVs into speciation genomics.

Another new, diminutive Rock Gecko (Cnemaspis Strauch) from Peninsular Malaysia and a discussion of resource partitioning in sympatric species pairs

Zootaxa ◽  
2010 ◽  
Vol 2569 (1) ◽  
pp. 55 ◽  
Author(s):  
L. LEE GRISMER ◽  
CHAN KIN ONN ◽  
EVAN QUAH ◽  
MOHD ABDUL MUIN ◽  
ANNA E. SAVAGE ◽  
...  
Keyword(s):  
New Species ◽  
Body Size ◽  
Endemic Species ◽  
Resource Partitioning ◽  
Sympatric Species ◽  
Southeast Asian ◽  
Peninsular Malaysia ◽  
Activity Period ◽  
Species Pairs

A new, diminutive species of Rock Gecko, Cnemaspis shahruli sp. nov. from Penang Island, Penang; Pulau Jerejak, Penang; Pulau Pangkor, Perak; and the adjacent mainland at Sungai Sedim, Kedah was previously confused with juveniles of the sympatric, endemic species C. affinis (Stoliczka) on Penang Island. Cnemaspis shahruli sp. nov. is diagnosed from all other Southeast Asian Cnemaspis on the basis of several unique aspects of squamation, coloration, and body size. It is proposed that this new species has a more extensive mainland distribution than is presented here based on its southernmost record on Pulau Pangkor, Perak. A pattern of resource partitioning on the basis of body size, habitat, and activity period among sympatric species pairs of Cnemaspis is discussed.

The role of competition in determining morphological differences between Victorian and Tasmanian passerine birds

1977 ◽  
Vol 25 (3) ◽  
pp. 429 ◽  
Author(s):  
I Abbott
Keyword(s):  
Wing Length ◽  
Sympatric Species ◽  
Congeneric Species ◽  
Tarsus Length ◽  
Frequency Distributions ◽  
Clear Cut ◽  
Significant Difference ◽  
Species Pairs ◽  
Morphological Differences ◽  
Bill Length

Bill length, tarsus length and wing length were measured in 107 passerine species in southern Victoria and 46 in Tasmania, and the possibility that the impoverishment of the Tasmanian avifauna elicits morphological shifts was evaluated. An hypothesis of competitor release failed to account for the main morphological features of the Tasmanian avifauna. There was no significant difference between the frequency distributions of the three variables in mainland and island species, which suggests that no character size on the mainland is over- or under-represented in Tasmania; in spite of this, in nearly all the species common to both areas all three variables are significantly larger in Tasmania. No significant difference was found between the frequency distributions of character-ratios for mainland and island congeneric species-pairs, though theory predicts the island distribution would be the more skew. In 17 pairs of congeners occurring in both areas, the bill length and tarsus length ratios are not significantly different, and though wing length ratios do differ significantly, it is the mainland pairs that have the larger ratio. The variability of the three characters in 25 species did not differ significantly between mainland and island. Many genera which are represented by several sympatric species in Victoria have only one representative (usually the larger) in Tasmania. Although the theory of competitor release predicts that the species in Tasmania should show decreased character sizes, a clear-cut trend to increased size was found. Congeneric species-pairs in Tasmania do not show large morphological differences, which cannot be necessary for successful coexistence there. The above results are discussed briefly, and an hypothesis based on the larger size of food items in Tasmania is proposed to explain them.

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
Keyword(s):  
Nest Predation ◽  
Species Complex ◽  
Food Source ◽  
Gasterosteus Aculeatus ◽  
Nest Site ◽  
Sympatric Species ◽  
Threespine Stickleback ◽  
Species Pairs ◽  
Threespine Sticklebacks

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.

scholarly journals Intestinal microbiota of whitefish (Coregonus sp.) species pairs and their hybrids in natural and controlled environment

2018 ◽  
Author(s):  
Maelle Sevellec ◽  
Martin Laporte ◽  
Alex Bernatchez ◽  
Nicolas Derome ◽  
Louis Bernatchez
Keyword(s):  
Intestinal Microbiota ◽  
Sympatric Species ◽  
Taxonomic Composition ◽  
Rrna Gene ◽  
Coregonus Clupeaformis ◽  
Symbiotic Interactions ◽  
Species Pairs ◽  
In The Wild ◽  
Species Effect ◽  
Evolutionary Paths

AbstractIt is becoming increasingly clear that wild animals have never existed without symbiotic interactions with microbiota. Therefore, investigating relationships between microbiota and their host is essential towards a full understanding of how animal evolve and adapt to their environment. The Lake Whitefish (Coregonus clupeaformis) is a well-documented model for the study of ecological speciation, where the dwarf species (limnetic niche specialist) evolved independently and repeatedly from the normal species (benthic niche specialist). In this study, we compared the transient intestinal microbiota among five wild sympatric species pairs of whitefish as well as captive representatives of dwarf and normal species and their reciprocal hybrids reared in identical controlled conditions. We sequenced the 16s rRNA gene V3-V4 regions of the transient intestinal microbiota present in a total of 185 whitefish to (i) test for parallelism in the transient intestinal microbiota among sympatric pairs of whitefish, (ii) test for transient intestinal microbiota differences among dwarf, normal and both hybrids reared under identical conditions and (iii) compare intestinal microbiota between wild and captive whitefish. A significant effect of host species on microbiota taxonomic composition was observed in the wild when all lakes where analyzed together, and species effect was observed in three of the five species pairs. In captive whitefish, an influence of host (normal, dwarf and hybrids) was also detected on microbiota taxonomic composition and tens of genera specific to dwarf, normal or hybrids were highlighted. Hybrid microbiota was not intermediate; instead its composition fell outside of that observed in the parental forms and this was observed in both reciprocal hybrid crosses. Interestingly, six genera formed a bacterial core which was present in captive and wild whitefish, suggesting a horizontal microbiota transmission. Although diet appeared to be a major driving force for microbiota evolution, our results suggested a more complex interaction among the host, the microbiota and the environment leading to three distinct evolutionary paths of the intestinal microbiota.

scholarly journals Patterns of Z chromosome divergence among Heliconius species highlight the importance of historical demography

2017 ◽  
Author(s):  
Steven M. Van Belleghem ◽  
Margarita Baquero ◽  
Riccardo Papa ◽  
Camilo Salazar ◽  
W. Owen McMillan ◽  
...  
Keyword(s):  
Gene Flow ◽  
Sex Chromosome ◽  
Null Model ◽  
Sympatric Species ◽  
Ancestral Population ◽  
Z Chromosome ◽  
Butterfly Species ◽  
Species Pairs ◽  
Species Comparisons ◽  
Strong Barrier

AbstractSex chromosomes are disproportionately involved in reproductive isolation and adaptation. In support of such a ‘large-X’ effect, genome scans between recently diverged populations or species pairs often identify distinct patterns of divergence on the sex chromosome compared to autosomes. When measures of divergence between populations are higher on the sex chromosome compared to autosomes, such patterns could be interpreted as evidence for faster divergence on the sex chromosome, i.e. ‘faster-X’, or barriers to gene flow on the sex chromosome. However, demographic changes can strongly skew divergence estimates and are not always taken into consideration. We used 224 whole genome sequences representing 36 populations from two Heliconius butterfly clades (H. erato and H. melpomene) to explore patterns of Z chromosome divergence. We show that increased divergence compared to equilibrium expectations can in many cases be explained by demographic change. Among Heliconius erato populations, for instance, population size increase in the ancestral population can explain increased absolute divergence measures on the Z chromosome compared to the autosomes, as a result of increased ancestral Z chromosome genetic diversity. Nonetheless, we do identify increased divergence on the Z chromosome relative to the autosomes in parapatric or sympatric species comparisons that imply post-zygotic reproductive barriers. Using simulations, we show that this is consistent with reduced gene flow on the Z chromosome, perhaps due to greater accumulation of species incompatibilities. Our work demonstrates the importance of constructing an appropriate demographic null model in order to interpret patterns of divergence on the Z chromosome, but nonetheless provides evidence to support the Z chromosome as a strong barrier to gene flow in incipient Heliconius butterfly species.

BIOSYSTEMATICS OF PISSODES GERMAR (COLEOPTERA: CURCULIONIDAE): FEEDING PREFERENCE AND BREEDING SITE SPECIFICITY OF P. STROBI AND P. APPROXIMATUS

1983 ◽  
Vol 115 (12) ◽  
pp. 1627-1636 ◽  
Author(s):  
Thomas W. Phillips ◽  
Gerald N. Lanier
Keyword(s):  
Field Tests ◽  
Breeding Site ◽  
Sympatric Species ◽  
Feeding Preference ◽  
White Pine ◽  
Breeding Sites ◽  
Pissodes Strobi ◽  
Species Pairs ◽  
Males And Females ◽  
Fertile Hybrids

AbstractPissodes strobi (Peck) and P. approximatus Hopkins are sibling species that can produce fertile hybrids in the laboratory, but in nature they are isolated by differences in their breeding habits. In a laboratory assay for feeding preference, these species exhibited similar patterns of acceptance of most conifer hosts in the fall, but differed distinctly in their preferences for certain conifers in the spring. Both species had high levels of feeding on white spruce in the fall and spring tests, hut these data apparently do not reflect host preference in nature. In field tests, P. strobi males and females confined on 1-year-old terminal leaders of eastern white pine (their usual breeding sites) produced abundant progeny, whereas P. approximatus pairs confined on leaders produced few progeny. Mixed species pairs were successful in killing and breeding in white pine leaders when the females were P. strobi, but not when the females were P. approximatus. Laboratory-reared hybrids were unsuccessful when forced to breed in leaders. When confined on red pine bolts (the usual breeding sites of P. approximatus), P. strobi and hybrids produced substantially fewer progeny than did P. approximatus. Breeding site separation provides compelling evidence of reproductive isolation between these sympatric species.

scholarly journals Reproductive interference explains persistence of aggression between species

2015 ◽  
Vol 282 (1804) ◽  
pp. 20142256 ◽  
Author(s):  
Jonathan P. Drury ◽  
Kenichi W. Okamoto ◽  
Christopher N. Anderson ◽  
Gregory F. Grether
Keyword(s):  
Species Differences ◽  
Sympatric Species ◽  
Reproductive Interference ◽  
Interspecific Aggression ◽  
Interspecific Territoriality ◽  
Interspecific Divergence ◽  
Species Pairs ◽  
Taxonomic Groups ◽  
Competitor Recognition ◽  
Female Coloration

Interspecific territoriality occurs when individuals of different species fight over space, and may arise spontaneously when populations of closely related territorial species first come into contact. But defence of space is costly, and unless the benefits of excluding heterospecifics exceed the costs, natural selection should favour divergence in competitor recognition until the species no longer interact aggressively. Ordinarily males of different species do not compete for mates, but when males cannot distinguish females of sympatric species, females may effectively become a shared resource. We model how reproductive interference caused by undiscriminating males can prevent interspecific divergence, or even cause convergence, in traits used to recognize competitors. We then test the model in a genus of visually orienting insects and show that, as predicted by the model, differences between species pairs in the level of reproductive interference, which is causally related to species differences in female coloration, are strongly predictive of the current level of interspecific aggression. Interspecific reproductive interference is very common and we discuss how it may account for the persistence of interspecific aggression in many taxonomic groups.

scholarly journals Polygenic selection drives the evolution of convergent transcriptomic landscapes across continents within a Nearctic sister-species complex

2018 ◽  
Author(s):  
Clément Rougeux ◽  
Pierre-Alexandre Gagnaire ◽  
Kim Praebel ◽  
Ole Seehausen ◽  
Louis Bernatchez
Keyword(s):  
Gene Expression ◽  
Natural Selection ◽  
Differential Gene Expression ◽  
Ecological Speciation ◽  
Sympatric Species ◽  
Benthic Species ◽  
Species Pairs ◽  
Differential Gene ◽  
Polygenic Selection

ABSTRACTIn contrast to the plethora of studies focusing on the genomic basis of adaptive phenotypic divergence, the role of gene expression during speciation has been much less investigated and consequently, less understood. Yet, the convergence of differential gene expression patterns between closely related species-pairs might reflect the role of natural selection during the process of ecological speciation. Here, we test for intercontinental convergence in differential transcriptional signatures between limnetic and benthic sympatric species-pairs of Lake Whitefish (Coregonus clupeaformis) and its sister-lineage, the European Whitefish (C. lavaretus), using six replicated sympatric species-pairs (two in North America, two in Norway and two in Switzerland). We characterized both sequence variation in transcribed regions and differential gene expression between sympatric limnetic and benthic species across regions and continents. Our first finding was that differentially expressed genes (DEG) between limnetic and benthic whitefish tend to be enriched in shared polymorphism among sister-lineages. We then used both genotypes and co-variation in expression in order to infer polygenic selection at the gene level. We identified parallel outliers and DEG involving genes primarily over-expressed in limnetic species relative to the benthic species. Our analysis finally revealed the existence of shared genomic bases underlying parallel differential expression across replicated species pairs from both continents, such as a cis-eQTL affecting the pyruvate kinase expression level involved in glycolysis. Our results are consistent with a longstanding role of natural selection in maintaining transcontinental diversity at phenotypic traits involved in ecological speciation between limnetic and benthic whitefishes.

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