Complex spatiotemporal variation in processes shaping song variation

Behaviour ◽  
2019 ◽  
Vol 156 (10) ◽  
pp. 1057-1082
Author(s):  
Claire M. Curry ◽  
Michael A. Patten
Keyword(s):  
Vegetation Structure ◽  
Environmental Gradient ◽  
Environmental Gradients ◽  
Spatiotemporal Variation ◽  
Hybrid Zones ◽  
Signal Evolution ◽  
Song Variation ◽  
Song Divergence ◽  
Tufted Titmouse ◽  
Two Hybrid

Abstract Understanding factors that contribute to song divergence bolsters our understanding of signal evolution and reproductive isolation. Hybrid zones often occur across environmental gradients; as such, they are excellent places to examine how signals diverge and how differentiation is maintained. We studied song variation across two hybrid zones, one old and one recent, of Tufted Titmouse (Baeolophus bicolor) and Black-crested Titmouse (B. atricristatus), across an environmental gradient where the two titmouse populations meet. In the recent zone, noise and vegetation structure were correlated with several song characteristics, but in the older zone, these features did not correlate despite similar gradients in song features. Our data, combined with previous studies, suggest that despite overall similarities in characteristics, songs in the older zone may be more shaped by sexual selection, whereas songs in the young zone are shaped by environment. Thus, even within the same species, processes shaping signal structure can vary spatially and temporally.

Vegetation structure and environmental gradients in the Sallum area, Egypt

2005 ◽  
Vol 31 (1) ◽  
pp. 15-32 ◽  
Author(s):  
Fawzy M. Salama ◽  
Monier Abd El-Ghani ◽  
Salah El Naggar ◽  
Khadija A. Baayo
Keyword(s):  
Vegetation Structure ◽  
Environmental Gradients

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 Reproductive performance in two hybrid zones between chromosome races of the common shrew Sorex araneus in Poland

2000 ◽  
Vol 45 ◽  
pp. 69-78 ◽  
Author(s):  
Agata Banaszek ◽  
Stanisław Fedyk ◽  
Katarzyna A. Szałaj ◽  
Włodzimierz Chętnicki
Keyword(s):  
Reproductive Performance ◽  
Common Shrew ◽  
Sorex Araneus ◽  
Hybrid Zones ◽  
Chromosome Races ◽  
The Common ◽  
Common Shrew Sorex Araneus ◽  
Two Hybrid

scholarly journals Increasing temporal variance leads to stable species range limits

2021 ◽  
Author(s):  
John W Benning ◽  
Ruth A Hufbauer ◽  
Christopher Weiss-Lehman
Keyword(s):  
Environmental Gradient ◽  
Environmental Gradients ◽  
Local Population ◽  
Evolutionary Model ◽  
Environmental Variation ◽  
Species Range ◽  
Range Limits ◽  
Stable Range ◽  
Species Expansion ◽  
Temporal Variance

What prevents populations of a species from adapting to the novel environments outside the species' geographic distribution? Previous models highlighted how gene flow across spatial environmental gradients determines species expansion vs. extinction and the location of species range limits. However, space is only one of two axes of environmental variation — environments also vary in time, and we know temporal environmental variation has important consequences for population demography and evolution. We used an individual based evolutionary model to explore how temporal stochasticity in environmental conditions influences the spread of populations across a spatial environmental gradient. We find that temporal stochasticity greatly alters our predictions for range dynamics compared to temporally static environments. When temporal variance is equal across the landscape, the fate of species (expansion vs. extinction) is determined by the interaction between the degree of temporal autocorrelation in environmental fluctuations and the steepness of the spatial environmental gradient. When the magnitude of temporal variance changes across the landscape, stable range limits form where this variance becomes large enough to prevent local population adaptation and persistence. These results illustrate the pivotal influence of temporal stochasticity on the likelihood of populations colonizing novel habitats and the location of species range limits.

scholarly journals Micromorphological character expression of the hybrid Quercus × dysophylla and its parental species (Q. crassifolia and Q. crassipes)

2017 ◽  
Vol 95 (3) ◽  
pp. 375
Author(s):  
Alfredo López-Caamal ◽  
Luz Del Carmen Ruiz-Amaro ◽  
Armando Zepeda-Rodríguez ◽  
Patricia Mussali-Galante ◽  
Efraín Tovar-Sánchez
Keyword(s):  
Parental Species ◽  
Environmental Gradients ◽  
Glandular Trichomes ◽  
Morphological Characters ◽  
Diagnostic Feature ◽  
Hybrid Zones ◽  
Intermediate Phenotypes ◽  
Study Sites ◽  
Micromorphological Characters ◽  
Spatial Genetic Pattern

<p><strong>Background:</strong> Hybridization leads to individuals with atypical phenotypes, leading to taxonomic confusion when hybridizing populations are studied. Micromorphological characters may enable taxonomists to discriminate between parental and hybrid categories due to their simple genetic inheritance.</p><p><strong>Species study:</strong> Three oak taxa distributed in the montane regions of the Mexico were studied: <em>Quercus crassifolia</em>, <em>Q. crassipes</em> and their hybrid <em>Q</em>. × <em>dysophylla</em>.</p><p><strong>Hypothesis:</strong> We describe the leaf micromorphological and macromorphological variation of these taxa. Specifically, we searched for a unique combination of micromorphological characters in hybrids. We hypothesize that spatial micromorphological variation will match the spatial pattern revealed by a previous genetic study.</p><p><strong>Study sites:</strong> Two allopatric stands for each parental species and seven hybrid zones were studied. Individuals within each stand were identified as belonging to parental or hybrid categories following previous genetic analyses.</p><p><strong>Methods:</strong> Stomata and trichome types for each taxa were determined through Scanning Electron Microscopy. Eight micromorphological characters for trichomes and stomata and four foliar macromorphological characters were measured.</p><p><strong>Results: </strong>We found the presence of both multirradiate and simple stellate non-glandular trichomes as a diagnostic feature of <em>Q</em>. × <em>dysophylla.</em> Overall populations, <em>Q</em>. × <em>dysophylla</em> showed intermediate phenotypes in 70 % of morphological characters. However, hybrid phenotype exhibited geographical variation. Lastly, spatial hybrid’s phenotype variation did not correlate with the spatial genetic pattern previously identified.</p><p><strong>Conclusions: </strong>The micromorphological features of <em>Q.</em> × <em>dysophylla</em> may enable taxonomists to accurately discriminate between this taxon and its parental species. Finally, we suggest that micromorphological expression of both parental species and hybrids may be influenced by environmental gradients and microclimates.</p>

scholarly journals Southern California margin benthic foraminiferal assemblages across a modern environmental gradient record recent centennial-scale changes in oxygen minimum zone

2019 ◽  
Author(s):  
Hannah M. Palmer ◽  
Tessa M. Hill ◽  
Peter D. Roopnarine ◽  
Sarah E. Myhre ◽  
Katherine R. Reyes ◽  
...  
Keyword(s):  
Water Depth ◽  
San Diego ◽  
Environmental Gradient ◽  
Environmental Gradients ◽  
Oxygen Minimum Zone ◽  
Shannon Index ◽  
Spatial Trends ◽  
Minimum Zone ◽  
Associated Species ◽  
Oxygen Minimum

Abstract. Microfossil assemblages provide valuable records to investigate variability in continental margin biogeochemical cycles, including dynamics of the oxygen minimum zone (OMZ). Analyses of modern assemblages across environmental gradients are necessary to understand relationships between assemblage characteristics and environmental factors. Here, we analyzed five cores from the San Diego Margin (32°42'00'' N, 117°30'00'' W, 300–1175 m water depth) for core top benthic foraminiferal assemblages to understand relationships between community assemblages and spatial hydrographic gradients and down core to identify changes in the oxygen minimum zone through time. Comparisons of benthic foraminiferal assemblages from two size fractions (63–150 and > 150 μm) exhibit similar trends across the spatial/environmental gradient, or in some cases exhibit more pronounced spatial trends in the > 150 μm fraction. We identify two hypoxic associated species (B. spissa and U. peregrina), one oxic associated species (G. subglobosa) and one OMZ edge-associated species (B. argentea). A range of species diversity exists within the modern OMZ (1.5–2.6 H, Shannon Index), suggesting that diversity is not driven by oxygenation alone. Down core analysis of indicator species reveal variability in upper margin of the OMZ (528 m water depth) while the core of the OMZ (800 m) and below the OMZ (1175 m) remained stable in the last 1.5 ka. We document expansion of the upper margin of the OMZ beginning 400 ybp on the San Diego Margin that is synchronous with other regional records of oxygenation.

scholarly journals Against the Odds: Hybrid Zones between Mangrove Killifish Species with Different Mating Systems

Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1486
Author(s):  
Waldir M. Berbel-Filho ◽  
Andrey Tatarenkov ◽  
George Pacheco ◽  
Helder M. V. Espírito-Santo ◽  
Mateus G. Lira ◽  
...  
Keyword(s):  
Mating Systems ◽  
Sympatric Species ◽  
Natural Hybridization ◽  
Hybrid Zones ◽  
Mating Opportunities ◽  
Plant Hybrid ◽  
Two Hybrid ◽  
Selfing Species ◽  
Shed Light ◽  
Mangrove Killifish

Different mating systems are expected to affect the extent and direction of hybridization. Due to the different levels of sexual conflict, the weak inbreeder/strong outbreeder (WISO) hypothesis predicts that gametes from self-incompatible (SI) species should outcompete gametes from self-compatible (SC) ones. However, other factors such as timing of selfing and unilateral incompatibilities may also play a role on the direction of hybridization. In addition, differential mating opportunities provided by different mating systems are also expected to affect the direction of introgression in hybrid zones involving outcrossers and selfers. Here, we explored these hypotheses with a unique case of recent hybridization between two mangrove killifish species with different mating systems, Kryptolebias ocellatus (obligately outcrossing) and K. hermaphroditus (predominantly self-fertilizing) in two hybrid zones in southeast Brazil. Hybridization rates were relatively high (~20%), representing the first example of natural hybridization between species with different mating systems in vertebrates. All F1 individuals were sired by the selfing species. Backcrossing was small, but mostly asymmetrical with the SI parental species, suggesting pattern commonly observed in plant hybrid zones with different mating systems. Our findings shed light on how contrasting mating systems may affect the direction and extent of gene flow between sympatric species, ultimately affecting the evolution and maintenance of hybrid zones.

scholarly journals Extensive sympatry and frequent hybridization of ecologically divergent aquatic plants on the Qinghai-Tibetan Plateau

2021 ◽  
Author(s):  
Zhigang Wu ◽  
Zhong Wang ◽  
Dong Xie ◽  
Juan Zhang ◽  
Pengsen Cai ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Aquatic Plants ◽  
Related Species ◽  
Environmental Gradients ◽  
Niche Overlap ◽  
Hybrid Zones ◽  
Limited Information ◽  
Freshwater Biodiversity ◽  
Genetic Incompatibility ◽  
Species Pairs

Hybridization has fascinated biologists in recent centuries for its evolutionary importance, especially in plants. Hybrid zones are commonly located in regions across environmental gradients due to more opportunities to contact and ecological heterogeneity. For aquatic taxa, intrazonal character makes broad overlapping regions in intermediate environments between related species. However, we have limited information on the hybridization pattern of aquatic taxa across an altitudinal gradient. In this study, we aimed to test the hypotheses that niche overlap and hybridization might be extensive in related aquatic plants in alpines. We evaluated the niche overlap in three related species pairs on the Qinghai-Tibetan Plateau and assessed the spatial pattern of hybrid populations. Obvious niche overlap and common hybridization were revealed in all three pairs of related aquatic plants. The plateau edge and river basins were broad areas for the sympatry of divergent taxa, where a large proportion of hybrid populations occurred. Hybrids are also discretely distributed in diverse habitats on the plateau. Differences in the extent of niche overlap, genetic incompatibility and phylogeographic history might lead to inconsistences in hybridization patterns among the three species pairs. Our results suggested that plateau areas are a hotspot for ecologically divergent aquatic species to contact and mate and implied that hybridization may be important for the freshwater biodiversity of highlands.

scholarly journals Grassland communities of Stol mountain (eastern Serbia ): Vegetation and environment al relationships

2013 ◽  
Vol 65 (1) ◽  
pp. 211-227 ◽  
Author(s):  
Svetlana Acic ◽  
U. Silc ◽  
S. Vrbnicanin ◽  
Svjetlana Cupac ◽  
G. Topisirovic ◽  
...  
Keyword(s):  
Species Composition ◽  
Environmental Gradient ◽  
Environmental Gradients ◽  
Detrended Correspondence Analysis ◽  
Ecological Indicator ◽  
Vegetation Types ◽  
Indicator Values ◽  
Grassland Vegetation ◽  
Data Set ◽  
Grassland Communities

The systematic survey of grassland communities was performed on Mt. Stol (eastern Serbia). The main aims of the research were to: (1) determine grassland vegetation types of the researched area; (2) correlate the impacts of the soil and environmental conditions on the occurrence of certain plant communities, and (3) comment on the conservational value of the grasslands in the researched area. The data set included 60 phytosociological relev?s of grasslands recorded between 2001 and 2004. The main environmental gradients of species composition were analyzed by Detrended Correspondence Analysis (DCA). For the ecological interpretation of ordination axes, ecological indicator values were used. Three associations were distinguished: Danthonietum calycinae, Asperulo-Agrostietum vulgaris and Ranunculo bulbosi- Arrhenatheretum elatioris belonging to two alliances and two classes: Chrysopogono-Danthonion - Festuco-Brometea and Arrhenatherion - Molinio-Arrhenatheretea. The results of the DCA support our assumption that the main environmental gradient in the species composition of the grasslands is related to nutrients and moisture. The conservational value of grasslands in the researched area is discussed.

Altitudinal implications in organ size in the Andrew’s toad (Bufo andrewsi)

2019 ◽  
Vol 69 (3) ◽  
pp. 365-376 ◽  
Author(s):  
Li Zhao ◽  
Chun Lan Mai ◽  
Guo Hou Liu ◽  
Wen Bo Liao
Keyword(s):  
Environmental Gradient ◽  
Oxygen Supply ◽  
Environmental Gradients ◽  
Relative Size ◽  
Organ Size ◽  
Phenotypic Flexibility ◽  
Energy Demands ◽  
Morphological And Physiological Traits ◽  
Bufo Andrewsi ◽  
Toad Bufo

Abstract Phenotypic flexibility of morphological and physiological traits within species is a common phenomenon across animal taxa. Hesse’s rule predicts that the size of an organ should exhibit an increase with increasing altitude along environmental gradients due to changes in oxygen supply and energy demands. Here, we test the prediction of Hesse’s rule by investigating geographical variation in the relative size of organs (i.e., heart, lungs, liver, and kidneys) across ten populations of Bufo andrewsi along an environmental gradient. We found that the relative size of these four specific organs did not increase with altitude or latitude across all populations. We also did not find that the relative size of the organs increased with increasing altitude among six populations located at a similar latitude and longitude, which is inconsistent with Hesse’s rule. Our findings suggest that oxygen supply and energy demands do not necessarily affect variation in organ size among populations.

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