scholarly journals Faster evolution of a premating reproductive barrier is not associated with faster speciation rates in New World passerine birds

2022 ◽  
Vol 289 (1966) ◽  
Author(s):  
Benjamin G. Freeman ◽  
Jonathan Rolland ◽  
Graham A. Montgomery ◽  
Dolph Schluter
Keyword(s):  
Comparative Study ◽  
New World ◽  
Field Experiments ◽  
Evolutionary Rates ◽  
Reproductive Barrier ◽  
Reproductive Barriers ◽  
Passerine Birds ◽  
Allopatric Populations ◽  
Speciation Rates ◽  
Song Discrimination

Why are speciation rates so variable across the tree of life? One hypothesis is that this variation is explained by how rapidly reproductive barriers evolve. We tested this hypothesis by conducting a comparative study of the evolution of bird song, a premating barrier to reproduction. Speciation in birds is typically initiated when geographically isolated (allopatric) populations evolve reproductive barriers. We measured the strength of song as a premating barrier between closely related allopatric populations by conducting 2339 field experiments to measure song discrimination for 175 taxon pairs of allopatric or parapatric New World passerine birds, and estimated recent speciation rates from molecular phylogenies. We found evidence that song discrimination is indeed an important reproductive barrier: taxon pairs with high song discrimination in allopatry did not regularly interbreed in parapatry. However, evolutionary rates of song discrimination were not associated with recent speciation rates. Evolutionary rates of song discrimination were also unrelated to latitude or elevation, but species with innate song (suboscines) evolved song discrimination much faster than species with learned song (oscines). We conclude that song is a key premating reproductive barrier in birds, but faster evolution of this reproductive barrier between populations does not consistently result in faster diversification between species.

scholarly journals Morning glory species co-occurrence is associated with asymmetrically decreased and cascading reproductive isolation

2019 ◽  
Author(s):  
Kate L Ostevik ◽  
Joanna L Rifkin ◽  
Hanhan Xia ◽  
Mark D Rausher
Keyword(s):  
Gene Flow ◽  
Biological Diversity ◽  
Seed Set ◽  
Morning Glory ◽  
Reproductive Barrier ◽  
Mixed Mating ◽  
Reproductive Barriers ◽  
Separate Species ◽  
Ipomoea Lacunosa ◽  
Allopatric Populations

AbstractHybridization between species can affect the strength of the reproductive barriers that separate those species. Two extensions of this effect are: (1) the expectation that asymmetric hybridization will have asymmetric effects on reproductive barrier strength and (2) the expectation that local hybridization will affect only local reproductive barrier strength and could therefore alter within-species compatibility. We tested these hypotheses in a pair of morning glory species that exhibit asymmetric gene flow from highly selfing Ipomoea lacunosa into mixed mating I. cordatotriloba in regions where they co-occur. Because of the direction of this gene flow, we predicted that reproductive barrier strength would be more strongly affected in I. cordatotriloba than I. lacunosa. We also predicted that changes to reproductive barriers in sympatric I. cordatotriloba populations would affect compatibility with allopatric populations of that species. We tested these predictions by measuring the strength of a reproductive barrier to seed set across the species’ ranges. Consistent with our first prediction, we found that sympatric and allopatric I. lacunosa produce the same number of seeds in crosses with I. cordatotriloba, whereas crosses between sympatric I. cordatotriloba and I. lacunosa are more successful than crosses between allopatric I. cordatotriloba and I. lacunosa. This difference in compatibility appears to reflect an asymmetric decrease in the strength of the barrier to seed set in sympatric I. cordatotriloba, which could be caused by I. lacunosa alleles that have introgressed into I. cordatotriloba. We further demonstrated that changes to sympatric I. cordatotriloba have decreased its ability to produce seeds with allopatric populations of the same species, in line with our second prediction. Thus, in a manner analogous to cascade reinforcement, we suggest that introgression associated with hybridization not only influences between-species isolation but can also contribute to isolation within a species.Impact StatementBiological diversity depends on traits that prevent different species from successfully interbreeding. However, these reproductive barriers are often imperfect, leading to hybrid matings and possible genetic exchange between species where they occur together. When this happens, the reproductive barriers that separate species can themselves evolve to become stronger or weaker. Understanding the effects of hybridization on reproductive barriers is key to predicting the potential for future hybridization between species and ultimately whether hybridizing species will diverge, persist, or merge in regions where they co-occur. Here we hypothesize and show that hybridization in only one direction causes unidirectional changes to reproductive barrier strength and that geographically restricted hybridization causes local changes to barrier strength that can affect interbreeding within a species. Specifically, we found that gene flow from one species of morning glory into another likely caused a reproductive barrier to decrease in regions where they co-occur. The decreased reproductive barrier is caused by changes in only the species that received gene flow. We also found that the locally reduced barriers in the species that received gene flow affected reproductive compatibility between populations within that species. Thus, a breakdown of barriers between species can cause a build-up of barriers within a species. Our work demonstrates critical and rarely explored interactions at species boundaries.

Alerting and Message Components in Songs of Rufous-Sided Towhees

Behaviour ◽  
1981 ◽  
Vol 76 (3-4) ◽  
pp. 223-249 ◽  
Author(s):  
Douglas G. Richards
Keyword(s):  
Signal Detection Theory ◽  
Field Experiments ◽  
Species Recognition ◽  
Defense Responses ◽  
Time Of Arrival ◽  
Sufficient Information ◽  
Passerine Birds ◽  
Frequency Range ◽  
Narrow Frequency Range ◽  
Species Specific

AbstractIn numerous species of passerine birds the initial few notes of the song have a narrow frequency range and wide temporal spacing when compared with the rest of the song. This structure is well adapted for high detectability when the song is acoustically degraded during passage through the environment. The song of the rufous-sided towhee (Pipilo eythrophtalmus) consists of relatively tonal introductory syllables followed by a complex rapid trill. The trill is capable of carrying more information than the introduction, but is inherently less detectable at a distance owing to degradation by reverberation, amplitude fluctuation, and frequency-dependent attenuation. Signal detection theory predicts that the detectability of the trill will be increased when it is preceded by the introductory syllables, owing to the removal of uncertainty concerning the time of arrival of the signal. This is alerted detection. I performed field experiments using playback of recorded song to towhees to test the hypothesis that these introductory syllables facilitate detection of conspecific song at a distance. Tape recordings of normal and artificially degraded full songs, introduction, and trills were played to territorial male towhees. Normal songs, degraded songs, and normal trills elicited strong territorial defense responses, indicating recognition as adequate species-specific song, and confirming that sufficient information is contained in the trill for species recognition. Degraded trills alone elicited little response. Both normal and degraded introductions also elicited little response, demonstrating that the increased response to a degraded full song over that to a degraded trill is not due to any species-specific characteristics of the introduction, but rather to its function as an alerting stimulus.

The Energy Efficiency Of Willow Biomass Production In Poland – A Comparative Study

2015 ◽  
Vol 22 (1) ◽  
pp. 123-130 ◽  
Author(s):  
Stefan Szczukowski ◽  
Józef Tworkowski ◽  
Mariusz J. Stolarski ◽  
Michał Krzyżaniak
Keyword(s):  
Energy Efficiency ◽  
Comparative Study ◽  
Biomass Production ◽  
Field Experiments ◽  
Energy Gain ◽  
Short Rotation ◽  
Energy Inputs ◽  
The University

Abstract Field experiments with willow (Salix L.) coppice cultivation and Eko-Salix systems have been conducted at the University of Warmia and Mazury since 1992. In that wider context, the aim of the work described here was to compare energy inputs involved in setting up a plantation and producing biomass, and to assess the efficiency of willow-chips production under the coppice and Eko-Salix systems. The energy gain determined in the experiments was several to more than twenty times as great as the inputs needed to operate the plantation and to harvest willow biomass, this leaving both systems of willow cultivation under study attractive where setting up short-rotation coppices is concerned.

scholarly journals Morphology of immature stages of Paraegidium costalimai (Coleoptera: Scarabaeidae: Orphninae) and remarks on egg-busters in Scarabaeidae first‑instar larvae

2020 ◽  
Author(s):  
Rafael Clayton De Jesus e Sousa ◽  
Juares Fuhrmann
Keyword(s):  
Comparative Study ◽  
New World ◽  
Immature Stages ◽  
Old World ◽  
The Third ◽  
First Instar ◽  
Third Instar Larvae

Studies about the immature stages of Orphninae (Coleoptera: Scarabaeidae) species are scarce. The subfamily includes 214 species, but only 5 have the immature stages described: Chaetonyx robustus liguricus Mariani, 1946, Hybalus benoiti Tournier, 1864, H. rotroui Petrovitz, 1964 and Triodontus nitidulus (Guérin, 1844) from Old World; and Aegidium cribratum Bates, 1887 from the New World. The Neotropical genus Paraegidium Vulcano, Pereira & Martinez, 1966 encompass five species, mainly recorded from Brazil. Herein, the immature stages of P. costalimai Vulcano, Pereira & Martinez, 1966 are described and illustrated, along with remarks on the presence of egg-buster in Scarabaeidae first-instar larvae. A key to the third-instar larvae of known Orphninae and a comparative study of chaetotaxy are also provided.

scholarly journals Evolutionary rates of mitochondrial genomes correspond to diversification rates and to contemporary species richness in birds and reptiles

2010 ◽  
Vol 277 (1700) ◽  
pp. 3587-3592 ◽  
Author(s):  
Soo Hyung Eo ◽  
J. Andrew DeWoody
Keyword(s):  
Species Richness ◽  
Nuclear Data ◽  
Synonymous Substitution ◽  
Evolutionary Rates ◽  
Rate Variation ◽  
Substitution Rates ◽  
Diversification Rates ◽  
Extinction Process ◽  
Molecular Evolutionary Rates ◽  
Speciation Rates

Rates of biological diversification should ultimately correspond to rates of genome evolution. Recent studies have compared diversification rates with phylogenetic branch lengths, but incomplete phylogenies hamper such analyses for many taxa. Herein, we use pairwise comparisons of confamilial sauropsid (bird and reptile) mitochondrial DNA (mtDNA) genome sequences to estimate substitution rates. These molecular evolutionary rates are considered in light of the age and species richness of each taxonomic family, using a random-walk speciation–extinction process to estimate rates of diversification. We find the molecular clock ticks at disparate rates in different families and at different genes. For example, evolutionary rates are relatively fast in snakes and lizards, intermediate in crocodilians and slow in turtles and birds. There was also rate variation across genes, where non-synonymous substitution rates were fastest at ATP8 and slowest at CO 3. Family-by-gene interactions were significant, indicating that local clocks vary substantially among sauropsids. Most importantly, we find evidence that mitochondrial genome evolutionary rates are positively correlated with speciation rates and with contemporary species richness. Nuclear sequences are poorly represented among reptiles, but the correlation between rates of molecular evolution and species diversification also extends to 18 avian nuclear genes we tested. Thus, the nuclear data buttress our mtDNA findings.

A Comparative Study of the Arterial Systems of Some New World Crotalinae (Reptilia: Ophidia)

1969 ◽  
Vol 81 (1) ◽  
pp. 107 ◽  
Author(s):  
Therese M. Van Bourgondien ◽  
Richard C. Bothner
Keyword(s):  
Comparative Study ◽  
New World
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