scholarly journals Multiple routes to interspecific territoriality in sister species of North American perching birds

2019 ◽  
Author(s):  
Madeline C. Cowen ◽  
Jonathan P. Drury ◽  
Gregory F. Grether
Keyword(s):  
North American ◽  
Resource Competition ◽  
Sister Species ◽  
Unstable State ◽  
Multiple Origins ◽  
Interspecific Territoriality ◽  
Wide Range ◽  
Species Pairs ◽  
Multiple Routes ◽  
Range Overlap

ABSTRACTBehavioral interference between species can influence a wide range of ecological and evolutionary processes. Here we test foundational hypotheses regarding the origins and maintenance of interspecific territoriality, and evaluate the role of interspecific territoriality and hybridization in shaping species distributions and transitions from parapatry to sympatry in sister species of North American perching birds (Passeriformes). We found that interspecific territoriality is pervasive among sympatric sister species pairs, and that interspecifically territorial species pairs have diverged more recently than sympatric non-interspecifically territorial pairs. None of the foundational hypotheses alone explain the observed patterns of interspecific territoriality, but our results support the idea that some cases of interspecific territoriality arise from misdirected intraspecific aggression while others are evolved responses to resource competition. The combination of interspecific territoriality and hybridization appears to be an unstable state associated with parapatry, while species that are interspecifically territorial and do not hybridize are able to achieve extensive fine- and coarse-scale breeding range overlap. In sum, these results suggest that interspecific territoriality has multiple origins and that interspecific territoriality and hybridization together can have striking impacts on species ranges.

scholarly journals Multiple routes to interspecific territoriality in sister species of North American perching birds

Evolution ◽  
2020 ◽  
Vol 74 (9) ◽  
pp. 2134-2148
Author(s):  
Madeline C. Cowen ◽  
Jonathan P. Drury ◽  
Gregory F. Grether
Keyword(s):  
North American ◽  
Sister Species ◽  
Interspecific Territoriality ◽  
Multiple Routes

scholarly journals The geography and ecology of plant speciation: range overlap and niche divergence in sister species

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132980 ◽  
Author(s):  
Brian L. Anacker ◽  
Sharon Y. Strauss
Keyword(s):  
Evolutionary Biology ◽  
Character Displacement ◽  
Sister Species ◽  
Fine Scale ◽  
Species Pairs ◽  
Shared Ancestry ◽  
Ecological Shifts ◽  
Range Overlap ◽  
Close Relatives ◽  
Age Range

A goal of evolutionary biology is to understand the roles of geography and ecology in speciation. The recent shared ancestry of sister species can leave a major imprint on their geographical and ecological attributes, possibly revealing processes involved in speciation. We examined how ecological similarity, range overlap and range asymmetry are related to time since divergence of 71 sister species pairs in the California Floristic Province (CFP). We found that plants exhibit strikingly different age-range correlation patterns from those found for animals; the latter broadly support allopatric speciation as the primary mode of speciation. By contrast, plant sisters in the CFP were sympatric in 80% of cases and range sizes of sisters differed by a mean of 10-fold. Range overlap and range asymmetry were greatest in younger sisters. These results suggest that speciation mechanisms broadly grouped under ‘budding’ speciation, in which a larger ranged progenitor gives rise to a smaller ranged derivative species, are probably common. The ecological and reproductive similarity of sisters was significantly greater than that of sister–non-sister congeners for every trait assessed. However, shifts in at least one trait were present in 93% of the sister pairs; habitat and soil shifts were especially common. Ecological divergence did not increase with range overlap contrary to expectations under character displacement in sympatry. Our results suggest that vicariant speciation is more ubiquitous in animals than plants, perhaps owing to the sensitivity of plants to fine-scale environmental heterogeneity. Despite high levels of range overlap, ecological shifts in the process of budding speciation may result in low rates of fine-scale spatial co-occurrence. These results have implications for ecological studies of trait evolution and community assembly; despite high levels of sympatry, sister taxa and potentially other close relatives, may be missing from local communities.

scholarly journals Extinction of North American Cuvieronius (Mammalia: Proboscidea: Gomphotheriidae) driven by dietary resource competition with sympatric mammoths and mastodons

Paleobiology ◽  
2020 ◽  
Vol 46 (1) ◽  
pp. 41-57
Author(s):  
Gregory James Smith ◽  
Larisa R. G. DeSantis
Keyword(s):  
North America ◽  
Late Pleistocene ◽  
North American ◽  
Resource Competition ◽  
Feeding Strategy ◽  
Atlantic Coastal Plain ◽  
Dental Microwear ◽  
Wide Range ◽  
Alternative Hypotheses ◽  
Abundance And Diversity

AbstractThe gomphotheres were a diverse and widespread group of proboscideans occupying Eurasia, North America, and South America throughout the Neogene. Their decline was temporally and spatially heterogeneous, and the gomphotheres ultimately became extinct during the late Pleistocene; however, the genus Cuvieronius is rarely represented in late Pleistocene assemblages in North America. Two alternative hypotheses have been invoked to explain this phenomenon: (1) competitive exclusion by sympatric mammoths and mastodons or (2) ecologic displacement due to an environmental transition from closed forests to open grasslands. To test whether competition for resources contributed to the demise of North American Cuvieronius, we present herein a large collection of stable isotope and dental microwear data from populations occupying their Pleistocene refugium in the Atlantic Coastal Plain. Results suggest that Cuvieronius consumed a wide range of resources with variable textural and photosynthetic properties and was not specialized on either grasses or browse. Further, we document evidence for the consumption of similar foods between contemporaneous gomphotheres, mammoths, and mastodons. The generalist feeding strategy of the gomphotheres likely facilitated their high Miocene abundance and diversity. However, this “jack of all trades and master of none” feeding strategy may have proved challenging following the arrival of mammoths and likely contributed to the extirpation of Cuvieronius in North America.

scholarly journals A Cross-sectional Survey of the North American Skull Base Society: Current Practice Patterns of Vestibular Schwannoma Evaluation and Management in North America

2017 ◽  
Vol 79 (03) ◽  
pp. 289-296 ◽  
Author(s):  
Jamie Van Gompel ◽  
R. Wiet ◽  
Nicole Tombers ◽  
Anand Devaiah ◽  
Devyani Lal ◽  
...  
Keyword(s):  
North America ◽  
Skull Base ◽  
Vestibular Schwannoma ◽  
North American ◽  
Management Practices ◽  
Current Practice ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Number Of Patients ◽  
Wide Range

Background Very few studies have examined vestibular schwannoma (VS) management trends across centers and between providers. The objective of this study is to examine current practice trends, variance in treatment philosophies, and nuanced or controversial aspects of VS care across North America. Methods This is a cross-sectional survey of North American Skull Base Society (NASBS) members who report regular involvement in VS care. Results A total of 57 completed surveys were returned. Most respondents claimed to have over 20 years of experience and the majority reported working in an academic practice with an affiliated otolaryngology and/or neurosurgery residency program. Sixty-three percent of respondents claimed to evaluate VS patients in clinic with both an otolaryngologist and neurosurgeon involved. Eighty-six percent of respondents claimed to operate on VS with both an otolaryngologist and neurosurgeon involved, while only 18% of neurosurgeons and 9% of otolaryngologists performed surgery alone. There was a wide range in the number of cases evaluated at each center annually. Similarly, there was wide variation in the number of patients treated with microsurgery and radiation at each center. Additional details regarding management preferences for microsurgery, stereotactic radiosurgery, stereotactic radiotherapy, and conservative observation are presented. Conclusion VS management practices vary between providers and centers. Overall, most centers employ a multidisciplinary approach to management with collaboration between otolaryngology and neurosurgery. Overall, survey responses concur with previous studies suggesting a shift toward conservatism in management.

scholarly journals North American channel catfish, Ictalurus punctatus: a neglected but potentially invasive freshwater fish species?

2021 ◽  
Vol 23 (5) ◽  
pp. 1563-1576 ◽  
Author(s):  
Phillip J. Haubrock ◽  
Gordon H. Copp ◽  
Iva Johović ◽  
Paride Balzani ◽  
Alberto F. Inghilesi ◽  
...  
Keyword(s):  
North America ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
North American ◽  
Disease Transmission ◽  
Native Species ◽  
Assessment Protocol ◽  
South Italy ◽  
Wide Range ◽  
North And South

AbstractThe North American channel catfish Ictalurus punctatus has been introduced to several locations in Europe but has received little or no scientific study despite its invasive attributes, including prolific reproduction, tolerance to a wide range of conditions, opportunistic feeding, at least partial ‘predator release’, and some evidence of environmental impacts (e.g. disease transmission). To assess the species’ potential invasiveness and the likely risks to native species and ecosystems in Europe, available literature from both North America and Europe was reviewed and used to carry out risk screenings of the species for the risk assessment areas, North and South Italy, using the Aquatic Invasiveness Screening Kit (AS-ISK), which was followed by a more detailed evaluation (for both North America and Europe) of the species’ potential impacts using the Environmental Impact Classification of Alien Taxa (EICAT) assessment protocol. The AS-ISK score indicated that channel catfish is likely to pose a high risk of being invasive in both North and South Italy, with EICAT scores indicating “Major” impacts for both North America and Europe, at high and medium confidence levels, respectively. The present results emphasise the urgent need to carry out in-depth studies on introduced populations of this species to understand better its invasive potential so as to inform management decisions on the appropriate control or eradication measures for invaded water bodies.

scholarly journals Seed conditioning of red oak: a recalcitrant North American seed

1998 ◽  
Vol 55 (spe) ◽  
pp. 67-73 ◽  
Author(s):  
D.K. Struve
Keyword(s):  
North American ◽  
Seed Quality ◽  
Quercus Rubra ◽  
Production Systems ◽  
Red Oak ◽  
High Quality ◽  
Stand Establishment ◽  
Conditioning Treatment ◽  
Wide Range ◽  
Seed Conditioning

A ten day aerated water soak was developed as a seed conditioning treatment for red oak (Quercus rubra L.). Conditioned seeds had higher germination completeness, uniformity and speed compared to control seeds. Seeds could be conditioned under a wide range of temperatures and durations. Conditioned seeds were maintained at 7(0)C for 30 days without loss of seed quality. During conditioning, pericarps split in response to seed hydration. Split pericarps could be used as a pre-sowing indicator for high quality seeds. Seed conditioning was ineffective on dormant seeds. Increased crop uniformity and higher stand establishment can be realized by subjecting red oak acorns to an aerated water soak treatment followed by selecting seeds with split pericarps. These results are especially important in container production systems where limited numbers of value seeds are available.

scholarly journals Tissue-specific cis-regulatory divergence implicates a fatty acid elongase necessary for inhibiting interspecies mating in Drosophila

2018 ◽  
Author(s):  
Peter A. Combs ◽  
Joshua J. Krupp ◽  
Neil M. Khosla ◽  
Dennis Bua ◽  
Dmitri A. Petrov ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Candidate Genes ◽  
Molecular Mechanisms ◽  
Sister Species ◽  
F1 Hybrids ◽  
Rna Seq ◽  
Fatty Acid Elongase ◽  
Tissue Specific ◽  
Regulatory Changes ◽  
Wide Range

AbstractPheromones known as cuticular hydrocarbons are a major component of reproductive isolation in Drosophila. Individuals from morphologically similar sister species produce different sets of hydrocarbons that allow potential mates to identify them as a suitable partner. In order to explore the molecular mechanisms underlying speciation, we performed RNA-seq in F1 hybrids to measure tissue-specific cis-regulatory divergence between the sister species D. simulans and D. sechellia. By focusing on cis-regulatory changes specific to female oenocytes, we rapidly identified a small number of candidate genes. We found that one of these, the fatty acid elongase eloF, broadly affects both the complement of hydrocarbons present on D. sechellia females and the propensity of D. simulans males to mate with those females. In addition, knockdown of eloF in the more distantly related D. melanogaster led to a similar shift in hydrocarbons as well as lower interspecific mate discrimination by D. simulans males. Thus, cis-regulatory changes in eloF appear to be a major driver in the sexual isolation of D. simulans from multiple other species. More generally, our RNA-seq approach proved to be far more efficient than QTL mapping in identifying candidate genes; the same framework can be used to pinpoint cis-regulatory drivers of divergence in a wide range of traits differing between any interfertile species.

scholarly journals Ongoing production of low-fitness hybrids limits range overlap between divergent cryptic species

2021 ◽  
Author(s):  
Else K. Mikkelsen ◽  
Darren Irwin
Keyword(s):  
First Generation ◽  
Sex Chromosome ◽  
Genomic Variation ◽  
F1 Hybrids ◽  
The Pacific ◽  
Species Pairs ◽  
Genetic Clusters ◽  
Range Overlap ◽  
Female Specific

AbstractContact zones between recently-diverged taxa provide opportunities to examine the causes of reproductive isolation and to examine the processes that determine whether two species can coexist over a broad region. The Pacific Wren (Troglodytes pacificus) and the Winter Wren (Troglodytes hiemalis) are two morphologically similar songbird species that started diverging about 4 million years ago, older than most sister species pairs. The ranges of these species come into narrow contact in western Canada, where the two species remain distinct in sympatry. To assess evidence for differentiation, hybridization, and introgression in this system, we examined variation in over 250,000 single nucleotide polymorphism markers distributed across the genomes of the two species. The two species formed highly divergent genetic clusters, consistent with long-term differentiation. In a set of 75 individuals from allopatry and sympatry, two first-generation hybrids (i.e., F1’s) were detected, indicating only moderate levels of assortative mating between these taxa. We found no recent backcrosses or F2’s or other evidence of recent breeding success of F1 hybrids, indicating very low or zero fitness of F1 hybrids. Examination of genomic variation shows evidence for only a single backcrossing event in the distant past. The sizeable rate of hybridization combined with very low fitness of F1 hybrids is expected to result in a population sink in the contact zone, largely explaining the narrow overlap of the two species. If such dynamics are common in nature, they could explain the narrow range overlap often observed between pairs of closely related species. Additionally, we present evidence for a rare duplication of a large chromosomal segment from an autosome to the W chromosome, the female-specific sex chromosome in birds.

Vehicle/Track Interaction Tests of Three Freight Vehicles on Revenue Service Tracks

2001 ◽  
Author(s):  
Dingqing Li ◽  
Semih F. Kalay ◽  
William Shust
Keyword(s):  
North American ◽  
Test Results ◽  
Track Geometry ◽  
Technology Center ◽  
Car Body ◽  
Operation Conditions ◽  
Wide Range ◽  
Vehicle Response ◽  
Freight Vehicles

Abstract Transportation Technology Center Inc. (TTCI), a subsidiary of the Association of American Railroads (AAR), conducted extensive vehicle/track interaction tests from 1998 to 2000 on revenue service tracks for three freight vehicles (covered hopper, tank car and coal gondola). During those tests, both track geometry and the corresponding vehicle response were collected simultaneously. All together, more then 1,400 miles of revenue tracks were tested on three North American railroads, covering a wide range of track and operation conditions. This paper presents the test results and findings in two main areas: how vehicle responses relate to measured track geometry conditions and how vehicle responses compare to the AAR Chapter XI (vehicle track worthiness) criteria. Vehicle response includes wheel/rail forces and L/V ratios via instrumented wheelsets, as well as car body accelerations. Track geometry conditions are characterized by curvature, superelevation, vertical surfaces, cross-level, lateral alignments, and gage.

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