scholarly journals The role of hybridization during ecological divergence of southwestern white pine (Pinus strobiformis) and limber pine (P. flexilis)

2017 ◽  
Author(s):  
Mitra Menon ◽  
Justin C. Bagley ◽  
Christopher Friedline ◽  
Amy V. Whipple ◽  
Anna W. Schoettle ◽  
...  
Keyword(s):  
Gene Flow ◽  
Hybrid Zone ◽  
Ecological Niche Modeling ◽  
Life History Strategies ◽  
Species Boundaries ◽  
Disruptive Selection ◽  
Hybrid Index ◽  
Extrinsic Factors ◽  
Intrinsic Factors ◽  
Demographic Modeling

AbstractInteractions between extrinsic factors, such as disruptive selection, and intrinsic factors, such as genetic incompatibilities among loci, can contribute to the maintenance of species boundaries. The relative roles of these factors in the establishment of reproductive isolation can be examined using species pairs characterized by gene flow throughout their divergence history. We investigated the process of speciation and the maintenance of species boundaries between Pinus strobiformis and P.flexilis. Utilizing ecological niche modeling, demographic modeling, and genomic cline analyses, we illustrated a history of divergence with continuous gene flow between these species. We found an abundance of advanced generation hybrids and a lack of loci exhibiting large allele frequency differences across the hybrid zone. Additionally, we found evidence for climate-associated variation in the hybrid index and niche divergence between parental species and the hybrid zone. Our results are consistent with extrinsic factors, such as climate, being an important isolating mechanism for these species. A buildup of intrinsic incompatibilities and of co-adapted gene complexes is also apparent in our results, although these appear to be in the earliest stages of development. This supports previous work in coniferous species demonstrating the importance of extrinsic factors in creating and enforcing species boundaries. Overall, we lend support to the hypothesis that varying strengths and directions of selection pressures across the long lifespans of conifers, in combination with their life history strategies, delay the evolution of strong intrinsic incompatibilities.

scholarly journals Selection and gene flow define polygenic barriers between incipient butterfly species

2020 ◽  
Author(s):  
Steven M. Van Belleghem ◽  
Jared M. Cole ◽  
Gabriela Montejo-Kovacevich ◽  
Caroline N. Bacquet ◽  
W. Owen McMillan ◽  
...  
Keyword(s):  
Gene Flow ◽  
Recombination Rate ◽  
Genomic Variation ◽  
Species Boundaries ◽  
Secondary Contact ◽  
Butterfly Species ◽  
Demographic Modeling ◽  
Incipient Species ◽  
Genome Wide ◽  
Genomic Divergence

AbstractCharacterizing the genetic architecture of species boundaries remains a difficult task. Hybridizing species provide a powerful system to identify the factors that shape genomic variation and, ultimately, identify the regions of the genome that maintain species boundaries. Unfortunately, complex histories of isolation, admixture and selection can generate heterogenous genomic landscapes of divergence which make inferences about the regions that are responsible for species boundaries problematic. However, as the signal of admixture and selection on genomic loci varies with recombination rate, their relationship can be used to infer their relative importance during speciation. Here, we explore patterns of genomic divergence, admixture and recombination rate among hybridizing lineages across the Heliconius erato radiation. We focus on the incipient species, H. erato and H. himera, and distinguish the processes that drive genomic divergence across three contact zones where they frequently hybridize. Using demographic modeling and simulations, we infer that periods of isolation and selection have been major causes of genome-wide correlation patterns between recombination rate and divergence between these incipient species. Upon secondary contact, we found surprisingly highly asymmetrical introgression between the species pair, with a paucity of H. erato alleles introgressing into the H. himera genomes. We suggest that this signal may result from a current polygenic species boundary between the hybridizing lineages. These results contribute to a growing appreciation for the importance of polygenic architectures of species boundaries and pervasive genome-wide selection during the early stages of speciation with gene flow.

Institutional Environment, Entrepreneurial Self-Efficacy and Entrepreneurial Intention of Company Employees

1970 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Devi Angrahini Anni Lembana ◽  
Yu Yu Chang ◽  
Wen Ke Liang
Keyword(s):  
Self Efficacy ◽  
Institutional Environment ◽  
Practical Experience ◽  
Entrepreneurial Intention ◽  
Entrepreneurial Intentions ◽  
New Venture ◽  
Hierarchical Regression ◽  
Market Demand ◽  
Extrinsic Factors ◽  
Intrinsic Factors

From the intentionality-based view, individuals' actual behaviors to initiate a new venture is driven by their entrepreneurial intentions. Company employees have accumulated professionalism and practical experience, which both enable them to discover some unmet market demand and industrial gaps. However, in establishing a new business, not everyone with certain knowledge or expertise has the desire to become an entrepreneur. Prior research has shown that entrepreneurial intentions are under the profound influences of intrinsic factors and extrinsic factors. On the one hand, entrepreneurial self-efficacy is one of the key psychological states that makes someone dare to initiate entrepreneurial activities. Institutional environment, on the other hand, can either enhance and hinder an individuals' entrepreneurial motivation by offering incentives or causing barriers. Little work has been done to understand how the institutional environment and entrepreneurial self-efficacy jointly affect company employees' intention to quit their job and start an enterprising career. By using hierarchical regression on a sample of 325 Indonesian company employees, this paper shows that the entrepreneurial cognition and entrepreneurial self-efficacy are positively related to employees' entrepreneurial intentions. Also, entrepreneurial self-efficacy strengthens the effect of normative Approval on entrepreneurial intention, whereas the regulatory Support from Government is detrimental to company employees' intention to start a new venture regardless the entrepreneurial self-efficacy is high or low.

scholarly journals Modulation of odour-guided behaviour in mosquitoes

2021 ◽  
Vol 383 (1) ◽  
pp. 195-206
Author(s):  
Sharon R. Hill ◽  
Rickard Ignell
Keyword(s):  
Functional Genomics ◽  
Life Stage ◽  
Blood Feeding ◽  
Model Systems ◽  
Extrinsic Factors ◽  
Intrinsic Factors ◽  
Host Seeking ◽  
Enhancing Resources ◽  
Maturation Age ◽  
Behavioural Repertoire

AbstractMosquitoes are emerging as model systems with which to study innate behaviours through neuroethology and functional genomics. Decades of work on these disease vectors have provided a solid behavioural framework describing the distinct repertoire of predominantly odour-mediated behaviours of female mosquitoes, and their dependence on life stage (intrinsic factors) and environmental cues (extrinsic factors). The purpose of this review is to provide an overview of how intrinsic factors, including adult maturation, age, nutritional status, and infection, affect the attraction to plants and feeding on plant fluids, host seeking, blood feeding, supplemental feeding behaviours, pre-oviposition behaviour, and oviposition in female mosquitoes. With the technological advancements in the recent two decades, we have gained a better understanding of which volatile organic compounds are used by mosquitoes to recognise and discriminate among various fitness-enhancing resources, and characterised their neural and molecular correlates. In this review, we present the state of the art of the peripheral olfactory system as described by the neural physiology, functional genomics, and genetics underlying the demonstrated changes in the behavioural repertoire in female mosquitoes. The review is meant as a summary introduction to the current conceptual thinking in the field.

scholarly journals Landscape Characteristics Based on Effectiveness of Wildlife Crossing Structures in South Korea

2021 ◽  
Vol 13 (2) ◽  
pp. 675
Author(s):  
Hyunjin Seo ◽  
Chulhyun Choi ◽  
Kyeongjun Lee ◽  
Donggul Woo
Keyword(s):  
Landscape Management ◽  
Spatial Pattern Analysis ◽  
Extrinsic Factors ◽  
Intrinsic Factors ◽  
Landscape Characteristics ◽  
Crossing Structures ◽  
Significant Difference ◽  
Management Plans ◽  
Wildlife Crossing Structures ◽  
Surrounding Landscape

Roads are notable and responsible for the loss of biodiversity and disruption of wildlife habitats connectivity. Wildlife crossing structures (WCS) help wildlife move between habitats by connecting fragmented habitats. Their effectiveness is affected by various factors. Here, to identify methods for improving the effectiveness of wildlife crossing structures, we controlled the effect of intrinsic factors, such as size, that are difficult to improve in an already installed area, and then, evaluated the differences in extrinsic factors using 12 landscape characteristics. Our results show that 18 wildlife crossing structures were selected with propensity-score (PS) matching method. The surrounding landscape characteristics differed between high-effectiveness wildlife crossing structures and low-effectiveness wildlife crossing structures. Particularly, there was a significant difference between the ‘statutory protected area’ and the ‘edge’ index of the morphological spatial pattern analysis among the landscape characteristic variables derived within 1 km2 of wildlife crossing structures. We empirically demonstrate that characteristics around highly effective WCS, statutory protected areas are widely distributed, and the ratio of edge of MSPA is low (within 1 km2). Therefore, an important outcome of our research is the demonstration that management of WCS itself is important, but conservation of surrounding habitats and landscape management plans are also significant.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

The Use of Protein Electrophoresis for Determining Species Boundaries in Amphipods

Crustaceana ◽  
1993 ◽  
Vol 65 (2) ◽  
pp. 265-277 ◽  
Author(s):  
Barbara A. Stewart
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Morphological Variation ◽  
Protein Electrophoresis ◽  
Species Boundaries ◽  
Allopatric Populations ◽  
A Value ◽  
Electrophoretic Data

AbstractThe use of protein electrophoretic data for determining species boundaries in amphipods is addressed. Analysis of published literature on genetic differentiation in amphipods showed that pairs of allopatric populations which have genetic identities (I) above a value of 0.85 probably represent intraspecific populations, whereas pairs of populations which have genetic identities below about 0.45 probably represent different species. It was recommended that if I values fall between 0.45 and 0.85, additional factors such as evidence of a lack of gene flow between the populations, and concordant morphological variation should be considered.

Foraging behavior and predation success of the sand viper (Cerastes vipera)

2009 ◽  
Vol 87 (6) ◽  
pp. 520-528 ◽  
Author(s):  
Aziz Subach ◽  
Inon Scharf ◽  
Ofer Ovadia
Keyword(s):  
Length Ratio ◽  
Annual Rainfall ◽  
Activity Levels ◽  
Extrinsic Factors ◽  
Hunger Level ◽  
Intrinsic Factors ◽  
Thermal Range ◽  
Capture Success ◽  
Study Sites ◽  
Consequent Increase

Activity levels and foraging success of ectotherms are dependent both on extrinsic factors (e.g., ambient temperature) and intrinsic factors (e.g., hunger level). We focus here on activity and foraging of sand vipers ( Cerastes vipera (L., 1758)) (Squamata: Viperidae) in the northwestern Negev desert of Israel. Viper activity is bounded by a specific thermal range, but within this range, temperature does not affect the distance moved. Movement distances are, however, positively correlated with relative humidity. The capture success of lizards, the main prey of this viper, is strongly related both to movement distances of the snake and to the number of the lizard burrows scanned. Body size and shape have a direct effect on the number of burrows scanned and on the number of lizards captured. The increase in capture success with size is probably due to the consequent increase in the range of prey items the sand viper can subdue or handle. Vipers are larger and have a higher mass to length ratio in one of the three study sites, characterized by higher mean annual rainfall and vegetation cover. Finally, females tend to have a higher mass to length ratio than males, which may provide some space within the female body for reproductive materials such as eggs.

scholarly journals Formation of a recent hybrid zone offers insight into the geographic puzzle and maintenance of species boundaries in musk turtles

2019 ◽  
Vol 28 (4) ◽  
pp. 761-771 ◽  
Author(s):  
Peter A. Scott ◽  
Travis C. Glenn ◽  
Leslie J. Rissler
Keyword(s):  
Hybrid Zone ◽  
Species Boundaries ◽  
Insight Into

Individual Variation in the Strength of Territory Defense in Male Song Sparrows: Correlates of Age, Territory Tenure, and Neighbor Aggressiveness

Behaviour ◽  
2004 ◽  
Vol 141 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Jeremy Hyman ◽  
Melissa Hughes ◽  
Stephen Nowicki ◽  
William Searcy
Keyword(s):  
Individual Differences ◽  
Reproductive Success ◽  
Extrinsic Factors ◽  
Territory Defense ◽  
Intrinsic Factors ◽  
Territorial Aggression ◽  
Male Song ◽  
Song Sparrows ◽  
Territory Owner ◽  
Older Males

AbstractIn many species, the ability to defend a territory is essential for a male to obtain any reproductive success at all, and even among territorial individuals, variation in the strength of territory defense could have a significant impact on how much reproductive success is obtained. Previous studies have documented consistent individual differences in the vigor with which male song sparrows (Melospiza melodia) defend their territories, as measured by the strength of their reactions to territorial intrusions simulated through song playback. Variation in the strength of defense could reflect intrinsic differences among individuals in their resource holding potential (RHP), or variation in extrinsic factors. In this study, we examined whether variation in the strength of territory defense corresponds to differences in intrinsic factors such as the age or experience of the territory owner, the extrinsic factor of the level of aggression shown by neighbours, or both. Results indicate that males that previously held territories on the study site, regardless of whether they were holding the same territory as the previous year, show higher levels of territory defense than males that are new to the study site, and, assuming that returning males are older males, suggest that age is more important than experience on a specific territory in determining strength of territory defense. In addition, we found evidence that males with high levels of territorial aggression tend to be spatially clustered. The pattern observed suggests that a combination of intrinsic and extrinsic factors contribute to the expression of individual differences in territorial aggression.

Sign in / Sign up

Export Citation Format

Share Document