Transcript Correlation of Spray Patterns with Droplet Size for Pressurized

Evolutionary Aspects of Invasion
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Overview
Summary of Papers
General Themes
Summary
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Summary of Lee Paper: Evolutionary genetics of invasive species
Various genetic changes can improve a species ability to respond to
natural selection, and consequently to adapt and invade.
Genetic characteristics, such as gene interaction, expression and
rearrangement enable the evolutionary process.
Following invasion, evolutionary process continues, selecting in
response to local environmental conditions and species.
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Summary of Mooney and Cleland: Evolutionary impact of
invasive species
Evolutionary effects of changing biotas (species introductions,
invasives).
Invaders respond evolutionarily in response to the new
environment and the new species.
As evolution influences success of new species, the change in its
abundance can also prompt the evolution of other community
populations in response.
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Summary of Petit: Biological invasions at the gene level
Considering the gene rather than the species may be more
informative and appropriate.
Exotic gene flow is not restricted to exotic seed flow.
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General Themes
1. Genetics of Invasion
2. Mechanisms for Evolution in Invasive Species
3. Evolutionary Responses in Local Species
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1. Genetics of Invasion
Broad Interpretation:
The more variation, the higher the chance of success, improved fitness
Genetic components of natural selection:
Additive genetic variance (AGV)
The proportion of variance that is due to the additive component of
allelic effects
AGV is the most important component affecting selection because it
predicts how well phenotype is transferred from parent to offspring
Additional explanation for observed tolerance and plasticity:
Copepod complex Eurytemora affinis
Observed lag time
Epistasis: interaction between gene loci resulting in a unique effect on
phenotype
Lee
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1. Genetics of Invasion (cont…)
Genomic rearrangements: chromosomal inversions
Associated with temperature gradient, latitude
Fitness tradeoffs: various environments can create distinct races
based on pre-existing fitness tradeoffs
Fly larvae, Rhagoletis pomonella
Influence of particular genes: one or a few genes can have great
impact
Fire ant, Solenopsis invicta
Lee
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1. Genetics of Invasion (cont…)
Hybridization:
Increased genetic variation
new gene interactions
masking of deleterious alleles
acquisition of favorable genes
Genetically engineered crops conveying herbicide resistance to non-crops.
Lee, Mooney, Petit
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1. Genetics of Invasion (cont…)
Gene flow in plants:
Pollen from the male estimated dispersal is an order of magnitude greater
than seed flow. Though seed dispersal is limited to a degree; pollen
flow is much less
Mix of foreign and local genes facilitates introduction of the invading genes
Hybrid soup: the many combinations
Inter- and intraspecific hybridization- both contaminate the local gene pool
Cryptic invasions: detectable?
European hazelnut, Corylus avellana
The case for considering the gene rather than the species regarding
invasions
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Petit
2. Mechanisms for Evolution in Invasive Species
As a result of genetic variance, populations are able to evolve local
adaptations to new environments-
Selection on dispersal (Butterfly, Pararge aegeria) and tolerance to site
conditions
Once established, populations can evolve in response to
Local environmental conditions: Light, climate, pH
Resident species: predators, prey and competitors
crop mimic; predator release
Lee
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2. Mechanisms for Evolution in Invasive Species (cont..)
Respond with changes in:
Phenology (Goldenrods, Solidago altissima and S. Gigantea)
Morphology (fruit fly wing size cline)
Physiology
Plasticity (Velvetleaf, Abutilon theophrasti)
Lee
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3. Evolutionary Responses in Local Species
Traits change: soapberry bug, Jadera hematoloma
Behavioral change: Euphydras butterfly
Niche displacement: 250 new species in the Mediterranean Sea
Competitive exclusion
Mutualism
Host switching
Extinctions (Introgression, competitive exclusion…)
Mooney
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Possible Invasion
Facilitators and
Interactions
Community
Effects
Expansion/
Invasion
Increased
AGV
Local Population
Gene Changes
Introduction
Hybridization
Establishment
Increased
AGV
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Expansion/
Invasion
Questions
How does the rate of species introductions affect the interactions
and outcomes?
How is the mixing of species and gene pools different than
historic invasions (glacial retreat after the ice age, etc)?
Are these evolutionary processes any different for native
species? Non-invasives?
If population genetics do affect the likelihood of invasiveness,
what are the implications for predicting invasiveness?
How does human activity influence the genetic structure of
populations?
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