This study examined how proximity to sunflower crops affects the abundance and community structure of mutualists and antagonists of wild sunflowers, and how this alters natural selection on floral traits. The researchers found that mutualists like pollinators were more abundant near crops, while antagonists like seed predators were more abundant farther from crops. Natural selection on floral traits also differed between wild sunflowers near and far from crops, driven by changes in mutualist and antagonist communities with proximity to agriculture. This suggests agricultural landscapes can alter natural selection in native plant species.

1. Effects of agriculture on evolution of native species
Scott A. Chamberlain1, Kenneth D. Whitney2, and Jennifer A. Rudgers2
1 Simon Fraser University, Canada – 2 Rice University, USA
The Idea What did we find? What did we find?...
• Agriculture covers ~50% of vegetated land surface Predictions Results
4. Contribution of mutualists and antagonists to
• Evolution is altered in agricultural landscapes selection on native plant floral traits?
– Gene flow occurs from crops to wild relative plants Does proximity to crops alter:
– Evolution of resistance occurs in plants to GMOs 1. Abundance of mutualists and antagonists?
– Evolution of plants and insect pests in response to
Visits inflorescence-1
herbicides and peseticides
Abundance
• Yet, we know less of how natural selection is altered
min-1
in agricultural landscapes through species interactions
• Much evidence for altered biotic communities Far Near
• How do changes in abundance and community structure
of mutualists and antagonists near sunflower crops
Abundance
alter natural selection on flower traits in wild
sunflowers
Far Near
The Questions
Does proximity to crops alter: 2. Community structure of mutualists and antagonists?
1. Abundance of mutualists and antagonists?
2. Community structure of mutualists and antagonists?
3. Selection on native plant floral traits? What does it mean
4. Contribution of mutualists and antagonists to
Conclusions
selection on native plant floral traits? • Sunflower mutualists more abundant near,
antagonists more abundant far from crops
The Approach No difference for antagonists • Beta-diversity of mutualists greater near crops
Natural habitat • Natural selection altered by proximity to sunflower
Agricultural
crops
Other Crop
landscape [corn/sorghum/ • Changes in mutualist/antagonist communities drive
wheat/cotton]
differences in selection near vs. far from crops
Distance Far
~ 2.5 km
3. Selection on native plant floral traits? • This is one of few studies to show agricultural
effects on natural selection across a landscape in a
native plant species
Sunflower Crop
Distance
Implications
Near ≤ 10 m • Mutualist-antagonist framework may be useful in
Proximity to sunflowers (2 levels) understanding agricultural effects on plant evolution
X
Seed source (2 levels)
• Natural selection altered in agricultural landscapes,
BUT contrary to expectation
@ 5 sites in ‘10, @ 2 sites in ‘11
Data Collected
• Pollinators: pollinator observations Scott Chamberlain
• Seed predators: counted damaged seeds
scott.sfu@gmail.com - @recology_ QR Code
• Folivores: leaf damage
http://schamberlain.github.com/scott here