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

The Approach

What did we find?

What does it mean?

•  Agriculture covers ~50% of vegetated land surface

•  Evolution is altered in agricultural landscapes –  Gene flow occurs from crops to wild relative plants

–  Evolution of resistance occurs in plants to GMOs

–  Evolution of plants/insects to herbicides/pesticides

•  Yet, we know less of how natural selection is altered in agricultural landscapes through species interactions

•  There is much evidence for altered biotic communities

•  How do changes in abundance and community structure of mutualists and antagonists near sunflower crops alter natural selection on flower traits in wild sunflowers?

Does proximity to crops alter:

1. Abundance of mutualists and antagonists? 2. Community structure of mutualists and antagonists? 3. Selection on native plant floral traits? 4. Contribution of mutualists and antagonists to selection on native plant floral traits?

Conclusions •  Sunflower mutualists more abundant near,

antagonists more abundant far from crops •  Beta-diversity of mutualists greater near crops •  Natural selection altered by proximity to sunflower

crops •  Changes in mutualist/antagonist communities drive

differences in selection near vs. far from crops •  This is one of few studies to show agricultural

effects on natural selection across a landscape in a native plant species

Implications •  Mutualist-antagonist framework may be useful in

understanding agricultural effects on plant evolution •  Natural selection altered in agricultural landscapes,

BUT contrary to expectation

The Questions

Does proximity to sunflower crops alter:

1. …abundance of mutualists and antagonists?

2. …community structure of mutualists and antagonists?

3. …selection on native plant floral traits?

Does proximity to sunflower crops alter:

4. …contribution of mutualists and antagonists to selection on native plant floral traits?

Scott Chamberlain scott.sfu@gmail.com t: @recology_ http://schamberlain.github.com/scott

Far Near

Abundance

Visits inflorescence

-1

min

-1

Far Near

Abundance

…what did we find?

No difference for antagonists

Sunflower Crop

Near

Far

Distance ≤ 10 m

Distance ~ 2.5 km

Agricultural landscape

Other Crop [corn/sorghum/wheat/cotton]

Natural habitat

Proximity to sunflowers (2 levels) X

Seed source (2 levels) @ 5 sites in ‘10, @ 2 sites in ‘11

Data Collected •  Pollinators: pollinator observations •  Seed predators: counted damaged seeds •  Folivores: leaf damage

Floral  traits   Inflor.  traits  

Iso  sp.   N.  hel.   Pollen  

Fitness  

-­‐0.06   0.004  Site  1  2011  

Site  2  2011  

Far   Near  Floral  traits   Inflor.  traits  

Iso  sp.   N.  hel.   Pollen  

Fitness  

Floral  traits   Inflor.  traits  

Iso  sp.   N.  hel.   Pollen  

Fitness  

0.002   -­‐0.01  

Floral  traits   Inflor.  traits  

Iso  sp.   N.  hel.   Pollen  

Fitness  N. Helianthi a

bundance

Mutualists more abundant near, antagonists more abundant far from crops

Silhouettes from phylopic.org

Beta-diversity of mutualists greater near crops

Natural selection altered by proximity to sunflower crops, and more variable near sunflower crops

= the take-home message

Predictions Results

Predictions Results

Changes in mutualist/antagonist communities drive differences in selection near vs. far from crops