1. Plant defences and herbivore coexistence
Sara Magalhães
cE3c: Centre for Ecology, Evolution and Environmental changes
Faculdade de Ciências, Universidade de Lisboa

2. My scientific path
Arne Janssen & Mous Sabelis
University of Amsterdam
Ecological interactions in plant-herbivore food webs
Isabel Gordo
Instituto Gulbenkian de Ciência
Evolution of competing mutations in E. coli
Isabelle Olivieri
University of Montpellier
Evolution of host-plant use in spider mites

3. Current position Group leader Adaptation in heterogeneous environments
2008-Present

4. People who did the work
Diogo Godinho
Jéssica Paulo

5. Understanding complex communities
A “simplified” food web for the Northwest Atlantic

6. Food webs in agriculture
predatory mite
predatory bug
Food webs in agriculture
predatory mite
spider mite1
thrips
spider mite2
Plant

7. Food webs in agriculture
Plant
thrips
predatory mite
spider mite1
predatory bug
spider mite2
Predation

8. Food webs in agriculture
Plant
thrips
predatory mite
spider mite1
predatory bug
spider mite2
Competition

9. Three traits that define competitionB
Competitive ability C1 C2
Niche width A C R C1 B C2 A B
Niche construction C1 C2 R
These traits act simultaneously on species evolution and distribution.
These traits shape and are shaped by the evolution of organisms.

10. To understand complex communities we need to disentangle the relative role of traits that shape the evolution and distribution of competing populations in a simplified system
Just read it

11. The system Tetranychus urticae Tetranychus evansi Tomato plant B C1 C2

12. Competitive ability C1 B C2 C1 B C2
1 GEN

13. Niche width
Resource type
Resource used

14. Tomato, a metal-accumulating plant

15. The elemental defence hypothesis

16. Cadmium concentrations (μM)
Niche width
T. evansi
T. urticae Cd
Eggs / day
Cadmium concentrations (μM)

17. Plant ‘quality’: Sugar leaf content

18. Effect of mites on plant defences
Niche construction
Effect of mites on plant defences
Wild type
T. urticae
T. evansi
We will focus on niche construction, a trait that has been given much attention lately, and one that is particularly important for eco-evo feedbacks. In our system, one spider mite downregulates plant defences, such that the performance of all herbivores is better on preinfested plants than on clean plants. This is a clear example of niche construction. The other species upregulates plant defences, like most herbivores do.

19. Effect of mites on plant defences
Niche construction
Effect of mites on plant defences
Wild type
Def-1
T. urticae
T. evansi x
Importantly, in our system, we have a tomato mutant (def-1, for defenceless), which is similar to the wild-type plant in all aspects except that plant defences do not respond to infestation by herbivores. So the two environments differ exclusively in the possibility of mites to construct their niche. This property is unique to our system, and it thus represents an exceptional experimental tool. x

20. T. evansi performance on wild-type and def-1 plants
Eggs / day

21. Does niche construction vary with niche location?OR
How do organic and elemental defences interact?

22. Down- and up-regulation on plants with different cadmium concentrations

23. Experimental evolution. Mite generation time: 12-15 days
The questions
Individual differences
Coexistence between competitors
Competition traits
(Co)evolution with competitors
Our second question concerns how competitive traits shape and are shaped by coevolution with competitors.
To address this issue we will use the explanatory power of experimental evolution, in which populations evolve in controlled environments. This is made possible in our system by the short generation time of spider mites (at least 25 generations in one year).
Experimental evolution. Mite generation time: days

24. Major contributions of the project
Addresses key issues:
- How individual differences affects coexistence.
- Evolution of niche construction and its consequences.
An integrative view of how ecology and evolution shape competition.
Generating predictions for the role of competition in complex communities.
e.g. our recent work on plant-mite interactions: Calatayud et al PNAS