1. Herbivory

2. Herbivory Importance? Great! Affects plant distribution
Escape hypothesis: seed dispersal = escape herbivores
Seed shadow

3. Herbivory Why world green? What controls herbivores? Top-down control:
Bottom-up control:
Food chain
predators
herbivores
plants

4. Herbivory Tritrophic interactions: Plants use
Food chain
predators
Tritrophic interactions: Plants use
Ex, corn releases volatile
Volicitin (saliva) triggers VOC
Parasitic wasp
herbivores
plants

5. Herbivory Plant-plant communication
Ex, sagebrush (Artemisia tridentata) & wild tobacco (Nicotiana attenuata)
Damaged sagebrush lvs.

6. Herbivory
How plants handle herbivory?
1) Resistance:
2) Tolerance:

7. Plant defenses Physical Chemical Behavioral
Crypsis (camouflage/mimicry)
Associational

8. Plant defenses (Bottom-up)
1) Physical defenses:
A) pointy things
Spines?
Thorns?
Prickles?

9. Plant defenses
1) Physical defenses
B) trichomes (

10. Plant defenses 1) Physical defenses C) sharp cells: astrosclerids
Shadow Battlecrab:
Babylon 5
1) Physical defenses
C) sharp cells: astrosclerids

11. Plant defenses
2) Chemical defenses
A) organic defenses

12. Plant defenses 2) Chemical defenses A) organic defenses
1) indigestible carbohydrates (cell walls): cellulose & lignin

13. Plant defenses 2) Chemical defenses A) organic defenses
-ine!
2) Chemical defenses
A) organic defenses
2) toxins: small molecules, low dose
ex: alkaloids
(end -ine):
caffeine
cocaine
coca plant

14. Plant defenses 2) Chemical defenses A) organic defenses 2) toxins
ex: terpenes & terpenoids.

15. Plant defenses 2) Chemical defenses Ex: terpenes—pyrethroids
monoterpenes (10 carbons) from Chrysanthemum

16. Plant defenses 2) Chemical defenses A) organic defenses 2) toxins
ex: cyanogenic glycosides: release
Found in >2500 plant species!

17. Plant defenses 2) Chemical defenses A) organic defenses
3) digestibility reducers: large,
Bind proteins: digestive
ex, tannins (polyphenols)
phenol

18. Plant defenses 2) Chemical defenses B) elemental defenses: From
Silicon (Si): phytoliths cell walls

19. Plant defenses 2) Chemical defenses B) elemental defenses
Metal hyperaccumulation
Ex: >1,000 ppm dry weight Ni

20. Boyd in Africa!

21. Elemental Defense Senecio coronatus
Ni hyper. (12,100 µg Ni/g) & non-hyper. (680 µg Ni/g) pops. on serpentine
Test herbivore?

22. Elemental Defense Snails: choice high-Ni/ low-Ni leaf Mean % damage
Hyperaccumulator: 1.9%
Non-hyperaccumulator: 20%
Helix aspersa

23. Defense against pathogens
Ex, bacterium Xanthomonas campestris
Bioluminescence gene
Streptanthus polygaloides,
glowcolony
shaw

24. Defense against pathogens
Inoculate low-Ni S. polygaloides
Growth after 72 hr.
Ambient light
No light

25. Defense against pathogens
Inoculate high-Ni S. polygaloides
Growth after 72 hr.
Ambient light
No light

26. Plant defenses
3) Behavioral defenses: phenology

27. Plant defenses
3) Behavioral defenses:
shed

28. Plant defenses 4) Crypsis: look like
Biological version of “where’s waldo?”

29. Plant defenses
4) Crypsis: look like
Camouflage: look
Urban…

30. Plant defenses
4) Camouflage
stone plants (Lithops):

31. Plant defenses

32. Plant defenses
4) Camouflage
stone plants (Lithops):
Stone(d) plants

33. Plant defenses 4) Crypsis Mimicry: look Wasp Wasp mimics The Hair Band

34. Plant defenses 4) Mimicry Passiflora (passionflower) leaves
Heliconius:
Heliconius butterfly

35. Plant defenses
4) Mimicry
Passiflora egg mimics: