Herbivory Herbivory Importance Great Affects plant distribution Escape

Herbivory

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

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

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

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

Herbivory • How plants handle herbivory? – 1) Resistance: – 2) Tolerance:

Plant defenses 1) Physical 2) Chemical 3) Behavioral 4) Crypsis (camouflage/mimicry) 5) Associational

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

Plant defenses • 1) Physical defenses – B) trichomes (

Plant defenses • 1) Physical defenses – C) sharp cells: astrosclerids Shadow Battlecrab: Babylon 5

Plant defenses • 2) Chemical defenses • A) organic defenses

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

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

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

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

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

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

Plant defenses • 2) Chemical defenses – B) elemental defenses: From – Silicon (Si): phytoliths cell walls

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

Boyd in Africa!

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

Elemental Defense • Snails: choice high-Ni/ low-Ni leaf • Mean % damage – Hyperaccumulator: 1. 9% – Non-hyperaccumulator: 20% Helix aspersa

Defense against pathogens • Ex, bacterium Xanthomonas campestris – Bioluminescence gene – Streptanthus polygaloides, glowcolony shaw

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

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

Plant defenses • 3) Behavioral defenses: phenology

Plant defenses • 3) Behavioral defenses: – shed

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

Plant defenses • 4) Crypsis: look like • Camouflage: look Urban…

Plant defenses • 4) Camouflage – stone plants (Lithops):

Plant defenses

Plant defenses • 4) Camouflage – stone plants (Lithops): Stone(d) plants

• 4) Crypsis Plant defenses – Mimicry: look Wasp mimics Wasp The Hair Band W. A. S. P.

• 4) Mimicry Plant defenses – Passiflora (passionflower) leaves – Heliconius: Heliconius butterfly

• 4) Mimicry Plant defenses – Passiflora egg mimics: