Download REU2011 - University of Virginia

Plant - Insect Interactions
Seeing The Universe
From An Insect’s Perspective
T’ai Roulston
The problems faced by animals that eat plant products
Get Food
Find Mates
Avoid Being Eaten
The problems faced by plants
Get Pollinated
Disperse Seeds
Avoid Being Eaten
How Insects Affect Plants
Pollination
Positive
Insect
Plant
Negative
Herbivory
How Insects Affect Plants
Seed dispersal
Photo:Benoit Guenard
Positive
Insect
Plant
Negative
Frugivory - seed
destruction
How Insects Affect Plants
Predation/
Parasitism
Positive
Insect
Negative
Plant
How Insects Affect Plants
jeffcogardener.blogspot.com
Positive
Insect
Plant
Negative
Anti-predator
defense
Photo: Marin Rice
cirrusimage.com
How Insects Affect Plants
Positive
Insect
Plant
Negative
Spread disease
Photo: Jude Boucher
squash bugs
Cucurbit Yellow Vine Disease
Net Effect = Sum of Interactions
Insect 1
Insect 3
Plant Performance
Insect 4
Insect 2
Implications for both agriculture and ecosystems
Physalis longifolia study system
Mary McCauley, Berea College (2004); Maggie Triska, Viterbo University (2005);
Jacob Elstein, Virginia Tech (2005); Cedric Jones, Howard University (2006);
Brandon Lingbeek, Calvin College (2007); Linnea Meier, Earlham College (2008);
Alysia Soper, Luther College (2008); Ricky Rivera, UPR-Bayamon (2009); Stephanie
Cruz-Maysonet, UPR-Bayamon (2010)
Generalists
Stored
Energy
Flower
Production
Fruit
Induction
Specialist
Fruit
Maturation
Seed
Production
Why might specialists be important?
Generalist foraging strategy when
several acceptable hosts
Specialist foraging strategy or generalist strategy
if the generalist acts as a temporary specialist
Tracking Pollinators
• Recapture and movement of specialist
and generalist pollinators of Physalis
during 2004 and 2005
Type
Specialist
Generalists
Specialist*
Generalists*
# marked # recaptured
proportion
# movements
76
21(53)
0.28
16
24
0
0
0
82
27(43)
0.33
1
58
0
0
0
Plot Visits per Survey Hour for Each Species
Visits per Survey Hour
7
July 7-14, 2004
July 15-22, 2004
July 23-30, 2004
6
5
4
3
2
1
0
Colletes Lasiogl.
Augochl. Epeolus Bombus
Number of flowers visited per plot visit per species
Flowers visited per plot visit
6
5
4
3
2
1
0
Colletes
Augochl
Lasiogl.
Species
Epeolus
Proportion Fruits Initiated from Single Visits
Fruit Initiation From Single Visits
1.0
p < 0.05
0.8
0.6
0.4
0.2
0.0
Colletes
Lasioglossum
Augochlorinae
Pollinator Conclusions
The specialist prevails in
abundance
flowers visited
pollination efficiency
pollen dispersal
Pollinators
Pollen Deposition
Stored
Energy
Flower
Production
Fruit
Induction
Fruit
Maturation
Seed
Production
Initially Interested in Pollination
What Governs Presence of Herbivore?
Proportion Yearly Total
0.5
Lema daturaphila larvae
0.4
0.3
Flowering
0.2
0.1
0.0
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18
Week
Susceptible Genotypes? Induced defenses?
Predation?
Survival to Mature Larva of 10 Lema
Placed on 10 Caged and 10 Uncaged Plants
NOTE TO SELF --THESE
PICTURES DO NOT DISPLAY
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are needed to see this picture.
QuickTime™ and a
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REU student Brandon Lingbeek
QuickTime™ and a
decompressor
are needed to see this picture.
One cause of mortality to Lema eggs
Q1: Early season decline not explained by late season
predators or parasites.
Nocturnal predators? Plant is saved by whatever is controlling
early herbivores.
Interaction web for
Physalis longifolia
Parasitism
Pollen Deposition
Stored
Energy
Flower
Production
Fruit
Maturation
Fruit
Induction
Seed
Production
Frugivory
Foliar Herbivory
Predation
Parasitism
Development of Symmetrischema sp.
Interaction web for
Physalis longifolia
Parasitism
Pollen Deposition
Florivory
Stored
Energy
Flower
Production
Fruit
Maturation
Fruit
Induction
Seed
Production
Frugivory
Foliar Herbivory
Predation
Parasitism
Part 2. How Do Plants Affect Insects?
Bee Diversity and Plant Utilization Patterns
20,000 spp worldwide 140 (so far) at Blandy
Center of Diversity: arid areas –southwestern USA, Mediterranean
Diet: pollen and nectar
Development of the sweat bee Lasioglossum zephyrum
Variation in Pollen Chemistry
Constituent
Max
Min
% Starch
23.7
0
Calories/g
6750
4407
% Protein
60
Amino acid variation: ??
Toxicity??
2.5
Ongoing Research: Understand the plant traits that influence
insect foraging decisions, and the results of those foraging
decisions on insect development
What Is Known About Pollen - Bee Interactions?
Extremely important
Pollen varies in many ways
Bees make flower choices based on
accessibility
nectar reward
floral color
floral odor
Q2:
Do bees recognize quality and adjust choice?
What are the characteristics of quality?
What plants (either natives or invasives) may best support
wild pollinator populations?
Specific Possible Avenues for Inquiry
Herbivory on wild tomatillo:
What early season factors protect the plant
from an enemy that could destroy all of it?
Foraging Cues:
What pollen traits influence larval development and body size
in bees? Do bees recognize them?
The End
Research Areas
Why pollinators choose the plants they do
Nutritional quality of pollen
The implications of foraging choices of pollinators
on success of their host plants
Why herbivores choose their host plants
What governs herbivore populations
Potential Applications
Understanding how to promote wild pollinators in agriculture
Understanding ecosystem level processes to control pests