Transcript Plant
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 QuickTime™ and a decompressor are needed to see this picture. QuickTime™ and a decompressor are needed to see this picture. 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