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A Multitrophic Interaction between a Fly, a Fungus and Orchardgrass in the Willamette Valley Undergraduate Researcher: Denise Baumann Mentor: Dr. Sujaya.

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Presentation on theme: "A Multitrophic Interaction between a Fly, a Fungus and Orchardgrass in the Willamette Valley Undergraduate Researcher: Denise Baumann Mentor: Dr. Sujaya."— Presentation transcript:

1 A Multitrophic Interaction between a Fly, a Fungus and Orchardgrass in the Willamette Valley Undergraduate Researcher: Denise Baumann Mentor: Dr. Sujaya Rao Oregon State University Summer 2003

2 Orchardgrass in the Willamette Valley Dactylis glomerata Dactylis glomerata Approx. 20,000 acres in the Willamettte Valley Seed Crop Forage Crop

3 Structure of Grass Single grass plant Seed Stalk Tillers Blade (leaf) Seed Head

4 Endophyte Association Single grass plant Seed Stalk Tillers Fungal Stroma Endophytic Fungi

5 + ++ + -- - - -- - - Spermatial Transfer (Egg Deposition) Sexual Development of the Fungus (Egg Hatch) (Larval Feeding) Harvest (Pupae Formation) Overwintering & New growth in Spring (Adult Emergence)

6 Choke in orchardgrass (Epichloe typhina) Unfertilized Fertilized Fungus Fungal Stoma

7 Past Research Bultman and White (midwest) Trials carried out in the wild (isolated grass plants) Trials carried out in the wild (isolated grass plants) 0-7 larvae per fungal stroma 0-7 larvae per fungal stroma 63.8 % of stromata collected had 1 larva only and less than 6% had >3 larvae per stroma 63.8 % of stromata collected had 1 larva only and less than 6% had >3 larvae per stroma Stomata with mesh bag had NO perithecia; uncovered stromata had 86.6 % perithecia Stomata with mesh bag had NO perithecia; uncovered stromata had 86.6 % perithecia Fly is necessary for fungal fertilization

8 Hypothesis In this fly-fungal interaction in orchardgrass in the Willamette Valley, the fly is not the sole factor for fungal fertilization.

9 Objective One To determine whether this fly- fungal interaction is mutualistic. To determine whether this fly- fungal interaction is mutualistic. Two treatments 1. Fly physically excluded, spore allowed 2. Control (no exclusion)

10 1 2 3 4 5 6 7 8 9 10

11 Objective One Research Plot on Peoria Rd.

12 Results Treatment% Fertilization Exclusion (Fly Only) 56% ns No Exclusion69% ns Conclusion: The fly is not necessary for fungal fertilization in a grass field setting here in the Willamette Valley. ns = no significant difference

13 Objective Two Surveying orchardgrass in the Willamette Valley to determine the presence of the fly. Surveying orchardgrass in the Willamette Valley to determine the presence of the fly.

14 Orchardgrass Sites Benton Co. Linn Co. Lane Co. SR Corvallis HPLR CH WD AD KR IB PR ND RR3 RR2 RR1

15

16 Results 0-10 larvae per fungal stroma 0-10 larvae per fungal stroma 49.2 % of stromata collected had 1 larva/stroma and 15 % had >3 larva/stroma 49.2 % of stromata collected had 1 larva/stroma and 15 % had >3 larva/stroma When 10 larvae were present, >90% of the fertilized stroma was consumed When 10 larvae were present, >90% of the fertilized stroma was consumed 100 % of stromata fertilized irrespective of larval presence 100 % of stromata fertilized irrespective of larval presence

17 Results continued… % Perithecial development at 3 sites SR = 94% (Average of.62 larva/stroma) SR = 94% (Average of.62 larva/stroma) CH = 97% (no fly found at this site) CH = 97% (no fly found at this site) RR1 = 95.7% (Average of 4.16 larva/stroma) RR1 = 95.7% (Average of 4.16 larva/stroma)

18 In Comparison… Past Research Past Research 1. Stated that the fly was obligatory for fungal fertilization 2. 63.8% of stromata collected had 1 larva only and less than 6% had >3 larvae per stroma 3. Without presence of the fly 0% fungal stroma developed perithecia My Research My Research 1. Shows that there may be other factors besides the fly fertilizing the fungus here in the Valley 2. 49.2% of stromata collected had 1 larva/stroma and 15% had >3 larva/stroma 3. 100% of fungal stroma developed perithecia irrespective of fly presence

19 Final Summation It appears the fly benefits from this interaction in the Willamette Valley; however it is unclear whether there is a positive or negative effect on the fungus.

20 Future Research Preference Studies Preference Studies Fungal host preferences by the fly Fungal host preferences by the fly Isolation trials Isolation trials How does fertilization occur? How does fertilization occur? Other factors of fungal fertilization Other factors of fungal fertilization Wind, other insects, etc.? Wind, other insects, etc.?

21 Acknowledgements Howard Hughes Medical Institute (HHMI) Howard Hughes Medical Institute (HHMI) Undergraduate Research Innovation, Scholarship, Creativity (URISC) Undergraduate Research Innovation, Scholarship, Creativity (URISC) Sujaya Rao, Jon Umble, Devorah Shamah, Bill Pfender, Steve Alderman, Mark Mellbye, Glenn Fisher, Lynn Royce Sujaya Rao, Jon Umble, Devorah Shamah, Bill Pfender, Steve Alderman, Mark Mellbye, Glenn Fisher, Lynn Royce Orchardgrass Growers, especially James VanLeeuwen Orchardgrass Growers, especially James VanLeeuwen

22 Questions?


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