Presentation on theme: "Undergraduate Researcher: Denise Baumann Mentor: Dr. Sujaya Rao"— Presentation transcript:
1 A Multitrophic Interaction between a Fly, a Fungus and Orchardgrass in the Willamette Valley Undergraduate Researcher: Denise BaumannMentor: Dr. Sujaya RaoOregon State UniversitySummer 2003
2 Orchardgrass in the Willamette Valley Dactylis glomerataApprox. 20,000 acres in the Willamettte ValleySeed CropForage Crop
3 Structure of Grass Seed Head Blade (leaf) Tillers Seed Stalk Single grass plantSeed StalkTillersBlade (leaf)
4 Endophyte Association Fungal StromaTillersSeed StalkEndophytic FungiSingle grass plant
5 - - + Sexual Development of the Fungus (Egg Hatch) Spermatial Transfer (Egg Deposition)+Overwintering &New growth in Spring(Adult Emergence)(Larval Feeding)Harvest(Pupae Formation)
6 Choke in orchardgrass (Epichloe typhina) Fungal StomaUnfertilizedFertilized Fungus
7 Past Research Bultman and White (midwest) Trials carried out in the wild (isolated grass plants)0-7 larvae per fungal stroma63.8 % of stromata collected had 1 larva only and less than 6% had >3 larvae per stromaStomata with mesh bag had NO perithecia; uncovered stromata had 86.6 % peritheciaFly is necessary for fungal fertilization
8 HypothesisIn this fly-fungal interaction in orchardgrass in the Willamette Valley, the fly is not the sole factor for fungal fertilization.
9 Objective OneTo determine whether this fly-fungal interaction is mutualistic.Two treatmentsFly physically excluded, spore allowedControl (no exclusion)
11 Research Plot on Peoria Rd. Objective OneResearch Plot on Peoria Rd.
12 Results Treatment % Fertilization Exclusion (Fly Only) 56% ns No Exclusion69% nsns = no significant differenceConclusion:The fly is not necessary for fungal fertilization in agrass field setting here in the Willamette Valley.
13 Objective TwoSurveying orchardgrass in the Willamette Valley to determine the presence of the fly.
14 Orchardgrass Sites Corvallis Benton Co. Linn Co. Lane Co. SR HP LR CH WDADKRIBPRNDRR3RR2RR1
16 Results 0-10 larvae per fungal stroma 49.2 % of stromata collected had 1 larva/stroma and 15 % had >3 larva/stromaWhen 10 larvae were present, >90% of the fertilized stroma was consumed100 % of stromata fertilized irrespective of larval presence
17 Results continued… % Perithecial development at 3 sites SR = 94% (Average of .62 larva/stroma)CH = 97% (no fly found at this site)RR1 = 95.7% (Average of 4.16 larva/stroma)
18 In Comparison… My Research Past Research Stated that the fly was obligatory for fungal fertilization63.8% of stromata collected had 1 larva only and less than 6% had >3 larvae per stromaWithout presence of the fly 0% fungal stroma developed peritheciaMy ResearchShows that there may be other factors besides the fly fertilizing the fungus here in the Valley49.2% of stromata collected had 1 larva/stroma and 15% had >3 larva/stroma100% of fungal stroma developed perithecia irrespective of fly presence
19 Final SummationIt 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 Isolation trials Fungal host preferences by the flyIsolation trialsHow does fertilization occur?Other factors of fungal fertilizationWind, other insects, etc.?
21 Acknowledgements Howard Hughes Medical Institute (HHMI) Undergraduate Research Innovation, Scholarship, Creativity (URISC)Sujaya Rao, Jon Umble, Devorah Shamah, Bill Pfender, Steve Alderman, Mark Mellbye, Glenn Fisher, Lynn RoyceOrchardgrass Growers, especially James VanLeeuwen