Effects of spatial scale and genetic identity on the associated pollinator community of Solidago altissma Julie A. Ragsdale and Ray S. Williams Appalachian State University

Introduction Community genetics: How ecology and evolution interact to influence diversity Plant genotypic variation affects the species richness and abundance of associated arthropod species Plant intraspecific diversity may affect community and ecosystem functioning Previous research demonstrates effects of plant genotypic diversity on arthropod communities in S. altissima Whitham et al. 2013; Tack and Roslin, 2011; Crutsinger et al. 2006

Solidago altissima Tall goldenrod Wide-spread Old-field dominant Self-incompatible Important source of nectar Intraspecific variation can influence the associated insect pollinator community The pollinator community can vary by host-plant genotype Genung et al. 2012; Burkle et al. 2013

Genotype and Terpenes Secondary metabolites are known to affect insect visitation to flowers Terpenes are a large, diverse class of plant secondary metabolites Terpenes provide a way to examine potential mechanisms used by pollinators – previous work in Williams’ laboratory suggest terpene variation between genotypes explains pollinator abundance in patches Schiestl and Glaser 2012; Das et al. 2013; Milet-Pinheiro et al. 2013

Spatial Scale Effect of plant genotype and environment may be scale- dependent Large-scale (environmental effects) Small-scale (genetic effects) Johnson and Agrawal 2005; Tack et al. 2010; Genung et al. 2012

Pollinators

Objectives Examine how genotype and spatial scale affect variation in insect pollinator community and secondary metabolites Ask if… Genotypic diversity between patches and sites influences flower phytochemistry Genotype and site influence pollinator community Phytochemical and pollinator variation within sites is greater or lesser than that between sites (genetic identity vs. environment)

Methods Pollinator surveys 3x per patch with 5 minute observations Pollinators identified to lowest possible taxa and assigned a morphospecies Terpene analysis (gas chromatography) Collected inflorescence Stored several weeks in pentane at 4 ° C Samples ground and evaporated to 0.5 mL 1 μL sample injected into a Shimadzu 14-A GC Compounds identified with analytical standards and quantified with an IS

Watauga county, NC

Statistical Analysis One-way ANOVA with site as main effect Contribution of genotype determined by calculating the r 2 Total Abundance (ln)Sum of SquaresFP >F Model Error7.71 Corrected Total8.81 r 2 = 1.09/8.81 = or 12.4 % variation explained by site

r 2 = p = 0.646

α-pinene: r 2 = β-pinene: r 2 = Germacrene D: r 2 = 0.252

Summary and Discussion Hymenoptera dominate the pollinator community Apis mellifera is the dominant pollinator at some sites and may vary between genotypes Pollinator abundance and phytochemistry varies more within sites than between sites My results suggest that genotype has a greater influence on flower chemistry and pollinator abundance than does location

Future Work Linear regression of individual compounds to pollinator abundance and diversity Partial Least Squares Regression (PSLR) to relate pollinator choice of genotype to terpenes Use both techniques to focus on key species or groups

Acknowledgements Ray Williams Ph.D. Mike Madritch Ph.D. Jennifer Geib Ph.D. Office of Student Research Brian Bonville Marae Lindquist Jose Garrido Haley Pratt Jessica Phillips Jacob Pawlick Bryan Taylor David Kale