Plant genotype, nutrients, and G × E interactions structure floral visitor communities

Laura A Burkle,Lara Souza,Mark A Genung,Gregory M Crutsinger

doi:10.1890/es13-00039.1

Abstract

Intraspecific variation in plants is driven by both genetic and environmental factors and has been shown to play an important role in determining assemblages of herbivores, predators, and pathogens. Yet, the consequences of genetic (G) and environmental (E) factors, as well as potential (G × E) interactions, for floral visitor communities remains poorly explored. In a common garden experiment, we compared the relative effects of host‐plant genotype and genotypic diversity as well as soil nutrient enrichment on floral resource abundance and insect floral visitors associated with tall goldenrod, Solidago altissima. We found that the floral visitor community varied considerably among genotypes, driven predominantly by variation in floral phenology among S. altissima clones. Floral visitors also varied among nutrient treatments, though this response was much weaker than to different plant genotypes, and was likely driven by effects of floral rewards rather than of floral phenology. Importantly, we also detected several G × E interactions for both flowering and floral visitors. Taken together, our results suggest that the effects of host‐plant genetic variation, and to a lesser extent G × E interactions, are key agents in structuring the diversity and composition of floral visitors.

Highlights

A growing focus in ecology has been on the role of intraspecific variation in determining community dynamics and ecosystem function (Bolnick et al 2011, Violle et al 2012)
Using a factorial common garden experiment, we addressed the following three inter-related questions: (1) Does the identity or diversity of S. altissima genotypes influence floral resource production and floral visitor abundance, richness, and composition? (2) How do the effects of S. altissima genetic variation and genotypic diversity compare to those of soil nutrient enrichment? And (3) what is the role of G 3 E interactions in shaping floral visitor assemblages associated with S. altissima?
We compared the relative and interactive effects of genetic variation, genotypic diversity and nutrient enrichment on percent flowering and insect floral visitors associated with Solidago altissima

Summary

Introduction

A growing focus in ecology has been on the role of intraspecific variation in determining community dynamics and ecosystem function (Bolnick et al 2011, Violle et al 2012). One key environmental factor for plants and their associated floral visitors is soil nutrient availability, as nutrients can vary considerably at a local level and are known to influence flower production and bloom duration (e.g., Campbell and Halama 1993, Asikainen and Mutikainen 2005, Munoz et al 2005, Burkle and Irwin 2009a). Variation in soil nutrients can lead to shifts in flower production and the rates of floral visitors to plants (Burkle and Irwin 2010) Along with such direct effects, soil nutrient availability might interact with plant genetic variation to influence floral traits, and it is these genotype by environment (G 3 E) interactions that could shape the structure of associated communities (e.g., Johnson and Agrawal 2005, Tetard-Jones et al 2007, Genung et al 2012). The role of G 3 E interactions for communities associated with floral resources and with floral visitors has been ignored

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Conclusion