Chapter 8 Fungi, Plants, and Pollinators: Sex, Disease, and Deception Tobias J. Policha and Bitty A. Roy Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA Most of us would not necessarily put fungi and flowers together. Fungi are decomposers or pathogens and thus have little in common with flowers. As it turns out, flowers and fungi intersect in many ways, often with insects involved. Similar to flowers, some fungi use insects to help them reproduce, and in the process of attracting insects, vie with flowers in terms of color, fragrance, and nectar production. Other fungi use insects to transmit infectious spores to new hosts (Roy 1994b). The relationships can go the other way: flowers may use insects that normally visit fungi as pollinators, and to that end deploy mushroom-mimicking shapes and smells (Ackerman and Mesler 1979; Okuyama et al. 2004; Endara et al. 2010). We begin with an overview of pollination biology and mimicry, then move into interactions between fungi and plant pollinators. 8.1. POLLINATION AND ITS MIMICS Due to their sessile nature, many plants require floral visitors to fulfill their sexual life cycle. Plants attract pollinators by fragrances and visual cues (Raven 1972; Proctor et al. 1996; Roy and Raguso 1997; Raguso 2008; Majetic et al. 2009). Visual cues include colors that contrast against background vegetation, nectar guides, and UV reflectance, which coincides with the visual spectrum of many insects (Menzel 1975; Hansen et al. 2011). Fragrances span a range of organic chemicals and attractiveness, including pheromones imperceptible to humans (Flach et al. 2006), sickly sweet odors (Majetic et al. 2009), and the smell of rotting flesh or feces (Burgess et al. 2004; Johnson and Jurgens 2010). Floral odor is an important allocation of secondary compounds made by plants (Dudareva and Pichersky 2006). Fungi have evolved many of these same traits, visual and olfactory, to attract insects for much the same purposes. Advertising displays of flowers and production of pollinator rewards are energetically costly for the plant (Chaplin and Walker 1982); color and fragrance derive from specialized biosyn- thetic pathways (Dudareva and Pichersky 2006; Tanaka et al. 2008); and nectar production requires allocation of photosynthates (Pacini et al. 2003). While pollination services are usually a worthwhile benefit, some plants have evolved strategies to avoid these costs. Deception in pol- lination strategies is widespread in some groups, with an estimated one-third of orchid species engaging in some form of deceit (Jersakova et al. 2006). Deceptions range from the basic, in Biocomplexity of Plant–Fungal Interactions, First Edition. Edited by Darlene Southworth. C  2012 John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc. 165