What’s on the Menu? Floral Exudate Composition in Areas Subjected to Different Levels of Abiotic Severity

Resource allocation in floral exudate composition is a trade-off between energy cost to the plant and pollinator reward. For example, carbohydrates offer less reward to pollinators but at less cost to the plant when compared with lipids. We suggest plant and community allocation to carbohydrates and lipids may vary across environmental gradients, with plants in resource-limited communities able to allocate fewer resources to higher-cost compounds in floral exudates. Plant and community resource allocation is important for understanding the behavior of pollinators and understanding how it relates to environment may help predict changes in behavior in response to climate change. In this study, we characterized the composition of floral exudates across three sites across a water resource availability gradient. Our results allow us to reject the hypothesis that fewer resources are allocated to pollinator reward in water-poor environments and we suggest that this may be due to increased pollinator competition. Our results also highlight the prevalence of pectins in floral exudates in drier environments, supporting the hypothesis that pectins are required to prevent exudates from crystallizing in drier environments.