Sandy seeds: Armor or invisibility cloak? Mucilage-bound sand physically protects seeds from rodents and invertebrates

Seeds represent a stage of a plant’s life cycle that is extremely vulnerable to predation, which, unlike most vegetative herbivory, is fatal to the individual. As such, understanding the distribution and abundance of plants may rely upon understanding seed defenses: characteristics of seeds that make them more difficult for granivores to locate, make them less beneficial for granivores to consume, or both. Seeds that produce mucilage are widespread and found across many families and species. Although short-term (single-day) studies indicate that mucilage may be a fundamental seed defense found throughout the plant kingdom, it is not clear whether mucilage provides long-term benefits to seeds via reducing granivory. Moreover, it is not clear whether this long-term defense occurs because mucus reduces seed apparency because substrate-coated seeds are more difficult to detect, because substrate-coated seeds are of less value, or both. In this field experiment, we factorially manipulated sa...