Herrera, C. M. 2009, in press. Multiplicity in unity. Plant subindividual variation and interactions with animals. University of Chicago Press.
Individual plants produce a considerable number of structures of one kind, like leaves, flowers, fruits or seeds, and this reiteration is a truly quintessential feature of the body plan of higher plants. Since not all structures of the same kind produced by a plant are exactly identical, subindividual variation arises as a distinct source of phenotypic variance in plant populations, the magnitude of which often exceeds that of differences among individuals. This book conveys the message that, when one looks at subindividual variability with open, unprejudiced eyes, a feature that was either unnoticed or taken as a nuisance turns into an opportunity for framing new questions, identifying novel biological mechanisms linking sessile plants and mobile choosy animals, and deepening our understanding of the ecological and evolutionary factors involved in plant-animal interactions. Far from being just noise or an annoyance, subindividual variability is part of the essence of being a plant, and its neglect can hide from our view significant ecological and evolutionary facets of plant-animal interactions. Phenotypic variation at the subindividual scale has diverse ecological implications for the interaction between plants and the animals that use reiterated organs as food, including herbivores, flower visitors, frugivores, and granivores. Animal consumers will respond to subindividual variability in plant organ traits and, depending on its magnitude and the nature of the factors causing it, they may eventually become selective agents of patterns and levels of subindividual phenotypic variation through a variety of mechanisms. In this way, animals interacting with plants may ultimately condition, constrain or modify plant ontogenetic patterns, developmental stability, and the extent to which feasible phenotypic variants are expressed by individuals.