Subindividual Variation Research Articles

Subindividual variability in sea pens (Octocorallia: Pennatulacea)

Comparisons between plants and sessile modular colonial invertebrates offer interesting parallelisms between plant and animal body plans after millions of years of divergent evolution. Among these parallelisms might be the existence and distribution of intraindividual heterogeneity in organ traits, also named subindividual variability. Subindividual variability is quantitatively important and has many consequences for plant individuals, populations and communities, and for animal consumers as well. However, could a similar process of subindividual variability occur in sea pens, which have a modular architecture similar to that of plants? In the literature of marine invertebrates very little is known about the presence and magnitude of subindividual variability in modular organisms. This study provides for the first time a quantitative assessment of subindividual variability in sea pens, analysing certain biometric features of reiterated structures that presumably have some ecological function, and offers an initial comparison of quantitative levels of subindividual variation between plants and sea pens.

Induction of subindividual variation: a commentary on 'Intra-individual variation in Galium odoratum is affected by experimental drought and shading'.

Induction of subindividual variation: a commentary on 'Intra-individual variation in Galium odoratum is affected by experimental drought and shading'.

Subindividual variation accounts for most of the variability in two reproductive traits in Cistusladanifer

There is increasing evidence of within species flower trait variability. In Cistus ladanifer, there is a great variation in the number of locules of the ovary (6–12). In this study, we assessed the variation in the number of ovary locules and ovule production at population, individual and intraindividual levels in 5 localities in the Madrid Region (Central Spain). We have answered the following questions: What level present larger variation? Is there a relationship between the number of ovary locules and ovule production? And if yes, does it hold across all levels? We sampled almost 500 flowers from 50 individuals for five localities. We counted the number of locules of the ovary and estimate the number of ovules per flower. The partitioning of total variation among populations, individuals and within-individuals was estimated for both variables. To analyze differences among locations, we performed general linear models. We found that within-individual variation was the main source of variation for all measured variables. Inter-individual variation was relevant only for the number of locules, and inter-population variation was almost negligible for all variables. Despite the positive correlation between the number of locules per flower and ovule production, populations with more locules did not present more ovules per flower. In summary, we found that variation in the number of locules and its relationship with ovule production is scale dependent.

Within-Species Trait Variation Can Lead to Size Limitations in Seed Dispersal of Small-Fruited Plants

The inability of small-gaped animals to consume very large fruits may limit seed dispersal of the respective plants. This has often been shown for large-fruited plant species that remain poorly dispersed when large-gaped animal species are lost due to anthropogenic pressure. Little is known about whether gape-size limitations similarly influence seed dispersal of small-fruited plant species that can show a large variation in fruit size within species. In this study, fruit sizes of 15 plant species were compared with the gape sizes of their 41 animal dispersers in the temperate, old-growth Białowieża Forest, Poland. The effect of gape-size limitations on fruit consumption was assessed at the plant species level, and for a subset of nine plant species, also at the individual level, and subindividual level (i.e., fruits of the same plant individual). In addition, for the species subset, fruit-seed trait relationships were investigated to determine whether a restricted access of small-gaped animals to large fruits results in the dispersal of fewer or smaller seeds per fruit. Fruit sizes widely varied among plant species (74.2%), considerably at the subindividual level (17.1%), and to the smallest extent among plant individuals (8.7%). Key disperser species should be able to consume fruits of all plant species and all individuals (except those of the largest-fruited plant species), even if they are able to consume only 28-55% of available fruits. Fruit and seed traits were positively correlated in eight out of nine plant species, indicating that gape size limitations will result in 49% fewer (in one) or 16–21% smaller seeds (in three plant species) dispersed per fruit by small-gaped than by large-gaped main dispersers, respectively. Our results show that a large subindividual variation in fruit size is characteristic for small-fruited plant species, and increases their connectedness with frugivores at the level of plants species and individuals. Simultaneously, however, the large variation in fruit size leads to gape-size limitations that may induce selective pressures on fruit size if large-gaped dispersers become extinct. This study emphasizes the mechanisms by which gape-size limitation at the species, individual and subindividual level shape plant-frugivore interactions and the co-evolution of small-fruited plants.

Spatial, genetic and biotic factors shape within‐crown leaf trait variation and herbivore performance in a foundation tree species

Abstract Functional trait variation within individual plants is predicted to have important ecological consequences. However, our understanding of the sources contributing to subindividual trait heterogeneity, and the ramifications thereof, is poor. In a common garden, we sampled multiple genotypes of mature trembling aspen Populus tremuloides at different vertical crown levels and quantified the contributions of genetic, spatial and biotic (herbivory) factors to subindividual morphological and chemical leaf trait variance. Bioassays using gypsy moth Lymantria dispar L. caterpillars were conducted to study the impacts of spatial and genotypic factors on insect performance. Crown position was the primary source of subindividual variation in leaf morphology and explained more of the variance in morphological traits than tree genotype. Effects of spatial, genetic and biotic factors on within‐crown chemistry were highly compound specific. For many compounds, changes in within‐crown concentrations differed among genotypes, revealing that genotypic variation not only contributes to phytochemical diversity among individuals of the same population, but also affects subindividual chemical trait heterogeneity. For many defence‐related compounds, total within‐crown variance itself differed among genotypes and was in many cases a heritable trait. Bioassays revealed that effects of crown position on caterpillar performance varied among tree genotypes and caterpillar sexes. We demonstrate that even relatively small trees can express subtle but distinct levels of within‐crown leaf trait variation. In aspen, this variation is shaped not only by spatial factors, but also by genetics and to a lesser degree by herbivory. Within‐crown variation in defence chemistry might itself provide a defensive phenotype against herbivores and contribute to the biological diversity of canopy insect communities. A free Plain Language Summary can be found within the Supporting Information of this article.

Physical defenses and herbivory vary more within plants than among plants in the tropical understory shrub Piper polytrichum

There is a growing appreciation that much of the trait variation within plant species is represented within individuals, for example, occurring among leaves within a plant. Subindividual variation is predicted to have key ecological consequences, but empirical understanding of how subindividual variation relates to species interactions, such as herbivory, is limited. We measured two physical defenses and herbivore damage on multiple leaves within individual plants of Piper polytrichum C.DC. (Piperaceae), a tropical understory shrub. We partitioned variance among- and within-plants and quantified patterns of trait and damage variation vis-à-vis leaf size and architectural position. We found that variance was considerably higher within plants than among plants for toughness (97%) and trichome density (57%), and that herbivore damage also varied most within plants (74%). Surprisingly, leaf position and size explained only small amounts of variance in traits (2.5%–16.5%) and herbivory (≤4%), indicating subindividual variability had low spatial predictability. The data suggest that individual P. polytrichum plants represent heterogeneous and spatially unpredictable landscapes of physical traits, and that interactions with herbivores are similarly variable. Our results are consistent with the hypothesis that subindividual variability defends plants against herbivores by increasing the difficulty of foraging for high-quality tissue.

Exploring sub-individual variability: role of ontogeny, abiotic environment and seed-dispersing birds.

Within-individual trait variation - otherwise known as sub-individual variation - is an important component of phenotypic variation, with both a genetic and epigenetic basis. We explore its adaptive value and the effects of ontogeny and the environment on sub-individual variability. We conducted a field study to analyse the effects of tree age, soil pH, soil water content and soil nutrients on sub-individual variability in fruit size of hawthorn (Crataegus monogyna) in three sites in northwest Spain. Additionally, we examined how bird-mediated selection influences average and sub-individual variation in fruit size. Results show that average and sub-individual variations in fruit size were related to fitness affecting seed dispersal. Older trees produced larger fruits, but tree age did not affect sub-individual variation in fruit size. Abiotic environmental factors differently affected sub-individual variation and average fruit size. Seed-dispersing birds exerted correlated selection on average and variation in fruit size, favouring trees with larger and less variable fruit size at one site. Our work suggests that the fruit size variation within individual trees, the sub-individual variation, is modified by abiotic environmental factors and, additionally, is an adaptive trait that responds to natural selection.

The ecology of subindividual variability in plants: patterns, processes, and prospects

Abstract. Diversification of ecology into subdisciplines that run from macroecology to landscape, community, and population ecology largely reflects its specialization on different segments of the spatial gradient over which recognizable ecological patterns and processes occur. In all these cases, the elemental units involved in the patterns and processes of interest to ecologists are individuals from the same or different species. No distinct flavor of ecology has yet emerged that focuses on patterns and processes revolving around the lowermost end of the spatial gradient, which in the case of plants corresponds to the within-individual domain. Intraindividual heterogeneity in organ traits, however, is quantitatively important and has multiple consequences for plant individuals, populations, and communities, and for animal consumers as well. This paper first provides an overview of current knowledge on plant traits that vary subindividually, the magnitude of subindividual variation, and its spatial patterning. Examples will then be presented on the consequences of subindividual variation for plants and animal consumers at individual, population, or community levels. Finally, the recently emerging links between genetics, epigenetics, subindividual variation, and population ecology will be illustrated using results on variation in seed size, a functional plant trait playing an important role in plant population dynamics. Further observational and experimental studies are needed which link ecological and phenotypic measurements of plants to their epigenetic and genetic characteristics, in order to understand the three-way relationships between subindividual variability, genetic features, and epigenetic mosaicism. Another proposed line of inquiry should focus on evaluating whether subindividual epigenetic mosaics eventually translate into epigenetically heterogeneous progeny, thus contributing to the maintenance of population and community functional diversity.

Within-plant variation in seed size and inflorescence fecundity is associated with epigenetic mosaicism in the shrub Lavandula latifolia (Lamiaceae).

Sub-individual variation in traits of homologous structures has multiple ecological consequences for individuals and populations. Assessing the evolutionary significance of such effects requires an improved knowledge of the mechanisms underlying within-plant phenotypic heterogeneity. The hypothesis that continuous within-plant variation in some phenotypic traits can be associated with epigenetic mosaicism was examined. Fifteen individuals of the long-lived, evergreen Mediterranean shrub Lavandula latifolia were studied. Five widely spaced 'modules', each consisting of a single inflorescence plus all its subtending basal leaves, were collected from each shrub. Genomic DNA was extracted from leaf samples and genome-wide cytosine methylation determined by reversed phase high-performance liquid chromatography (HPLC) with spectrofluorimetric detection. The number and mean mass of seeds produced were determined for each inflorescence. An assessment was made of whether (1) leaves from different modules in the same plant differed significantly in global DNA cytosine methylation, and (2) mosaicism in cytosine methylation contributed to explain variation across modules in number and size of seeds. Leaves from different modules in the same plant differed in global DNA cytosine methylation. The magnitude of epigenetic mosaicism was substantial, as the variance in DNA methylation among modules of the same shrub was greater than the variance between individuals. Number and mean mass of seeds produced by individual inflorescences varied within plants and were quadratically related to cytosine methylation of subtending leaves, with an optimum at an intermediate methylation level (approx. 25 %). The results support a causal link between global cytosine methylation of leaves in a module and the size and numbers of seeds produced by the associated inflorescence. It is proposed that variation in global DNA methylation within L. latifolia shrubs may result from the concerted action of plant sectoriality and differential exposure of different plant parts to some environmental factor(s) with a capacity to induce durable epigenetic changes.

Effects of within‐plant variability in seed weight and tannin content on foraging behaviour of seed consumers

Summary Individual plants provide a habitat patch for foragers where the sought‐after resources (e.g. leaves, fruits and seeds) are clustered in locally dense aggregations. Characteristics of these resources often vary greatly even within individual plants, which is known as within‐plant or subindividual variation. To best describe properties of the patch (individual plants), the higher moments of trait‐value distributions must be included in addition to the mean values. However, the question whether differences in within‐plant variability of a given trait influence the foraging behaviours of consumers has been mostly untested. To test the hypothesis that differences in within‐plant variation of traits can influence the patch selection behaviour of seed consumers, we used the mean, coefficient of variation (CV) and skewness of within‐plant distributions of two Quercus serrata (Thunb) seed traits (weight and tannin content) as descriptors of plant phenotypes. We then examined the relationships between these descriptors and patch selection by the wood mouse Apodemus speciosus, where individual Quercus trees formed a foraging patch for seed removal. We collected 8594 seeds from 26 individual trees in a forest in northern Japan. We then measured their weight and tannin content, marked and returned them to the locations where they were found, and traced their fates in relation to seed removal by the wood mouse. Tannin content was nondestructively estimated using near‐infrared spectroscopy (NIRS). There was notable within‐plant variation in seed weight and tannin content. Generalized additive modelling revealed that trees with a large mean and CV of seed weight and those with a small CV and skewness of tannin content had a high frequency of seed removal. These results highlight the importance of considering the within‐plant distribution of seed trait values, in addition to the mean trait values of individual seeds, when describing plant phenotypes. The inclusion of these data is essential to understand the ecological and evolutionary processes at work in plant–animal interactions.

Spatial and temporal distribution patterns of nectar-inhabiting yeasts: how different floral microenvironments arise in winter-blooming Helleborus foetidus

Yeasts frequently colonise floral nectar, where they can reach high densities. Recent investigations have further shown that yeast metabolism alters nectar properties by decreasing its total sugar content, modifying sugar composition, or raising nectar local temperature. However, the distribution patterns of nectar yeasts remain poorly investigated at multiple spatial and temporal scales. Here, we study natural variation of the nectar yeasts in a single host plant, Helleborus foetidus , in a mountainous region. We quantified spatio-temporal variation in the frequency and abundance of yeast species across six populations located along an altitudinal gradient. Variance partitioning techniques were used to estimate the relative magnitude of variation in yeast abundance between individual plants, flowers within plants, and nectaries within flowers. Although yeast frequency and abundance varied widely across sites and dates, the largest part of total variance occurred at the sub-individual level (i.e., flowers on the same plant). Pollinator composition and activity seemed the main factors explaining the observed patterns of yeast frequency and abundance across floral nectar samples. • Nectar yeast incidence varied widely across sites and dates for a single host plant. • However, the largest part of total variance occurred at the sub-individual level. • Pollinator features were the main factors explaining yeast abundance patterns. • Nectar yeast patchy distribution may affect pollinator choice and plant fitness. • Sub-individual variation may disfavour plant selective forces against nectar yeasts.

Population differentiation in the tiller architecture of Microstegium vimineum (Poaceae) in relation to habitat

AbstractGrass tillers grow by addition of modular units known as phytomers. Differences in phytomer organ size produce subindividual variation with potential adaptive value. Here, patterns in organ mass along tillers in the invasive annual Microstegium vimineum are related to habitat and tiller architecture. In an earlier study, seed families were collected from two populations: one from a sunny, woodland edge and the other from a shady understory in New Jersey, USA. Plants from these seeds were grown in a greenhouse. Phytomers along primary tillers were divided into culms, leaves, and cleistogamous or chasmogamous spikelets and seeds, dried and weighed. These data were used to examine the quantitative genetics of subindividual variation among families and populations, and the relationship of tiller fitness (based on total seed mass) to the mean or subindividual variance of phytomer traits. Phytomer position along a tiller was the major determinant of organ mass. Leaf mass increased from basal to upper nodes; cleistogamous reproductive mass decreased from upper to lower nodes. Phytomer organs were heaviest in the population from the sunny habitat. Family explained < 18% of variation in organ mass. Tiller fitness was positively correlated with mean culm, and leaf mass, but negatively correlated with coefficients of variation. Field‐collected tillers showed evidence of selection for increased leaf mass. Subindividual variation in M. vimineum is mostly due to phytomer position along a tiller and the prevailing light environment. Differentiation between sunny and shady populations suggests selection favors heavier phytomer leaves and culms, especially in the shady understory where this species is most invasive.

Seed predators exert selection on the subindividual variation of seed size

Subindividual variation among repeated organs in plants constitutes an overlooked level of variation in phenotypic selection studies, despite being a major component of phenotypic variation. Animals that interact with plants could be selective agents on subindividual variation. This study examines selective pressures exerted during post-dispersal seed predation and germination on the subindividual variation of seed size in hawthorn (Crataegus monogyna). With a seed offering experiment and a germination test, we estimated phenotypic selection differentials for average and subindividual variation of seed size due to seed predation and germination. Seed size affects germination, growth rate and the probability of an individual seed of escaping predation. Longer seeds showed higher germination rates, but this did not result in significant selection on phenotypes of the maternal trees. On the other hand, seed predators avoided wider seeds, and by doing so exerted phenotypic selection on adult average and subindividual variation of seed size. The detected selection on subindividual variation suggests that the levels of phenotypic variation within individual plants may be, at least partly, the adaptive consequence of animal-mediated selection.

Selective Pressure along a Latitudinal Gradient Affects Subindividual Variation in Plants

Individual plants produce repeated structures such as leaves, flowers or fruits, which, although belonging to the same genotype, are not phenotypically identical. Such subindividual variation reflects the potential of individual genotypes to vary with micro-environmental conditions. Furthermore, variation in organ traits imposes costs to foraging animals such as time, energy and increased predation risk. Therefore, animals that interact with plants may respond to this variation and affect plant fitness. Thus, phenotypic variation within an individual plant could be, in part, an adaptive trait. Here we investigated this idea and we found that subindividual variation of fruit size of Crataegus monogyna, in different populations throughout the latitudinal gradient in Europe, was explained at some extent by the selective pressures exerted by seed-dispersing birds. These findings support the hypothesis that within-individual variation in plants is an adaptive trait selected by interacting animals which may have important implications for plant evolution.

Multiplicity in unity. Plant subindividual variation & interactions with animals

Differences between individuals are one of the things that all humans learn early in life; babies soon grasp the important differences between daddy and mommy. In general terms, however, variability within an individual is not so obvious because most animals lack repetitive structures. But organisms such as plants or corals do exhibit intra-individual variability – a common characteristic often displaying marked differences between individuals or populations. Traditionally, research in biology and ecology has concentrated on studying the mean of these entities, but in trying to understand processes that distinguish two types of individuals, populations, communities or ecosystem processes, most investigations have tried to put the variance under the carpet. In Multiplicity in unity, Carlos Herrera gives an elegant and detailed explanation on why we have to take into account variation around the mean, because variation itself gives information about individuals, populations and communities. It is this variation that is under natural selection pressure. The author focuses on plants to explain how variation around a character trait is not only related with individuals, but that there is substantial intra-individual variation related with ontogeny. The author emphasizes the importance of the ontogenetic contingency for plants that is determined by the interplay between position of a particular organ, developmental history, and internal and external environment. An interesting discovery when considering variation around the mean in addition to the mean itself, is that sampling one plant population or one character once is no bad thing, since for many organs or characters (e.g. seed size, fruit diameter, water content) inter-annual variation is very low while simultaneous variation is very high. Therefore when studying natural populations on a single occasion you may be capturing all the variation present in the entity without the necessity of sampling several times. The information presented throughout the book is abundant with examples and has good graphic companions that reinforce the arguments presented. Therefore it is a good text that can be used by students and researchers interested in the topic. The first chapters explain how intra-individual variation occurs, the plant organs that present the variability with higher frequency, the importance of environment for intra-individual variation and, most importantly, highlights the fact that this variation has a genetic origin and therefore can respond to selective pressures. Subsequent chapters give examples on how this variability determines the strength and type of interaction with herbivores, pollinators and seed dispersers. Interestingly, the author highlights the fact that very few studies have taken into consideration this variability and many open questions remain to be studied. Throughout, the author emphasizes the consequences of within-plant variation for interactions with animals, and proposes that intra-individual variation is the pivotal element for mutualistic and antagonistic interactions. As a result, Herrera's book offers an excellent overview of the evolutionary ecology of plant–animal interactions with different approaches, while highlighting the relative lack of emphasis given to intra-individual variation in classical studies on this topic. For anyone interested in the ecology or evolutionary biology of plant–animal interactions this book therefore provides a new way of looking at an old question.

Multiplicity in Unity: Plant Subindividual Variation & Interactions with Animals

Multiplicity in Unity: Plant Subindividual Variation & Interactions with Animals

Multiplicity in unity: plant subindividual variation and interactions with animals

The implications of modularity for plants have been recognized for a long time. As Herrera points out in the first chapter, Theophrastus identified reiteration of modules in plants two thousand years ago, and agronomists and horticulturalists have grappled with the ‘problem’ of within-plant variation for decades because of practical reasons. The analysis and understanding of within-plant variation is a prime example of the substantial contribution that applied disciplines (e.g. horticulture, forestry) can make to disciplines that are more theory driven (e.g. plant ecology, evolutionary biology), a link that has huge latent potential to add value to science, but is seldom exploited. Herrera acknowledges at the start of Multiplicity in Unity that his approach is not theory driven, but descriptive instead and aimed at defining the problem as a foundation for further theoretical development, particularly in terms of understanding the evolutionary aspects of within-plant variation. The focus on plantanimal interactions is mainly because that is a field with which Herrera is most familiar, but the concept of within-plant variation could presumably be extended to any interactions between plants and other organisms that operate at the appropriate scale. In the first twothirds of the book, Herrera goes to great trouble to describe the problem and its mechanisms, using a wide diversity of examples, combined with his own extensive insights emerging from a career devoted to understanding the problem.The depth of treatment of the topic is ample. Multiplicity in Unity is one of those books that is a good example of how decades of work on a particular question by a visionary leader and co-workers can generate a rich contribution to a niche in science. Generally, most of the chapters include sections on variation in leaves, flowers, fruits and seeds. Because my own interest is the interaction between trees and mammal herbivores, my attention soon turned to picking out the sections about leaves in the first half of the book, but my real interest was the last few chapters that focus specifically on plant-animal interactions and the evolutionary aspects of within-plant variation in traits. Herrera’s attention is mainly on insects, rather than mammals, which he explains as an outcome of mammals generally taking bites at scales larger than single organs. I would not agree entirely because several small and medium-size antelope do pick individual leaves or fruit from certain woody species, for example, duiker, steenbok, impala and goats, and I suspect that skirting the plant-mammal interaction is partly an artefact of the generally much greater attention paid to insect herbivores, particularly in Europe and North America, for obvious reasons.The relationship between scales of within-plant variation and scales of mammal herbivore foraging are still quite unclear and need to be further elucidated, if for no other reason than to define the relationship and refine sampling and data analysis methods. As such, Herrera does offer practical and comprehensive overviews of techniques that would be useful for anyone planning a study of within-plant variation. Throughout Multiplicity in Unity, the ubiquity of greater within-plant than among-plant variation is stressed (ad nauseum) and the value of variance as a useful trait in its own right in addition to trait means is emphasized. The message could probably have been delivered in a much shorter book.The text is loose and long winded in places and some concepts are hammered home repeatedly from one chapter to the next, which prompts one to soon start skipping paragraphs or pages if one reads the book from beginning to end. The upside is that one can just as well pick one or two chapters to read and get the gist. The reference list alone occupies a substantial fraction of the book (78 pp., 17%), but is a useful resource in itself. The chapter headings are exaggerated with long subtitles, presumably intended to highlight the key focus of each chapter, but I feel the ‘take-home’ message in each subtitle could have been reserved for a summary at the end of each chapter, yielding space on the

VARIATIONS ON A THEME-THE ECOLOGY AND EVOLUTION OF WITHIN-PLANT DIVERSITY

Review of: Herrera, C.M. 2009. Multiplicity in Unity: Plant Subindividual Variation and Interactions with Animals. University of Chicago Press. 437 Pages. ISBN 978-0-226-32794-5. Paper. $40. Biologists engage in a love–hate relation with variation. On one hand, interspecific diversity and differences among conspecifics motivate most biological hypotheses. On the other hand, variation that is peripheral to a hypothesis is typically dismissed as noise that confounds understanding. However, there is a fine line between love and hate, which is crossed repeatedly in one direction during the development of biology, as variation that was once ignored as mundane is recognized as interesting and so comes to stimulate its own hypotheses. In his recent book on variation within individual plants, Carlos Herrera strives to lead readers across this line, making the case that by influencing plant interactions with animals components of such variation can be adaptive and so warrant broader attention. As unitary organisms, we biologists tend to view the limited variation within our own bodies, such as between the sides of our faces, and those of other unitary organisms either as inconsequential or negatively as a sign of developmental instability (e.g., Moller 2006). This perspective is reinforced by recognition that a body’s cells share the same genome, so that stochastic withinindividual variation cannot be transmitted to offspring. Even if somatic mutation creates genetic variation within a body, its transmission is unlikely because of the independence of somatic and germinative cell lines within unitary organisms. In contrast, modular organisms, such as vascular plants, corals, and bryozoans grow by the reiterated production of somatic components, each of which has the capacity to make reproductive organs. This characteristic body plan creates opportunities for variation among reiterated organs within individuals that are not possible for unitary organisms. Such variation is readily observed by overlaying leaves from the nearest house or garden plant or ordering the grapes within a bunch from smallest to largest. Furthermore, to the extent that systematic patterns of phenotypic variation among organs are genetically determined, they represent traits that can be subject to selection. Thus, at least some aspects of the variation within modular organisms could represent adaptations to specific environments, including interactions with herbivores and agents of pollen and fruit dispersal. In his book, Herrera builds on an extensive, scholarly review of literature from Theophrastus to 2007 (supported by 78 pages of references) to argue that within-individual variation and its ecological and evolutionary implications deserve much more attention than they have received to date. After a largely historical introduction, Herrera develops his argument in four sections encompassing nine chapters. In the first section, Herrera devotes a quarter of his overall text to convincing doubting readers that the traits of leaves, flowers, fruits, and seeds often vary extensively within plants. He achieves this objective through the weight of evidence drawn primarily from the ecological and agronomic literature. In this section, Herrera establishes that virtually all above-ground traits vary within plants (Chapter 2: