Florian P Schiestl

• Professor (Full) at University of Zurich

Global warming changes flowering times of many plant species, with potential impacts on frost damage and their synchronization with pollinator activity. These effects can have severe impacts on plant fitness, yet we know little about how frequently they occur and the extent of damage they cause. We addressed this topic in a thermophilic orchid with...

The geographic mosaic of coevolution predicts reciprocal selection, the first step in coevolution, to vary with changing biotic and abiotic environmental conditions. Studying how temperature affects reciprocal selection is essential to connect effects of global warming on the microevolutionary patterns of coevolution to the ecological processes und...

Increased temperature can induce plastic changes in many plant traits. However, little is known about how these changes affect plant interactions with insect pollinators and herbivores, and what the consequences for plant fitness and selection are. We grew fast‐cycling Brassica rapa plants at two temperatures (ambient and increased temperature) and...

Although different ecological factors shape adaptative evolution in natural habitats, we know little about how their interactions impact local adaptation. Here we used eight generations of experimental evolution with outcrossing Brassica rapa plants as a model system, in eight treatment groups that varied in soil type, herbivory (with/without aphid...

Shifts in pollinator occurrence and their pollen transport effectiveness drive the evolution of mating systems in flowering plants. Understanding the genomic basis of these changes is essential for predicting the persistence of a species under environmental changes. We investigated the genomic changes in Brassica rapa over nine generations of polli...

Divergent evolution leads to variation among populations and thus promotes diversification. In plants, adaptation to different soils, pollinator guilds, and herbivores is thought to be a key ecological driver of adaptive divergence, but few studies have investigated this process experimentally. Here we use experimental evolution with fast cycling B...

Although different ecological factors shape adaptative evolution in natural habitats, we know little about how their interactions impact local adaptation. Here we used eight generations of experimental evolution with outcrossing Brassica rapa plants as a model system, in eight treatment groups that varied in soil type, herbivory (with/without aphid...

Background Insect pollinators shape rapid phenotypic evolution of traits related to floral attractiveness and plant reproductive success. However, the underlying genomic changes remain largely unknown despite their importance in predicting adaptive responses to natural or to artificial selection. Based on a nine-generation experimental evolution st...

Background: Shifts in pollinator occurrence and their pollen transport effectiveness drive the evolution of mating systems in flowering plants. A decline in pollinator numbers can lead to the phenotypic evolution of floral traits favoring self-pollination (selfing syndrome). Understanding the genomic basis involved in such shifts of the mating syst...

The reproductive success of flowering plants with generalized pollination systems is influenced by the interactions with a diverse pollinator community and abiotic factors. However, knowledge about the adaptative potential of plants to complex ecological networks and the underlying genetic mechanisms is still limited. Based on a pool-sequencing app...

Many organisms change their phenotype in response to the environment, a phenomenon called phenotypic plasticity. Although plasticity can dramatically change the phenotype of an organism, we hardly understand how this can affect biotic interactions and the resulting phenotypic selection. Here we use fast cycling Brassica rapa plants in an experiment...

Volatile organic compounds are of great importance for communication within biological systems. For the experimental investigation of the functions of volatiles, methods for experimental manipulation are needed. Based on scent-release methods from pheromone research, we describe a simple and cheap method for scent manipulation using silicone rubber...

The reproductive success of generalist flowering plants is influenced by a complex ecological network that includes interactions with a diverse pollinator community and abiotic factors. However, knowledge about of the adaptative potential of plants to complex ecological networks and the underlying genetic mechanisms is still limited. Based on a poo...

Animals use odors in many natural contexts, for example, for finding mates or food, or signaling danger. Most analyses of natural odors search for either the most meaningful components of a natural odor mixture, or they use linear metrics to analyze the mixture compositions. However, we have recently shown that the physical space for complex mixtur...

Many organisms change their phenotype in response to the environment, a phenomenon called phenotypic plasticity. Yet we hardly understand how such plasticity can affect biotic interactions and the resulting phenotypic selection. Here we use fast cycling Brassica rapa plants in a proof-of-concept experiment in the greenhouse to study the link betwee...

Background Insect pollinators shape rapid phenotypic evolution of traits related to floral attractiveness and plant reproductive success. However, the underlying genomic changes remain largely unknown despite their importance in predicting adaptive responses to natural or to artificial selection. Based on a nine-generation experimental evolution st...

In many communication systems, signal receivers profit from honest signals that indicate the signaller's quality, whereas low‐quality signallers should profit from cheating. Under such a conflict of interests between signallers and signal receivers, the maintenance of honest signals presents a puzzle. In theory, honesty can represent an evolutionar...

Ecotypes are relatively frequent in flowering plants and considered central in ecological speciation as local adaptation can promote the insurgence of reproductive isolation. Without geographic isolation, gene flow usually homogenizes the allopatrically generated phenotypic and ecological divergences, unless other forms of reproductive isolation ke...

Many flowering plants rely on pollinators for their reproductive success. Plant-pollinator interactions usually depend on a complex combination of traits based on a fine-tuned biosynthetic machinery, with many structural and regulatory genes involved. Yet, the physiological mechanisms in plants are the product of evolutionary processes. While evolu...

Volatiles are of key importance for host-plant recognition in insects. In the pollination system of Lithophragma flowers and Greya moths, moths are highly specialized on Lithophragma, in which they oviposit and thereby pollinate the flowers. Floral volatiles in Lithophragma are highly variable between species and populations, and moths prefer to ov...

Theory predicts that herbivory should primarily determine the evolution of herbivore‐induced plasticity in plant defenses, but little is known about the influence of other interactions such as pollination. Pollinators may exert negative selection on the herbivore‐induced plasticity of chemical defenses when floral signals and rewards are indirectly...

Background: Angiosperms employ an astonishing variety of visual and olfactory floral signals that are generally thought to evolve under natural selection. Those morphological and chemical traits can form highly correlated sets of traits. It is not always clear which of these are used by pollinators as primary targets of selection and which would b...

Plants produce distinct blends of volatile compounds that attract pollinators (floral odors) or natural enemies of insect herbivores (herbivore-induced plant volatiles). The admixture of these blends in the atmosphere may alter the attraction of insect mutualists and ultimately affect plant fitness. Here, using synthetic blends of Brassica rapa flo...

Animals use odors in many natural contexts, for example, for finding mates or food, or signaling danger. Analyses of natural odors search for either the most meaningful components of a natural odor mixture, or they use linear metrics to analyze the mixture compositions. Both analyses assume that the odor space itself is Euclidian, like visual and a...

Despite the paramount role of floral fragrance in pollinator attraction and reproduction in flowering plants, we know little about its evolution under natural conditions. Here we show that by reducing herbivore load with pesticide application, plants showed evolutionary changes in their floral fragrance within 4 generations when compared to plants...

Volatiles mediate the interaction of plants with pollinators, herbivores and their natural enemies, other plants and micro‐organisms. With increasing knowledge about these interactions the underlying mechanisms turn out to be increasingly complex. The mechanisms of biosynthesis and perception of volatiles are slowly being uncovered. The increasing...

Background Angiosperms employ an astonishing variety of visual and olfactory floral signals that are generally thought to evolve under natural selection. Those morphological and chemical traits can form highly correlated sets of traits. It is not always clear which of these are used by pollinators as primary targets of selection and which would be...

Adaptation by way of compromise Many plants rely on animal pollinators to spread pollen and increase the genetic diversity of their offspring. However, there are trade-offs, because attracting pollinators may also attract herbivores and deterring predation may diminish floral displays. Ramos and Schiestl studied the interplay between mating system,...

Maintenance of polymorphism by overdominance (heterozygote advantage) is a fundamental concept in evolutionary biology. In most examples known in nature, overdominance is a result of homozygotes suffering from deleterious effects. Here we show that overdominance maintains a non-deleterious polymorphism with black, red and white floral morphs in the...

The puzzling diversity of flowers is primarily shaped by selection and evolutionary change caused by the plant's interaction with animals. The contribution of individual animal species to net selection, however, may vary depending on the network of interacting organisms. Here we document that in the buckler mustard, Biscutella laevigata, the crab s...

Biotic stress can induce plastic changes in fitness-relevant plant traits. Recently, it has been shown that such changes can be transmitted to subsequent generations. However, the occurrence and extent of transmission across different types of traits is still unexplored. Here, we assessed the emergence and transmission of herbivory-induced changes...

Receiver bias in plant-animal interactions is here defined as "selection mediated by behavioral responses of animals, where those responses have evolved in a context outside the interactions." As a consequence, the responses are not necessarily linked to fitness gains in interacting animals. Thus, receiver bias can help explain seemingly maladaptiv...

Speciation is typically accompanied by the formation of isolation barriers between lineages. Commonly, reproductive barriers are separated into pre-and post-zygotic mechanisms that can evolve with different speed. In this study, we measured the strength of different reproductive barriers in two closely related, sympatric orchids of the Ophrys insec...

Pollinator-driven diversification is thought to be a major source of floral variation in plants. Our knowledge of this process is, however, limited to indirect assessments of evolutionary changes. Here, we employ experimental evolution with fast cycling Brassica rapa plants to demonstrate adaptive evolution driven by different pollinators. Our stud...

Supplementary Figures and Supplementary Tables

Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta‐analysis to characterize patterns of covariation in CCDs and ide...

A striking feature of the angiosperms that use animals as pollen carriers to sexually reproduce is the great diversity of their flowers with regard to morphology and traits such as color, odor, and nectar. These traits are underpinned by the synthesis of secondary metabolites such as pigments and volatiles, as well as carbohydrates and amino acids,...

Through their preferences for floral cues, pollinators and herbivores can mediate selection on a variety of plant traits. Selection by mutualists and antagonists may not be independent from each other, however, as the selection on a trait through one interaction can depend on the presence or intensity of another interaction. Bumble bees (Bombus ter...

Plants have to fine-tune their signals to optimise the trade-off between herbivore deterrence and pollinator attraction. An important mechanism in mediating plant-insect interactions is the regulation of gene expression via DNA methylation. However, the effect of herbivore-induced DNA methylation changes on pollinator-relevant plant signalling has...

In an artificial selection experiment using fast-cycling Brassica rapa plants it was recently shown that floral VOCs respond rapidly to selection for increased amounts. Here we carried out transcriptome analysis in these plants to explore the molecular bases of the augmentation in the artificially selected scent compound, phenylacetaldehyde (PAA),...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Mimicry is a classic example of adaptation through natural selection. The traditional focus of mimicry research has been on defense in animals (protective mimicry), but there is now also a highly developed and rapidly growing body of research on floral mimicry in plants. Being literally rooted to one spot, plants generally have to use food bribes t...

Geographically structured phenotypic selection can lead to adaptive divergence. However, in flowering plants, such divergent selection has rarely been shown, and selection on floral signals is generally little understood. In this study, we measured phenotypic selection on display size, floral color, and floral scent in four lowland and four mountai...

Percentage of plants experiencing floral herbivory (upper graphs) and differences in the mean (± SE) floral herbivory (lower graphs) in lowland and mountain populations of Gymnadenia odoratissima. Floral herbivory was quantified as (A) number of eaten flowers per inflorescence and (B) aphid load (scale from 1 [no aphids] to 6 [many aphids]). Sample...

Linear selection gradients β ± SE for principal components (PCs) in lowland (left) and mountain (right) populations in Gymnadenia odoratissima for the 2011 data set, which included floral color. Several PCs showed significant selection gradients and PC6A was significantly different among mountain populations (***P < 0.001, **P < 0.01, *P < 0.05). A...

Comparison of the trait-value distribution of the principle components (PCs) used for selection analysis in lowland (grey bars) and mountain (white bars) regions. The distributions of the PC scores are compared with superimposed normal distributions. (PDF)

Female reproductive success (mean ± SE) of Gymnadenia odoratissima plants in the four lowland and the four mountain populations and the statistical tests between lowland populations, between mountain populations, and between the two altitudinal regions. (PDF)

Pollinator limitation in lowland and mountain populations of Gymnadenia odoratissima in 2010 and 2011 assessed in a pollination experiment. (PDF)

Pollinators caught and/or observed on Gymnadenia odoratissima inflorescences in the four lowland populations (Döttingen, Remigen, Linn, and Rossweid) and the three mountain populations (Schatzalp, Albulapass, and Corviglia). (PDF)

Median (minimum-maximum) coefficient of variation for the three floral-signal groups of Gymnadenia odoratissima plants. (PDF)

Correlogram of among-population Euclidean distance in floral signals and among-population Euclidean distance in selection gradients on these PCs. For the Euclidian distances in the signals, only the variables were used that exhibited the highest loadings on the principal components (PCs) used in the selection analysis. For scent PC4 and PC5, a sign...

Geographic locations of the four lowland and the four mountain study-populations of Gymnadenia odoratissima and year(s), in which selection and floral signals was measured and hand pollinations were conducted. (PDF)

Factor loadings of floral signals of Gymnadenia odoratissima on principal components (PCs) using the 2011 data set, which included also floral color. (PDF)

Differences in floral traits between lowland and mountain plants. (PDF)

Factor loadings of display size and floral scent compounds of Gymnadenia odoratissima plants on principal components (PCs) using the two-year data set. (PDF)

Contribution of pollinator taxa to the differences in the pollinator communities between the lowland and the mountain region as well as between populations within altitudinal regions of Gymnadenia odoratissima using SIMPER (Similarity Percentages) analyses. (PDF)

Linear selection gradients β ± SE for principal components (PCs) in the lowland and mountain region in Gymnadenia odoratissima for the 2011 data set, which included floral color. Whereas several PCs showed significant selection gradients (marked with asterisks above bars), only PC1 showed significant differences between the regions (***P < 0.001, *...

(PDF)

The role of plant ontogeny on investment in direct defense against herbivores is well accepted, but the transition from the vegetative to the reproductive stage can also affect indirect resistance traits (i.e. attraction of the natural enemies of plant attackers). Here, we conducted behavioral bioassays in olfactometers to determine whether the dev...

The evolution of the vast diversity of floral volatiles is little understood, although they serve fundamental functions, such as pollinator attraction and herbivore deterrence. Floral volatiles are often species specific, yet highly variable and sensitive to environmental factors. To date, nothing is known about the heritability of floral volatiles...

Floral scents and nectar attract both pollinators and other animals that may reduce the plant's fitness, and therefore put flowering plants in a challenging situation.

In dioecious plants, reproductive efforts of male and female plants can be differentially affected by herbivory due to sex-specific allocation and re-modulation of resources. Here, we investigate the effects of foliar herbivory by the polyphagous species Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) on male and female reproductive trai...

Although the effect of herbivory on plant reproduction has been investigated in some detail, little is known about how herbivores affect floral signalling. Here, we investigated the effect of foliar herbivory by the African Cotton Leafworm (Spodoptera littoralis) on floral signalling and fruit set in the White Campion (Silene latifolia). We found n...

Background and aims: Polyploidization, the doubling of chromosome sets, is common in angiosperms and has a range of evolutionary consequences. Newly formed polyploid lineages are reproductively isolated from their diploid progenitors due to triploid sterility, but also prone to extinction because compatible mating partners are rare. Models have su...

Pollinators visit flowers for rewards and should therefore have a preference for floral signals that indicate reward status, so called ‘honest signals’. We investigated honest signalling in Brassica rapa L. and its relevance for the attraction of a generalised pollinator, the bumble bee Bombus terrestris (L.). We found a positive association betwee...

High pollinator specificity and the potential for simple genetic changes to affect pollinator attraction make sexually deceptive orchids an ideal system for the study of ecological speciation, in which change of flower odour is likely important. This study surveys reproductive barriers and differences in floral phenotypes in a group of four closely...

The crucial role of reproductive isolation in speciation has long being recognized, however a limited number of studies quantify different isolation barriers and imbed reproductive isolation in the phylogenetic context. In this study, we investigate reproductive isolation between the often sympatrically-occurring orchid species, Gymnadenia conopsea...

Floral signaling, especially through floral scent, is often highly complex, and little is known about the molecular mechanisms and evolutionary causes of this complexity. In this study, we focused on the evolution of "floral scent genes" and the associated changes in their functions in three closely related orchid species of the genus Gymnadenia. W...

High pollinator specificity and the potential for simple genetic changes to affect polli-nator attraction make sexually deceptive orchids an ideal system for the study of ecological speciation, in which change of flower odour is likely important. This study surveys reproductive barriers and differences in floral phenotypes in a group of four closel...

Pollination systems differ in pollen transfer efficiency, a variable that may influence the evolution of flower number. Here we apply a comparative approach to examine the link between pollen transfer efficiency and the evolution of inflorescence size in food and sexually deceptive orchids. We examined pollination performance in nine food-deceptive...

The trade-off between defence and reproduction has been investigated in some detail, but little is known about how herbivores affect floral signalling and related pollinator attraction. Here we investigated the effect of foliar herbivory by the invasive African Cotton Leafworm (Spodoptera littoralis) on floral signalling and fruit set in the White...