Bloch Werdenberg Erhardt 2006_Pollination crisis in Dianthus carthusianorum? (original) (raw)
Related papers
Pollination crisis in the butterfly-pollinated wild carnation Dianthus carthusianorum?
New Phytologist, 2006
• Knowledge of pollination services provided by flower visitors is a prerequisite for understanding (co)evolutionary processes between plants and their pollinators, for evaluating the degree of specialization in the pollination system, and for assessing threats from a potential pollination crisis. • This study examined pollination efficiency and visitation frequency of pollinators-key traits of pollinator-mediated fecundity-in a natural population of the wild carnation Dianthus carthusianorum. • The five lepidopteran pollinator species observed differed in pollination efficiency and visitation frequency. Pollinator importance, the product of pollination efficiency and visitation frequency, was determined by the pollinator's visitation frequency. Pollination of D. carthusianorum depended essentially on only two of the five recorded pollinator species. Seed set was pollen-limited and followed a saturating dose-response function with a threshold of c. 50 deposited pollen grains for fruit development. • Our results confirm that D. carthusianorum is specialized to lepidopteran pollinators, but is not particularly adapted to the two main pollinator species identified. The local persistence of D. carthusianorum is likely to be at risk as its reproduction depends essentially on only two of the locally abundant, but generally vulnerable, butterfly species.
New Phytologist, 2006
• Knowledge of pollination services provided by flower visitors is a prerequisite for understanding (co)evolutionary processes between plants and their pollinators, for evaluating the degree of specialization in the pollination system, and for assessing threats from a potential pollination crisis. • This study examined pollination efficiency and visitation frequency of pollinators-key traits of pollinator-mediated fecundity-in a natural population of the wild carnation Dianthus carthusianorum. • The five lepidopteran pollinator species observed differed in pollination efficiency and visitation frequency. Pollinator importance, the product of pollination efficiency and visitation frequency, was determined by the pollinator's visitation frequency. Pollination of D. carthusianorum depended essentially on only two of the five recorded pollinator species. Seed set was pollen-limited and followed a saturating dose-response function with a threshold of c. 50 deposited pollen grains for fruit development. • Our results confirm that D. carthusianorum is specialized to lepidopteran pollinators, but is not particularly adapted to the two main pollinator species identified. The local persistence of D. carthusianorum is likely to be at risk as its reproduction depends essentially on only two of the locally abundant, but generally vulnerable, butterfly species.
2009
Darwin’s meticulous observations on the function of floral shape led to his famous prediction of a long-tongued pollinator, which he believed to be the evolutionary trigger for the long-spurred flowers of the Madagascar star orchid. Although tubular flowers are common, long tubes or spurs are an exception, suggesting that selection maintaining short flowers is widespread. Using the butterfly-pollinated carnation Dianthus carthusianorum and two butterfly species differing in proboscis length (Melanargia galathea and Inachis io) as model organisms, we experimentally demonstrate a reduction in pollinator efficiency with an increasing difference between proboscis length and floral tube length. Such a relationship is a prerequisite for the evolution of floral shape in response to pollinator morphology.
Oecologia, 1989
Abundance and flower visitation rate of the pollinators of Lavandula latifolia (Labiatae), an insect-pollinated shrub, were studied over a 6-year period. The objective was to elucidate interspecific patterns in the "quantity" component of the plant-pollinator interaction. A total of 54 insect taxa are considered in the analyses, including hymenopterans, dipterans and lepidopterans. Most pollinators were comparatively scarce, with a few taxa acounting collectively for the majority of individuals. Pollinators differed broadly in flower visitation rate (0.2-30 flowers/rain). Most of this variation was explained by differences in flower handling time (HT). Regardless of proboscis length, hymenopterans had intrinsically shorter handling times than lepidopterans. Within each group, HT decreased exponentially with increasing proboscis length. Abundance and visitation rate were uncorrelated across pollinator taxa. The total number of visits that each pollinator contributed to the plant (NFV) was estimated as the product of abundance x visitation rate. NFV values spanned four orders of magnitude. A small, taxonomically diverse group of species (1 moth, I butterfly, 4 bees) accounted for most visits and thus could effectively exert some selection on floral features. Nevertheless, the morphological diversity represented in this group of dominant pollinators probably constrains plant specialization, as they will most likely select for different floral features or in opposing directions on the same traits.
Pollination ecology: Understanding plant-pollinator relationships
International Journal of Research in Agronomy, 2024
Pollination, the transfer of pollen between flowers, forms the very foundation of plant reproduction and ecosystem health. Pollination ecology delves into the intricate and fascinating relationships between flowering plants and their pollinators, a story of coevolution spanning millions of years. Pollination ecology is a multidisciplinary field that explores the intricate relationships between plants and their pollinators, encompassing a diverse array of species interactions, ecological processes, and environmental dynamics. Understanding these plant-pollinator relationships is essential for elucidating the mechanisms of pollination, the ecological and evolutionary consequences of these interactions, and the factors shaping their stability and resilience. This article explores the various approaches used to understand these vital partnerships. At the heart lies the intricate language of flowers. Plants advertise their wares through a symphony of colors, scents, and shapes, each meticulously designed to attract specific pollinators. This study delves into the adaptations employed by plants, from vibrant flower displays to nectar production, to entice and reward their pollinators. Conversely, it explores how pollinators, primarily insects, birds, and bats, have coevolved specialized behaviors and morphologies to efficiently access pollen and nectar. It further explores the delicate balance and mutual benefit within these relationships. Plants rely on pollinators to transfer pollen and ensure successful reproduction, while pollinators depend on pollen and nectar for sustenance. This intricate dance, however, faces threats from habitat loss, climate change, and pesticide use. The study concludes by highlighting the importance of pollination ecology in understanding these threats and promoting sustainable practices that safeguard this vital ecological process.
Methods in Ecology and Evolution, 2013
1. The relative importance of specialized and generalized plant-pollinator relationships is contentious, yet analyses usually avoid direct measures of pollinator quality (effectiveness), citing difficulties in collecting such data in the field and so relying on visitation data alone. 2. We demonstrate that single-visit deposition (SVD) of pollen on virgin stigmas is a practical measure of pollinator effectiveness, using 13 temperate and tropical plant species. For each flower the most effective pollinator measured from SVD was as predicted from its pollination syndrome based on traditional advertisement and reward traits. Overall, c. 40% of visitors were not effective pollinators (range 0-78% for different flowers); thus, flower-pollinator relationships are substantially more specialized than visitation alone can reveal. 3. Analyses at species level are crucial, as significant variation in SVD occurred within both higher-level taxonomic groups (genus, family) and within functional groups. 4. Other measures sometimes used to distinguish visitors from pollinators (visit duration, frequency, or feeding behaviour in flowers) did not prove to be suitable proxies. 5. Distinguishing between 'pollinators' and 'visitors' is therefore crucial, and true 'pollination networks' should include SVD to reveal pollinator effectiveness (PE). Generating such networks, now underway, could avoid potential misinterpretations of the conservation values of flower visitors, and of possible extinction threats as modelled in existing networks.
Mechanisms of pollination : quantifying insect and plant contributions
2018
Global agricultural production is reliant on insect-mediated pollination, which is largely provided by the European honey bee (Apis mellifera L.). Recent concern about the health of honey bees has raised significant concern about the future of food production and, as a result, alternate pollinators have been explored to provide these services. However, identifying which insect species are efficient pollinators of a particular plant species is challenging and labor-intensive. Additionally, even if an alternate pollinator is identified, its services may be insufficient to prevent pollination failure, which may be due to other factors. This thesis explores different measures that can be used to assess a species' effectiveness as a pollinator and the causes of pollination failure. Particularly, it addresses four main questions: 1) whether insect behavior or pollen transport can be used to predict single-visit pollen deposition (and thus pollinator efficiency) in four vegetable seed ...
Pollinators, Flowering Plants, and Conservation Biology
BioScience, 1997
ore than a century ago, Darwin (lg59) observed that "the number of bumblebees in any district depends in a great measure upon the number of fieldmice, which destroy their combs and nests ... che number of mice is largely Jependent, as everyone knows, on the number of cats .. .it is quite credible that the presence of a feline animal in large numbers in a district might uetermine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!" (p.-125). Dar-\'{in recoglllzed the importance of interactions among organisms, specifically the role that pollinators play as links in communities. Yet, almost 140 years later, our understanding of pollination interactions is still rudimentary. The extent of dependence and linkage in pollination sys-Carol Ann Kt'arns is an instructor in Environmental, Population, and Organismic Biology and assistant director of the Wil-Jiams Village Residential Academic Program in environmental science, Campus Box 334, University of Colorado, Boulder, CO 80309. Her interests are in pollination of montane and alpine plants, plant pOPlllation genetics, and conservation biology. David William Inouy~ is an associate professor at the University of Maryland in both the Zoology andPJant Biology departments, College Park, MD 20742. He also directs the graduate program in Snst<"linable Development and Conservation Biology at the University of Maryland and conducts long-term studies of plants and insects at the Rocky f"vlountain Biological Laboratory, Crested Entre, CO 81224.
A global test of the pollination syndrome hypothesis
2009
Pollination syndromes' are suites of phenotypic traits hypothesized to reflect convergent adaptations of flowers for pollination by specific types of animals. They were first developed in the 1870s and honed during the mid 20th Century. In spite of this long history and their central role in organizing research on plant -pollinator interactions, the pollination syndromes have rarely been subjected to test. The syndromes were tested here by asking whether they successfully capture patterns of covariance of floral traits and predict the most common pollinators of flowers. † Methods Flowers in six communities from three continents were scored for expression of floral traits used in published descriptions of the pollination syndromes, and simultaneously the pollinators of as many species as possible were characterized. † Key Results Ordination of flowers in a multivariate 'phenotype space' defined by the syndromes showed that almost no plant species fall within the discrete syndrome clusters. Furthermore, in approximately two-thirds of plant species, the most common pollinator could not be successfully predicted by assuming that each plant species belongs to the syndrome closest to it in phenotype space. † Conclusions The pollination syndrome hypothesis as usually articulated does not successfully describe the diversity of floral phenotypes or predict the pollinators of most plant species. Caution is suggested when using pollination syndromes for organizing floral diversity, or for inferring agents of floral adaptation. A fresh look at how traits of flowers and pollinators relate to visitation and pollen transfer is recommended, in order to determine whether axes can be identified that describe floral functional diversity more successfully than the traditional syndromes.
Ecological Monographs, 2019
Pollinator service is essential for successful sexual reproduction and long-term population persistence of animal-pollinated plants, and innumerable studies have shown that insufficient service by pollinators results in impaired sexual reproduction ("pollen limitation"). Studies directly addressing the predictors of variation in pollinator service across species or habitats remain comparatively scarce, which limits our understanding of the primary causes of natural variation in pollen limitation. This paper evaluates the importance of pollinationrelated features, evolutionary history, and environment as predictors of pollinator service in a large sample of plant species from undisturbed montane habitats in southeastern Spain. Quantitative data on pollinator visitation were obtained for 191 insect-pollinated species belonging to 142 genera in 43 families, and the predictive values of simple floral traits (perianth type, class of pollinator visitation unit, and visitation unit dry mass), phylogeny, and habitat type were assessed. A total of 24,866 pollinator censuses accounting for 5,414,856 flower-minutes of observation were conducted on 510 different dates. Flowering patch and single flower visitation probabilities by all pollinators combined were significantly predicted by the combined effects of perianth type (open vs. restricted), class of visitation unit (single flower vs. flower packet), mass of visitation unit, phylogenetic relationships, and habitat type. Pollinator composition at insect order level varied extensively among plant species, largely reflecting the contrasting visitation responses of Coleoptera, Diptera, Hymenoptera, and Lepidoptera to variation in floral traits. Pollinator composition had a strong phylogenetic component, and the distribution of phylogenetic autocorrelation hotspots of visitation rates across the plant phylogeny differed widely among insect orders. Habitat type was a key predictor of pollinator composition, as major insect orders exhibited decoupled variation across habitat types in visitation rates. Comprehensive pollinator sampling of a regional plant community has shown that pollinator visitation and composition can be parsimoniously predicted by a combination of simple floral features, habitat type, and evolutionary history. Ambitious community-level studies can help to formulate novel hypotheses and questions, shed fresh light on long-standing controversies in pollination research (e.g., "pollination syndromes"), and identify methodological cautions that should be considered in pollination community studies dealing with small, phylogenetically biased plant species samples.