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Philosophical Transactions of the Royal... Jun 2022Nectar, the main floral reward for pollinators, varies greatly in composition and concentration. The assumption that nectar quality is equivalent to its sugar (energy)... (Review)
Review
Nectar, the main floral reward for pollinators, varies greatly in composition and concentration. The assumption that nectar quality is equivalent to its sugar (energy) concentration is too simple. Diverse non-sugar components, especially amino acids and secondary metabolites, play various roles in nutrition and health of pollinators. Many nectar compounds have indirect effects by altering the foraging behaviour of pollinators or protecting them from disease. This review also emphasizes the water component of nectar, often ignored because of evaporative losses and difficulties in sampling small nectar volumes. Nectar properties vary with environmental factors, pollinator visits and microbial contamination. Pollination mutualisms depend on the ability of insect and vertebrate pollinators to cope with and benefit from the variation and diversity in nectar chemistry. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
Topics: Amino Acids; Plant Nectar; Pollination
PubMed: 35491604
DOI: 10.1098/rstb.2021.0163 -
Current Biology : CB Jan 2021The majority of flowering plants relies on animal pollinators for sexual reproduction and many animal pollinators rely on floral resources. However, interests of plants... (Review)
Review
The majority of flowering plants relies on animal pollinators for sexual reproduction and many animal pollinators rely on floral resources. However, interests of plants and pollinators are often not the same, resulting in an asymmetric relationship that ranges from mutualistic to parasitic interactions. Our understanding of the processes that underlie this asymmetry remains fragmentary. In this Review, we bring together evidence from evolutionary biology, plant chemistry, biomechanics, sensory ecology and behaviour to illustrate that the degree of symmetry often depends on the perspective taken. We also highlight variation in (a)symmetry within and between plant and pollinator species as well as between geographic locations. Through taking different perspectives from the plant and pollinator sides we provide new ground for studies on the maintenance and evolution of animal pollination and on the (a)symmetry in plant-pollinator interactions.
Topics: Animals; Bees; Biological Evolution; Birds; Butterflies; Feeding Behavior; Geography; Magnoliopsida; Pollination; Symbiosis
PubMed: 33497641
DOI: 10.1016/j.cub.2020.11.020 -
The Plant Journal : For Cell and... Aug 2020The great diversity of flowers, their color, odor, taste, and shape, is mostly a result of the metabolic processes that occur in this reproductive organ when the flower... (Review)
Review
The great diversity of flowers, their color, odor, taste, and shape, is mostly a result of the metabolic processes that occur in this reproductive organ when the flower and its tissues develop, grow, and finally die. Some of these metabolites serve to advertise flowers to animal pollinators, other confer protection towards abiotic stresses, and a large proportion of the molecules of the central metabolic pathways have bioenergetic and signaling functions that support growth and the transition to fruits and seeds. Although recent studies have advanced our general understanding of flower metabolism, several questions still await an answer. Here, we have compiled a list of open questions on flower metabolism encompassing molecular aspects, as well as topics of relevance for agriculture and the ecosystem. These questions include the study of flower metabolism through development, the biochemistry of nectar and its relevance to promoting plant-pollinator interaction, recycling of metabolic resources after flowers whiter and die, as well as the manipulation of flower metabolism by pathogens. We hope with this review to stimulate discussion on the topic of flower metabolism and set a reference point to return to in the future when assessing progress in the field.
Topics: Flowers; Fusarium; Nitrogen; Plant Nectar; Pollination
PubMed: 32410253
DOI: 10.1111/tpj.14814 -
Emerging Topics in Life Sciences Jul 2020The mutualism between plants and their pollinators provides globally important ecosystem services, but it is likely to be disrupted by global warming that can cause... (Review)
Review
The mutualism between plants and their pollinators provides globally important ecosystem services, but it is likely to be disrupted by global warming that can cause mismatches between both halves of this interaction. In this review, we summarise the available evidence on (i) spatial or (ii) phenological shifts of one or both of the actors of this mutualism. While the occurrence of future spatial mismatches is predominantly theoretical and based on predictive models, there is growing empirical evidence of phenological mismatches occurring at the present day. Mismatches may also occur when pollinators and their host plants are still found together. These mismatches can arise due to (iii) morphological modifications and (iv) disruptions to host attraction and foraging behaviours, and it is expected that these mismatches will lead to novel community assemblages. Overall plant-pollinator interactions seem to be resilient biological networks, particularly because generalist species can buffer these changes due to their plastic behaviour. However, we currently lack information on where and why spatial mismatches do occur and how they impact the fitness of plants and pollinators, in order to fully assess if adaptive evolutionary changes can keep pace with global warming predictions.
Topics: Animals; Biological Evolution; Diet; Ecosystem; Global Warming; Greenhouse Effect; Host-Parasite Interactions; Insecta; Plant Development; Plants; Pollination; Symbiosis; Temperature
PubMed: 32558904
DOI: 10.1042/ETLS20190139 -
Current Biology : CB Oct 2022Johnson gives an overview of bird pollinators and the plant species they pollinate.
Johnson gives an overview of bird pollinators and the plant species they pollinate.
Topics: Animals; Pollination; Flowers; Birds; Plants
PubMed: 36283359
DOI: 10.1016/j.cub.2022.06.081 -
Biological Reviews of the Cambridge... Dec 2021Global changes are severely affecting pollinator insect communities worldwide, resulting in repeated patterns of species extirpations and extinctions. Whilst negative... (Review)
Review
Global changes are severely affecting pollinator insect communities worldwide, resulting in repeated patterns of species extirpations and extinctions. Whilst negative population trends within this functional group have understandably received much attention in recent decades, another facet of global changes has been overshadowed: species undergoing expansion. Here, we review the factors and traits that have allowed a fraction of the pollinating entomofauna to take advantage of global environmental change. Sufficient mobility, high resistance to acute heat stress, and inherent adaptation to warmer climates appear to be key traits that allow pollinators to persist and even expand in the face of climate change. An overall flexibility in dietary and nesting requirements is common in expanding species, although niche specialization can also drive expansion under specific contexts. The numerous consequences of wild and domesticated pollinator expansions, including competition for resources, pathogen spread, and hybridization with native wildlife, are also discussed. Overall, we show that the traits and factors involved in the success stories of expanding pollinators are mostly species specific and context dependent, rendering generalizations of 'winning traits' complicated. This work illustrates the increasing need to consider expansion and its numerous consequences as significant facets of global changes and encourages efforts to monitor the impacts of expanding insect pollinators, particularly exotic species, on natural ecosystems.
Topics: Animals; Bees; Climate Change; Ecosystem; Insecta; Pollination; Species Specificity
PubMed: 34288353
DOI: 10.1111/brv.12777 -
PeerJ 2022Changes in environmental conditions are likely to have a complex effect on the growth of plants, their phenology, plant-pollinator interactions, and reproductive...
Changes in environmental conditions are likely to have a complex effect on the growth of plants, their phenology, plant-pollinator interactions, and reproductive success. The current world is facing an ongoing climate change along with other human-induced environmental changes. Most research has focused on the impact of increasing temperature as a major driving force for climate change, but other factors may have important impacts on plant traits and pollination too and these effects may vary from season to season. In addition, it is likely that the effects of multiple environmental factors, such as increasing temperature, water availability, and nitrogen enrichment are not independent. Therefore, we tested the impact of two key factors-water, and nitrogen supply-on plant traits, pollination, and seed production in (Brassicaceae) in three seasons defined as three temperature conditions with two levels of water and nitrogen supply in a factorial design. We collected data on multiple vegetative and floral traits and assessed the response of pollinators in the field. Additionally, we evaluated the effect of growing conditions on seed set in plants exposed to pollinators and in hand-pollinated plants. Our results show that water stress impaired vegetative growth, decreased flower production, and reduced visitation by pollinators and seed set, while high amount of nitrogen increased nectar production under low water availability in plants grown in the spring. Temperature modulated the effect of water and nitrogen availability on vegetative and floral traits and strongly affected flowering phenology and flower production. We demonstrated that changes in water and nitrogen availability alter plant vegetative and floral traits, which impacts flower visitation and consequently plant reproduction. We conclude that ongoing environmental changes such as increasing temperature, altered precipitation regimes and nitrogen enrichment may thus affect plant-pollinator interactions with negative consequences for the reproduction of wild plants and insect-pollinated crops.
Topics: Humans; Pollination; Sinapis; Brassicaceae; Dehydration; Crops, Agricultural
PubMed: 35462774
DOI: 10.7717/peerj.13009 -
Philosophical Transactions of the Royal... Jun 2022Disease is an integral part of any organisms' life, and bees have evolved immune responses and a suite of hygienic behaviours to keep them at bay in the nest. It is now... (Review)
Review
Disease is an integral part of any organisms' life, and bees have evolved immune responses and a suite of hygienic behaviours to keep them at bay in the nest. It is now evident that flowers are another transmission hub for pathogens and parasites, raising questions about adaptations that help pollinating insects stay healthy while visiting hundreds of plants over their lifetime. Drawing on recent advances in our understanding of how bees of varying size, dietary specialization and sociality differ in their foraging ranges, navigational strategies and floral resource preferences, we explore the behavioural mechanisms and strategies that may enable foraging bees to reduce disease exposure and transmission risks at flowers by partitioning overlapping resources in space and in time. By taking a novel behavioural perspective, we highlight the missing links between disease biology and the ecology of plant-pollinator relationships, critical for improving the understanding of disease transmission risks and the better design and management of habitat for pollinator conservation. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
Topics: Animals; Appetitive Behavior; Bees; Ecosystem; Flowers; Insecta; Pollination
PubMed: 35491598
DOI: 10.1098/rstb.2021.0157 -
Trends in Ecology & Evolution Apr 2022Wild bee populations are declining due to human activities, such as land use change, which strongly affect the composition and diversity of available plants and food... (Review)
Review
Wild bee populations are declining due to human activities, such as land use change, which strongly affect the composition and diversity of available plants and food sources. The chemical composition of food (i.e., nutrition) in turn determines the health, resilience, and fitness of bees. For pollinators, however, the term 'health' is recent and is subject to debate, as is the interaction between nutrition and wild bee health. We define bee health as a multidimensional concept in a novel integrative framework linking bee biological traits (physiology, stoichiometry, and disease) and environmental factors (floral diversity and nutritional landscapes). Linking information on tolerated nutritional niches and health in different bee species will allow us to better predict their distribution and responses to environmental change, and thus support wild pollinator conservation.
Topics: Animals; Bees; Biodiversity; Ecosystem; Flowers; Phenotype; Plants; Pollination
PubMed: 34955328
DOI: 10.1016/j.tree.2021.11.013 -
Annals of Botany Jan 2019The male fitness pathway, from pollen production to ovule fertilization, is thought to strongly influence reproductive trait evolution in animal-pollinated plants. This... (Review)
Review
BACKGROUND
The male fitness pathway, from pollen production to ovule fertilization, is thought to strongly influence reproductive trait evolution in animal-pollinated plants. This pathway is characterized by multiple avenues of pollen loss which may lead to reductions in male fitness. However, empirical data on the mechanistic processes leading to pollen loss during transport are limited, and we therefore lack a comprehensive understanding of how male fitness is influenced by each step in the pollination process.
SCOPE
This review assesses the history of studying male function in plants and identifies critical gaps in our understanding of the ecology and evolution of pollen transport. We explore male reproductive function along the steps of the pathway to paternity and discuss evolutionary options to overcome barriers to siring success. In particular, we present a newly emerging idea that bodies of pollinators function as a dynamic arena facilitating intense male-male competition, where pollen of rival males is constantly covered or displaced by competitors. This perspective extends the pollen-competitive arena beyond the confines of the stigma and style, and highlights the opportunity for important new breakthroughs in the study of male reproductive strategies and floral evolution.
Topics: Animals; Magnoliopsida; Pollen; Pollination
PubMed: 30535041
DOI: 10.1093/aob/mcy167