scholarly journals Evolution of honest reward signal in flowers

2021 ◽  
Vol 288 (1943) ◽  
pp. 20202848
Author(s):  
Koichi Ito ◽  
Miki F. Suzuki ◽  
Ko Mochizuki
Keyword(s):  
Flower Colour ◽  
Floral Traits ◽  
Honest Signal ◽  
Floral Trait ◽  
Learning Abilities ◽  
Honest Signals ◽  
Pollinator Community ◽  
Rewardless Flowers ◽  
Plant Level ◽  
Signal Accuracy

Some flowering plants signal the abundance of their rewards by changing their flower colour, scent or other floral traits as rewards are depleted. These floral trait changes can be regarded as honest signals of reward states for pollinators. Previous studies have hypothesized that these signals are used to maintain plant-level attractiveness to pollinators, but the evolutionary conditions leading to the development of honest signals have not been well investigated from a theoretical basis. We examined conditions leading to the evolution of honest reward signals in flowers by applying a theoretical model that included pollinator response and signal accuracy. We assumed that pollinators learn floral traits and plant locations in association with reward states and use this information to decide which flowers to visit. While manipulating the level of associative learning, we investigated optimal flower longevity, the proportion of reward and rewardless flowers, and honest- and dishonest-signalling strategies. We found that honest signals are evolutionarily stable only when flowers are visited by pollinators with both high and low learning abilities. These findings imply that behavioural variation in learning within a pollinator community can lead to the evolution of an honest signal even when there is no contribution of rewardless flowers to pollinator attractiveness.

scholarly journals Using Matching Traits to Study the Impacts of Land-Use Intensification on Plant–Pollinator Interactions in European Grasslands: A Review

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 680
Author(s):  
Jérémie Goulnik ◽  
Sylvain Plantureux ◽  
Isabelle Dajoz ◽  
Alice Michelot-Antalik
Keyword(s):  
Land Use ◽  
Flower Colour ◽  
Floral Traits ◽  
Knowledge Gaps ◽  
Land Use Intensification ◽  
Pollinator Community ◽  
Wide Range ◽  
Suitable Habitats ◽  
Underlying Mechanisms ◽  
Plant Pollinator

Permanent grasslands are suitable habitats for many plant and animal species, among which are pollinating insects that provide a wide range of ecosystem services. A global crisis in pollination ecosystem service has been highlighted in recent decades, partly the result of land-use intensification. At the grassland scale, however, the underlying mechanisms of land-use intensification that affect plant–pollinator interactions and pollination remain understudied. In this review, we first synthesise the literature to provide new insights into the relationships between land-use intensification and pollination by using matching community and interaction traits. We then identify knowledge gaps and summarise how land-use intensification of grassland influences floral traits that may in turn be associated with modifications to pollinator matching traits. Last, we summarise how these modifications may affect pollination function on permanent grasslands. Overall, land-use intensification may lead to a shift in flower colour, a decrease in mean nectar tube depth and a decrease in reward production and pollen quality at the community level. This, in turn, may generate a decrease in pollinator mouthparts length and body size, that may favour pollinators that require a low amount of floral reward. We found no study citing the effect of land-use intensification on volatile organic compounds emitted by flowers despite the importance of these molecules in pollinator community composition. Overall, our review highlighted major knowledge gaps about the effects of land-use intensification on plant–pollinator interactions, and suggests that land-use intensification could favour plants with generalised floral traits that adversely affect pollination.

scholarly journals Phenotypic Selection on Flower Color and Floral Display Size by Three Bee Species

2021 ◽  
Vol 11 ◽  
Author(s):  
Johanne Brunet ◽  
Andrew J. Flick ◽  
Austin A. Bauer
Keyword(s):  
Plant Species ◽  
Display Size ◽  
Flower Color ◽  
Phenotypic Selection ◽  
Floral Traits ◽  
Floral Display ◽  
Floral Trait ◽  
Correlational Selection ◽  
Floral Display Size ◽  
Plant Level

Plants exhibit a wide array of floral forms and pollinators can act as agent of selection on floral traits. Two trends have emerged from recent reviews of pollinator-mediated selection in plants. First, pollinator-mediated selection on plant-level attractants such as floral display size is stronger than on flower-level attractant such as flower color. Second, when comparing plant species, distinct pollinators can exert different selection patterns on floral traits. In addition, many plant species are visited by a diverse array of pollinators but very few studies have examined selection by distinct pollinators. In the current study, we examined phenotypic selection on flower color and floral display size by three distinct bee species, the European honey bee, Apis mellifera, the common eastern bumble bee, Bombus impatiens, and the alfalfa leafcutting bee, Megachile rotundata, foraging on Medicago sativa. To estimate phenotypic selection by each bee species and for all bees combined simultaneously and on the same group of plants, we introduce a new method that combines pollinator visitation data to seed set and floral trait measurements data typical of phenotypic selection study. When comparing floral traits, all bee species selected on the number of racemes per stem and the number of stems per plant, two components of floral display size. However, only leafcutting bees selected on hue or flower color and only bumble bees selected on chroma or darkness of flowers. Selection on chroma occurred via correlational selection between chroma and number of open flowers per raceme and we examine how correlational selection may facilitate the evolution of flower color in plant populations. When comparing bee species, the three bee species exerted similar selection pattern on some floral traits but different patterns on other floral traits and differences in selection patterns were observed between flower-level and plant-level attractants. The trends detected were consistent with previous studies and we advocate the approach introduced here for future studies examining the impact of distinct pollinators on floral trait evolution.

scholarly journals Identification of major quantitative trait loci underlying floral pollination syndrome divergence in Penstemon

2014 ◽  
Vol 369 (1648) ◽  
pp. 20130349 ◽  
Author(s):  
Carolyn A. Wessinger ◽  
Lena C. Hileman ◽  
Mark D. Rausher
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Flower Colour ◽  
Floral Traits ◽  
Pollination Syndrome ◽  
Pollination Syndromes ◽  
Floral Trait ◽  
Nectar Volume ◽  
Hummingbird Pollination ◽  
Trait Loci

Distinct floral pollination syndromes have emerged multiple times during the diversification of flowering plants. For example, in western North America, a hummingbird pollination syndrome has evolved more than 100 times, generally from within insect-pollinated lineages. The hummingbird syndrome is characterized by a suite of floral traits that attracts and facilitates pollen movement by hummingbirds, while at the same time discourages bee visitation. These floral traits generally include large nectar volume, red flower colour, elongated and narrow corolla tubes and reproductive organs that are exerted from the corolla. A handful of studies have examined the genetic architecture of hummingbird pollination syndrome evolution. These studies find that mutations of relatively large effect often explain increased nectar volume and transition to red flower colour. In addition, they suggest that adaptive suites of floral traits may often exhibit a high degree of genetic linkage, which could facilitate their fixation during pollination syndrome evolution. Here, we explore these emerging generalities by investigating the genetic basis of floral pollination syndrome divergence between two related Penstemon species with different pollination syndromes—bee-pollinated P. neomexicanus and closely related hummingbird-pollinated P. barbatus . In an F 2 mapping population derived from a cross between these two species, we characterized the effect size of genetic loci underlying floral trait divergence associated with the transition to bird pollination, as well as correlation structure of floral trait variation. We find the effect sizes of quantitative trait loci for adaptive floral traits are in line with patterns observed in previous studies, and find strong evidence that suites of floral traits are genetically linked. This linkage may be due to genetic proximity or pleiotropic effects of single causative loci. Interestingly, our data suggest that the evolution of floral traits critical for hummingbird pollination was not constrained by negative pleiotropy at loci that show co-localization for multiple traits.

Duchenne Smiles as Honest Signals of Chronic Positive Mood

2021 ◽  
pp. 174569162095983
Author(s):  
Kennon M. Sheldon ◽  
Mike Corcoran ◽  
Melanie Sheldon
Keyword(s):  
Positive Emotion ◽  
Positive Mood ◽  
Honest Signal ◽  
Happy People ◽  
Honest Signals ◽  
Neutral Mood ◽  
Duchenne Smiles ◽  
Positivity Offset ◽  
Behavioral Influences ◽  
Better Than

Chronic positive mood (CPM) has been shown to confer a wide variety of social, functional, and health benefits. Some researchers have argued that humans evolved to feel CPM, which explains why most people report better than neutral mood (the “positivity offset bias”) and why particularly happy people have particularly good outcomes. Here, we argue that the Duchenne smile evolved as an honest signal of high levels of CPM, alerting others to the psychological fitness of the smiler. Duchenne smiles are honest because they express felt positive emotion, making it difficult for unhappy people to produce them. Duchenne smiles enable happy people to signal and cooperate with one another, boosting their advantages. In our literature review, we found (a) that not all Duchenne smiles are “honest,” although producing them in the absence of positive emotion is difficult and often detectable, and (b) that the ability to produce and recognize Duchenne smiles may vary somewhat by a person’s cultural origin. In the final section of the article, we consider behavioral influences on CPM, reviewing research showing that engaging in eudaimonic activity reliably produces CPM, as posited by the eudaimonic-activity model. This research suggests that frequent Duchenne smiling may ultimately signal eudaimonic personality as well as CPM.

Morph-specific correlations between floral traits in a distylous Ophiorrhiza napoensis (Rubiaceae) population in southern China

2001 ◽  
Vol 17 (5) ◽  
pp. 719-728 ◽  
Author(s):  
HIROSHI KUDOH ◽  
TAKASHI SUGAWARA ◽  
SUGONG WU ◽  
JIN MURATA
Keyword(s):  
Southern China ◽  
Principal Component ◽  
Corolla Tube ◽  
Floral Traits ◽  
Evergreen Forest ◽  
Tube Length ◽  
Multiple Traits ◽  
Floral Trait ◽  
Subtropical Evergreen Forest ◽  
Positive Correlations

Floral trait correlations were compared between the two flower morphs of a distylous Ophiorrhiza napoensis population in a subtropical evergreen forest at the Defu Natural Animal Preserve, Guangxi, China. Common principal component analyses indicated that overall patterns in correlations among floral traits were morph specific in the study population. Strong positive correlations (r > 0.9) between anther height and corolla-tube length were found in both morphs. Stigma height correlated positively with corolla-tube length in the long-styled morph (r = 0.843), but not in the short-styled morph (r = −0.018). Flower-morph-specific correlation suggests that natural selection by pollinators has moulded trait covariance among floral traits. Because morph-specific correlations are expressed as the patterns of within-morph variation among multiple traits, putative genes responsible for the stigma-corolla tube correlation should not link to the supergene for sex-organ reciprocity between the morphs, but their expression is limited in the long-styled morph.

scholarly journals Mauritian coloured nectar no longer a mystery: a visual signal for lizard pollinators

2006 ◽  
Vol 2 (2) ◽  
pp. 165-168 ◽  
Author(s):  
Dennis M Hansen ◽  
Karin Beer ◽  
Christine B Müller
Keyword(s):  
Experimental Evidence ◽  
Plant Species ◽  
Flowering Plants ◽  
Visual Signal ◽  
Honest Signal ◽  
Endemic Plant ◽  
Floral Trait ◽  
Flower Visitation ◽  
Artificial Flowers ◽  
Endemic Plant Species

Most floral nectars are clear as water, and the enigmatic coloured nectar in three endemic plant species in Mauritius has puzzled scientists studying it. One hypothesis about the possible ecological function of coloured nectar is that it serves as a visual signal for pollinators. Recent studies have shown that at least two of the three Mauritian plant species with coloured nectar are visited and pollinated by endemic Phelsuma geckos. We here provide experimental evidence for the visual signal hypothesis by showing that Phelsuma ornata geckos prefer coloured over clear nectar in artificial flowers. In flowering plants, coloured nectar could additionally function as an honest signal that allows pollinators to assert the presence and judge the size of a reward prior to flower visitation, and to adjust their behaviour accordingly, leading to increased pollinator efficiency. Our study provides a first step in understanding this rare and intriguing floral trait.

Floral trait variation and links to climate in the mixed-mating annual Clarkia pulchella

Botany ◽  
2018 ◽  
Vol 96 (7) ◽  
pp. 425-435 ◽  
Author(s):  
Devin E. Gamble ◽  
Megan Bontrager ◽  
Amy L. Angert
Keyword(s):  
Mating System ◽  
Common Garden ◽  
Moisture Stress ◽  
Floral Traits ◽  
Mixed Mating ◽  
Floral Trait ◽  
Local Climate ◽  
Self Fertilization ◽  
Clarkia Pulchella ◽  
Watering Treatment

The benefits of self-fertilization can vary across environments, leading to selection for different reproductive strategies and influencing the evolution of floral traits. Although stressful conditions have been suggested to favour self-pollination, the role of climate as a driver of mating-system variation is generally not well understood. Here, we investigate the contributions of local climate to intraspecific differences in mating-system traits in Clarkia pulchella Pursh in a common-garden growth chamber experiment. We also tested for plastic responses to soil moisture with watering treatments. Herkogamy (anther–stigma spacing) correlated positively with dichogamy (timing of anther–stigma receptivity) and date of first flower, and northern populations had smaller petals and flowered earlier in response to experimental drought. Watering treatment alone had little effect on traits, and dichogamy unexpectedly decreased with annual precipitation. Populations also differed in phenological response to watering treatment, based on precipitation and winter temperature of their origin, indicating that populations from cool and dry sites have greater plasticity under different levels of moisture stress. While some variation in floral traits is attributable to climate, further investigation into variation in pollinator communities and the indirect effects of climate on mating system can improve our understanding of the evolution of plant mating.

scholarly journals From words to connections: Word use similarity as an honest signal conducive to employees’ digital communication

2020 ◽  
pp. 016555152092993 ◽  
Author(s):  
Andrea Fronzetti Colladon ◽  
Johanne Saint-Charles ◽  
Pierre Mongeau
Keyword(s):  
Online Community ◽  
Social Dynamics ◽  
Semantic Networks ◽  
Past Research ◽  
Internal Communication ◽  
Honest Signal ◽  
Word Use ◽  
Honest Signals ◽  
Main Driver ◽  
Language Characteristics

Bringing together considerations from three research trends (honest signals of collaboration, socio-semantic networks and homophily theory), we hypothesise that word use similarity and having similar social network positions are linked with the level of employees’ digital interaction. To verify our hypothesis, we analyse the communication of close to 1600 employees, interacting on the intranet communication forum of a large company. We study their social dynamics and the ‘honest signals’ that, in past research, proved to be conducive to employees’ engagement and collaboration. We find that word use similarity is the main driver of interaction, much more than other language characteristics or similarity in network position. Our results suggest carefully choosing the language according to the target audience and have practical implications for both company managers and online community administrators. Understanding how to better use language could, for example, support the development of knowledge sharing practices or internal communication campaigns.

scholarly journals Variation in context dependent foraging behavior across pollinators

2017 ◽  
Author(s):  
Heather M. Briggs ◽  
Stuart Graham ◽  
Callin M. Switzer ◽  
Robin Hopkins
Keyword(s):  
Foraging Behavior ◽  
Plant Traits ◽  
Flower Color ◽  
Color Preference ◽  
Field Conditions ◽  
Floral Traits ◽  
Floral Display ◽  
Floral Trait ◽  
Color Preferences ◽  
Natural Field

Pollinator foraging behavior has direct consequences for plant reproduction and has been implicated in driving floral trait evolution. Exploring the degree to which pollinators exhibit flexibility in foraging behavior will add to a mechanistic understanding of how pollinators can impact selection on plant traits. Although plants have evolved suites of floral traits to attract pollinators, flower color is a particularly important aspect of the floral display. Some pollinators show strong innate color preference, but many pollinators display flexibility in preference due to learning associations between rewards and color, or due to variable perception of color in different environments or plant communities. This study examines the flexibility in flower color preference of two groups of native butterfly pollinators under natural field conditions. Our study reveals that pipevine swallowtails and skippers, the predominate pollinators of the two native Texas Phlox species, display distinct patterns of color preferences across different contexts. Pipevine swallowtails exhibit highly flexible color preferences and likely utilize other floral traits to make foraging decisions. In contrast, skippers have consistent color preferences and likely use flower color as a primary cue for foraging. As a result of this variation in color preference flexibility, the two pollinator groups impose concordant selection on flower color in some contexts but discordant selection in other contexts. This variability could have profound implications for how flower traits respond to pollinator-mediated selection. Our findings suggest that studying dynamics of behavior in natural field conditions is important for understanding plant-pollinator interactions.

Disentangling the ecological basis of floral trait variation in Neotropical Piper species

2020 ◽  
Author(s):  
Adriano Valentin-Silva ◽  
Marco Antonio Batalha ◽  
Elza Guimarães
Keyword(s):  
Sexual Reproduction ◽  
Phylogenetic Signal ◽  
Abiotic Factors ◽  
Floral Traits ◽  
Minor Role ◽  
Floral Trait ◽  
Floral Diversification ◽  
Pollen Vectors ◽  
A Minor ◽  
Pollination Systems

Abstract In generalist pollination systems, it has been assumed that pollinators play a minor role in the diversification of floral traits, but recent studies have pointed to a different scenario. Although pollination in Piper is considered generalist, there are flower and inflorescence variations among subclades that may be associated with different pollinator functional groups. Based on this, we aimed to test whether pollinators influenced the evolution of floral traits in a clade of generalist plants, by studying 17 co-occurring Piper spp. Sixteen species were insect-pollinated (46 species: bees, beetles and flies). We found no evidence of anemophily. Eight species were dependent on pollen vectors for sexual reproduction, but no correlation between floral and pollinator traits was recorded. None of the floral traits presented phylogenetic signal, and the evolution of these traits was not correlated. Nine species were independent of pollen vectors for sexual reproduction. We did not find any evidence of pollinator-driven floral diversification of Piper spp.; we suggest a possible role of abiotic factors as agents of selection on floral diversification. As self-pollination seems to be a common feature in the genus, the flexibility of mating systems could be another important factor related to the maintenance of floral phenotypic variation.

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