scholarly journals Flower Color as Predictor for Nectar Reward Quantity in an Alpine Flower Community

2021 ◽  
Vol 9 ◽  
Author(s):  
Martin Streinzer ◽  
Johann Neumayer ◽  
Johannes Spaethe
Keyword(s):  
Sugar Content ◽  
Color Space ◽  
Flower Color ◽  
Bumble Bees ◽  
Color Category ◽  
Flower Visitors ◽  
Floral Color ◽  
High Reward ◽  
Color Categories ◽  
Floral Displays

Entomophilous plants have evolved colorful floral displays to attract flower visitors to achieve pollination. Although many insects possess innate preferences for certain colors, the underlying proximate and ultimate causes for this behavior are still not well understood. It has been hypothesized that the floral rewards, e.g., sugar content, of plants belonging to a particular color category correlate with the preference of the flower visitors. However, this hypothesis has been tested only for a subset of plant communities worldwide. Bumble bees are the most important pollinators in alpine environments and show a strong innate preference for (bee) “UV-blue” and “blue” colors. We surveyed plants visited by bumble bees in the subalpine and alpine zones (>1,400 m a.s.l.) of the Austrian Alps and measured nectar reward and spectral reflectance of the flowers. We found that the majority of the 105 plant samples visited by bumble bees fall into the color categories “blue” and “blue-green” of a bee-specific color space. Our study shows that color category is only a weak indicator for nectar reward quantity; and due to the high reward variance within and between categories, we do not consider floral color as a reliable signal for bumble bees in the surveyed habitat. Nevertheless, since mean floral reward quantity differs between categories, naïve bumble bees may benefit from visiting flowers that fall into the innately preferred color category during their first foraging flights.

scholarly journals Floral Color Diversity: How Are Signals Shaped by Elevational Gradient on the Tropical–Subtropical Mountainous Island of Taiwan?

2020 ◽  
Vol 11 ◽  
Author(s):  
King-Chun Tai ◽  
Mani Shrestha ◽  
Adrian G. Dyer ◽  
En-Cheng Yang ◽  
Chun-Neng Wang
Keyword(s):  
Phylogenetic Signal ◽  
Color Space ◽  
Flower Color ◽  
Character Displacement ◽  
Elevational Gradient ◽  
Data Sets ◽  
Color Preferences ◽  
Floral Color ◽  
Key Driver ◽  
Over Dispersion

Pollinators with different vision are a key driver of flower coloration. Islands provide important insights into evolutionary processes, and previous work suggests islands may have restricted flower colors. Due to both species richness with high endemism in tropical–subtropical environments, and potentially changing pollinator distributions with altitude, we evaluated flower color diversity across the mountainous island of Taiwan in a comparative framework to understand the cause of color diversity. We sampled flower color signaling on the tropical–subtropical island of Taiwan considering altitudes from sea level to 3300 m to inform how over-dispersion, random processes or clustering may influence flower signaling. We employed a model of bee color space to plot loci from 727 species to enable direct comparisons to data sets from continental studies representing Northern and Southern Hemispheres, and also a continental mountain region. We observed that flower color diversity was similar to flowers that exist in mainland continental studies, and also showed evidence that flowers predominantly had evolved color signals that closely matched bee color preferences. At high altitudes floras tend to be phylogenetically clustered rather than over-dispersed, and their floral colors exhibited weak phylogenetic signal which is consistent with character displacement that facilitated the co-existence of related species. Overall flower color signaling on a tropical–subtropical island is mainly influenced by color preferences of key bee pollinators, a pattern consistent with continental studies.

Transitions between color categories mapped with a reverse Stroop task

2006 ◽  
Vol 23 (3-4) ◽  
pp. 453-460 ◽  
Author(s):  
HANNAH E. SMITHSON ◽  
SABAH S. KHAN ◽  
LINDSAY T. SHARPE ◽  
ANDREW STOCKMAN
Keyword(s):  
Stroop Task ◽  
Color Word ◽  
Color Space ◽  
Reaction Times ◽  
Color Appearance ◽  
Target Color ◽  
Color Category ◽  
Color Categories ◽  
Distractor Color ◽  
Hue Scaling

In the reverse Stroop task, observers are instructed to ignore the ink color in which a color word is printed (the distractor color) and to respond to the meaning of the color word (the target). Reaction times (RTs) are faster with congruent combinations when the ink color matches the word than with incongruent combinations when the ink color does not match the word. We manipulated the distracting ink color from congruent to incongruent and measured the transition from facilitation to interference. In Experiment 1, we confirmed that this transition could be assessed independently from the contextual influence of particular sets of stimuli and responses, implying that the color space in which interference and facilitation occurs is generalizable. In Experiment 2, we obtained reverse Stroop data for transitions between red and yellow, yellow and green, green and blue, and blue and red, and compared them with independent estimates of color appearance obtained by hue scaling for the same chromaticity samples. We find that the magnitude of the reverse Stroop effect can provide a reliable index of the similarity of color appearance between the distracting chromaticity and the color category represented by the target color word. Moreover, it will allow us to quantify the mapping between the chromaticity space defined at the cone photoreceptors and a cognitive color space defined at an advanced level of neural processing.

scholarly journals What we talk about when we talk about color

2020 ◽  
Author(s):  
Colin R. Twomey ◽  
Gareth Roberts ◽  
David Brainard ◽  
Joshua B. Plotkin
Keyword(s):  
Visible Light ◽  
Color Space ◽  
Color Perception ◽  
Geographic Location ◽  
Cross Cultural ◽  
Cultural Variation ◽  
Inference Algorithm ◽  
Color Categories ◽  
New Directions ◽  
Different Color

Names for colors vary widely across languages, but color categories are remarkably consistent [1–5]. Shared mechanisms of color perception help explain consistent partitions of visible light into discrete color vocabularies [6–10]. But the mappings from colors to words are not identical across languages, which may reflect communicative needs – how often speakers must refer to objects of different color [11]. Here we quantify the communicative needs of colors in 130 different languages, using a novel inference algorithm. Some regions of color space exhibit 30-fold greater demand for communication than other regions. The regions of greatest demand correlate with the colors of salient objects, including ripe fruits in primate diets. Using the mathematics of compression we predict and empirically test how languages map colors to words, accounting for communicative needs. We also document extensive cultural variation in communicative demands on different regions of color space, which is partly explained by differences in geographic location and local biogeography. This account reconciles opposing theories for universal patterns in color vocabularies, while opening new directions to study cross-cultural variation in the need to communicate different colors.

Color, consciousness, and the isomorphism constraint

1999 ◽  
Vol 22 (6) ◽  
pp. 923-943 ◽  
Author(s):  
Stephen E. Palmer
Keyword(s):  
Scientific Explanation ◽  
Color Space ◽  
Scientific Progress ◽  
Dimensional Structure ◽  
Color Experience ◽  
Color Categories ◽  
Color Similarity ◽  
Brain Behavior ◽  
Behavioral Methods ◽  
Color Composition

The relations among consciousness, brain, behavior, and scientific explanation are explored in the domain of color perception. Current scientific knowledge about color similarity, color composition, dimensional structure, unique colors, and color categories is used to assess Locke's “inverted spectrum argument” about the undetectability of color transformations. A symmetry analysis of color space shows that the literal interpretation of this argument – reversing the experience of a rainbow – would not work. Three other color-to-color transformations might work, however, depending on the relevance of certain color categories. The approach is then generalized to examine behavioral detection of arbitrary differences in color experiences, leading to the formulation of a principled distinction, called the “isomorphism constraint,” between what can and cannot be determined about the nature of color experience by objective behavioral means. Finally, the prospects for achieving a biologically based explanation of color experience below the level of isomorphism are considered in light of the limitations of behavioral methods. Within-subject designs using biological interventions hold the greatest promise for scientific progress on consciousness, but objective knowledge of another person's experience appears impossible. The implications of these arguments for functionalism are discussed.

scholarly journals Flower Diversification Across “Pollinator Climates”: Sensory Aspects of Corolla Color Evolution in the Florally Diverse South American Genus Jaborosa (Solanaceae)

2020 ◽  
Vol 11 ◽  
Author(s):  
Marcela Moré ◽  
Ana C. Ibañez ◽  
M. Eugenia Drewniak ◽  
Andrea A. Cocucci ◽  
Robert A. Raguso
Keyword(s):  
Visual Space ◽  
Flower Color ◽  
South American ◽  
Large White ◽  
Pollinator Abundance ◽  
Color Evolution ◽  
Floral Color ◽  
Ecological Changes ◽  
History Of ◽  
Pollination Mode

Flower phenotype may diverge within plant lineages when moving across “pollinator climates” (geographic differences in pollinator abundance or preference). Here we explored the potential importance of pollinators as drivers of floral color diversification in the nightshade genus Jaborosa, taking into account color perception capabilities of the actual pollinators (nocturnal hawkmoths vs. saprophilous flies) under a geographic perspective. We analyzed the association between transitions across environments and perceptual color axes using comparative methods. Our results revealed two major evolutionary themes in Jaborosa: (1) a “warm subtropical sphingophilous clade” composed of three hawkmoth-pollinated species found in humid lowland habitats, with large white flowers that clustered together in the visual space of a model hawkmoth (Manduca sexta) and a “cool-temperate brood-deceptive clade” composed of largely fly-pollinated species with small dark flowers found at high altitudes (Andes) or latitudes (Patagonian Steppe), that clustered together in the visual space of a model blowfly (Lucilia sp.) and a syrphid fly (Eristalis tenax). Our findings suggest that the ability of plants to colonize newly formed environments during Andean orogeny and the ecological changes that followed were concomitant with transitions in flower color as perceived by different pollinator functional groups. Our findings suggest that habitat and pollination mode are inextricably linked in the history of this South American plant lineage.

scholarly journals Chemical Basis of Floral Color Signals in Gesneriaceae: The Effect of Alternative Anthocyanin Pathways

2020 ◽  
Vol 11 ◽  
Author(s):  
Ezgi Ogutcen ◽  
Karine Durand ◽  
Marina Wolowski ◽  
Laura Clavijo ◽  
Catherine Graham ◽  
...  
Keyword(s):  
High Performance ◽  
Flower Color ◽  
Pollination Syndromes ◽  
Angiosperm Evolution ◽  
Ecological Diversification ◽  
Floral Color ◽  
Wide Range ◽  
Hummingbird Pollination ◽  
Color Signals ◽  
Physical And Chemical

Changes in floral pigmentation can have dramatic effects on angiosperm evolution by making flowers either attractive or inconspicuous to different pollinator groups. Flower color largely depends on the type and abundance of pigments produced in the petals, but it is still unclear whether similar color signals rely on same biosynthetic pathways and to which extent the activation of certain pathways influences the course of floral color evolution. To address these questions, we investigated the physical and chemical aspects of floral color in the Neotropical Gesnerioideae (ca. 1,200 spp.), in which two types of anthocyanins, hydroxyanthocyanins, and deoxyanthocyanins, have been recorded as floral pigments. Using spectrophotometry, we measured flower reflectance for over 150 species representing different clades and pollination syndromes. We analyzed these reflectance data to estimate how the Gesnerioideae flowers are perceived by bees and hummingbirds using the visual system models of these pollinators. Floral anthocyanins were further identified using high performance liquid chromatography coupled to mass spectrometry. We found that orange/red floral colors in Gesnerioideae are produced either by deoxyanthocyanins (e.g., apigenidin, luteolinidin) or hydroxyanthocyanins (e.g., pelargonidin). The presence of deoxyanthocyanins in several lineages suggests that the activation of the deoxyanthocyanin pathway has evolved multiple times in the Gesnerioideae. The hydroxyanthocyanin-producing flowers span a wide range of colors, which enables them to be discriminated by hummingbirds or bees. By contrast, color diversity among the deoxyanthocyanin-producing species is lower and mainly represented at longer wavelengths, which is in line with the hue discrimination optima for hummingbirds. These results indicate that Gesnerioideae have evolved two different biochemical mechanisms to generate orange/red flowers, which is associated with hummingbird pollination. Our findings also suggest that the activation of the deoxyanthocyanin pathway has restricted flower color diversification to orange/red hues, supporting the potential constraining role of this alternative biosynthetic pathway on the evolutionary outcome of phenotypical and ecological diversification.

scholarly journals White flowers finish last: pollen-foraging bumble bees show biased learning in a floral color polymorphism

2016 ◽  
Vol 31 (2) ◽  
pp. 173-191 ◽  
Author(s):  
Avery L. Russell ◽  
China Rae Newman ◽  
Daniel R. Papaj
Keyword(s):  
Color Polymorphism ◽  
Bumble Bees ◽  
Pollen Foraging ◽  
Floral Color

scholarly journals Color Categories in Language Contact: ‘Pygmy’ Hunter-Gatherers and Bantu Farmers

2012 ◽  
Vol 38 ◽  
pp. 31
Author(s):  
Nadine Grimm
Keyword(s):  
Language Contact ◽  
Second Step ◽  
Hunter Gatherers ◽  
Color Category ◽  
Color Term ◽  
Color Categories ◽  
Southern Cameroon

<p>When speakers adopt colors from another language, do they only borrow certain lexical forms or do they absorb whole concepts? And if both a lexical term and a color category are borrowed, are they both borrowed at the same time or is one of them borrowed first? In this paper, I address the question of how color categories are borrowed, providing evidence from Gyeli ‘Pygmy’ hunter-gatherers (PHGs) in contact with Bantu farmers in southern Cameroon. The data shows rich variability in borrowing patterns. Color categories are not borrowed in toto, but only partially, i.e. the resulting color category in the recipient language only partially coincides with the color category in the donor language. Further, the borrowing of a color category may or may not be in conjunction with the borrowing of a color term from the recipient language. While Gyeli PHGs borrow a lexical term first from neighboring Bantu farmer languages and then expand the color category in a second step, the path of borrowing of Bantu farmers from colonial languages is the inverse. Farmer languages first adopt a new color category, but reject loanwords. Their second step in acquiring a new color is to find a name for the new color category.</p>

scholarly journals Delving Deeper Into Color Space

i-Perception ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 204166951879206 ◽  
Author(s):  
Yasmina Jraissati ◽  
Igor Douven
Keyword(s):  
Color Space ◽  
Color Naming ◽  
English Speakers ◽  
Color Terms ◽  
Color Categories ◽  
Basic Color ◽  
Basic Color Terms

So far, color-naming studies have relied on a rather limited set of color stimuli. Most importantly, stimuli have been largely limited to highly saturated colors. Because of this, little is known about how people categorize less saturated colors and, more generally, about the structure of color categories as they extend across all dimensions of color space. This article presents the results from a large Internet-based color-naming study that involved color stimuli ranging across all available chroma levels in Munsell space. These results help answer such questions as how English speakers name a more complex color set, whether English speakers use so-called basic color terms (BCTs) more frequently for more saturated colors, how they use non-BCTs in comparison with BCTs, whether non-BCTs are highly consensual in less saturated parts of the solid, how deep inside color space basic color categories extend, or how they behave on the chroma dimension.

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