Male Coloration Research Articles

Colour Variation in the Crocodile Lizard (Shinisaurus crocodilurus) and Its Relationship to Individual Quality.

Simple SummaryThis study examines colour variation in the highly endangered crocodile lizard, Shinisaurus crocodilurus. Both males and females vary in the extent to which their throats and venters are red. Their colouration is easily visible to a lizard receiver, and we found evidence that colour signals individual quality. Females with red venters had larger heads while females with red throats had greater bite force. In males, redder individuals were older. Finally, we found links between colour and fitness in males but not females. Aspects of male colouration were linked to reproductive output such that they sired offspring from heavier litters. The potential fitness consequences of colour should be considered in captive breeding and release programs.Colour plays a key role in animal social communication including as an indicator of individual quality. Using spectrophotometry, we examined colour variation in the throat and venter of the crocodile lizard (Shinisaurus crocodilurus), an endangered species native to southern China and northern Vietnam. We detected two broad colour variants, individuals with and without red, for each body region and each sex. A cluster analysis of spectral colour measurements (hue, chroma, luminance) revealed discrete throat and ventral morphs when measured in a single snapshot in time. However, photographic evidence revealed that the amount of red relative to body size increased as they got older. Individuals with red were equally likely to be male or female and throat colour was unrelated to ventral colour. Therefore, it is premature to claim that crocodile lizards have discrete colour morphs. We used visual modelling to show that the throat and venter were easily discriminable to a lizard visual system, suggesting they function in social communication. We also asked whether colour variation signalled individual quality. Females with red throats had greater bite force while males with red throats were older. In addition, females with red venters had larger heads. We also detected differences in morphology linked to colour. Females with red throats had slender bodies and longer tails, while individuals lacking red on their throats were stouter and had shorter tails. Finally, throat and ventral colour were unrelated to reproductive output (litter size and mass) in females. Males with greater ventral luminance contrast sired offspring from litters with greater litter mass (including stillborns), while males with greater ventral chromatic contrast sired offspring whose collective live mass (excluding stillborns) was greater. Males with greater luminance contrast also sired more live offspring (excluding stillborns). Collectively, these results suggest that male ventral colour signals individual quality in males. Conservation initiatives should take colour variation into account when planning future captive breeding and release programs for this endangered species.

Colour morph predicts social behaviour and contest outcomes in a polymorphic lizard (Podarciserhardii)

Space is a limited resource in which many animals need to perform basic functions such as feeding and reproducing. Competition over access to space can induce a variety of behaviours that may result in differential access to crucial resources related to survival and fitness. The Aegean wall lizard, Podarcis erhardii , is a colour-polymorphic lizard that inhabits dry stone walls where they access food, safely thermoregulate, shelter from predators and interact with other lizards. Many colour-polymorphic species have morphs with distinct behavioural strategies, which may play a role in morph evolution and maintenance. Here, we conducted the first behavioural experiments on P. erhardii colour morphs. Our goal was to compare morph competitive ability and characterize morph differences in social behaviours using laboratory contest experiments over limited heated space on a stone wall in a neutral arena. Contest experiments revealed that colour morph, not size, predicted intermorph contest outcomes. White and yellow morphs were associated with winning and the orange morph was associated with losing contests. Male colour morphs exhibited different levels of aggressive, boldness, chemical signalling and visual signalling behaviours depending on which morph they were in contest with. White morphs always performed aggressive and scent-marking behaviours more frequently during contests with other morphs. Yellow morphs performed aggressive, bold, chemical signalling and visual signalling behaviours at intermediate frequencies relative to other morphs. Orange morphs performed aggressive behaviours equally often when in contest with yellow morphs but performed all other behaviours less frequently against yellow and white morphs. Considering these results, behavioural variation among P. erhardii colour morphs may promote morph maintenance. • Male lizard colour morphs differed in their ability to win staged contests for space. • White and yellow morphs were associated with winning contests over space. • Larger orange morphs were associated with losing and were the least aggressive. • White morphs were the most aggressive and scent-marked territories often. • Different social strategies among morphs may help maintain polymorphism.

Two billion registered students affected by stereotyped educational environments: an analysis of gender-based color bias

According to the literature, educational technologies present several learning benefits to promote online education. However, there are several associated challenges, and some studies illustrate the limitations in elaborating educational technologies, called Design limitations. This aspect is responsible for unleashing various issues in the learning process, such as gender inequality, creating adverse effects on cognitive, motivational, and behavioral mediators, which opposes the fifth UN’s Sustainable Development Goal. Therefore, many studies notice the harmful effects of stereotypes in educational technologies. These effects can be included in the design, like colors or other stereotyped elements, or how the activity is conducted. Based on this, the present study aimed to verify the predominance of color bias in educational technologies available on the WEB. This study developed a computational solution to calculate male and female color bias in the available educational technology web pages. The results suggest the prevalence of the development of educational technologies with a male color bias, with an imbalance among genders, without adequate customization for age groups. Furthermore, some environments, such as Computer Science, present a higher color bias for men when compared to women. Despite both scales being independent, results indicated interesting evidence of a substantial prevalence of colors associated with the male scale. According to the literature, this may be associated with dropout and lack of interest in female students, especially in sciences, technology, engineering, and mathematics domains.

What do male and female zebrafish prefer? Directional and colour preference in maze tasks.

Studies regarding the animals' innate preferences help elucidate and avoid probable sources of bias and serve as a reference to improve and develop new behavioural tasks. In zebrafish research, data obtained in behavioural assessments are often not replicated between research groups or even inside the same laboratory raising huge concerns about replicability and reproducibility. Among the potential causes that are not well considered, sexual differences can be a probable source of bias. Thus, this study aimed to investigate the male and female zebrafish directional and colour preferences in the plus-maze and T-maze behavioural tasks. Experiment 1 evaluated directional preference, and experiment 2 evaluated colour preference in a plus-maze task; experiment 3 evaluated preference between black or white in a T-maze task. Individual preferences were expressed as the percentage of time spent in each zone. Our results showed that male and female zebrafish demonstrated no difference in directional preference in the plus-maze task. Surprisingly, male and female zebrafish showed colour preference differences in the plus-maze task; males did not show any colour preference, while female zebrafish demonstrated a red preference compared to white, blue and yellow colours. Moreover, both male and female zebrafish demonstrated a strong black colour preference compared to the white colour in the T-maze task. Our findings characterized the spontaneous preference of male and female zebrafish for direction and colour, identifying possible biases and providing insights that contribute to the standardization of future protocols.

IDENTIFIKASI KARAKTERISTIK FISIK TERNAK KAMBING DI PULAU TIDORE

The aim of this study was to identify the potential of goat farming on Tidore island through the identification of physical characteristics, e.g. body coat color, coat color pattern, facial profile, beard profile, and back profile. The physical characteristics of 101 goats (11 males and 90 females; aged 1 to 2 years) were observed, tabulated, and analyzed using descriptive statistics as number of observations and percentage. The results showed that the majority of the studied goats had the following physical characteristics: a combination of brown and white and of black, white, and brown for body coat color in males (45.45%) and females (27.78%), respectively, striped coat color pattern (63.64% in males; 78.89% in females), straight facial profile (81.82% in males; 95.56% in females), bearded in males (63.64%) and beardless in females (95.56%), and straight back profile (81.82% in males; 91.11% in females). It can be concluded that the studied goat population had variations in the physical characteristics, suggesting their potential use as a basis for development of goat genetic resources on Tidore island.

Experimental test of selection against hybridization as a driver of avian signal divergence.

Signal divergence may be pivotal in the generation and maintenance of new biodiversity by allowing closely related species to avoid some costs of co-occurrence. In birds, closely related, sympatric species are more divergent in their colour patterns than those that live apart, but the selective pressures driving this pattern remain unclear. Traditionally, signal divergence among sympatric species is thought to result from selection against hybridization, but broad evidence is lacking. Here, we conducted field experiments on naïve birds using spectrometer-matched, painted 3D-printed models to test whether selection against hybridization drives colour pattern divergence in the genus Poecile. To address selection for male colour pattern divergence without the influence of learning or the evolution of female discrimination in sympatry, we simulated secondary contact between Poecile species, and conducted mate choice experiments on naïve, allopatric females. We found that female black-capped chickadees (Poecile atricapillus) are equally likely to perform copulation solicitation displays to sympatric and allopatric heterospecific congeners when they are paired with conspecifics, but exhibit a strong preference for less divergent males when presented with paired heterospecific congeners. These results suggest that increased colour pattern divergence among sympatric species can reduce the likelihood of mixed mating in some contexts, and therefore should be favoured by selection against hybridization.

The conspicuousness contradiction: brighter males have lower mating chances in the damselfly Argia hasemani but not in Argia croceipennis

Abstract In odonates, male coloration is often more conspicuous than female coloration. This difference is frequently attributed to the role of male colour in male–male competition to access females. However, there are sexually dimorphic odonate species, such as the damselflies Argia hasemani and Argia croceipennis, in which male–male interactions are much less intense. In these species, it might be that male coloration affects male success directly when interacting with females. Therefore, we hypothesized that males with more intense coloration present higher copulation success. To investigate this hypothesis, we registered which males copulated in the field during 4 days and estimated the coloration of all observed males in the female visual spectrum. Surprisingly, we found that dull males had higher chances of copulation in A. hasemani, whereas in A. croceipennis male coloration did not influence the chances of copulation. Our data also indicated that brighter males of A. hasemani were also more conspicuous to potential avian predators, whereas this was not the case in A. croceipennis. We suggest that females of A. hasemani might avoid brighter males owing to increased risk of predation during copulation.

Rosyjskie słownictwo barw u kobiet i mężczyzn (badania wstępne)

The aim of the paper is to present the results of a study of psychological salience of colour terms for women and men who are native speakers of Russian. In our study, we employed the elicitation list task which is a five-minute psychological test designed to determine which and to what degree colour terms are psychologically important to language users. There were 26 Russian speakers – 13 women and 13 men – who participated in the test. The test results provide us with adequate material to be used to analyze both quantitative and qualitative differences between the female and male colour lexicons, and additionally, to estimate the scope of these differences. The study confirms the observations made by other researchers, as well as the popular opinion that women have a richer selection of colour words at their disposal and that they actually know many more metonymic colour terms than men.

Same Colors for Different Functions: Implications for the Evolution of Carotenoid-Based Ornamentation.

AbstractSexual ornamentation is often assumed to be costly, allowing honest signaling of individual quality, and carotenoid-based colors have been proposed to bear significant costs. If carotenoid-based colors are costly to produce, sexually selected signals should use more concentrated carotenoid pigments and have more saturated color than nonsexual signals, where honesty-guaranteeing costs are not required. We tested this prediction comparing carotenoid-based colors across canaries, goldfinches, and allies because many of these species use yellow plumage as sexual ornamentation but also have yellow rumps that appear to be nonsexual flash marks. Only in the breast, but not the rump, was there an asymmetric codistribution of male and female color saturation, with males similarly or more saturated than females, indicating evolution of breast color by sexual selection. Yellow was not consistently more saturated in the breast than in the rump, and the codistribution of rump and breast color saturation indicated that saturated rumps can persist irrespective of breast color. This challenges the assumption that carotenoid-based colors bear significant costs. The use of carotenoid coloration as sexual signals in this clade may instead be due to social costs, cost-free index mechanisms for signaling quality, and/or socially monogamous species evolving low-cost signals to mostly discriminate against the lowest-quality mates.

Intra‐population variation in male nuptial coloration and diet across anthropogenically altered visual microhabitats in an African cichlid

Human activities are altering natural ecosystems, leading to widespread environmental change that can vary across spatiotemporal scales, thus creating dynamic, novel conditions at both large and small scales. In highly disturbed aquatic systems, elevated turbidity is one common stressor that alters the sensory environment of fishes and can disrupt communication, including mate choice, driving population-level shifts in visual communication traits such as nuptial coloration. At a smaller, within-population scale, we can expect similar adaptive divergence to a heterogeneous visual landscape. Using the cichlid fish, Pseudocrenilabrus multicolor, we investigated within-population variation in diet and nuptial coloration by sampling fish from microhabitats within a relatively small site (~0.14 km2). These visual microhabitats are affected by different types of human disturbance at a very small scale leading to significant differences in water clarity (i.e. turbidity). We used three, non-mutually exclusive working hypotheses to test if (1) males in low turbidity invest more in carotenoid-based coloration (economy of pigments hypothesis), (2) fish from low-turbidity sites eat more carotenoid-rich foods (diet hypothesis), and (3) fish are habitat matching. Stomach content analyses revealed relatively high overlap in diet across microhabitats; however, fish from stations with the lowest turbidity consumed relatively more plant material (high in carotenoid content) than fish captured at high-turbidity stations. Males from clearer waters displayed significantly more carotenoid-based, red and yellow coloration than fish found in microhabitats with higher turbidity, similar to between-population color variation in this species. Furthermore, larger fish displayed more carotenoid coloration overall, but there was no difference in mean male size among microhabitats suggesting that fish were not sorting into microhabitats. Our results suggest that within-population variation in nuptial coloration could be associated with microhabitat heterogeneity in the visual landscape driven by turbidity, a diet with more carotenoid-rich prey items, or a combination of both.

Body size is not correlated with the evolution of male coloration in darters (Percidae: Etheostomatinae)

Abstract Coloration and body size are among the many morphological traits that vary among fish lineages. Elaborate coloration and body size covary in other animal groups, but relationships between these two morphological characteristics have not been rigorously examined in fishes. We formally test for correlations between coloration and body size in darters (Percidae: Etheostomatinae), a group of North American freshwater fishes that vary in the presence of male coloration and maximum body size. Although uncorrected analyses indicate a significant correlation between colour traits and body size in darters, phylogenetically corrected logistic regression models and ANOVAs revealed no significant correlations, suggesting body size does not act as a constraint on elaborate coloration or vice versa. These results are discussed in an ecological and behavioural context.

A Novel Human Sex Difference: Male Sclera Are Redder and Yellower than Female Sclera.

In a seminal study, Kobayashi and Kohshima (1997) found that the human sclera-the white of the eye-is unique among primates for its whitish color, and subsequent work has supported the notion that this coloration underlies the human ability to gaze follow. Kobayashi and Kohshima also claimed that there is no significant sex difference in sclera color, though no data were presented to support the claim. We investigated sclera color in a standardized sample of faces varying in age and sex, presenting the first data comparing male and female sclera color. Our data support the claim that indeed there is a sex difference in sclera color, with male sclera being yellower and redder than female sclera. We also replicated earlier findings that female sclera vary in color across the adult lifespan, with older sclera appearing yellower, redder, and slightly darker than younger sclera, and we extended these findings to male sclera. Finally, in two experiments we found evidence that people use sclera color as a cue for making judgements of facial femininity or masculinity. When sclera were manipulated to appear redder and yellower, faces were perceived as more masculine, but were perceived as more feminine when sclera were manipulated to appear less red and yellow. Though people are typically unaware of the sex difference in sclera color, these findings suggest that people nevertheless use the difference as a visual cue when perceiving sex-related traits from the face.

Correction to 'Can female guppies learn to like male colours? A test of the role of associative learning in originating sexual preferences'.

Open AccessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Herdegen-Radwan M. 2022Correction to ‘Can female guppies learn to like male colours? A test of the role of associative learning in originating sexual preferences’Proc. R. Soc. B.2892022072220220722http://doi.org/10.1098/rspb.2022.0722SectionOpen AccessCorrectionCorrection to ‘Can female guppies learn to like male colours? A test of the role of associative learning in originating sexual preferences’ M. Herdegen-Radwan M. Herdegen-Radwan http://orcid.org/0000-0001-6593-3256 Google Scholar Find this author on PubMed Search for more papers by this author M. Herdegen-Radwan M. Herdegen-Radwan http://orcid.org/0000-0001-6593-3256 Google Scholar Find this author on PubMed Search for more papers by this author Published:27 April 2022https://doi.org/10.1098/rspb.2022.0722This article corrects the followingResearch ArticleCan female guppies learn to like male colours? A test of the role of associative learning in originating sexual preferenceshttps://doi.org/10.1098/rspb.2022.0212 Magdalena Herdegen-Radwan volume 289issue 1972Proceedings of the Royal Society B: Biological Sciences06 April 2022Proc. R. Soc. B289, 20220212. (Published online; 6 April 2022). (doi:10.1098/rspb.2022.0212)Block effect in models presented in tables 1–3 was entered incorrectly. Corrected tables are presented below. The results and conclusions of the paper were not affected by these changes. Table 1. LMM testing female preferences for SC simulated males. The response variable was the proportion of time spent by the female in the orange male's preference zone. The significant term is in italics. Collapse termestimates.e.d.f.tp-valuefixed effectsintercept0.040.81114.70.050.962female treatment (orange)1.080.37116.62.940.004female size (small)0.650.37116.81.780.077block 2−1.200.45116.9−2.660.009block 3−0.460.45115.7−1.030.303repeat−0.320.37115.2−0.860.390male side0.220.37118.10.580.564preference before0.140.58119.40.240.811random effectsvariances.d.female ID: (Intercept)0.00000.0000aquarium: block (intercept)0.00000.0000male model: (intercept)0.09390.3066residual4.02662.0067Table 2. LMM testing female preferences for MC simulated males. The response variable was the proportion of time spent by the female in the orange-dominant male's preference zone. The significant term is in italics. Collapse termestimates.e.d.f.tp-valuefixed effectsintercept0.290.12111.62.530.013female treatment (orange)0.110.60113.41.910.058female size (small)−0.010.60113.3−0.110.909block 50.120.07113.01.600.112block 6−0.110.14112.5−0.810.420repeat0.070.06112.21.190.238male side0.000.06114.10.000.996random effectsvariances.d.female id: (intercept)0.00000.0000aquarium: block (intercept)0.00000.0000male model: (intercept)0.00120.0347residual0.10610.3257Table 3. GLMM testing the reproductive success of experimental males with experimental females, with female size as covariate. The response variable was the proportion of offspring in a brood that were sired by the orange-dominant male. The significant term is in italics. Collapse termestimates.e.zp-valuefixed effectsintercept8.2110.760.760.445female treatment (orange)−18.667.39−2.520.012female size−0.750.94−0.800.424block 50.9810.480.090.925block 6−1.1810.82−0.110.913random effectsvariances.d.aquarium: block (intercept)201.514.2With this, the correct values of the respective t and z statistics and p-value for the treatment effects are also replacing those reported in the text of the paper.AcknowledgementsI thank Lechosław Kuczyński for spotting this error.Footnotes© 2022 The Authors.Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. Previous Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsRelated articlesCan female guppies learn to like male colours? A test of the role of associative learning in originating sexual preferences06 April 2022Proceedings of the Royal Society B: Biological Sciences This Issue27 April 2022Volume 289Issue 1973 Article InformationDOI:https://doi.org/10.1098/rspb.2022.0722PubMed:35473387Published by:Royal SocietyOnline ISSN:1471-2954History: Manuscript received14/04/2022Manuscript accepted19/04/2022Published online27/04/2022Published in print27/04/2022 License:© 2022 The Authors.Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. Citations and impact Subjectsbehaviour Large datasets are available through Proceedings B's partnership with Dryad

From a pair to a dozen: the piscivorous species of Haplochromis (Cichlidae) from the Lake Edward system

Piscivory is a common trophic niche among cichlids of the East African Great Lakes, including Lakes Edward and George. From these two lakes, we examined the taxonomic diversity of cichlid species with a piscivorous morphology. Prior to this study, two piscivorous species were formally described, Haplochromis squamipinnis and H. mentatus. We redescribe both species and describe an additional ten new species of Haplochromis with a piscivorous morphology: H. latifrons sp. nov., H. rex sp. nov., H. simba sp. nov., H. glaucus sp. nov., H. aquila sp. nov., H. kimondo sp. nov., H. falcatus sp. nov., H. curvidens sp. nov., H. pardus sp. nov., and H. quasimodo sp. nov. All twelve species differ in dominant male colour pattern (unknown for H. latifrons sp. nov. and H. curvidens sp. nov.) and morphological traits. The species can be divided into two morphological groups: the macrodontic piscivores and the microdontic piscivores. This division potentially reflects an ecological differentiation in habitat use, hunting technique, prey species, and prey size. We conclude that some 12–20% of the species from the cichlid assemblage of Lake Edward have a piscivorous morphology.

A practical approach to revise the Oxynoemacheilus bergianus species group (Teleostei: Nemacheilidae).

The Oxynoemacheilus bergianus species group is revised based on tree topology (ML, NJ, MP), distance (K2P and ASAP) and Poisson tree process analyses of DNA barcode data tested against morphometric and morphological characters including colour patterns. The O. bergianus species group is distinguished from other Oxynoemacheilus groups based on morphological characters: its constituent species have a slender caudal peduncle, a suborbital flap in the male, a mottled or blotched colour pattern, and lack bold, black spots on the caudal-fin base. It is also supported as a monophyletic unit in our molecular analysis. The O. bergianus group includes 10 molecular clades following congruently well-supported NJ, MP and ML based entities. Species described as O. bergianus, O. banarescui, O. erdali, O. fatsaensis, O. samanticus, and O. simavicus from Turkey, O. lenkoranensis from Azerbaijan, and O. longipinnis and O. parvinae from Iran belong to this species group. The group includes also four unnamed molecular clades. We were unable to detect external differences between any of the molecular clades in colour pattern or any morphometric or morphological characters examined. In the 10 molecular clades in the O. bergianus species group, the intraclade K2P distance ranges from 0.01.8% while the distances between molecular clades ranges from 0.65.9%. To resolve the species diversity of this group, we also analysed the intraspecific and interspecific variability in the K2P distance of DNA barcode data from 53 other Oxynoemacheilus species. Here, the intraspecific variability ranges from 0.02.4% while the interspecific K2P distance ranges from 1.220.8%. In the O. bergianus species group, only four groups are detected by the mPTP species delimitation approach distinguished by a K2P distance of 2.9% or more. We treat these four groups as valid species, corresponding to O. banarescui, O. bergianus, O. fatsaensis, and O. simavicus. Oxynoemacheilus samanticus from the Kzlrmak and Seyhan drainages, O. lenkoranensis from the Caspian basin, O. erdali from the Euphrates, and O. longipinnis and O. parvinae from the Tigris drainage are treated as synonyms of O. bergianus. Fishes from an unnamed molecular clade from the upper Tigris, and from a second unnamed clade from the upper Euphrates, are both identified as O. bergianus. Oxynoemacheilus bergianus might be a junior synonym of O. bergi from the Kura. The distribution range of O. simavicus, described from the Simav drainage in the Marmara basin, is expanded to the east and two molecularly differentiated population groups occur in the Sakarya drainage, the Byk Melen River and potentially in other adjacent coastal streams. Oxynoemacheilus fatsaensis, described from the coastal stream Eleki in northern Anatolia, is also widespread in the Yeilrmak drainage. Morphological characters proposed to distinguish O. fatsaensis from the other species of the O. bergianus group could not be confirmed by our data on fishes from the Yeilrmak. This study also discusses the theoretical background, our reasons for conducting this revision in the way we did, and what the alternatives would be.

A global analysis of aerial displays in passerines revealed an effect of habitat, mating system and migratory traits.

Aerial displaying is a flamboyant part of the sexual behaviour of several volant animal groups, including birds. Nevertheless, little attention has been focused on identifying correlates of large-scale diversity in this trait. In this study, we scored the presence and absence of aerial displays in males of 1732 species of passerine birds (Passeriformes) and employed Bayesian phylogenetically informed mixed models to test for associations between aerial displays and a set of life-history and environmental predictors. Our multi-variate models revealed that species with males that perform aerial displays inhabited open rather than closed (forested) habitats. These species also exhibited higher levels of polygyny, had more elongated wings, migrated over longer distances and bred at higher latitudes. When we included species where the sexual function of displays has not been explicitly described but is likely to occur, we found that aerial displaying was also associated with smaller body size and increased male plumage coloration. Our results suggest that both sexual selection and natural selection have been important sources of selection on aerial displays in passerines.

Can female guppies learn to like male colours? A test of the role of associative learning in originating sexual preferences.

How do female sexual preferences for male ornamental traits arise? The developmental origins of female preferences are still an understudied area, with most explanations pointing to genetic mechanisms. One intriguing, little-explored, alternative focuses on the role of associative learning in driving this process. According to this hypothesis, a preference learned in an ecological context can be transferred into a sexual context, resulting in changes in mating preferences as a by-product. I tested this hypothesis by first training female guppies to associate either orange or black colour with food delivery; I then presented videos of males with computer-manipulated coloured spots and measured female preference towards them. I also allowed females from both treatments to mate with males differing in their ratio of orange-to-black spots and measured the males' reproductive success. After training, female sexual preferences significantly diverged among treatments in the expected direction. In addition, orange males sired a greater proportion of offspring with females food-conditioned on orange compared to those conditioned on black. These results show that mating preferences can arise as a by-product of associative learning, which, via translation into variation in male fitness, can become associated with indirect genetic benefits, potentially leading to further evolution.

High Resolution Quantitative Trait Locus Mapping and Whole Genome Sequencing Enable the Design of an Anthocyanidin Reductase-Specific Homoeo-Allelic Marker for Fruit Colour Improvement in Octoploid Strawberry (Fragaria × ananassa).

Fruit colour is central to the sensorial and nutritional quality of strawberry fruit and is therefore a major target in breeding programmes of the octoploid cultivated strawberry (Fragaria × ananassa). The red colour of the fruit is caused by the accumulation of anthocyanins, which are water-soluble flavonoids. To facilitate molecular breeding, here we have mapped with high resolution fruit colour quantitative trait loci (QTLs) (COLOUR, scored visually as in selection programmes) and associated flavonoid metabolic QTLs (5 anthocyanins compounds together with 8 flavonols and flavan-3-ols) to specific subgenomes of cultivated strawberry. Two main colour-related QTLs were located on the LG3A linkage group (Fragaria vesca subgenome). Genetic mapping, transcriptome analysis and whole genome sequencing enabled the detection of a homoeo-allelic variant of ANTHOCYANIDIN REDUCTASE (ANR) underlying the major male M3A COLOUR and pelargonidin-3-glucoside (PgGs) QTLs (up to ∼20% of explained variance). Consistent with previously published functional studies, ANR transcript abundance was inversely related with PgGs content in contrasted progeny individuals. Genetic segregation analyses further indicated that a molecular marker designed using an 18 bp deletion found in the 5′UTR of the candidate ANR homoeo-allelic variant is effective in identifying genotypes with intense red fruit colour. Our study provides insights into the genetic and molecular control of colour-related traits in strawberry and further defines a genetic marker for marker-assisted selection of new strawberry varieties with improved colour. The QTLs detected and the underlying candidate genes are different from those described to date, emphasising the importance of screening a wide diversity of genetic resources in strawberry.

Intrinsic climatic predictability affects ornamental coloration of adult males: Evidence for compensation among carotenoid‐ and melanin‐based coloration

Abstract Ornamental coloration is frequently an honest signal of quality associated with sexual selection. While changes in average environmental conditions affect carotenoid‐ and melanin‐based coloration, no evidence exists that changes in intrinsic environmental predictability affect coloration. Here we experimentally manipulated the intrinsic predictability of precipitation in semi‐natural populations of common lizards Zootoca vivipara and tested its effect on ornamental coloration and reproduction of adult males. Less predictable precipitation decreased hue of carotenoid‐based coloration and the extent of melanin‐based coloration. Hue was positively correlated and the extent of melanin‐based coloration was negatively correlated with the male's number of confirmed mate partners. Treatment effects on hue were associated with reduced, and treatment effects on the extent of melanin‐based coloration with increased access to females, in line with differential effects on sexual selection. Neither survival nor reproductive success of adult males significantly differed among predictability treatments, suggesting that negative effects on reproduction caused by changes in carotenoid‐based coloration may have been compensated by changes in melanin‐based coloration. The results also showed that ornamentation, rather than reproduction and survival of adult males, was affected by less favourable conditions. Together with previous results, this suggests that coloration might be more sensitive to changes in environmental conditions than direct fitness proxies. Read the free Plain Language Summary for this article on the Journal blog.

A large and diverse autosomal haplotype is associated with sex-linked colour polymorphism in the guppy

Male colour patterns of the Trinidadian guppy (Poecilia reticulata) are typified by extreme variation governed by both natural and sexual selection. Since guppy colour patterns are often inherited faithfully from fathers to sons, it has been hypothesised that many of the colour trait genes must be physically linked to sex determining loci as a ‘supergene’ on the sex chromosome. Here, we phenotype and genotype four guppy ‘Iso-Y lines’, where colour was inherited along the patriline for 40 generations. Using an unbiased phenotyping method, we confirm the breeding design was successful in creating four distinct colour patterns. We find that genetic differentiation among the Iso-Y lines is repeatedly associated with a diverse haplotype on an autosome (LG1), not the sex chromosome (LG12). Moreover, the LG1 haplotype exhibits elevated linkage disequilibrium and evidence of sex-specific diversity in the natural source population. We hypothesise that colour pattern polymorphism is driven by Y-autosome epistasis.