Female Coloration Research Articles

Gene expression in male and female stickleback from populations with convergent and divergent throat coloration.

Understanding of genetic mechanisms underlying variation in sexual dichromatism remains limited, especially for carotenoid‐based colors. We addressed this knowledge gap in a gene expression study with threespine stickleback. We compared male and female throat tissues across five populations, including two in which female red coloration has evolved convergently. We found that the expression of individual genes, gene ontologies, and coexpression networks associated with red female color within a population differed between California and British Columbia populations, suggesting differences in underlying mechanisms. Comparing females from each of these populations to females from populations dominated by dull females, we again found extensive expression differences. For each population, genes and networks associated with female red color showed the same patterns for males only inconsistently. The functional roles of genes showing correlated expression with female color are unclear within populations, whereas genes highlighted through inter‐population comparisons include some previously suggested to function in carotenoid pathways. Among these, the most consistent patterns involved TTC39B (Tetratricopeptide Repeat Domain 39B), which is within a known red coloration QTL in stickleback and implicated in red coloration in other taxa.

Multiple Mechanisms of Photoreceptor Spectral Tuning in Heliconius Butterflies.

The evolution of color vision is often studied through the lens of receptor gain relative to an ancestor with fewer spectral classes of photoreceptor. For instance, in Heliconius butterflies, a genus-specific UVRh opsin duplication led to the evolution of UV color discrimination in Heliconius erato females, a rare trait among butterflies. However, color vision evolution is not well understood in the context of loss. In Heliconius melpomene and Heliconius ismenius lineages, the UV2 receptor subtype has been lost, which limits female color vision in shorter wavelengths. Here, we compare the visual systems of butterflies that have either retained or lost the UV2 photoreceptor using intracellular recordings, ATAC-seq, and antibody staining. We identify several ways these butterflies modulate their color vision. In H. melpomene, chromatin reorganization has downregulated an otherwise intact UVRh2 gene, whereas in H. ismenius, pseudogenization has led to the truncation of UVRh2. In species that lack the UV2 receptor, the peak sensitivity of the remaining UV1 photoreceptor cell is shifted to longer wavelengths. Across Heliconius, we identify the widespread use of filtering pigments and co-expression of two opsins in the same photoreceptor cells. Multiple mechanisms of spectral tuning, including the molecular evolution of blue opsins, have led to the divergence of receptor sensitivities between species. The diversity of photoreceptor and ommatidial subtypes between species suggests that Heliconius visual systems are under varying selection pressures for color discrimination. Modulating the wavelengths of peak sensitivities of both the blue- and remaining UV-sensitive photoreceptor cells suggests that Heliconius species may have compensated for UV receptor loss.

A lot of convergence, a bit of divergence: Environment and interspecific interactions shape body colour patterns in Lissotriton newts.

Coexistence with related species poses evolutionary challenges to which populations may react in diverse ways. When exposed to similar environments, sympatric populations of two species may adopt similar phenotypic trait values. However, selection may also favour trait divergence as a way to reduce competition for resources or mates. The characteristics of external body parts, such as coloration and external morphology, are involved to varying degrees in intraspecific signalling as well as in the adaptation to the environment and consequently may be diversely affected by interspecific interactions in sympatry. Here, we studied the effect of sympatry on various colour and morphological traits in males and females of two related newt species Lissotriton helveticus and L.vulgaris. Importantly, we did not only estimate how raw trait differences between species respond to sympatry, but also the marginal responses after controlling for environmental variation. We found that dorsal and caudal coloration converged in sympatry, likely reflecting their role in adaptation to local environments, especially concealment from predators. In contrast, aspects of male and female ventral coloration, which harbours sexual signals in both species, diverged in sympatry. This divergence may reduce opportunities for interspecific sexual interactions and the associated loss of energy, suggesting reproductive character displacement (RCD). Our study emphasizes the contrasting patterns of traits involved in different functions and calls for the need to consider this diversity in evolutionary studies.

Aculeate Hymenopterans as Aposematic and Mimetic Models

Aposematism and mimicry are complex phenomena which have been studied extensively; however, much of our knowledge comes from just a few focal groups, especially butterflies. Aposematic species combine a warning signal with a secondary defense that reduces their profitability as prey. Aculeate hymenopterans are an extremely diverse lineage defined by the modification of the ovipositor into a stinger which represents a potent defense against predators. Aculeates are often brightly colored and broadly mimicked by members of other arthropod groups including Diptera, Lepidoptera, Coleoptera, and Araneae. However, aculeates are surprisingly understudied as aposematic and mimetic model organisms. Recent studies have described novel pigments contributing to warning coloration in insects and identified changes in cis-regulatory elements as potential drivers of color pattern evolution. Many biotic and abiotic factors contribute to the evolution and maintenance of conspicuous color patterns. Predator distribution and diversity seem to influence the phenotypic diversity of aposematic velvet ants while studies on bumble bees underscore the importance of intermediate mimetic phenotypes in transition zones between putative mimicry rings. Aculeate hymenopterans are attractive models for studying sex-based intraspecific mimicry as male aculeates lack the defense conferred by the females’ stinger. In some species, evolution of male and female color patterns appears to be decoupled. Future studies on aposematic aculeates and their associated mimics hold great promise for unraveling outstanding questions about the evolution of conspicuous color patterns and the factors which determine the composition and distribution of mimetic communities.

Dark-eyed females: sexually dimorphic prespawning coloration results from sex-specific physiological response to hormone exposure in the sand gobyPomatoschistus minutus(Gobiiformes: Gobiidae)

AbstractThe function and regulation of female nuptial colour signals are poorly understood. In fish, colour is often mediated by chromatophores, allowing for rapid and versatile signalling. Here, we examine a distinct but temporary black line around the eyes and snout (‘dark eyes’) displayed by female sand gobies before spawning and never observed in males. We investigate the regulatory mechanism of the display by analysing the number of melanophores in both sexes in vitro and their response to hormonal exposure. We also test the hypothesis that dark eyes serve an anti-glare function and focus the line of sight, by analysing the frequency, intensity and duration of the display in bright and dim light, with and without males present. We show that the sexes do not differ in terms of the number of melanophores, but that males and females respond in different ways to exposure to melanocyte-stimulating hormone, which has a stronger dilatory effect in females and results in a darker line. However, the darkness of the iris is not affected. Neither light levels nor the presence of potential mates affect the frequency of the dark eye display, but the display is longer lasting and more intense in the presence of smaller nest-holding males.

A Review of the Genus Cloeon from Chinese Mainland (Ephemeroptera: Baetidae)

Simple SummaryThe mayflies of baetid genus Cloeon Leach, 1815 are common inhabitants of lentic environments, such as ponds, lakes, reservoirs, and even some temporary bodies of water near human communities. Therefore, they are frequently collected and comprehensively researched around the world. In China, however, although nine Cloeon species names have been reported, few of them are confirmed historically. In this study of over 1000 specimens from over 50 sites on the Chinese mainland, four species of Cloeon were identified, namely C. bicolor Kimmins, 1947, C. dipterum (Linnaeus, 1761), C. harveyi (Kimmins, 1947), and C. viridulum Navás, 1931. The record of C. bicolor is the first in China, and its nymphs are described for the first time. Three junior synonyms are proposed for the species C. viridulum. The present research is not only a revised review of the genus Cloeon for the Chinese mainland but also a solid base for future works on Chinese and Asian Cloeon taxonomy.The widely distributed and species diverse genus Cloeon Leach, 1815 has never been reviewed in China, although nine species names have been reported from this country. After checking types of two species (C. viridulum and C. apicatum) and newly collected materials from more than 50 sites, four species are recognized, compared, and photographed in this research. Among them, the species C. bicolor Kimmins, 1947 is first recorded in China, and its nymphs are described for the first time. The distribution in China of two other species (C. dipterum (Linnaeus, 1761) and C. harveyi (Kimmins, 1947)) are also confirmed. The two species established by Navás (C. apicatum Navás, 1933 = C. navasi Bruggen, 1957, C. pielinum Navás, 1933, syn. nov.) and the species C. micki named by Tong and Dudgeon in 2021 are synonymized with C. viridulum Navás, 1931—the fourth species in this study. Furthermore, the C. virens Klapálek, 1905 from the Chinese mainland, found by Ulmer in 1925, is also regarded as the last species. Among the four species, the C. dipterum and C. harveyi seem closer because of the similar female color patterns of their stigma and ventral abdomen, while the species C. viridulum and C. bicolor are more alike because they have neither pigmented stigma nor stripes on abdominal sterna.

Biology of the oldest butterfly species in the world, Baronia brevicornis: food, abundance, polymorphism, and survival

The study of the basic biology of panchronic species could help understand their persistence through geological time. One of the least studied panchronic species is Baronia brevicornis Salvin (Lepidoptera: Papilionidae), the oldest known butterfly species endemic to Mexico. Here we report on our findings from studying a population of B. brevicornis in Sierra de Huautla, Morelos, for 3 years. In this population we identified 3 male and 3 female color morphs, making it perhaps the most complex polymorphism described yet for a panchronic species. We found a balanced sex ratio in newly emerged adults but a sex ratio biased to males at reproductive sites. Significantly, we found adults of the butterfly only on patches of the host plant Vachellia campechiana (Mill.) Seigler & Ebinger (Fabaceae) that also offered feeding sources for adults and report for the first-time adults feeding on 5 plant species. Additionally, differences in water use in trees of V. campechiana in zones with or without B. brevicornis suggest a relationship between butterfly food sources and plant water expenditure. Our findings on B. brevicornis could be used to develop conservation plans for this species.

Adult coloration of the Bearded Vulture (Gypaetus barbatus) in the Pyrenees: relation to sex, mating system and productivity

Cosmetic coloration is not a common phenomenon among bird species. Adult Bearded Vultures Gypaetus barbatus typically show orange coloration in head, chest, belly and tarsus feathers that is the result of mud baths in ferruginous substrates. Several non‐mutually exclusive visual signalling hypotheses can be proposed to explain this phenomenon. Coloration could be used to signal: (1) dominance towards conspecifics, with darker birds being dominant (status signalling hypothesis); (2) sex (gender signalling hypothesis) because females are usually more intensely coloured; (3) individual quality for mate choice (quality signalling hypothesis); or (4) different reproductive strategies between individuals (e.g. in polyandrous trios). Here we report results from systematic monitoring of breeding Bearded Vultures in the pre‐laying period in the central and western Pyrenees (Spain and France) between 2016 and 2020, including 162 individuals from 70 reproductive units (48 pairs and 22 trios). We classified individuals as being white, pale, medium or dark, and analysed the relationship with sex, mating system (pair or trios) and average productivity across years. Our results showed that the most common form was medium (67%), then pale (22%), dark (9%) and white (2%) morphs. Overall, females were darker than males, but with a large overlap in coloration. In trios, dominant males were darker than subordinate males, although differences were not statistically significant. The mating system (pair or trio) did not influence female coloration. A multimodel comparison showed that the number of years of territory occupation, mating system and their combination (but not coloration) were the best predictors of average productivity. Our results do not support the gender signalling hypothesis. The reproductive strategy signalling hypothesis might be supported because beta males were, on average, paler than males in pairs, but this topic requires further investigations because our results were inconclusive. Finally, that females (thought to be dominant because of their slightly larger size) were on average darker than males agrees with the status signalling hypothesis, although an experimental approach would be needed to formally test this hypothesis.

Conspicuous female plumage is common among open cup-nesting passerine birds

Alfred Russel Wallace hypothesized that the use of cavity or dome nests releases incubating birds from predation risk, and that this allows the evolution of conspicuous coloration in females. By this hypothesis, females that use open nests are subject to strong selection for crypsis. Here, we test the validity of Wallace’s proposed evolutionary correlation between nest type and conspicuous coloration in females across the largest avian radiation, the Passeriformes, using phylogenetic comparative methods. We also test an alternate hypothesis that cavity-nesting results in greater conspicuousness because competition for cavities is stronger than for other nest sites, and such competition can drive social selection on female plumage. By this hypothesis, dome-nesting females should generally be less conspicuous than cavity-nesting species. We found no support for Wallace’s hypothesis that concealed nests yield conspicuous plumage while open nests yield dull plumage, and some support for the social selection hypothesis in smaller-bodied, gregarious species. While our analyses do not support the core part of Wallace’s hypothesis, they corroborate his contention that evolutionary transitions in nest type are rare, indicating that nest types may influence macroevolutionary selective regimes for other traits.

Correlated evolution of distinct signals associated with increased social selection in female white-shouldered fairywrens.

Conspicuous female signals have recently received substantial scientific attention, but it remains unclear if their evolution is the result of selection acting on females independently of males or if mutual selection facilitates female change. Species that express female, but not male, phenotypic variation among populations represents a useful opportunity to address this knowledge gap. White‐shouldered fairywrens (Malurus alboscapulatus) are tropical songbirds with a well‐resolved phylogeny where female, but not male, coloration varies allopatrically across subspecies. We explored how four distinct signaling modalities, each putatively associated with increased social selection, are expressed in two populations that vary in competitive pressure on females. Females in a derived subspecies (M. a. moretoni) have evolved more ornamented plumage and have shorter tails (a signal of social dominance) relative to an ancestral subspecies (M. a. lorentzi) with drab females. In response to simulated territorial intrusions broadcasting female song, both sexes of M. a. moretoni are more aggressive and more coordinated with their mates in both movement and vocalizations. Finally, M. a. moretoni songs are more complex than M. a. lorentzi, but song complexity does not vary between sexes in either population. These results suggest that correlated phenotypic shifts in coloration and tail morphology in females as well as song complexity and aggression in both sexes may have occurred in response to changes in the intensity of social selection pressures. This highlights increased competitive pressures in both sexes can facilitate the evolution of complex multimodal signals.

Differences in plumage coloration predict female but not male territorial responses in three antbird sister species pairs

Social selection, via intra- and intersexual competition for sexual (e.g. mates) and/or nonsexual (e.g. territories) resources, is thought to drive the evolution of ornaments in both sexes. However, the relative importance of intra- and intersexual competition in promoting the evolution of female and male ornamentation and, hence, sexual dichromatism remains poorly understood. We addressed this issue in antbirds (Thamnophilidae), a radiation of sexually dichromatic passerines wherein eumelanic plumage patches have evolved multiple times in both sexes. In antbirds, the degree of sexual dichromatism differs between closely related species primarily due to eumelanic dark patches in either sex. If eumelanic patches evolved by social selection, individuals of species bearing more conspicuous eumelanic patches should display stronger territorial responses regardless of their sex. Using playback experiments, we simulated three conspecific territorial intrusion types – a social pair, a female and a male – and measured responses by social pairs of two sister species pairs exhibiting greater interspecific differences in female coloration and one sister species pair exhibiting greater interspecific differences in male coloration. We found that females of species bearing more conspicuous eumelanic patches responded more strongly than females of species bearing less conspicuous eumelanic patches, but only towards simulated female and/or male intruders. However, males responded similarly to all intrusions regardless of interspecific coloration differences. Our results suggest that eumelanic patches in antbirds may function as ornaments and that greater female ornamentation may function in intra- and intersexual contexts and reflect stronger social competition in ornamented females for territories and, possibly, mates. In contrast, in species pairs with greater interspecific differences in male ornamentation, territorial competition may occur predominantly among males and female mate choice may drive the evolution of male ornamentation. Our study highlights that social selection pressures acting on both sexes may drive the evolution of contrasting sexual dichromatism patterns. • Antbird sister species differed in female or male eumelanic coloration. • Female coloration was positively associated with female territorial responses. • Male coloration was not associated with male territorial responses. • Both sexes may show intra- and intersexual territorial responses. • Patterns of sexual dichromatism may evolve by social selection acting on both sexes.

Zerdeçal Tozu İlave Edilmiş Diyetlerin Sarı Kuyruk Çiklit Pseudotropheus acei (Regan 1922)'nin Vücut Pigmentasyonu ve Büyüme Performansı Üzerindeki Etkileri

There are few studies about the effect of turmeric powder on the skin pigmentation of fish in the literature. This study was conducted to research body and tail pigmentation and growth performance of Pseudotropheus acei (Regan 1922) fed supplemented diets with different ratio turmeric (Curcuma longa) powder. Five diets were prepared by adding four different ratios of turmeric powder (T1: 1%, T3: 3%, T5: 5%, and T7: 7% ) to C: control diet (without turmeric powder). A total of 75 broodstock (mean weight 6g) were randomly stocked (4♀:1♂) in 15 aquariums (70x30x40cm), with three replications. The fish were fed twice daily at 8:30 and 20:30 with the diets supplemented turmeric as ad libitum during the 90 days. At the end of the experiment, the body and tail pigmentation of P. acei significantly increased with increasing turmeric rate in diets (P <0.05). The blue indicator –b values in male and female body color were high in all turmeric supplemented groups compared to the control group (P˂0.05). Also, the yellow color indicator + b value in the color of the male and female tail increased with the addition of turmeric. Hab values were determined in the blue area for the body and in the yellow area for the tail. However, pigmentation of all groups supplemented turmeric powder was visually not different from the color of the control group. There were no significant differences between final weights, weight gain SGR, FCR, and survival rates of P. acei fed diets supplemented with turmeric powder compared to the control (P˃0.05). As a result of the study, skin and tail pigmentation and growth performance of P. acei were not improved by supplementing with turmeric powder to diets.

Different stress from parasites and mate choice in two female morphs of the blue-tailed damselfly

In Odonates, female colour polymorphism is common and implies the presence of two or more female types with different colours and behaviours. To explain this phenomenon, several hypotheses have been proposed that consider morph frequency, population density, the presence of parasites, and mating behaviour. We studied the blue-tailed damselfly Ischnura elegans, a species with a blue androchrome morph and two gynochrome morphs (the common green infuscans, and the rare orange rufescens-obsoleta). The size of adult males and females, the presence of parasites, and pairing behaviour between males and the three female morphs was assessed in field conditions throughout the reproductive season in NW Italy. Moreover, growth and emergence success of larvae produced by the different morphs was analyzed in standardized conditions. In the field, males showed a preference for the gynochrome infuscans females, despite a similar frequency of androchrome females. In test conditions, male preference for the infuscans females was also observed. Paired males and paired androchrome females were larger than unpaired individuals, while there were no differences in size between paired and unpaired infuscans females. Males and androchrome females were more parasitized than infuscans females. The survival and emergence success of larvae produced by androchrome females was higher than those of offspring produced by the infuscans females. Our results suggest that a higher survival of progeny at the larval stage could counterbalance the higher parasitism and the lower pairing success of andromorph adult females and highlight the importance of considering the whole life-cycle in polymorphism studies.

The evolution of primate coloration revisited

AbstractPrimates are noted for their varied and complex pelage and bare skin coloration but the significance of this diverse coloration remains opaque. Using new updated information, novel scoring of coat and skin coloration, and controlling for shared ancestry, we reexamined and extended findings from previous studies across the whole order and the five major clades within it. Across primates, we found (i) direct and indirect evidence for pelage coloration being driven by protective coloration strategies including background matching, countershading, disruptive coloration, and aposematism, (ii) diurnal primates being more colorful, and (iii) the possibility that pelage color diversity is negatively associated with female trichromatic vision; while (iv) reaffirming avoidance of hybridization driving head coloration in males, (v) darker species living in warm, humid conditions (Gloger’s rule), and (vi) advertising to multiple mating partners favoring red genitalia in females. Nonetheless, the importance of these drivers varies greatly across clades. In strepsirrhines and cercopithecoids, countershading is important; greater color diversity may be important for conspecific signaling in more diurnal and social strepsirrhines; lack of female color vision may be associated with colorful strepsirrhines and platyrrhines; whereas cercopithecoids obey Gloger’s rule. Haplorrhines show background matching, aposematism, character displacement, and red female genitalia where several mating partners are available. Our findings emphasize several evolutionary drivers of coloration in this extraordinarily colorful order. Throughout, we used coarse but rigorous measures of coloration, and our ability to replicate findings from earlier studies opens up opportunities for classifying coloration of large numbers of species at a macroevolutionary scale.

Ecological effects on female bill colour explain plastic sexual dichromatism in a mutually-ornamented bird

Sex differences in ornamentation are common and, in species with conventional sex roles, are generally thought of as stable, due to stronger sexual selection on males. Yet, especially in gregarious species, ornaments can also have non-sexual social functions, raising the possibility that observed sex differences in ornamentation are plastic. For example, females may invest in costly ornamentation more plastically, to protect body and reproductive ability in more adverse ecological conditions. We tested this hypothesis with experimental work on the mutually-ornamented common waxbill (Estrilda astrild), supplementing their diets either with pigmentary (lutein, a carotenoid) or non-pigmentary (vitamin E) antioxidants, or alleviating winter cold temperature. We found that both lutein and vitamin E supplementation increased red bill colour saturation in females, reaching the same mean saturation as males, which supports the hypothesis that female bill colour is more sensitive to environmental or physiological conditions. The effect of vitamin E, a non-pigment antioxidant, suggests that carotenoids were released from their antioxidant functions. Alleviating winter cold did not increase bill colour saturation in either sex, but increased the stability of female bill colour over time, suggesting that female investment in bill colour is sensitive to cold-mediated stress. Together, results show that waxbill bill sexual dichromatism is not stable. Instead, sexual dichromatism can be modulated, and even disappear completely, due to ecology-mediated plastic adjustments in female bill colour.

Effect of female body color on mate selection by male Mozambique tilapia (Oreochromis mossambicus)

ABSTRACT The effect of female body color on mate selection by male Mozambique Tilapia (Oreochromis mossambicus) was assessed. A single black or gold male was placed in each of nine spawning net cages along with three gold and three black females. Number of spawns and day of spawns were recorded over a 14-day period. All males spawned, and 29 of 54 of females spawned. Female body color had no effect on the number of spawns or day of spawn with either gold or black males. Body color of females did not elicit sexual selection by either gold or black males.

Speciation rates are positively correlated with the rate of plumage color evolution in hummingbirds.

A fascinating pattern in nature is the uneven distribution of biodiversity among clades, some with low species richness and phenotypic variation in contrast to others with remarkable species richness and phenotypic diversity. In animals, communication signals are crucial for intra- and interspecific interactions and are likely an important factor in speciation. However, evidence for the association between the evolution of such signals and speciation is mixed. In hummingbirds, plumage coloration is an important communication signal, particularly for mate selection. Here, using reflectance data for 237 hummingbird species (∼66% of total diversity), we demonstrate that color evolution rates are associated with speciation rates, and that differences among feather patches are consistent with an interplay between natural and sexual selection. We found that female color evolution rates of multiple plumage elements, including the gorget, were similar to those of males. Although male color evolution in this patch was associated with speciation, female gorget color evolution was not. In other patches, the relationship between speciation and color evolution rates was pervasive between sexes. We anticipate that future studies on animal communication will likely find that evolution of signaling traits of both sexes has played a vital role in generating signal and species diversity.

Does male mate choice select for female coloration in a promiscuous primate species?

The traditional view of sex roles and sexual selection emphasizes the evolution of male ornaments as a result of female mate choice and male–male competition. Female ornaments are now receiving more attention, although their roles in mating decisions are still less well understood, especially considering cases in which colourful ornaments are expressed by both sexes. In this study, we analysed whether female skin coloration (luminance and redness of the face and hindquarters) influenced male mate choice and sexual behaviours in relation to intracycle (cycle phase), intercycle (number of consecutive cycles, conceptive nature of the cycle) and interindividual (age, social rank, weight and parity) variation in a captive social group of Japanese macaques, Macaca fuscata . Males did not preferentially choose darker/redder females. Moreover, males did not appear to use female skin coloration to apportion their mating efforts on the fertile phase of the menstrual cycle or during cycles that led to conception, or to discriminate between females. Collectively, our results suggest that female skin coloration may not have been sexually selected in this species and that males mated regardless of such variation across females. To our knowledge, our study is among the few to report a lack of male choice for female coloration in a species where both sexes display ornamentation. Our findings provide novel insights on the role and evolution of female coloration in sexual signalling and mating decisions. • Nonsex-specific colourful traits can potentially influence mate choice. • In most primate species, it is unclear if males attend to colourful female traits. • We tested the effect of female coloration on male mate choice in Japanese macaques. • Males did not discriminate between/within females or cycles based on coloration. • Female coloration is unlikely to be a sexually selected trait in Japanese macaques.

Integrative taxonomy and a new species description in the sturtevanti subgroup of the Drosophila saltans group (Diptera: Drosophilidae)

Although the biological concept of species is well established in animals, sometimes the decision about the specific status of a new species is difficult and hence requires support of an integrative analysis of several character sets. To date, the species Drosophila sturtevanti, D. magalhaesi, D. milleri and D. dacunhai, belonging to the sturtevanti subgroup of the Neotropical saltans species group, are identified mainly by the aedeagus morphology, but also present some differences in spot coloration and patterning of the female sixth tergite and in the shape and size of the spermathecae, parallel to a pattern of reproductive isolation. In the present study, we describe a novel saltans group species from French Guiana belonging to the sturtevanti subgroup. Our species designation is based on an integrative approach covering (i) aedeagi and spermathecae morphology by scanning electron microscopy, (ii) analysis of female sixth-tergite color, (iii) morphometrical analysis of aedeagi and wings, (iv) analysis of partial sequence of the COI, COII and ND4 mitochondrial genes as well as (v) intercrosses for analysis of reproductive isolation. The comparative analysis of the results on these markers with those of D. sturtevanti, D. milleri and D. dacunhai supports that this line belongs to a new species of the sturtevanti subgroup that we name Drosophila lehrmanae sp. nov. in honor of Prof. Lee Ehrman´s 85th birthday.

The effect of the doublesex gene in body colour masculinization of the damselfly Ischnura senegalensis.

Odonata species display a remarkable diversity of colour patterns, including intrasexual polymorphisms. In the damselfly (Ischnura senegalensis), the expression of a sex-determining transcription factor, the doublesex (Isdsx) gene is reportedly associated with female colour polymorphism (CP) (gynomorph for female-specific colour and andromorph for male-mimicking colour). Here, the function of Isdsx in thoracic coloration was investigated by electroporation-mediated RNA interference (RNAi). RNAi of the Isdsx common region in males and andromorphic females reduced melanization and thus changed the colour pattern into that of gynomorphic females, while the gynomorphic colour pattern was not affected. By contrast, RNAi against the Isdsx long isoform produced no changes, suggesting that the Isdsx short isoform is important for body colour masculinization in both males and andromorphic females. When examining the expression levels of five genes with differences between sexes and female morphs, two melanin-suppressing genes, black and ebony, were expressed at higher levels in the Isdsx RNAi body area than a control area. Therefore, the Isdsx short isoform may induce thoracic colour differentiation by suppressing black and ebony, thereby generating female CP in I. senegalensis. These findings contribute to the understanding of the molecular and evolutionary mechanisms underlying female CP in Odonata.