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Data from: UV photoreceptors and UV-yellow wing pigments in Heliconius butterflies allow a color signal to serve both mimicry and intraspecific communication
Mimetic wing coloration evolves in butterflies in the context of predator confusion. Unless butterfly eyes have adaptations for discriminating mimetic color variation, mimicry also carries a risk of confusion for the butterflies themselves. Heliconius butterfly eyes, which express recently duplicated UV opsins, have such an adaptation. To examine bird and butterfly color vision as sources of selection on butterfly coloration we studied yellow wing pigmentation in the tribe Heliconiini. We confirmed using reflectance and mass spectrometry that only Heliconius use 3-hydroxy-DL kynurenine (3-OHK) as a wing pigment. 3-OHK looks yellow to humans but it reflects both UV- and long-wavelength light whereas butterflies in related genera have chemically unknown yellow pigments mostly lacking UV-reflectance. Modeling of these color signals reveals that the two UV photoreceptors of Heliconius are better suited to separating 3-OHK from non-3-OHK spectra compared to the photoreceptors of related genera or birds. The co-occurrence of potentially enhanced UV-vision and a UV-reflecting 'yellow' wing pigment could allow unpalatable Heliconius private intraspecific communication in the presence of mimics. Our results are the best available evidence for the correlated evolution of a color signal and color vision. They also suggest that predator visual systems are error-prone in the context of mimicry.
Data from: The meaning of melanin, carotenoid, and pterin pigments in the bluefin killifish, Lucania goodei
Male bluefin killifish (Lucania goodei) exhibit extensive color variation in their fins, but the utility of this variation has not yet been determined. We collected males from multiple populations and spectrophotometrically determined the pigment types responsible for fin coloration. We determined that the orange coloration in the caudal fin is caused by carotenoid pigmentation. In contrast, color in the anal fin is either pterin based (yellow and red) or structural (blue) with a melanic fin border. As these colors have different developmental origins, the potential for complex signaling is high. Therefore, we sought to determine whether behavior, reproductive success, or health correlated with pigmentation. Males with more melanin on the anal fin were more dominant and had higher spawning success. Male–male aggression was greater between males with similar-sized melanic borders, indicating that melanic markings function as badges of status between males. Caudal carotenoid pigmentation did not correlate with dominance, but this highly labile ornament was correlated with body condition, parasite infection, and spawning success, suggesting a role in intersexual selection by signaling health to potential mates. Similar results were found for caudal fin coloration using digital photography. Pterin pigmentation in the anal fin was not related to dominance but was related to overall spawning levels and parasite infection, suggesting that pterin pigmentation may also signal immune status. Thus, the coloration of male bluefin killifish provides multiple messages to multiple receivers through these 3 pigments (melanin, pterin, and carotenoid) that have distinct developmental origins.
Data from: Molecular evolution of anthocyanin pigmentation genes following losses of flower color
Background: Phenotypic transitions, such as trait gain or loss, are predicted to carry evolutionary consequences for the genes that control their development. For example, trait losses can result in molecular decay of the pathways underlying the trait. Focusing on the Iochrominae clade (Solanaceae), we examine how repeated losses of floral anthocyanin pigmentation associated with flower color transitions have affected the molecular evolution of three anthocyanin pathway genes (Chi, F3h, and Dfr). Results: We recovered intact coding regions for the three genes in all of the lineages that have lost floral pigmentation, suggesting that molecular decay is not associated with these flower color transitions. However, two of the three genes (Chi, F3h) show significantly elevated dN/dS ratios in lineages without floral pigmentation. Maximum likelihood analyses suggest that this increase is due to relaxed constraint on anthocyanin genes in the unpigmented lineages as opposed to positive selection. Despite the increase, the values for dN/dS in both pigmented and unpigmented lineages were consistent overall with purifying selection acting on these loci. Conclusions: The broad conservation of anthocyanin pathway genes across lineages with and without floral anthocyanins is consistent with the growing consensus that losses of pigmentation are largely achieved by changes in gene expression as opposed to structural mutations. Moreover, this conservation maintains the potential for regain of flower color, and indicates that evolutionary losses of floral pigmentation may be readily reversible.
Data from: The chemical basis of a signal of individual identity: Shell pigment concentrations track the unique appearance of Common Murre eggs
In group-living species with parental care, the accurate recognition of one's own young is critical to fitness. Because discriminating offspring within a large colonial group may be challenging, progeny of colonial breeders often display familial or individual identity signals to elicit and receive costly parental provisions from their own parents. For instance, the Common Murre (or Common Guillemot: Uria aalge) is a colonially breeding seabird that does not build a nest and lays and incubates an egg with an individually unique appearance. How the shell's physical and chemical properties generate this individual variability in coloration and maculation has not been studied in detail. Here, we quantified two characteristics of the avian-visible appearance of murre eggshells collected from the wild: background coloration spectra and maculation density. As predicted by the individual identity hypothesis, there was no statistical relationship between avian-perceivable shell background coloration and maculation density within the same eggs. In turn, variation in both sets of traits was statistically related to some of their physico-chemical properties, including shell thickness and concentrations of the eggshell pigments biliverdin and protoporphyrin IX. These results illustrate how individually unique eggshell appearances, suitable for identity signaling, can be generated by a small number of structural mechanisms.
Data from: Physiological conditions and genetic controls of phaeomelanin pigmentation in nestling barn swallows
Phaeomelanin is a common pigment that confers a reddish color to animals. Since phaeomelanogenesis requires the sulfhydryl group from cysteine or glutathione (GSH), which is an important antioxidant, this pigmentation and the associated coloration may be an honest signal, whereby only high-quality individuals (e.g., with lower oxidative stress) are able to develop showy plumage. The present study tested the mechanisms underlying the honest signal hypothesis using nestling barn swallows, Hirundo rustica gutturalis, which exhibit phaeomelanic throat plumage patches. We examined the relationship between phaeomelanin pigmentation levels and physiological condition during trait development, and the expression of the phaeomelanin-related gene agouti-signaling protein (ASIP) and the GSH-related gene glutathione S-transferase (GST) in throat feather follicles. We found that during phaeomelanogenesis, heavier nestlings produced more pigmented feathers, indicating that nestlings with high phaeomelanin concentrations are in better condition. We also found that phaeomelanin concentration was negatively correlated with total GSH level, but not significantly related with measures of oxidative stress. Among the GST genes, GSTM3 exhibited the highest expression in the developing feathers during phaeomelanogenesis. The expression levels of ASIP were positively associated with the amount of phaeomelanin deposition and negatively associated with the expression of GSTM3, reducing the amount of GSH that was available as an antioxidant. These findings suggest that high-quality individuals produce high concentrations of phaeomelanin in their plumage without experiencing increased oxidative stress, despite phaeomelanin production, which is triggered by ASIP, potentially actively consuming the sulfhydryl group from GSH.
Data from: Phylogeny and generic delimitation in Molluginaceae, new pigment data in Caryophyllales, and the new family Corbichoniaceae
The circumscription of Molluginaceae has changed radically in recent years, with Corbichonia being moved to Lophiocarpaceae, Limeum to Limeaceae, Macarthuria to Macarthuriaceae and all species of Hypertelis, except the type, to Kewa in Kewaceae. In a broad analysis of core Caryophyllales using plastid trnK-matK and rbcL sequences, the position of Molluginaceae in a strict sense as sister to the Portulacineae clade is corroborated, as are the positions of Corbichonia, Limeum and Kewa outside the family. The phylogeny of Molluginaceae is reconstructed based on trnK-matK and nuclear ITS sequences of about half of the currently recognized species in the family and with representatives from all recognized genera. Mollugo is found to be polyphyletic and a new taxonomy for the family with 11 genera is proposed. Mollugo in its new restricted sense is a mainly American genus of about 15 species, including M. ulei comb. nov., previously placed in the monotypic Glischrothamnus. The Australian and Asian genus Trigastrotheca is resurrected for T. molluginea, T. pentaphylla comb. nov. and T. stricta comb. nov. The name Paramollugo nom. nov. is proposed for the Mollugo nudicaulis group and the combinations P. angustifolia comb. nov., P. cuneifolia comb. nov., P. decandra comb. nov., P. deltoidea comb. nov., P. navassensis comb. nov. and P. nudicaulis comb. nov. are made. Hypertelis is expanded to include, besides the type H. spergulacea, also H. cerviana comb. nov., H. fragilis comb. nov., H. umbellata comb. nov. and H. walteri comb. nov. In Pharnaceum, the new combination P. namaquense comb. nov. is made, Hypertelis longifolia is treated as a synonym of P. lineare and Mollugo tenella as a synonym of P. subtile. Corbichonia is proposed to be treated as a family of its own, Corbichoniaceae fam. nov. Several names are lectotypified, including the Linnaean Mollugo pentaphylla and M. stricta. An anthocyanin is reported for the first time from Simmondsiaceae. The detection of anthocyanins in members of Kewaceae and Molluginaceae agree with previous reports and corroborate the view that these families represent reversals from betalains to anthocyanins. The report of an anthocyanin in Limeaceae, previously regarded as unpigmented, apparently represents a newly detected reversal from betalains to anthocyanins in this family.
Data from: Protoporphyrin-based eggshell pigmentation is associated with female plumage colouration and predicts offspring sex ratio in the barn swallow
Inter- and intraspecific variation in eggshell colouration has long fascinated evolutionary biologists. Among species, such variation may accomplish different functions, the most obvious of which is camouflage and background matching. Within species, it has been proposed that inter-female variation in eggshell pigmentation patterns can reflect egg, maternal or paternal traits and hence may provide cues to conspecifics about egg, maternal or paternal phenotypic quality. However, the relationship between protoporphyrin-based eggshell pigmentation and egg or maternal/paternal traits appears to be highly variable among species. We investigated patterns of intraspecific variation in Eurasian barn swallow (Hirundo r. rustica) protoporphyrin-based eggshell pigmentation, and analysed its association with egg and clutch characteristics, maternal/paternal phenotypic traits and parental feeding effort. Eggshell pigmentation pattern significantly varied between breeding colonies, was significantly repeatable in clutches laid by the same females in different years (intraclass correlation coefficient ranging between 0.56 and 0.63), but it was not significantly associated with egg traits, such as position in the laying sequence, egg mass, yolk testosterone concentration and antioxidant capacity. It was weakly or non-significantly associated with female and male traits (sexual ornaments), but females laying darker (higher pigment intensity) first clutches had higher hatching success, suggesting that eggshell pigment intensity may predict fitness. Nevertheless, males did not significantly modulate their parental nestling feeding effort accordingly. In addition, females with darker breast plumage colouration (a melanin-based trait related to fitness) laid highly protoporphyrin-covered eggs, suggesting the presence of a previously unappreciated link between protoporphyrin biosynthesis and plumage melanisation. Moreover, the proportion of male offspring increased in clutches originating from highly protoporphyrin-covered eggs, suggesting that parents could acquire visual cues about their future brood sex composition before egg hatching. Our results support the idea that intraspecific signalling via eggshell pigmentation is a species-specific rather than a general feature of avian taxa.
Differential influence of Slc7a11 expression and body condition on pheomelanin‐based pigmentation in two Eurasian nuthatch Sitta europaea populations with different predation risk
<p><span><span><span><span><span><span><span><span><span><span><span>The expression of the gene <i>Slc7a11</i>promotes the antioxidant capacity of cells by providing them with cysteine that can be used for the synthesis of glutathione (GSH), the most important intracellular antioxidant. In melanocytes, intracellular cysteine can also enter melanosomes and get incorporated in the pigment pheomelanin synthesis pathway, thus decreasing cysteine availability for GSH synthesis and potentially creating chronic oxidative stress. We thus hypothesized that a mechanism limiting the use of intramelanocytic cysteine for pheomelanin synthesis in environmental conditions generating oxidative stress may be physiologically advantageous and favored by natural selection. Here we searched for evidence of such a mechanism by comparing the influence of melanocytic <i>Slc7a11</i>expression on pheomelanin-based pigmentation in developing Eurasian nuthatch <i>Sitta europaea</i>nestlings from two populations differing in predation risk, a natural source of oxidative stress. Pheomelanin synthesis and pigmentation tended to increase with <i>Slc7a11</i>expression in the low-risk population as expected from the activity of this gene, but decreased with <i>Slc7a11</i>expression in the high-risk population. The same was not observed in the expression of five other genes influencing pheomelanin synthesis without affecting cysteine availability in melanocytes. The influence of body condition on the intensity of pheomelanin-based pigmentation also differed between populations, being positive in the low-risk population and negative in the high-risk population. The resulting pigmentation of birds was more intense in the high-risk population. These findings suggest that birds perceiving high predation risk may limit the use of cysteine for pheomelanin synthesis, which becomes independent of <i>Slc7a11</i>expression. Some birds may have thus evolved the ability to adjust their pigmentation phenotype to environmental stress.</span></span></span></span></span></span></span></span></span></span></span></p>
Data from: Transcriptome analysis reveals novel patterning and pigmentation genes underlying Heliconius butterfly wing pattern variation
BACKGROUND: Heliconius butterfly wing pattern diversity offers a unique opportunity to investigate how natural genetic variation can drive the evolution of complex adaptive phenotypes. Positional cloning and candidate gene studies have identified a handful of regulatory and pigmentation genes implicated in Heliconius wing pattern variation, but little is known about the greater developmental networks within which these genes interact to pattern a wing. Here we took a large-scale transcriptomic approach to identify the network of genes involved in Heliconius wing pattern development and variation. This included applying over 140 transcriptome microarrays to assay gene expression in dissected wing pattern elements across a range of developmental stages and wing pattern morphs of Heliconius erato. RESULTS: We identified a number of putative early prepattern genes with color-pattern related expression domains. We also identified 51 genes differentially expressed in association with natural color pattern variation. Of these, the previously identified color pattern "switch gene" optix was recovered as the first transcript to show color-specific differential expression. Most differentially expressed genes were transcribed late in pupal development and have roles in cuticle formation or pigment synthesis. These include previously undescribed transporter genes associated with ommochrome pigmentation. Furthermore, we observed upregulation of melanin-repressing genes such as ebony and Dat1 in non-melanic patterns. CONCLUSIONS: This study identifies many new genes implicated in butterfly wing pattern development and provides a glimpse into the number and types of genes affected by variation in genes that drive color pattern evolution.
Data from: Inter-chromosomal coupling between vision and pigmentation genes during genomic divergence
Recombination between loci underlying mate choice and ecological traits is a major evolutionary force acting against speciation with gene flow. The evolution of linkage disequilibrium between such loci is therefore a fundamental step in the origin of species. Here, we show that this process can take place in the absence of physical linkage in hamlets—a group of closely related reef fishes from the wider Caribbean that differ essentially in colour pattern and are reproductively isolated through strong visually-based assortative mating. Using full-genome analysis, we identify four narrow genomic intervals that are consistently differentiated among sympatric species in a backdrop of extremely low genomic divergence. These four intervals include genes involved in pigmentation (sox10), axial patterning (hoxc13a), photoreceptor development (casz1) and visual sensitivity (SWS and LWS opsins) that develop islands of long-distance and inter-chromosomal linkage disequilibrium as species diverge. The relatively simple genomic architecture of species differences facilitates the evolution of linkage disequilibrium in the presence of gene flow.
Data from: Ecology and sexual selection: evolution of wing pigmentation in calopterygid damselflies in relation to latitude, sexual dimorphism and speciation
Our knowledge about how the environment influences sexual selection regimes and how ecology and sexual selection interact is still limited. We performed an integrative study of wing pigmentation in calopterygid damselflies, combining phylogenetic comparative analyses, field observations and experiments. We investigated the evolutionary consequences of wing pigmentation for sexual dimorphism, speciation and extinction and addressed the possible thermoregulatory benefits of pigmentation. First, we reconstructed ancestral states of male and female phenotypes and traced the evolutionary change of wing pigmentation. Clear wings are the ancestral state and that pigmentation dimorphism is derived, suggesting that sexual selection results in sexual dimorphism. We further demonstrate that pigmentation elevates speciation and extinction rates. We also document a significant biogeographic association with pigmented species primarily occupying northern temperate regions with cooler climates. Field observations and experiments on two temperate sympatric species suggest a link between pigmentation, thermoregulation and sexual selection, although body temperature is also affected by other phenotypic traits such as body mass, microhabitat selection and thermoregulatory behaviors. Taken together, our results suggest an important role for wing pigmentation in sexual selection in males and in speciation. Wing pigmentation might not increase ecological adaptation and species longevity, and its primary function is in sexual signalling and species recognition.
FIGURE 5 in Freshwater leech (Annelida: Hirudinida) distribution in the Canadian Province of Newfoundland and Labrador and adjacent regions: check-list, new records, new pigmentation forms, and Pleistocene refugia
FIGURE 5. Pigmentation patterns in Newfoundland and Labrador Erpobdella punctata (Leidy) by PH. A–B, Site 7, C Sites 14–15, D, Sites 12, 13, 24; E, Site 10; F, Sites 1–2.
FIGURE 1 in Freshwater leech (Annelida: Hirudinida) distribution in the Canadian Province of Newfoundland and Labrador and adjacent regions: check-list, new records, new pigmentation forms, and Pleistocene refugia
FIGURE 1. Surveyed sites in Newfoundland and Labrador. Circles, 2004 survey sites (numbered); Squares, literature locations of Pawlowski (1948) and in part, Davies (1973). The site numbers correspond to Table 1.
FIGURE 6 in Freshwater leech (Annelida: Hirudinida) distribution in the Canadian Province of Newfoundland and Labrador and adjacent regions: check-list, new records, new pigmentation forms, and Pleistocene refugia
FIGURE 6. Erpobdella obscura (Verrill) from Grand river, Ontario. A–E, G: Drawings by Susan Laurie-Bourque of CMNA 1984–0689. F by Peter Frank using Kodachrome film in May 1988. A, Anterior, ventral view; B, Anterior, dorsal view; C, Closeup of seminal vesicle; D, Well-developed male and female gonopores located between annuli; E, Posterior dorsal view; F, Photographs of two preserved leeches comparing the two color variations (ringed form on left and normal form on right); G, Dorsal view of dissected reproductive organs. The right side of the testes and spermduct are omitted on the right side. Broken lines show cut ends of organs. a, atrium; ejd, ejaculatory duct; ep, epididymis; fg, female gonopores; mg, male gonopores; lft, large follicles of testisacs; t, testisac; mft, multifollicular testisacs; nc, nerve chord. Ganglia are numbered in Roman numerals.
FIGURE 4 in Freshwater leech (Annelida: Hirudinida) distribution in the Canadian Province of Newfoundland and Labrador and adjacent regions: check-list, new records, new pigmentation forms, and Pleistocene refugia
FIGURE 4. Distribution of the four widespread leech species. Circles, 2004 survey; squares, literature locations (Pawlowski 1948, Davies 1973); triangles, museum specimens. A, Glossiphonia elegans (Verrill); B, Helobdella modesta (Verrill); C, Erpobdella punctata (Leidy); D, Erpobdella obscura (Verrill).
FIGURE 2 in Freshwater leech (Annelida: Hirudinida) distribution in the Canadian Province of Newfoundland and Labrador and adjacent regions: check-list, new records, new pigmentation forms, and Pleistocene refugia
FIGURE 2. Photographs of selected Newfoundland and Labrador leeches. D was collected by Cecelia McGrath in 1982. A, Dorsal view of Glossiphonia elegans (Verrill), site 17; B, Dorsal view of Helobdella modesta (Verrill), site 12; C, Dorsal view of Theromyzon sp., site 6; D, Lateral view of Haemopis lateromaculata Mathers, showing the plain ventrum separated from the speckled dorsum by a lighter pattern on the side, CMNA 1982–0654; E, Dorsal view of Haemopis marmorata (Say), site 12; F, Closeup of anal protrusion of Haemopis marmorata, Site 12; G, Erpobdella punctata (Leidy) (normal pigmentation), site 7; H, Erpobdella obscura (Verrill) [normal pigmentation], site 21. Scale bars are in cm unless otherwise indicated.
FIGURE 7 in Freshwater leech (Annelida: Hirudinida) distribution in the Canadian Province of Newfoundland and Labrador and adjacent regions: check-list, new records, new pigmentation forms, and Pleistocene refugia
FIGURE 7. Pigmentation patterns of Erpobdella obscura (Verrill). A–F are illustrations by PH from Labrador and Newfoundland: A, Site 28; B, Sites 22, 23; C, Site 21; D, Site 29; E, Site 18; F, Site 7. G–J are microscope photographs of typical examples of ringed and mottled patterns of Erpobdella obscura (Verrill) from Newfoundland and Labrador compared to specimens from the Grand River, Ontario. Scale bars are in mm. G, closeup of midportion of ringed specimen from Newfoundland, CMNA 2006–0023. H, anterior portion of ringed specimen from Newfoundland, CMNA 2006– 0020. I, anterior portion of mottled specimen from Newfoundland, CMNA 2006–0018. J, closeup of midportion of mottled specimen from Newfoundland, CMCA2006–0018.
FIGURE 5. Platynereis juvenile dorsal pigmentation pattern, A–C, P. australis, P in Taxonomy of sympatric New Zealand species of Platynereis, with description of three new species additional to P. australis (Schmarda) (Annelida: Polychaeta: Nereididae)
FIGURE 5. Platynereis juvenile dorsal pigmentation pattern, A–C, P. australis, P. mahanga sp. nov., P. k a u sp. nov. respectively. Scale bar 0.5 mm.
Fig. 1 in Cesiribacter roseus sp. nov., a pink-pigmented bacterium isolated from desert sand
Fig. 1. Neighbour-joining tree based on 16S rRNA gene sequences showing the phylogenetic relationship between strain 311T and related taxa. Bootstrap values (expressed as percentages of 1000 replications).70 % are shown at nodes. Escherichia coli ATCC 11775T was used as an outgroup (not shown). Bar, 0.02 changes per nucleotide position.
Fig. 2 in Cesiribacter roseus sp. nov., a pink-pigmented bacterium isolated from desert sand
Fig. 2. Transmission electron micrographs of cells of strain 311T grown on R2A agar at 30 ̊C for 60 h (a) and on 0.1× TSA at 30 ̊C for 60 h (b). Bars, 700 nm (a) and 1 µm (b).
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