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Mixed signals? Morphological and molecular evidence suggest a color polymorphism in some neotropical polythore damselflies.

Sánchez Herrera M, Kuhn WR, Lorenzo-Carballa MO, Harding KM, Ankrom N, Sherratt TN, Hoffmann J, Van Gossum H, Ware JL, Cordero-Rivera A, Beatty CD - PLoS ONE (2015)

Bottom Line: The study of color polymorphisms (CP) has provided profound insights into the maintenance of genetic variation in natural populations.Our results suggest that, while highly distinct and discrete wing patterns exist in Polythore, these "wingforms" do not represent monophyletic clades in the recovered topology.We discuss the implications of this polymorphism, and the potential evolutionary mechanisms that could maintain it.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Rutgers University, Newark, New Jersey, United States of America.

ABSTRACT
The study of color polymorphisms (CP) has provided profound insights into the maintenance of genetic variation in natural populations. We here offer the first evidence for an elaborate wing polymorphism in the Neotropical damselfly genus Polythore, which consists of 21 described species, distributed along the eastern slopes of the Andes in South America. These damselflies display highly complex wing colors and patterning, incorporating black, white, yellow, and orange in multiple wing bands. Wing colors, along with some components of the male genitalia, have been the primary characters used in species description; few other morphological traits vary within the group, and so there are few useful diagnostic characters. Previous research has indicated the possibility of a cryptic species existing in P. procera in Colombia, despite there being no significant differences in wing color and pattern between the populations of the two putative species. Here we analyze the complexity and diversity of wing color patterns of individuals from five described Polythore species in the Central Amazon Basin of Peru using a novel suite of morphological analyses to quantify wing color and pattern: geometric morphometrics, chromaticity analysis, and Gabor wavelet transformation. We then test whether these color patterns are good predictors of species by recovering the phylogenetic relationships among the 5 species using the barcode gene (COI). Our results suggest that, while highly distinct and discrete wing patterns exist in Polythore, these "wingforms" do not represent monophyletic clades in the recovered topology. The wingforms identified as P. victoria and P. ornata are both involved in a polymorphism with P. neopicta; also, cryptic speciation may have taking place among individuals with the P. victoria wingform. Only P. aurora and P. spateri represent monophyletic species with a single wingform in our molecular phylogeny. We discuss the implications of this polymorphism, and the potential evolutionary mechanisms that could maintain it.

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Examples of color polymorphism in Polythore taxa used in this study.For each wingform, the typical form is shown on the left, and extrema are shown on the right.
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pone.0125074.g001: Examples of color polymorphism in Polythore taxa used in this study.For each wingform, the typical form is shown on the left, and extrema are shown on the right.

Mentions: The genus Polythore currently contains 21 described species, distributed primarily along the eastern slopes of the Andes in South America [28,29]. Polythore typically dwell in small stream environments within healthy rainforests; larvae live in the streams and adults generally remain close to their stream habitat [28,30]. In most calopyterygid species, either red/orange pigments or black pigments are used, but not both [12,13,31]. Polythore, however, is the rare exception: many “wingforms” use at least two colors to generate combinations of black, white, yellow, and orange, displayed in bands and other geometric patterns that differ dramatically between described species (Fig 1). Their vibrant wing color pattern is the primary trait used to describe the species in this genus [28,32]. There is, in fact, a surprising lack of variability in other morphological traits: structures such as the male cerci, which function as a “lock and key” mechanism during copula in many other species [33] show little or no variation in Polythore, even over wide geographic distances. Why selection has brought about such elaborate wing patterning in Polythore is thus of interest, and a key first step to addressing this question would be the quantitative assessment of these patterns. Recent work by Sánchez Herrera et al. compared the variability in wing patterns of P. procera from Colombia, and analyzed genetic diversity in several populations; morphological characters (including wing color patterning and the structure of male accessory genitalia) were not significantly different among populations, but genetic diversity among certain populations was quite high, suggesting the presence of at least one cryptic species[34].


Mixed signals? Morphological and molecular evidence suggest a color polymorphism in some neotropical polythore damselflies.

Sánchez Herrera M, Kuhn WR, Lorenzo-Carballa MO, Harding KM, Ankrom N, Sherratt TN, Hoffmann J, Van Gossum H, Ware JL, Cordero-Rivera A, Beatty CD - PLoS ONE (2015)

Examples of color polymorphism in Polythore taxa used in this study.For each wingform, the typical form is shown on the left, and extrema are shown on the right.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414280&req=5

pone.0125074.g001: Examples of color polymorphism in Polythore taxa used in this study.For each wingform, the typical form is shown on the left, and extrema are shown on the right.
Mentions: The genus Polythore currently contains 21 described species, distributed primarily along the eastern slopes of the Andes in South America [28,29]. Polythore typically dwell in small stream environments within healthy rainforests; larvae live in the streams and adults generally remain close to their stream habitat [28,30]. In most calopyterygid species, either red/orange pigments or black pigments are used, but not both [12,13,31]. Polythore, however, is the rare exception: many “wingforms” use at least two colors to generate combinations of black, white, yellow, and orange, displayed in bands and other geometric patterns that differ dramatically between described species (Fig 1). Their vibrant wing color pattern is the primary trait used to describe the species in this genus [28,32]. There is, in fact, a surprising lack of variability in other morphological traits: structures such as the male cerci, which function as a “lock and key” mechanism during copula in many other species [33] show little or no variation in Polythore, even over wide geographic distances. Why selection has brought about such elaborate wing patterning in Polythore is thus of interest, and a key first step to addressing this question would be the quantitative assessment of these patterns. Recent work by Sánchez Herrera et al. compared the variability in wing patterns of P. procera from Colombia, and analyzed genetic diversity in several populations; morphological characters (including wing color patterning and the structure of male accessory genitalia) were not significantly different among populations, but genetic diversity among certain populations was quite high, suggesting the presence of at least one cryptic species[34].

Bottom Line: The study of color polymorphisms (CP) has provided profound insights into the maintenance of genetic variation in natural populations.Our results suggest that, while highly distinct and discrete wing patterns exist in Polythore, these "wingforms" do not represent monophyletic clades in the recovered topology.We discuss the implications of this polymorphism, and the potential evolutionary mechanisms that could maintain it.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Rutgers University, Newark, New Jersey, United States of America.

ABSTRACT
The study of color polymorphisms (CP) has provided profound insights into the maintenance of genetic variation in natural populations. We here offer the first evidence for an elaborate wing polymorphism in the Neotropical damselfly genus Polythore, which consists of 21 described species, distributed along the eastern slopes of the Andes in South America. These damselflies display highly complex wing colors and patterning, incorporating black, white, yellow, and orange in multiple wing bands. Wing colors, along with some components of the male genitalia, have been the primary characters used in species description; few other morphological traits vary within the group, and so there are few useful diagnostic characters. Previous research has indicated the possibility of a cryptic species existing in P. procera in Colombia, despite there being no significant differences in wing color and pattern between the populations of the two putative species. Here we analyze the complexity and diversity of wing color patterns of individuals from five described Polythore species in the Central Amazon Basin of Peru using a novel suite of morphological analyses to quantify wing color and pattern: geometric morphometrics, chromaticity analysis, and Gabor wavelet transformation. We then test whether these color patterns are good predictors of species by recovering the phylogenetic relationships among the 5 species using the barcode gene (COI). Our results suggest that, while highly distinct and discrete wing patterns exist in Polythore, these "wingforms" do not represent monophyletic clades in the recovered topology. The wingforms identified as P. victoria and P. ornata are both involved in a polymorphism with P. neopicta; also, cryptic speciation may have taking place among individuals with the P. victoria wingform. Only P. aurora and P. spateri represent monophyletic species with a single wingform in our molecular phylogeny. We discuss the implications of this polymorphism, and the potential evolutionary mechanisms that could maintain it.

Show MeSH
Related in: MedlinePlus