A Sensory Bias Has Triggered the Evolution of Egg-Spots in Cichlid Fishes

Although, generally, the origin of sex-limited traits remains elusive, the sensory exploitation hypothesis provides an explanation for the evolution of male sexual signals. Anal fin egg-spots are such a male sexual signal and a key characteristic of the most species-rich group of cichlid fishes, the haplochromines. Males of about 1500 mouth-brooding species utilize these conspicuous egg-dummies during courtship – apparently to attract females and to maximize fertilization success. Here we test the hypothesis that the evolution of haplochromine egg-spots was triggered by a pre-existing bias for eggs or egg-like coloration. To this end, we performed mate-choice experiments in the basal haplochromine Pseudocrenilabrus multicolor, which manifests the plesiomorphic character-state of an egg-spot-less anal fin. Experiments using computer-animated photographs of males indeed revealed that females prefer images of males with virtual (‘in-silico’) egg-spots over images showing unaltered males. In addition, we tested for color preferences (outside a mating context) in a phylogenetically representative set of East African cichlids. We uncovered a strong preference for yellow, orange or reddish spots in all haplochromines tested and, importantly, also in most other species representing more basal lines. This pre-existing female sensory bias points towards high-quality (carotenoids-enriched) food suggesting that it is adaptive

Correction: Genetic diversity, genetic structure and diet of ancient and contemporary red deer (Cervus elaphus L.) from north-eastern France

[This corrects the article DOI: 10.1371/journal.pone.0189278.]

Genetic diversity, genetic structure and diet of ancient and contemporary red deer (Cervus elaphus L.) from north-eastern France

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Haplotype genealogy based on maximum likelihood.

<p>Mitochondrial haplotype genealogy based on the mitochondrial control region and a maximum likelihood phylogenetic analysis. The haplotypes detected in red deer from the Vosges are indicated in red, all other haplotypes were taken from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0189278#pone.0189278.ref003" target="_blank">3</a>]. Haplotypes belonging to haplotype lineage A are indicated in black, those of haplotype lineages B, C are depicted in grey. Note that some of the haplotypes initially identified by Skog et al. 2009 have collapsed into a single haplotype in our analyses, which is due to the use of a shorter sequences alignment in our analysis to match the length of the newly obtained sequences.</p

Diversity measures (haplotype diversity = htdiv; nucleotide diversity = ND, mean number of pairwise distances = MNPD) within the concatenated 256 bp fragment of cyt b and d-loop in ancient and modern red deer from the Vosges in comparison with published ancient western-central European red deer [9].

<p>Diversity measures (haplotype diversity = htdiv; nucleotide diversity = ND, mean number of pairwise distances = MNPD) within the concatenated 256 bp fragment of cyt b and d-loop in ancient and modern red deer from the Vosges in comparison with published ancient western-central European red deer [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0189278#pone.0189278.ref009" target="_blank">9</a>].</p

Modern and archaeological study sites and distribution of ancient and contemporary red deer mtDNA haplotypes in north-eastern France.

<p>Pie charts on the right side show the relative distributions of ancient haplotypes AM235 and AM6, based on concatenated cyt b and d-loop 256 bp. Pie charts on the left side show the relative distribution of modern haplotypes (AM1 to AM5) based on combined 680 bp cyt b and 785 bp d-loop sequences. The sex of modern male samples is added when they are culled near or in a territory from which they are not originated. Drawing: Delphine Souan, Archéologie Alsace, France (Maps ASTER, Nasa).</p

Median joining network of combined cyt b and d-loop sequences (256 bp) showing lineage affiliations of ancient and modern red deer from the Vosges compared to published ancient and modern sequences from the European range of red deer.

<p>The networks includes ancient red deer (haplotypes of the A clade from the Vosges (AM235 = orange; AM6 = white), modern red deer from the Vosges (red = AM1, yellow = AM2, dark blue = AM3, green = AM4, grey = AM5), published western-central European ancient and modern haplotypes from the A and C clades (modern A clade = grey blue, modern C clade = olive, ancient A clade = light green, ancient C clade = light blue; data from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0189278#pone.0189278.ref010" target="_blank">10</a>]. The size of the circles are proportional to the number of individuals, dashes indicate mutational steps.</p

Scatter-plot of δ¹³C and δ¹⁵N values for archaeological red deer collagen according to their age and haplotype.

<p>Ellipses are drawn manually to encompass samples with the same haplotype. One ellipse (below) corresponds to individuals living deep in the forest (mostly browser habits); the other (above) individuals living in open habitats or open (plain) or herb-rich woodlands of the adjacent plains.</p