Red coloration of male northern cardinals correlates with mate quality and territory quality

I investigated how mate quality and territory quality influencean extravagant ornament in a socially monogamous species thatdefends multipurpose territories. Northern cardinals (Cardinaliscardinalis) are a highly dichromatic, socially monogamous species,and males are a brilliant red. I conducted a 3-year field studyof northern cardinals and found that redder males produced moreoffspring in a breeding season. Two selective factors mediatedthis fitness gain. Redder males were paired with earlier breedingfemales, an established measure of mate quality in birds. Second,redder males obtained territories of higher quality, as measuredby vegetation density. Interactions among these factors werealso important in explaining variance in male reproductive success.Multivariate analysis indicated that earlier breeding increasedreproductive success independent of territory quality. In turn,territory quality contributed to male reproductive success throughits effect on nest survival and possibly through its role in attractingan earlier breeding female.     

鹌鹑羽色遗传的研究及应用

鹌鹑的羽色主要有野生型、白色型、深色型、褐色型、黑白镶嵌型、褐白镶嵌型、黄色型、红色型和紫色型等,目前已发现大约有26个基因座与鹌鹑的羽色有关。这些基因座多数位于常染色体上,有5 个基因座位于Z染色体上,有4 个基因座存在有复等位基因系列。多数基因座的等位基因呈显隐性关系,少数表现为等显性或不完全显性。有5个基因座的显性羽色突变基因如黄羽、银色羽、白羽、孵化黑羽和亮绒羽在纯合状态下具有致死或半致死效应。羽色标记在鹌鹑育种和生产以及科学研究中已发挥了重要作用,作者就今后加强鹌鹑羽色标记研究提出了一些建议。 Abstract:The main plumage traits including wild-type,white,dark black,brown,dark-white inlays,brown-white inlays,yellow,red and purple have been reported,which are related to 26 loci.The majority of the loci are at the autosome and five loci at the Z chromosome.Four loci have multiple allelic series.The dominance or recessive relation are shown between allele of the most loci and few of them show allelic equivalence or incompletely dominance.There are five dominant plumage color mutations,such as yellow,silver,white,black at hatch and light down are lethal or semi-lethal in the homozygous state.These plumage color marker have played an important part in the breeding and production of quails and research fields.Some proposals are put forward in terms of strengthening the study of plumage color marks of quails.     

Sexual selection: when to expect trade-offs

Empirical evidence is mixed for interspecific trade-offs in investment among sexually selected traits. One important reason may be the way resources are allocated among species. Consider a set of species that obtains the same fitness pay-off for investment in song or plumage. Simulations where resources were normally distributed among species revealed significant trade-offs between song and plumage ( ± s.d. of r = −0.54 ± 0.06). However, simulations where resources were distributed in a negative binomial fashion usually produced positive correlations (r = 0.11 ± 0.09). Repeating simulations on three published studies that concomitantly quantified elaboration of song and plumage indicated that trade-offs are likely, although these analyses make assumptions that require further evaluation. Moreover, there are currently too few empirical distributions to make generalizations about the likelihood of interspecific trade-offs in sexually selected traits.     

Predator-elicited visual signal: why the turquoise-browed motmot wag-displays its racketed tail

Both sexes of the turquoise-browed motmot (Eumomota superciliosa)perform a wag-display in the presence of predators, wherebytheir long racketed tail is repeatedly rocked side-to-side ina pendulous fashion. I tested 3 hypotheses for the functionof the predator-elicited wag-display: 1) pursuit-deterrent signal,2) warning alarm signal, and 3) self-preservation alarm signal.These hypotheses were evaluated by testing whether the presenceof potential receivers (kin, conspecifics, mate) modified theway in which the wag-display was performed. Data on wag-displaywere collected when I experimentally presented predators tomotmots and when naturally occurring predators were observedat nesting colonies. The wag-display was performed by male andfemale motmots who were 1) alone and not within signaling distanceof conspecifics, 2) unpaired and therefore not signaling toa mate, and 3) paired but away from their mate. Motmots in thesecontexts performed the wag-display with similar probabilityand in a similar manner as individuals that were within signalingdistance of conspecifics, paired birds, and paired birds whowere near their mate. These results support the hypothesis thatthe predator-elicited wag-display is directed to the predatorand functions as a pursuit-deterrent signal.     

Dynamic colonization exchanges between continents and islands drive diversification in paradise‐flycatchers (Terpsiphone,Monarchidae)

Aim We use parametric biogeographical reconstruction based on an extensive DNA sequence dataset to characterize the spatio‐temporal pattern of colonization of the Old World monarch flycatchers (Monarchidae). We then use this framework to examine the role of dispersal and colonization in their evolutionary diversification and to compare plumages between island and continental Terpsiphone species. Location Africa, Asia and the Indian Ocean. Methods We generate a DNA sequence dataset of 2300 bp comprising one nuclear and three mitochondrial markers for 89% (17/19) of the Old World Monarchidae species and 70% of the Terpsiphone subspecies. By applying maximum likelihood and Bayesian phylogenetic methods and implementing a Bayesian molecular clock to provide a temporal framework, we reveal the evolutionary history of the group. Furthermore, we employ both Lagrange and Bayes‐ Lagrange analyses to assess ancestral areas at each node of the phylogeny. By combining the ancestral area reconstruction with information on plumage traits we are able to compare patterns of plumage evolution on islands and continents. Results We provide the first comprehensive molecular phylogenetic reconstruction for the Old World Monarchidae. Our phylogenetic results reveal a relatively recent diversification associated with several dispersal events within this group. Moreover, ancestral area analyses reveal an Asian origin of the Indian Ocean and African clades. Ancestral state reconstruction analyses of plumage characters provide an interpretation of the plumage differentiation on islands and continents. Ancestral plumage traits are inferred to be close to those of the Asian paradise‐flycatcher (Terpsiphone paradisi), and island species display a high degree of plumage autapomorphy compared with continental species. Main conclusions Terpsiphone paradisi is polyphyletic and comprises populations that have retained the ancestral plumage of the widespread Terpsiphone genus. The genus appears to have colonized south‐west Asia, the Indian Ocean and Africa from eastern Asia. The phylogeny and divergence time estimates indicate multiple simultaneous colonizations of the western Old World by Terpsiphone. These results reinforce a hypothesis of range expansions of a Terpsiphone paradisi‐like ancestor into eastern Asia and the western Old World.     

基于类胡萝卜素着色的鸟类羽色多样性形成机制

人们对动物体色的研究由来已久。作为一类让生物呈现出多变色彩的重要色素, 类胡萝卜素可以在鸟类的羽毛、鸟喙和皮肤等体表组织中沉积, 产生红、橙、黄、粉、紫等颜色。类胡萝卜素不能在鸟类体内合成, 需从食物中摄取, 进而在体内完成吸收、运输、代谢和沉积等一系列过程, 才能用于羽毛着色。与类胡萝卜素着色相关的生理及遗传调控机制一直备受关注, BCO2、SCARB1和CYP2J19等影响类胡萝卜素在鸟类羽毛中着色的关键基因, 推动了对羽色遗传调控机制的深入认识。本文介绍了鸟类可利用类胡萝卜素的主要类型和基本特征, 综述了类胡萝卜素着色相关的生理过程以及调控基因研究的最新进展, 旨在增加对鸟类羽毛中类胡萝卜素着色过程和相关遗传机制的理解。     

Offspring sex ratio allocation in the parasitic jaeger: selection for pale females and melanic males?

The maintenance of plumage color polymorphism in the parasiticjaeger (Stercorarius parasiticus) is still not well understood.Earlier studies indicated that selection may favor pale femalesand melanic males. If so, females would maximize their fitness,producing pale female and melanic male offspring. We thereforepredicted that females might bias their offspring sex ratiotoward daughters in pale pairs and toward sons in melanic pairs.Females might also choose to mate assortatively in relationto plumage color, thereby maximizing the probability of producingeither pale or melanic offspring. Because females are largerthan males, differential rearing costs may affect the offspringsex ratio independent of parental plumage color. We examinedoffspring sex ratio allocation, breeding variables indicativeof parental quality, and mating pattern in relation to plumagecolor in a colony of parasitic jaegers in northern Norway. Jaegerstended to mate assortatively in relation to plumage color. Thereproductive performance declined with season, and matched pairsappeared to be of lower quality than mixed pairs. The proportionof male offspring increased with hatching date in matched paleand mixed pairs, whereas the situation was reversed in matchedmelanic pairs. Matched pale pairs produced an overall surplusof favorable pale but costly daughters despite their lower quality,while melanic pairs produced a surplus of favorable melanicsons. However, differential offspring rearing costs and parentalrearing capacity may have additionally affected the realizedoffspring sex ratio. Mixed pairs producing an overall surplusof pale and melanic daughters allocated their resources accordingto differential rearing costs and parental quality only. Wesuggest that both strategies of sex ratio allocation togetherwith differences in reproductive success in matched versus mixedpairs may have a balancing effect on the mating pattern betweenplumage morphs and may contribute to the maintenance of thecolor polymorphism in this species.     

Multiple shifts between violet and ultraviolet vision in a family of passerine birds with associated changes in plumage coloration

Colour vision in diurnal birds falls into two discrete classes, signified by the spectral sensitivity of the violet- (VS) or ultraviolet-sensitive (UVS) short wavelength-sensitive type 1 (SWS1) single cone. Shifts between sensitivity classes are rare; three or four are believed to have happened in the course of avian evolution, one forming UVS higher passerines. Such shifts probably affect the expression of shortwave-dominated plumage signals. We have used genomic DNA sequencing to determine VS or UVS affinity in fairy-wrens and allies, Maluridae, a large passerine family basal to the known UVS taxa. We have also spectrophotometrically analysed male plumage coloration as perceived by the VS and UVS vision systems. Contrary to any other investigated avian genus, Malurus (fairy-wrens) contains species with amino acid residues typical of either VS or UVS cone opsins. Three bowerbird species (Ptilonorhynchidae) sequenced for outgroup comparison carry VS opsin genes. Phylogenetic reconstructions render one UVS gain followed by one or more losses as the most plausible evolutionary scenario. The evolution of avian ultraviolet sensitivity is hence more complex, as a single shift no longer explains its distribution in Passeriformes. Character correlation analysis proposes that UVS vision is associated with shortwave-reflecting plumage, which is widespread in Maluridae.     

The dual function of barred plumage in birds: camouflage and communication

A commonly held principle in visual ecology is that communication compromises camouflage: while visual signals are often conspicuous, camouflage provides concealment. However, some traits may have evolved for communication and camouflage simultaneously, thereby overcoming this functional compromise. Visual patterns generally provide camouflage, but it was suggested that a particular type of visual pattern – avian barred plumage – could also be a signal of individual quality. Here, we test if the evolution of sexual dimorphism in barred plumage, as well as differences between juvenile and adult plumage, indicate camouflage and/or signalling functions across the class Aves. We found a higher frequency of female- rather than male-biased sexual dimorphism in barred plumage, indicating that camouflage is its most common function. But we also found that, compared to other pigmentation patterns, barred plumage is more frequently biased towards males and its expression more frequently restricted to adulthood, suggesting that barred plumage often evolves or is maintained as a sexual communication signal. This illustrates how visual traits can accommodate the apparently incompatible functions of camouflage and communication, which has implications for our understanding of avian visual ecology and sexual ornamentation.