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1.
Sexual colouration and sperm traits in guppies   总被引:4,自引:0,他引:4  
The relationships among the area, hue, saturation and brightness of orange colouration and sperm traits in the guppy Poecilia reticulata were investigated. Males with greater areas of orange colouration had significantly larger sperm loads, more motile sperm and longer sperm relative to males with relatively little orange colouration. Males with greater areas of orange colouration did not possess more viable sperm than males with relatively little orange colouration. There was no evidence that any of the sperm traits were related to the hue, saturation or brightness of the orange colouration. These results are discussed in the context of the roles that direct and indirect selection might play in maintaining female preference for male guppies with large areas of orange colouration.  相似文献   
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Exaggerated male traits under sexual selection are often used for both competition and courtship, raising the question of whether ornaments evolved simultaneously for both functions, or if use in one context preceded use in another. Here, we apply a phylogenetic approach to study the evolution of ornamental dorsal fins in male poeciliid fish of the subgenera Mollienesia and Limia, which exhibit convergent development of an enlarged dorsal fin, and often direct erect‐fin displays to male and female conspecifics. Unlike prior categorical assessments of poeciliid adornments, we measure dorsal fin exaggeration with a continuous index of ornamentation. Phylogenetic logistic and generalized least squares regression analyses indicate that high index values are significantly associated with the use of two component postures of courtship and aggressive displays, dorsal fin erection and body curvature, but not with the presence of sexual dichromatism. Male displays initially evolved for male–male aggression in the common ancestor of Mollienesia and Limia, suggesting that this signal originated for competition, then became co‐opted for courtship. These results support the armament‐ornament hypothesis for evolution of exaggerated male traits, and are consistent with an evolutionary shift in the predominant mechanisms of sexual selection from intra‐ to intersexual.  相似文献   
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中国蓼属春蓼组植物果实形态及果皮微形态的研究   总被引:5,自引:1,他引:4  
应用解剖镜和扫描电镜对中国产蓼属春蓼组(Polygonum sect. Persicaria)19种3变种植物的果实形态和果皮微形态特征进行了观察和研究。结果表明,蓼属春蓼组植物的果实形态为卵形或椭圆状卵形,具三棱、双凹或双凸,顶端渐狭,有喙或无喙;果皮微形态可分为7种类型: 洼点、浅洼点,脑纹状纹饰,拟脑纹状纹饰,网状纹饰,不规则褶皱,不规则小疣状颗粒以及密浅网状纹饰。观察结果支持将绵毛酸模叶蓼(P. lapathifolium L. var. salicifolium Sibth.)合并到酸模叶蓼(P. lapathifolium L.),做为酸模叶蓼的异名处理;支持将长鬃蓼(P. longisetum De Br.)作为丛枝蓼(P. posumbu Buch. Ham. ex D.Don)的变种处理的意见;认为密毛酸模叶蓼(P. lapathifolium L. var. lanatum (Roxb.) Stew.)应恢复种级,圆基长鬃蓼(P. longisetum De Br. var. rotunatum A.J.Li)应升为种级;支持平武蓼(Polygonum pingwuense F. Z. Li et Y. T. Hou et S. J. Fan, sp. nov.)新种的成立。  相似文献   
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Studies of the relationship between sexual traits and immune function have been at the forefront of sexual selection during the last decade. Whereas evidence is accumulating that there is a trade-off between sexual ornamentation and immunocompetence, the reasons for this trade-off are still unknown. Importantly, most studies have addressed this issue only at the adult stage, when sexual ornamentation and immune function may be fully developed. We show here that juvenile cell-mediated immune response is negatively correlated with subsequent size of an adult sexual ornament in the Chinese quail, Coturnix chinensis. This suggests that the cost of development of a functional immune system is traded off against secondary sexual traits, and that costs of high immunocompetence in juveniles may not be manifested until sexual maturity. Ontogenetic studies of the development of the immune function and associated costs and trade-offs are likely to provide a more complete picture of the links between sexual selection and immunobiology.  相似文献   
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Local environmental and ecological conditions are commonly expected to result in local adaptation, although there are few examples of variation in phenotypic selection across continent‐wide spatial scales. We collected standardized data on selection with respect to the highly variable plumage coloration of pied flycatcher (Ficedula hypoleuca Pall.) males from 17 populations across the species' breeding range. The observed selection on multiple male coloration traits via the annual number of fledged young was generally relatively weak. The main aim of the present study, however, was to examine whether the current directional selection estimates are associated with distance to the sympatric area with the collared flycatcher (Ficedula albicollis Temminck), a sister species with which the pied flycatcher is showing character displacement. This pattern was expected because plumage traits in male pied flycatchers are changing with the distance to these areas of sympatry. However, we did not find such a pattern in current selection on coloration. There were no associations between current directional selection on ornamentation and latitude or longitude either. Interestingly, current selection on coloration traits was not associated with the observed mean plumage traits of the populations. Thus, there do not appear to be geographical gradients in current directional fecundity selection on male plumage ornamentation. The results of the present study do not support the idea that constant patterns in directional fecundity selection would play a major role in the maintenance of coloration among populations in this species. By contrast, the tendency for relatively weak mosaic‐like variation in selection among populations could reflect just a snapshot of temporally variable, potentially environment‐dependent, selection, as suggested by other studies in this system. Such fine‐grained variable selection coupled with gene flow could maintain extensive phenotypic variation across populations. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 808–827.  相似文献   
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The Australian wolf spider genus Hoggicosa Roewer, 1960 with the type species Hoggicosa errans (Hogg, 1905) is revised to include ten species: Hoggicosa alfi sp. nov. ; Hoggicosa castanea (Hogg, 1905) comb. nov. (= Lycosa errans Hogg, 1905 syn. nov. ; = Lycosa perinflata Pulleine, 1922 syn. nov. ; = Lycosa skeeti Pulleine, 1922 syn. nov. ); Hoggicosa bicolor (McKay, 1973) comb. nov. ; Hoggicosa brennani sp. nov. ; Hoggicosa duracki (McKay, 1975) comb. nov. ; Hoggicosa forresti (McKay, 1973) comb. nov. ; Hoggicosa natashae sp. nov. ; Hoggicosa snelli (McKay, 1975) comb. nov. ; Hoggicosa storri (McKay, 1973) comb. nov. ; and Hoggicosa wolodymyri sp. nov. The Namibian Hoggicosa exigua Roewer, 1960 is transferred to Hogna, Hogna exigua (Roewer, 1960) comb. nov. A phylogenetic analysis including nine Hoggicosa species, 11 lycosine species from Australia and four from overseas, with Arctosa cinerea Fabricius, 1777 as outgroup, supported the monophyly of Hoggicosa, with a larger distance between the epigynum anterior pockets compared to the width of the posterior transverse part. The analysis found that an unusual sexual dimorphism for wolf spiders (females more colourful than males), evident in four species of Hoggicosa, has evolved multiple times. Hoggicosa are burrowing lycosids, several constructing doors from sand or debris, and are predominantly found in semi‐arid to arid regions of Australia. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 83–123.  相似文献   
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Coloration plays an important role in sexual and social communication, and in many avian species both males and females maintain elaborate colours. Recent research has provided strong support for the hypothesis that elaborate female traits can be maintained by sexual or social selection; however, most research on female ornamentation has focused on pigment‐based colours, and less is known about how structural colours are maintained. Both sexes of the turquoise‐browed motmot (Eumomota superciliosa) have a blue‐green racket‐tipped tail, and it remains unknown if tail coloration serves as a sexual or social signal in one or both sexes. Here, we describe sexual dichromatism in the blue‐green portion of the tail racket, and we test for a relationship between coloration and condition, as indicated by growth bars. Tail colour of both sexes has a similar spectral shape, and there is significant, although moderate, sexual dichromatism: males are brighter than females, and males have marginally greater blue‐green saturation than females. The length of feather grown per day is positively related to overall feather brightness, but this relationship is only present in males. The relationship between male coloration and condition suggests that tail colour has the potential to convey information about individual quality during mate choice or contest competition. The lack of a similar relationship in females suggests that female tail colour does not convey the same condition‐dependent information that we suggest may be reflected by male colour. Female tail colour may therefore reflect other aspects of condition, be involved in other (non‐condition‐dependent) forms of communication, or be expressed as a non‐functional byproduct of genetic correlation between the sexes. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 673–681.  相似文献   
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