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1.
The wings of most pierid butterflies exhibit a main, pigmentary colouration: white, yellow or orange. The males of many species have in restricted areas of the wing upper sides a distinct structural colouration, which is created by stacks of lamellae in the ridges of the wing scales, resulting in iridescence. The amplitude of the reflectance is proportional to the number of lamellae in the ridge stacks. The angle-dependent peak wavelength of the observed iridescence is in agreement with classical multilayer theory. The iridescence is virtually always in the ultraviolet wavelength range, but some species have a blue-peaking iridescence. The spectral properties of the pigmentary and structural colourations are presumably tuned to the spectral sensitivities of the butterflies’ photoreceptors.  相似文献   

2.
Wing scales of male Euploea mulciber (E. mulciber) and Troides aeacus (T. aeacus) butterflies were investigated from interest in photonic crystal by scanning electron microscopy and optical reflectance measurement. On the basis of the structural observation, the colouration in different areas in their wings was discussed. It was particularly deduced that a violet-green iridescence characteristic of E. mulciber’s forewing is caused only in a wavelength range from ∼380 to ∼510 nm by multiple interference from a highly tilted, triple-layered cuticle arrangement on the brown scales. It was also found that T. aeacus does not produce a blue-green sheen such as observed by Troides magellanus because its scales have no multiple cuticle layers but microrib layers unable to produce any backscattering diffraction.  相似文献   

3.
Species showing intraspecific morphological variation tend to be very difficult to identify using morphological characters. One such example is the cicada genus Mogannia where some species show considerable intraspecific variation mainly exhibited by wing pattern and body colouration. Thirty-one variants covering different putative species of Mogannia were recognized and illustrated in the present paper. Molecular data of mitochondrial COI and Cytb sequences were employed to test the level of variation and phylogeny of them. The existence of a ‘barcoding gap’ between intraspecific and interspecific genetic divergences and the reciprocally monophyletic clades indicate that all the closely related variants represent a single species, and that all these variants correspond to six species, respectively. However, the evolutionary relationships of intraspecific variants are not resolved possibly due to insufficient genetic variation among them. Our results indicated that some morphological characters, especially the wing pattern and body colouration, and even the number of apical processes of the aedeagus in a couple of related species, must be used with great caution in delimiting Mogannia species and their relatives. The factors responsible for intraspecific morphological variation and phylogeny of Mogannia spp. are preliminarily discussed.  相似文献   

4.
高福元  石福习 《生态学报》2015,35(7):2029-2037
在三江平原沼泽湿地,基于不同零模型的点格局方法,研究了常年积水环境条件下沼泽湿地主要优势种毛苔草、漂筏苔草、狭叶甜茅以及小叶章种群的空间分布格局特征。结果表明:在0—200cm尺度范围内4种物种基本都偏离完全随机模型,表现为聚集分布,但偏离的程度不同;除了数量最少的小叶章种群外,其他3种物种都在一定尺度上偏离了泊松聚块模型;毛苔草和狭叶甜茅种群在极小尺度上偏离嵌套双聚块模型,但不显著,而漂筏苔草种群在所有尺度上符合嵌套双聚块模型。种群的实测值偏离完全随机模型的程度越大,越有可能符合符合泊松聚块模型,偏离泊松聚块模型的程度越大,越有可能符合嵌套双聚块模型。4种物种在0—200cm尺度范围内形成的聚块是由营养繁殖引起的,多个分株系统组成大聚块,而每个分株系统形成一个小聚块,聚块的形成加剧了种内竞争,使得种群的聚集强度降低。  相似文献   

5.
The modified midventral scales on Percina males probably function to induce tactile stimulation of the female during spawning. The midbelly row of modified scales presumably evolved as a result of increased selective advantage of larger and more strongly toothed scales on the midventer; primitive and intermediate conditions in the evolution of the modified scales as well as a distinctly modified row are extant, The morphology of the scales varies seasonally and ontogenetically. The scales are permanent rather than deciduous as described in the literature interspecific variation of the modified scales is pronounced intersubgenerically. less so intrasubgenerically.  相似文献   

6.
The angled sunbeam butterfly, Curetis acuta (Lycaenidae), is a distinctly sexually dimorphic lycaenid butterfly from Asia. The dorsal wings of female and male butterflies have a similar pattern, with a large white area in the female and an orange area in the male, framed within brown–black margins. The ventral wings of both sexes are silvery white, which is caused by stacks of overlapping, non‐pigmented, and specular‐reflecting scales. With oblique illumination, the reflected light of the ventral wings is strongly polarized. We show that the silvery reflection facilitates camouflage in a shaded, foliaceous environment. The ecological function of the silvery reflection is presumably two‐fold: for intraspecific signalling in flight, and for reducing predation risk at rest and during hibernation. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 279–289.  相似文献   

7.
Ultraviolet (UV) colour patterns, particularly those deriving from surface structures, serve a role in sexual signalling and mate choice in a range of animal groups. In the butterfly Colias eurytheme (Pieridae), male-limited iridescent UV functions in species recognition, and has potential as an intraspecific sexual signal of mate quality. I compared the dorsal colouration and body size of males discovered ‘in-copula’ (N = 95) with a random sample of free-flying individuals (N = 129), both collected from a high density agricultural population located in Chandler, U.S.A. Despite reasonable variance in each trait, I found no among-group differences in UV characters (brightness, hue and angular visibility) or in the coincident pigmentary yellowish-orange (brightness and saturation). Statistical power was sufficient to detect all but the smallest among-group differences, and there was a marginally significant tendency for in-copula males to be larger. These data do not support the hypothesis for intraspecific female choice upon male dorsal colouration. However, I discuss how the density and apparently very young age of individuals in the sampling population may have pre-disposed this result, and thus, how sexual selection on male colouration may operate in a density dependent manner.  相似文献   

8.
Scaling is relevant for the analysis of plant‐frugivore interaction, since the ecological and evolutionary outcomes of seed dispersal depend on the spatial and temporal scale at which frugivory patterns emerge. We analyse the relationship between fruit abundance and frugivore activity at local and landscape spatial scales in two different systems composed, respectively, by the bird‐dispersed woody plants Juniperus communis and Bursera fagaroides, and their frugivore assemblages. We use a hierarchical approach of nested patchiness of fruit‐resource, where patches are defined by individual plants within site, at the local scale, and by sites within region, at the landscape scale. The structure of patches is also described in terms of contrast (differences in fruit availability among patches) and aggregation (spatial distribution of patches). For J. communis, frugivore activity was positively related to fruit availability at the landscape scale, this pattern seldom emerging at the local scale; conversely, B. fagaroides showed a general trend of positive local pattern that disappeared at the landscape scale. These particular trends might be partially explained by differences in contrast and aggregation. The strong contrast among plants within site together with a high aggregation among sites would promote the B. fagaroides pattern to be only local, whereas in J. communis, low aggregation among sites within region would favour a sharp landscape‐scale pattern. Both systems showed discordant patterns of fruit‐resource tracking among consecutive spatial scales, but the sense of discordance differed among systems. These results, and the available multi‐scale frugivory data, suggest that discordance among successive scales allows to link directly frugivory patterns to resource‐tracking mechanisms acting at particular scales, resulting, thus, more informative than concordance observational data, in which landscape patterns might result from accumulated effect of local mechanisms. In this context, we propose new methodological approaches for a better understanding of the hierarchical behavioural mechanisms underpinning the multi‐scale resource tracking by frugivores.  相似文献   

9.
Two new species of the lampeye genus Hylopanchax are described from the Ivindo River basin in the Ogowe River drainage. Hylopanchax multisquamatus, new species, and Hylopanchax thysi, new species, differ from congeners by the presence of a hyaline urogenital male papilla with small black spots and a dark-brown reticulate pattern on the flanks of both males and females in preserved specimens. Hylopanchax multisquamatus is distinguished from congeners by the number of scales on the mid-longitudinal series (27–30 vs. 19–26, respectively) and by the relative anterior/posterior flank scale depth ratio (140%–150% vs. 170%–220%). Hylopanchax thysi is distinguished from all other congeners, except Hylopanchax paucisquamatus, by the presence of vertebrae (30 vs. 31–33) and is further distinguished from H. multisquamatus by the presence of a deeper caudal peduncle and much larger anterior flank scales. It is distinguished from H. paucisquamatus by the presence of a hyaline urogenital male papilla with small black spots and a dark-brown reticulate pattern on the flanks of both males and females in preserved specimens. Osteological data of Hylopanchax are presented for the first time, and an updated diagnosis based on external morphology, colouration pattern and osteology is provided. An osteological comparison with closely related species belonging to the genera Procatopus, Hypsopanchax and “Hypsopanchax” is presented. (a) A truncate and slightly downward-directed anterior process of the angulo-articular and (b) a guitar-shaped lachrymal with both its anterior and posterior margins sharply curved are here considered as diagnostic features of Hylopanchax.  相似文献   

10.
Coexistence in bumblebee communities has largely been investigated at local spatial scales. However, local resource partitioning does not fully explain the species diversity of bumblebee communities. Theoretical studies provide new evidence that partitioning of space can promote species coexistence, when species interact with their environment at different spatial scales. If bumblebee species possess specific foraging ranges, different spatial resource utilisation patterns might operate as an additional mechanism of coexistence in bumblebee communities. We investigated the effects of the landscape-wide availability of different resources (mass flowering crops and semi-natural habitats) on the local densities of four bumblebee species at 12 spatial scales (landscape sectors with 250–3,000 m radius) to indirectly identify the spatial scales at which the bumblebees perceive their environment. The densities of all bumblebee species were enhanced in landscapes with high proportions of mass flowering crops (mainly oilseed rape). We found the strongest effects for Bombus terrestris agg. and Bombus lapidarius at large spatial scales, implying foraging distances of 3,000 and 2,750 m, respectively. The densities of Bombus pascuorum were most strongly influenced at a medium spatial scale (1,000 m), and of Bombus pratorum (with marginal significance) at a small spatial scale (250 m). The estimated foraging ranges tended to be related to body and colony sizes, indicating that larger species travel over larger distances than smaller species, presumably enabling them to build up larger colonies through a better exploitation of food resources. We conclude that coexistence in bumblebee communities could potentially be mediated by species-specific differences in the spatial resource utilisation patterns, which should be considered in conservation schemes.  相似文献   

11.
Frequencies and sequences of visually-identifiable acts were investigated in male-female combinations of gerbils of the taxa Tatera brantsii, Gerbillurus paeba paeba, G. p. exilis, G. tytonis, G. setzeri, and G. vallinus. Sexual dimorphism of behaviour was most apparent in T. brantsii, G. setzeri, and G. vallinus, in which following, anogenital sniffing, and mounting were significantly more frequently performed by males than females. Females of all taxa presented and darted, while males did not perform these acts. Analysis of first-order transitions of acts in intraspecific encounters revealed remarkable similarity among species in the sequences identified as most significantly deviating from expected frequency. Species-specific patterns of behaviour were detected by discriminant analysis. G. p. paeba, G. p. exilis and G. vallinus were not clearly distinguished by discriminant analysis, and presented a behaviour pattern characterized by low levels of aggression and high levels of huddling behaviour. G. tytonis, G. setzeri and T. brantsii were characterized by low levels of huddling, G. tytonis performed the largest number of upright postures of all taxa, G. setzeri watched more than other taxa, and T. brantsii nasal sniffed less frequently than Gerbillurus taxa. Differences among taxa were more apparent in males than in females. Interspecific encounters were staged between G. p. paeba and G. p. exilis, G. p. paeba and G. tytonis, G. setzeri and G. vallinus. Males showed more evidence of changed behaviour in interspecific encounters than females. More sexual and less agonistic behaviour was detected in intraspecific encounters than in interspecific encounters, but this was statistically significant in only 5 of 12 combinations. Visual, tactile and olfactory communication during physical contact with another individual may complement auditory communication in promoting conspecific recognition in southern African gerbils.  相似文献   

12.
王进  朱江  艾训儒  姚兰  黄小  吴漫玲  朱强  刘松柏 《生态学报》2020,40(21):7709-7720
物种共存机制是生态学研究的重要问题。以同属物种山矾、光叶山矾为研究对象,分析其空间分布格局和种内、种间关联性特征。将山矾、光叶山矾分为4个径级,分别归属幼树、小树、中树和成年树4个生长阶段。采用单变量成对相关函数分析空间分布格局特征;双变量成对相关函数分析种内、种间关联性。结果显示:山矾和光叶山矾径级结构基本一致,均属增长型种群。在完全空间随机模型下,山矾和光叶山矾主要呈聚集分布,逐渐过渡为均匀分布;在异质泊松模型下,只在小尺度上聚集,较大尺度范围呈随机分布。种内关联上,山矾各生长阶段主要呈正关联,逐渐向无关联过渡,光叶山矾除小树与成年树外,其余均呈正关联;排除生境异质性影响后,小尺度呈正关联,其余尺度无关联。种间关联上,在幼树、小树物种对中主要呈负关联,中树、成年树物种对中多为无关联。研究表明,同属物种山矾和光叶山矾呈种内聚集、种间分离的空间构型,在竞争排除作用下实现同属共存,有利于亚热带常绿落叶阔叶混交林群落结构稳定和物种多样性维持。  相似文献   

13.
We investigated the spatial patterns of perennial species (Stipa tenacissima, Anthyllis cytisoidesGlobularia alypum, Brachypodium retusum and chamaephytes) in a 50 m × 50 m semi-arid steppe by using the combination of a linear model of coregionalization (LMC) and sampling units of varying size (1.25 m × 1.25 m, 2.5 m × 2.5 m, and 5 m × 5 m). The data-adjusted LMC showed the patchy structure of the vegetation, which was especially evident with the highest resolution grid. It also detected a periodic pattern in the distribution of S. tenacissima, as well as autocorrelation at two spatial scales for A. cytisoides and G. alypum. The latter species was negatively associated with the other species at both short and long distances. These negative associations were consistent for all sampling grids and suggest the presence of interference between G. alypum and the rest of the evaluated species. Despite species-specific differences, the LMC was fitted satisfactorily to all of them. This suggests a common variation pattern for all the species, which may be caused by an underlying environmental property driving the patterns of all the species or, alternatively, by the dominance of some species’ spatial pattern, or another kind of species association, over the rest. The spatial patterns found were profoundly affected by the observational scale. Our results reveal that the multivariate geostatistical approach introduced in this paper is a suitable technique for the spatial analysis of semi-arid plant communities. It allows plant ecologists to evaluate if the species forming the plant community of interest share a common spatial pattern, and to assess the spatial covariation between the species forming a plant community at different spatial scales independently.  相似文献   

14.
Important to the study of reef fish ecology is understanding the degree to which fish community structure varies across space, what factors can account for such variation, and whether these factors are scale dependent. This study examined the structure of reef fish communities across four spatial scales (1, 10 100, and 200 m2) visually censused from seven sites within Tague Bay, St. Croix, U.S. Virgin Islands. Relative differences in the number of individuals and species among sites indicated a pattern that was consistent across spatial scales. Spearmans rank correlation revealed significant positive correlation in site rankings, in terms of species richness, between 1 and 10 m2, and 100 and 200 m2; and for the abundance of individuals between 100 and 200 m2. In order to understand the degree to which quantified habitat variables account for patterns in the abundance of individuals and species, and whether these fish-habitat relationships were consistent regardless of spatial scale, separate canonical correlation analyses were conducted at each scale. Independent of scale, the total number of individuals and species were correlated with specific habitat variables, either negatively (with areas of pavement, sand, no algae, and low structural complexity) or positively (with areas of Amphiroa rigida, Halimeda incrassata, high structural complexity, and diverse algae/seagrass communities). These habitat variables explained 31–81% (at scales of 1–200 m2) of the variation in the number of individuals and species. Similar analyses were also performed on the abundances of the nine most common species, and whether their specific habitat associations were independent of scale. Results indicated that habitat variables explained 19–73% (at scales of 1–200 m2) of the variation in abundances of each species. Unique fish-habitat relationships were observed for each species, and most such relationships were consistent across spatial scales. The structure of reef fish communities of Tague Bay was explained in large part by the composition of coral and algae communities present. Both the spatial variation in community structure and the fish-habitat relationships, at the community and population level, appeared to be largely independent of the spatial scale examined. This suggests that generalizations across Tague Bay are possible. Similar habitat associations reported in the literature are discussed with regard to the possibility for generalizations across regions.  相似文献   

15.
The Western green lizard (Lacerta bilineata) is a lacertid distributed throughout Mediterranean and Central Europe. Little is known about the morphological variability and sexual shape differences in this species. In this paper, the variation of the cephalic scales in L. bilineata is analysed by means of a geometric morphometric approach. A main structural pattern is characterized by negative allometry of the frontal and interparietal areas, and positive allometry of the parietal and frontoparietal scales. Sexual differences are described both in size and shape. In males, the scales are generally larger, with relative shortening of the frontal area, frontoparietal enlargement, occipital lengthening and bulging of the parietal scales, which compresses and narrows the interparietal and occipital areas midsagittally. This pattern is based on a shared allometric trajectory, with males displaying a peramorphic morphotype. However, males show some shape differences in the occipital area that are not size‐related, and cannot be interpreted in terms of general head enlargement. This structural trajectory can be related to the development of the skull, but the role of soft tissues (temporal, nuchal and masticatory muscles) must also be considered. The development of the jaw and nuchal muscles involved in intra‐ and intersexual behaviours could have played a pivotal role in the evolution of this pattern.  相似文献   

16.
Aim The evolutionary processes structuring the composition of communities remain unclear due to the complexity of factors active at various spatial and temporal scales. Here, we conducted ecological and evolutionary analyses of communities of caddisflies in the genus Hydropsyche (Insecta: Trichoptera) composed of ecomorphologically differentiated species. Location River ecosystems in the Iberian Peninsula and northern Morocco. Methods Nineteen environmental variables were assessed at 180 local study sites and species presence/absence at these sites was used to determine their ecological niche. The evolutionary framework for all 19 species of Hydropsyche encountered was generated by phylogenetic analysis of the mitochondrial cytochrome c oxidase subunit I gene and three nuclear genes: wingless, elongation factor 1‐alpha and 28S RNA. The phylogenetic tree was used: (1) to assess evolutionary niche conservatism by ecological trait correlation with the tree; and (2) to analyse the phylogenetic relatedness of community member species, at three spatial scales (local stream reaches, drainage basins, biogeographical regions). Results Ecological measurements grouped most species into either headwater, mid‐stream or lowland specialists, and traits presumably relevant to river zonation were found to be phylogenetically conservative. Species assemblages at local stream reaches were mostly mono‐ or dispecific. Species diversity increased at larger spatial scales, by adding species with non‐overlapping ecological niches at the level of river basins and by turnover of anciently differentiated lineages at the level of biogeographical regions. This indicates the effects of competition and niche filtering on community structure locally, and ancient ecological diversification and allopatric speciation, respectively, in building up the species pool at basin and biogeographical scales. Main conclusions The study demonstrates the importance of scale (grain size) in studying what determines community composition. Current ecological factors (i.e. competitive exclusion) in Hydropsyche were evident only when studying narrow local sites, while studies of assemblages at larger spatial scales instead demonstrated the roles of ecological niche differentiation, phylogenetic history of trait diversification and allopatric speciation. Increasing the grain size of investigation reveals different portions of correlated spatial and evolutionary processes.  相似文献   

17.
Chen B  Kang L 《Oecologia》2005,144(2):187-195
Species that live in patchy and ephemeral habitats can compete strongly for resources within patches at a small scale. The ramifications of these interactions for population dynamics and coexistence at regional scales will depend on the intraspecific and interspecific distributions of individuals among patches. Spatial heterogeneity due to independent aggregation of competitors among patchy habitats is an important mechanism maintaining species diversity. I describe regional patterns of aggregation for four species of insect larvae in the fruits of Apeiba membranacea, a Neotropical rainforest tree. This aggregation results from variation in densities at a small scale (among the fruits under a single tree), compounded by significant variation among trees in both mean densities and degrees of aggregation. Both the degrees of aggregation and mean densities are statistically independent within and across species at both spatial scales. I evaluate the regional consequences of these spatial patterns by using maximum likelihood methods to parameterize a model that includes both explicit measures of the strength of competition and spatial variation at both within- and among-tree spatial scales. Despite strong competitive interactions among these species, during 2 years the observed spatial variation at both scales combined was sufficient to explain the coexistence of these species, although other coexistence mechanisms may also operate simultaneously. The observed spatial variation at small spatial scales may not be sufficient for coexistence, indicating the importance of considering multiple sources of spatial heterogeneity when scaling up from experiments that investigate local interactions to regional patterns of coexistence.  相似文献   

18.
Abstract. Single species and bivariate distribution patterns in a semi-arid shrubland in southeastern Spain, dominated by the tall leguminous shrub Retama sphaerocarpa, were investigated by second-order spatial analysis based on Ripley's K-function. Shrubs were significantly clumped because of a strong association of dwarf shrubs, mostly Artemisia barrelieri, under the canopy of Retama. Retama shrubs were randomly distributed, but when different size-classes were analysed separately, the pattern changed from significantly clumped to random and then to regular with increasing canopy diameter, suggesting increasing intraspecific competition with shrub size. Artemisia was significantly clumped at all scales because of aggregation under the canopy of large Retama shrubs. The association between the species became stronger with increasing canopy diameter of Retama shrubs, suggesting that facilitation prevailed over interspecific competition because of niche separation in different tiers, both above and below ground. Retama shrub size thus determined both the type of pattern for its own size class and tier, and the scale and intensity of the association with its understorey shrubs.  相似文献   

19.
Grazing is one of the most important factors influencing community structure and productivity in natural grasslands. Understanding why and how grazing pressure changes species diversity is essential for the preservation and restoration of biodiversity in grasslands. We use heavily grazed subalpine meadows in the Qinghai‐Tibetan Plateau to test the hypothesis that grazer exclusion alters plant diversity by changing inter‐ and intraspecific species distributions. Using recently developed spatial analyses combined with detailed ramet mapping of entire plant communities (91 species), we show striking differences between grazed and fenced areas that emerged at scales of just one meter. Species richness was similar at very small scales (0.0625 m2), but at larger scales diversity in grazed areas fell below 75% of corresponding fenced areas. These differences were explained by differences in spatial distributions; intra‐ and interspecific associations changed from aggregated at small scales to overdispersed in the fenced plots, but were consistently aggregated in the grazed ones. We conclude that grazing enhanced inter‐ and intraspecific aggregations and maintained high diversity at small scales, but caused decreased turnover in species at larger scales, resulting in lower species richness. Our study provides strong support to the theoretical prediction that inter‐ and intraspecific aggregation produces local spatial patterns that scale‐up to affect species diversity in a community. It also demonstrates that the impacts of grazing can manifest through this mechanism, lowering diversity by reducing spatial turnover in species. Finally, it highlights the ecological and physiological plant processes that are likely responding to grazing and thereby altering aggregation patterns, providing new insights for monitoring, and mediating the impacts of grazing.  相似文献   

20.
Light interacts with an organism''s integument on a variety of spatial scales. For example in an iridescent bird: nano-scale structures produce color; the milli-scale structure of barbs and barbules largely determines the directional pattern of reflected light; and through the macro-scale spatial structure of overlapping, curved feathers, these directional effects create the visual texture. Milli-scale and macro-scale effects determine where on the organism''s body, and from what viewpoints and under what illumination, the iridescent colors are seen. Thus, the highly directional flash of brilliant color from the iridescent throat of a hummingbird is inadequately explained by its nano-scale structure alone and questions remain. From a given observation point, which milli-scale elements of the feather are oriented to reflect strongly? Do some species produce broader "windows" for observation of iridescence than others? These and similar questions may be asked about any organisms that have evolved a particular surface appearance for signaling, camouflage, or other reasons.In order to study the directional patterns of light scattering from feathers, and their relationship to the bird''s milli-scale morphology, we developed a protocol for measuring light scattered from biological materials using many high-resolution photographs taken with varying illumination and viewing directions. Since we measure scattered light as a function of direction, we can observe the characteristic features in the directional distribution of light scattered from that particular feather, and because barbs and barbules are resolved in our images, we can clearly attribute the directional features to these different milli-scale structures. Keeping the specimen intact preserves the gross-scale scattering behavior seen in nature. The method described here presents a generalized protocol for analyzing spatially- and directionally-varying light scattering from complex biological materials at multiple structural scales.  相似文献   

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