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1.
Dietary niche breadth in a local community of passerine birds: an analysis using phylogenetic contrasts 总被引：1，自引：0，他引：1
The analysis of a local community of forest passerines (13 species) using phylogenetic contrasts shows a correlation between body size of bird species and mean prey size, minimum prey size, maximum prey size and the size range of dietary items. This suggests that larger birds drop small prey taxa from their prey list, because of the difficulty of capturing very small prey, for energetic reasons or because of microhabitat usage. We find some support for the third hypothesis. Dietary niche breadth calculated across prey taxa is not related to body size. Dietary niche breadth, however, is correlated with size-corrected measurements of the bill and locomotor apparatus. Long and slender bills increase the dietary niche breadth. Thus subtle differences constrain foraging and the techniques of extracting certain prey taxa form crevices. Dietary niche breadth and foraging diversity are positively correlated with population density: at least locally dietary generalists occur at higher breeding densities than specialists. 相似文献
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A growing body of literature seeks to explain variation in range shifts using species’ ecological and life‐history traits, with expectations that shifts should be greater in species with greater dispersal ability, reproductive potential, and ecological generalization. Despite strong theoretical support for species’ traits as predictors of range shifts, empirical evidence from contemporary range shift studies remains limited in extent and consensus. We conducted the first comprehensive review of species’ traits as predictors of range shifts, collecting results from 51 studies across multiple taxa encompassing over 11,000 species’ responses for 54 assemblages of taxonomically related species occurring together in space. We used studies of assemblages that directly compared geographic distributions sampled in the 20th century prior to climate change with resurveys of distributions after contemporary climate change and then tested whether species traits accounted for heterogeneity in range shifts. We performed a formal meta‐analysis on study‐level effects of body size, fecundity, diet breadth, habitat breadth, and historic range limit as predictors of range shifts for a subset of 21 studies of 26 assemblages with sufficient data. Range shifts were consistent with predictions based on habitat breadth and historic range limit. However, body size, fecundity, and diet breadth showed no significant effect on range shifts across studies, and multiple studies reported significant relationships that contradicted predictions. Current understanding of species’ traits as predictors of range shifts is limited, and standardized study is needed for traits to be valid indicators of vulnerability in assessments of climate change impacts. 相似文献
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1. Alternative life histories may be maintained in populations due to variation in the costs and benefits of the underlying strategies. In this study, potential costs of dispersal by flight were investigated as an alternative life‐history strategy in the mountain‐living chrysomelid beetle Oreina cacaliae. 2. In this species, previous mark–recapture studies showed a dispersal dimorphism in both males and females. While a fraction of the population engages in flight in autumn and spring (in the following referred to as ‘flyers’), the other part does not fly (non‐flyers). Flyers emerge earlier than non‐flyers and feed on a spring host plant before the emergence of the main host plant. 3. In this study, the overwintering and dispersal locations were recorded over 7 years in the field, flyers from the spring host plant were collected, and morphology and lifetime reproductive output and survival of collected flyers and non‐flyers were compared. 4. A potential trade‐off between flight and life‐history traits was observed: flyers were smaller in size, lighter in body mass, had a lower lifetime fecundity and a higher mortality. 5. Mating experiments of field‐caught beetles in the laboratory showed that larger beetles had a higher (multiple) mating success, but there was no evidence for size‐assortative mating. It is hypothesized that one reason for small beetles to disperse by flight might be to escape competition for mates with larger non‐flyers. 6. The overwhelming quantity of beetles found on the spring host every year reveals that the flying strategy is successful, despite the costs and risks. 相似文献
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The regional occupancy and local abundance of species are affected by various species traits, but their relative effects are poorly understood. We studied the relationships between species traits and occupancy (i.e., proportion of sites occupied) or abundance (i.e., mean local abundance at occupied sites) of stream invertebrates using small‐grained data (i.e., local stream sites) across a large spatial extent (i.e., three drainage basins). We found a significant, yet rather weak, linear relationship between occupancy and abundance. However, occupancy was strongly related to niche position (NP), but it showed a weaker relationship with niche breadth (NB). Abundance was at best weakly related to these explanatory niche‐based variables. Biological traits, including feeding modes, habit traits, dispersal modes and body size classes, were generally less important in accounting for variation in occupancy and abundance. Our findings showed that the regional occupancy of stream invertebrate species is mostly related to niche characteristics, in particular, NP. However, the effects of NB on occupancy were affected by the measure itself. We conclude that niche characteristics determine the regional occupancy of species at relatively large spatial extents, suggesting that species distributions are determined by environmental variation among sites. 相似文献
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Daniel A. Peterson Nate B. Hardy Geoffrey E. Morse Takao Itioka Jiufeng Wei Benjamin B. Normark 《Ecology and evolution》2020,10(23):12910
Most herbivorous insects are diet specialists in spite of the apparent advantages of being a generalist. This conundrum might be explained by fitness trade‐offs on alternative host plants, yet the evidence of such trade‐offs has been elusive. Another hypothesis is that specialization is nonadaptive, evolving through neutral population‐genetic processes and within the bounds of historical constraints. Here, we report on a striking lack of evidence for the adaptiveness of specificity in tropical canopy communities of armored scale insects. We find evidence of pervasive diet specialization, and find that host use is phylogenetically conservative, but also find that more‐specialized species occur on fewer of their potential hosts than do less‐specialized species, and are no more abundant where they do occur. Of course local communities might not reflect regional diversity patterns. But based on our samples, comprising hundreds of species of hosts and armored scale insects at two widely separated sites, more‐specialized species do not appear to outperform more generalist species. 相似文献
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Data for five closely related species of gammarid crustaceans are used to examine interspecific relationships between the breadth of fundamental tolerance or capacity and geographical range size. Gammarus duebeni is, almost without exception, the most tolerant species and that with the best physiological performance. Although there is some limited variation, the remaining species can be ranked broadly in the sequence G. zaddachi > G. salinus > G. oceanicus > G. locusta . The wide tolerance and high performance of G. duebeni is associated with the occupation of a wider range of environmental 'types' than any other of the species. In terms of geographical range size, the species can be ranked from most to least widespread in the sequence G. oceanicus > G. duebeni > G. zaddachi > G. salinus > G. locusta . This provides little support for Brown's hypothesis, or the argument that the more widely distributed species within a taxonomic assemblage also tend to have the widest fundamental niches. However, if marine ( G. oceanicus and G. locusta ) and estuarine ( G. duebeni , G. zaddachi , G. salinus) species are considered separately, then in each case the species with the largest geographical range is also the most tolerant/best performer. In this sense, the jack-of-all-trades is the master-of-all, rather than the master-of-none. 相似文献
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CHRISTER SOLBRECK 《Ecological Entomology》1986,11(4):435-444
ABSTRACT.
- 1 Horvathiolus gibbicollis (Costa), a ground-living seed-feeding bug of the mediterranean region, has two wing morphs. In macrop-terous bugs both pairs of wings are fully developed. In brachypterous ones forewings are reduced to about two-thirds and hindwings to less than a third of their length in macropters.
- 2 Each morph bred true with regard to wing length when reared under variable density, food and temperature conditions for several generations.
- 3 All F1 offspring between crosses of the two morphs were brachypterous. In F2 approximately 25% were macropters and 75% brachypters implying monogenic control of wingform.
- 4 Flight muscles in macropters vary from fully developed to totally reduced. This variation is determined by environmental conditions during adult life. Most young adult bugs have flight muscles, and totally starved or unmated bugs retain their flight muscles. Fed and mated females histolyse flight muscles as they start laying eggs, while most males of the same group retain their muscles.
- 5 Brachypterous bugs have a smaller thorax and larger abdomen than macropterous ones.
- 6 Brachypterous bugs reach adulthood slightly before macropterous ones, and they have a distinctly shorter adult preoviposition period.
- 7 Lifetime egg production does not differ significantly between the two wing morphs. However, the temporal pattern of egg laying is different in the two morphs. The mx-curve of macropters starts later, then attains a higher peak and finally decreases faster than that of brachypters.
- 8 Initially, macropters lay smaller eggs than brachypters, but egg volume increases with age in macropters and eventually approaches that of brachypters.
- 9 The initial increase in reproductive effort (egg volumexegg number) of macropters is concomitant with wing muscle histolysis and the mobilization of thorax space for reproduction.
- 10 Adult survival rate does not differ between the morphs.
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Richard F. Comont Helen E. Roy Owen T. Lewis Richard Harrington Christopher R. Shortall Bethan V. Purse 《Journal of Biogeography》2012,39(10):1772-1781
Aim Determining to what extent differing distribution patterns are governed by species’ life‐history and resource‐use traits may lead to an improved understanding of the impacts of environmental change on biodiversity. We investigated the extent to which traits can explain distribution patterns in the ladybird fauna (Coleoptera: Coccinellidae) of Great Britain. Location The British mainland and inshore islands (Anglesey, the Isle of Wight and the Inner Hebrides). Methods The distributions of 26 ladybird species resident in Britain were characterized in terms of their range size (from 2661 10‐km grid squares across Britain) and proportional range fill (at 10‐ and 50‐km scales). These were assessed relative to five traits (body length, elytral colour pattern polymorphism, voltinism, habitat specificity and diet breadth). The role of phylogenetic autocorrelation was examined by comparing the results of phylogenetic and generalized least‐squares regressions. Results Diet breadth was the only trait correlated with range size: species with broad diets had larger range sizes than dietary specialists. Range fill was sensitive to recording intensity (a per‐species measure of the mean number of records across occupied squares); models including both recording intensity and range size provided more explanatory power than models incorporating ecological traits alone. Main conclusions Habitat specificity is often invoked to explain the distribution patterns of species, but here we found diet breadth to be the only ecological correlate of both range fill and range size. This highlights the importance of understanding predator–prey interactions when attempting to explain the distribution patterns of predatory species. Our results suggest that the diet breadth of predatory species is a better correlate of range size and fill than other measures, such as habitat specificity. 相似文献
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Robert A. Briers 《Global Ecology and Biogeography》2003,12(1):47-51
Calcium is an essential requirement for the successful growth and development of gastropod molluscs. Data for British freshwater gastropods were used to examine the relationship between environmental calcium requirements and British and European range sizes. At both spatial scales calciphile species, which require a high level of environmental calcium, had significantly smaller range sizes than species able to exploit a wide range of environmental calcium levels. However, at least in Britain, range size may also be influenced by the availability of suitable habitat. British and European range sizes were significantly correlated. This study provides evidence for niche‐based explanations of range size variation, and suggests that both niche breadth and niche availability are important in determining range size. 相似文献
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Wilfried Thuiller Sandra Lavorel Miguel B. Araújo 《Global Ecology and Biogeography》2005,14(4):347-357
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蓝尾石龙子的头部两性异形和食性 总被引：10，自引：0，他引：10
通过测量头、体大小和胃检研究浙江泰顺产蓝尾石龙子 (Eumeceselegans)个体发育过程中两性异形和食性的变化。蓝尾石龙子成体个体大小和头部大小的两性差异显著 ,雄性大于雌性。不同发育阶段雌性头长与SVL的线性回归斜率无显著差异 ,头宽与SVL线性回归斜率的差异显著 ,成体和SVL <5 0mm幼体头宽随SVL的增长速率显著小于SVL为 5 0 - 6 9mm的幼体。雄性头部相对于SVL呈加速式异速生长。两性比较发现 :雌雄幼体头长和头宽随SVL的增长速率无显著差异 ,SVL <5 0mm幼体特定SVL的头长和头宽无显著的两性差异 ,但SVL为 5 0 - 6 9mm的雄性幼体头长和头宽大于SVL相同的雌性幼体 ;雄性成体头长和头宽随SVL的增长速率显著大于雌性。SVL <5 0mm的雌性幼体头部相对小于SVL为 5 0 - 6 9mm的同性幼体 ,性成熟雌体头部相对小于SVL为 5 0 - 6 9mm的同性幼体。雌性幼体、雄性幼体、雌性成体和雄性成体食物生态位宽度分别为 12 3、 12 5、 4 8和 14 4。雌雄幼体食物生态位重叠度最高 ,雌雄成体食物生态位重叠度次之 ,成体与幼体食物生态位重叠度较小。成体摄入食饵的大小 (用胃内完整食物长度的平均值表示 )和变化范围大于幼体。两性成、幼体摄入的食饵大小差异显著。两性个体摄入的食饵大小均与其SVL呈正相关 ,表明较大 相似文献
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The butterfly fauna on the Korean peninsula are comprised of both the Palearctic and Oriental species. We hypothesized that the Oriental species (immigrated across the sea) tend to have a wider niche breadth compared with the Palearctic species (immigrated from the continent) since the former migrates long distances across the sea and has to adapt to new environments. We tested this hypothesis using Korean butterfly data on distribution, habitat, food and life history traits. The distribution and ecological traits such as habitat breadth, overwintering stage, and voltinism of the Oriental species were found to be significantly different from the Palearctic species. However, the diet breadth and food plant type were not different. These results partly confirm the peninsula niche breadth hypothesis, which predicted that Oriental species have a broader niche breadth than Palearctic species. 相似文献
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The beet armyworm, Spodoptera exigua, is an important migratory insect pest in tropical and subtropical regions worldwide. The current study investigated genetic variation in the flight capacity of both female and male moths, using a quantitative genetics approach. The offspring–parent regression showed that parents had a significant influence on the flight duration of offspring, and the heritability estimated as 0.302. The upward selection increased mean flight duration from 123.7 to 284.6 min in females and from 113.9 to 254.0 min in males during 8 h of flight test; by contrast, downward selection decreased it from 123.7 to 65.6 min in females and from 113.9 to 29.8 min in males, while it did not change significantly in either females or males of the control line over eight generations. The mean realized heritability was estimated as 0.432 based on upward selection but 0.130 on downward selection, suggesting the asymmetry of response to selection on flight capacity. Reciprocal crosses between the two selected lines confirmed the dominance of ‘long‐flying genes’ in the inheritance of flight capacity. A positive genetic correlation was found between increased flight duration and pupal weight. The presence of such additive genetic variance and covariance for flight capacity and the fitness trait, pupal weight, in the population of S. exigua may have underpinned the evolution of its migratory behaviour. 相似文献
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Drosophila buzzatii and D. koepferae are two sibling species that breed on the necrotic tissues of several cactus species and show a certain degree of niche overlap. Also, they show differences in several life history traits, such as body size and developmental time, which probably evolved as a consequence of adaptation to different host plants. In this work we investigate the ecological and genetic factors affecting wing morphology variation both within and between species. Three wing traits were scored, distal and proximal wing length and width in isofemale lines reared in two of the most important host cacti: Opuntia sulphurea and Trichocereus terschekii. Our results revealed that differences between species and sexes in wing size and shape were significant, whereas the cactus factor was only significant for wing size. Intraspecific analyses showed that differences among isofemale lines were highly significant for both size and shape in both species, suggesting that an important fraction of variation in wing morphology has a genetic basis. Moreover, the line by cactus interaction, which can be interpreted as a genotype by environment interaction, also accounted for a significant proportion of variation. In summary, our study shows that wing size is phenotypically plastic and that populations of D. buzzatii and D. koepferae harbour substantial amounts of genetic variation for wing size and shape. Interspecific differences in wing size and shape are interpreted in terms of spatial predictability of the different host plants in nature. 相似文献