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1.
Eleven microsatellites were isolated from the vairone Leuciscus souffia (Risso 1826), an endangered fish that inhabits river systems in and around the Alps in Europe. The level of genetic diversity was assessed in 29 individuals of the subspecies L. s. souffia, and their variability was further estimated in seven individuals of a different subspecies, L. s. muticellus. Eight of these microsatellite loci were also applied to seven closely related cyprinid species. Availability of the reported microsatellite loci will facilitate the investigation of population genetic structure of these species with applications for the development of conservation strategies and phylogeographical approaches.  相似文献   
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We developed 21 polymorphic dinucleotide microsatellite loci, (CA)n and (CT)n, for the Holarctic freshwater fish, Lota lota, using an enriched genomic library protocol. The species has an interesting life history because winter‐spawning adults migrate over long distances to form spawning aggregations, a behaviour which should maintain genetic homogeneity across large spatial scales. Availability of the reported microsatellites will facilitate the investigation of population genetic structure with regard to postglacial colonization history and conservation strategies. The primers were screened on 30 individuals from a natural population (Lake Constance, southern Germany), revealing three to 24 alleles per locus with expected heterozygosities ranging from 0.48 to 0.93.  相似文献   
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Available information on the history, population dynamics, body weight and kidney fat indices in free-living Chinese water deer at Whipsnade Zoo were briefly reviewed.
Fifty eight culled animals were examined quantitatively for changing rumen papilla morphology through different seasons using surface enlargement factors (SEF). The results show a much reduced SEF of below four in winter and rarely above eight in spring, summer and autumn. This is atypical for the entire group of concentrate selectors and even for intermediate feeding types. The inference from the data is that the seasonal rumen development was poorer than expected perhaps indicating that this population was undernourished.  相似文献   
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Ectothermic organisms often face dramatic traverses of environmentaltemperature on a daily or seasonal basis; exemplars among thisgroup are invertebrates and fish of the rocky intertidal zone.Because of the extremes of temperature exposure, intertidalanimals have served as an excellent study system to examinethe expression of heat shock proteins (Hsps) in response tonatural variation in environmental temperature. Ecologicallyrelevant variation in Hsp expression has been observed withseasonal acclimatization, with small-scale temperature gradientsthat occur in microhabitats and between species with differentintertidal distributions. The maturing understanding of Hspexpression patterns in marine organisms has established a solidfoundation on which to build the next set of questions. In thispaper, I present an overview of the variation of Hsp expressionin intertidal animals in nature and then address two emergingareas of investigation in the ecological physiology of Hsps.One area addresses the plasticity of Hsp expression in marineinvertebrates and focuses on the mechanism of regulation ofHsp gene expression by environmental temperature. A second emergingarea of investigation concerns whether Hsps as molecular chaperonesdisplay functional diversity that correlates with species' adaptationtemperature.  相似文献   
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  1. Many entomologists strive to understand what consequences climate change will have on insect performance. Such understanding is important, not least, when trying to predict the future impact of pest insects.
  2. In this study, it was reported how the multiple effects of temperature, photoperiod, and food quality affected the survival, development, and the final weight of the European pine sawfly (Neodiprion sertifer Geoffr.), an herbivorous outbreak species in boreal pine (Pinus spp.) forests.
  3. Sawfly larvae were reared in two different temperatures (15 and 20 °C) and under two different light regimes (20 and 18 h light). The larvae were fed pine needles either low or high in diterpene content.
  4. A 5 °C higher temperature did not affect the survival of the larvae, but reduced the development time by 37–41%. The final weight was reduced by 22% in the warmer temperature, but only in combination with a short day length. A high content of diterpenes in the needles reduced the susceptibility to the virus by 31%, but did not otherwise affect the performance of the larvae.
  5. This study shows that the larval development could be shortened in a warmer climate and thereby decreasing the risk of predation. This per se may increase the risk for insect outbreaks, but the interactive effects of warmer temperatures with other abiotic and biotic factors such as day length and food quality (indicated in this study), and potential better performance of natural enemies and pathogens, illustrate the possibility for complex outcomes in a climate change perspective.
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The neotropical cichlid fish Cichlasoma citrinellum is polymorphic in the structure of its pharyngeal jaw apparatus and external morphology. The pharyngeal jaws are either gracile and bear slender, pointed teeth (papilliform) or robust with strong, rounded teeth (molariform). Molariform morphs have a ‘benthic’, and papilliform morphs a ‘limnetic’ body form. Furthermore, this species is also polychromatic, with yellow and black morphs. The molariform morphology of the pharyngeal jaw apparatus adapts the fish for cracking and feeding on snails. Based on analysis of stomach contents, 94% of the molariform morph ate snails whereas only 19%, of the papilliform morph did so. This result suggests that the morphs occupy different ecological niches. The morphology of the pharyngeal jaw apparatus does not correlate significantly with sex, but it does with body colouration (P<0.005). Cichlasoma citrinellum mate assortatively with their own colour; therefore a mating preference for colour may lead to genetic isolation of trophic morphs. The frequency of the molariform morph differs strikingly among populations of five Nicaraguan lakes and its abundance is correlated with the abundance of snails, the fishes' principal prey item. Among populations the frequency of molariform morphs decreases in the dry season. Morphology possibly changes reversibly within particular individuals between seasons. These results suggest that phenotypic plasticity and polymorphisms may be an adaptive characteristic of cichlid fishes. Patterns of intraspecific morphological variation match patterns of interspecific morphological diversification which suggests that universal developmental mechanisms canalize the possible expressions of morphology. The ability to respond morphologically to environmental shifts, in conjunction with genetically determined trophic polymorphisms and sexual selection via mate choice, could be the basis for speciation through intermediate stages of polymorphism of the impressive adaptive radiation of cichlid fishes.  相似文献   
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Sensory systems play crucial roles in survival and reproduction. Therefore, sensory plasticity has important evolutionary implications. In this study, we examined retinal plasticity in five species of cichlid fish from Lake Malawi. We compared the cone opsin expression profiles of wild‐caught fish to lab‐reared F1 that had been raised in a UV minus, reduced intensity light environment. All of the opsin genes that were expressed in wild‐caught fish were also expressed in lab‐reared individuals. However, we found statistically significant differences in relative opsin expression among all five species. The most consistent difference was in the SWS2B (violet) opsin, which was always expressed at higher levels in lab‐reared individuals. Estimates of visual pigment quantum catch suggest that this change in expression would increase retinal sensitivity in the light environment of the lab. We also found that the magnitude of plasticity varied across species. These findings have important implications for understanding the genetic regulation of opsin expression and raise many interesting questions about how the cichlid visual system develops. They also suggest that sensory plasticity may have facilitated the ecological diversification of cichlids in Lake Malawi.  相似文献   
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