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41.
According to the acoustic adaptation hypothesis, communication signals are evolutionary shaped in a way that minimizes its degradation and maximizes its contrast against the background noise. To compare the importance for call divergence of acoustic adaptation and hybridization, an evolutionary force allegedly promoting phenotypic variation, we compared the mate recognition signal of two species of poison frogs (Oophaga histrionica and O. lehmanni) at five localities: two (one per species) alongside noisy streams, two away from streams, and one interspecific hybrid. We recorded the calls of 47 males and characterized the microgeographic variation in their spectral and temporal features, measuring ambient noise level, body size, and body temperature as covariates. As predicted, frogs living in noisy habitats uttered high frequency calls and, in one species, were much smaller in size. These results support a previously unconsidered role of noise on streams as a selective force promoting an increase in call frequency and pleiotropic effects in body size. Regarding hybrid frogs, their calls overlapped in the signal space with the calls of one of the parental lineages. Our data support acoustic adaptation following two evolutionary routes but do not support the presumed role of hybridization in promoting phenotypic diversity. 相似文献
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Local adaptation versus historical isolation as sources of melanin‐based coloration in the white‐throated thrush Turdus assimilis
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Jano Núñez‐Zapata Pilar Benites Claudia Gutiérrez‐Arellano Marco F. Ortiz‐Ramírez Adolfo G. Navarro‐Sigüenza 《Journal of avian biology》2018,49(9)
Local adaptation seems to be one of the causes of variation in melanin‐based colors in bird plumages, related mainly to the heterogeneity of the environmental conditions along the distribution of a species. Based on comparisons of genetic (mtDNA sequences), ecological (niche models), and quantitative colorimetric data, we explored variation in plumage coloration of the white‐throated thrush Turdus assimilis, a Mesoamerican species whose dorsal color varies from brown (northern and central Mexico) to dark gray (southern Mexico and Central America). Our results suggest the existence of two major patterns of coloration in this bird, which are congruent with the genetic structure, and comparisons of ecological niche models showed that population's niches were more similar than expected by chance, suggesting that color variation in plumage of T. assimilis is not consequence of local adaptation to different environmental conditions. Our results also showed that a greater geographic distance between populations is correlated with greater colorimetric differences, suggesting that color variation in T. assimilis may be consequence of historical isolation. 相似文献
44.
Adolfo Marco Douglas P. Chivers Joseph M. Kiesecker Andrew R. Blaustein 《Ethology : formerly Zeitschrift fur Tierpsychologie》1998,104(9):781-788
Western redback and Dunn's salamanders (Plethodon vehiculum and Plethodon dunni, respectively) can distinguish between potential mates by using chemical cues. In laboratory choice tests, adult males of both species showed significant discrimination between chemical cues of gravid females over non-gravid females of equal body size. Furthermore, males of both species differentiated the odour of paired gravid females that differed by ? 5 mm snout-vent length (SVL). Given that clutch size is related to female body size in these species, adult males may be able to distinguish between females via cues that signal potentially high female reproductive success. In choice tests, P. vehiculum females did not discriminate between two relatively large males that differed by ? 5 mm SVL. However, females of P. vehiculum did discriminate between two relatively small males that differed by the same amount. Apparently, P. vehiculum females ranked males by both absolute and relative body size using chemical cues. This pattern could reflect a female preference for large males or that females avoid mating with the smallest males. 相似文献
45.
Growth Rate of the Microalga Tetraselmis suecica Changes the Biochemical Composition of Artemia Species 总被引:1,自引:0,他引:1
The impact of different microalgal semicontinuous cultures on growth and biochemical composition in the next link of the
food chain was tested using the filter feeder Artemia species as a model. The marine microalga Tetraselmis suecica was cultured semicontinuously with renewal rates between 10% and 50% and used to feed Artemia. Microalgal cultures maintained with a low renewal rate that had biochemical composition similar to that of the stationary-phase
cultures commonly used in aquaculture produced poor growth and survival and low food-conversion efficiency compared to cultures
maintained with a high renewal rate. Changes in the renewal rate in microalgal cultures also resulted in important changes
in the gross biochemical composition of the filter feeder. The gross biochemical composition of the Artemia resembled that of the microalgae used as food except for total lipid content. The percentage of protein in the organic fraction
of Artemia increased from 45% to 65% of the organic weight with increasing renewal rates in the microalgal cultures, while the carbohydrate
percentage decreased under the same conditions. Higher renewal rates resulted in higher lipid percentages in the microalga,
but in Artemia the percentage of lipids decreased from 19% of the organic weight with a renewal rate of 10%, to 13% with a renewal rate
of 50%. The percentage of all polyunsaturated fatty acids in Artemia, including 20:5n-3, increased slightly with increasing renewal rates in the microalgal cultures. Results emphasize the importance
of controlling microalgal nutritional value for the success of aquaculture food chains in which filter feeders are involved.
Received October 15, 2000; accepted December 29, 2000. 相似文献
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47.
Calvete JJ Sanz L Pérez A Borges A Vargas AM Lomonte B Angulo Y Gutiérrez JM Chalkidis HM Mourão RH Furtado MF Moura-Da-Silva AM 《Journal of Proteomics》2011,74(4):510-527
We describe two geographically differentiated venom phenotypes across the wide distribution range of Bothrops atrox, from the Colombian Magdalena Medio Valley through Puerto Ayacucho and El Paují, in the Venezuelan States of Amazonas and Orinoquia, respectively, and S?o Bento in the Brazilian State of Maranh?o. Colombian and Venezuelan venoms show an ontogenetic toxin profile phenotype whereas Brazilian venoms exhibit paedomorphic phenotypes. Venoms from each of the 16 localities sampled contain both population-specific toxins and proteins shared by neighboring B. atrox populations. Mapping the molecular similarity between conspecific populations onto a physical map of B. atrox range provides clues for tracing dispersal routes that account for the current biogeographic distribution of the species. The proteomic pattern is consistent with a model of southeast and southwest dispersal and allopatric fragmentation northern of the Amazon Basin, and trans-Amazonian expansion through the Andean Corridor and across the Amazon river between Monte Alegre and Santarém. An antivenomic approach applied to assess the efficacy towards B. atrox venoms of two antivenoms raised in Costa Rica and Brazil using Bothrops venoms different than B. atrox in the immunization mixtures showed that both antivenoms immunodepleted very efficiently the major toxins (PIII-SVMPs, serine proteinases, CRISP, LAO) of paedomorphic venoms from Puerto Ayacucho (Venezuelan Amazonia) through S?o Bento, but had impaired reactivity towards PLA(2) and P-I SVMP molecules abundantly present in ontogenetic venoms. The degree of immunodepletion achieved suggests that each of these antivenoms may be effective against envenomations by paedomorphic, and some ontogenetic, B. atrox venoms. 相似文献
48.
Orlando Adolfo Jara-Muñoz 《Brittonia》2011,63(2):227-232
Two new species of Erythroxylum from the Amotape-Huancabamba region are described and illustrated. Erythroxylum dillonii occurs in the arid zones of northern Peru, and Erythroxylum gentryi is known only from the Ecuadorian side of Cordillera del Condor. Their habitats and taxonomic relationships are discussed. 相似文献
49.
S.M. Teresa Hernndez-Sotomayor Marina Macías-Silva Magdalena PlebanÜski J. Adolfo García-Sinz 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1988,972(3)
In hepatocytes obtained from hypothyroid rats, phorbol myristate acetate (PMA) and vasopressin diminished the accumulation of cyclic AMP and the stimulation of ureagenesis induced by isoprenaline or glucagon without altering significantly the accumulation of cyclic AMP induced by forskolin. Pretreatment with PMA markedly reduced the stimulation of ureagenesis and the accumulation of cyclic AMP induced by isoprenaline or glucagon. In membranes from cells pretreated with PMA, the stimulation of adenylate cyclase induced by isoprenaline + GTP, glucagon + GTP or by Gpp[NH]p were clearly diminished as compared to the control, whereas forskolin-stimulated activity was not affected. The data indicate heterologous desensitization of adenylate cyclase. It was also observed that the homologous (García-Sáinz J.A. and Michel, B. (1987) Biochem. J. 246, 331–336) and this heterologous β-adrenergic desensitizations were additive. Pertussis toxin treatment markedly reduced the heterologous desensitization of adenylate cyclase but not the homologous β-adrenergic desensitization. It is concluded that the homologous and heterologous desensitizations involve different mechanisms. The homologous desensitization seems to occur at the receptor level, whereas the heterologous probably involves the guanine nucleotide-binding regulatory protein, Ns. 相似文献
50.
Cebollero E Martinez-Rodriguez A Carrascosa AV Gonzalez R 《FEMS microbiology letters》2005,246(1):1-9
The potential of several alternative genetic engineering based strategies in order to accelerate Saccharomyces cerevisiae autolysis for wine production has been studied. Both constitutively autophagic and defective in autophagy strains have been studied. Although both alternatives lead to impaired survival under starvation conditions, only constitutively autophagic strains, carrying a multicopy plasmid with the csc1-1 allele under the control of the TDH3 promoter, undergo accelerated autolysis in the experimental conditions tested. Fermentation performance is impaired in the autolytic strains, but industrial strains carrying the above-mentioned construction are still able to complete second fermentation of a model base wine. We suggest the construction of industrial yeasts showing a constitutive autophagic phenotype as a way to obtain second fermentation yeast strains undergoing accelerated autolysis. 相似文献