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71.
Acorn dispersal estimated by radio-tracking 总被引:2,自引:0,他引:2
Bird-dispersed seeds are difficult to track, especially in the case of long-distance dispersal events. To estimate the oak
dispersal distance and the seed shadow generated by the European jay (Garrulus glandarius), we inserted radio-transmitters in 239 acorns, placed them in bird-feeders and then located them by radio-tracking. Using
this methodology we located the exact caching site of 94 Quercus ilex and 54 Q. suber acorns and determined the caching habitat characteristics (vegetation type, distance, spatial distribution). The results
show that: (1) there is no differences in the dispersal distance distribution between the different acorn species or sizes,
(2) dispersal distances range from approximately 3 m up to approximately 550 m (mean = 68.6 m; median = 49.2 m), (3) recently
abandoned fields and forest tracks were the sites preferred by jays to cache acorns, whereas fields and shrublands were avoided
and (4) seed shadows showed acorn aggregation zones (i.e. clusters of caches) close to the feeder as well as isolated caches
at longer distances. The results also suggest that radio-transmitters are a cheap and reliable way to determine seed shadows
and quantify both seed dispersal and post-dispersal seed predation for medium to large seeds. 相似文献
72.
Marcelo R. de Carvalho Flávio A. Bockmann Dalton S. Amorim Carlos Roberto F. Brandão Mário de Vivo José L. de Figueiredo Heraldo A. Britski Mário C. C. de Pinna Naércio A. Menezes Fernando P. L. Marques Nelson Papavero Eliana M. Cancello Jorge V. Crisci John D. McEachran Robert C. Schelly John G. Lundberg Anthony C. Gill Ralf Britz Quentin D. Wheeler Melanie L. J. Stiassny Lynne R. Parenti Larry M. Page Ward C. Wheeler Julián Faivovich Richard P. Vari Lance Grande Chris J. Humphries Rob DeSalle Malte C. Ebach Gareth J. Nelson 《Evolutionary biology》2007,34(3-4):140-143
73.
Broggi J Joubert N Aucagne V Berteina-Raboin S Diez-Gonzalez S Nolan S Topalis D Deville-Bonne D Balzarini J Neyts J Andrei G Snoeck R Agrofoglio LA 《Nucleosides, nucleotides & nucleic acids》2007,26(10-12):1391-1394
Hitherto unknown 1,4-disubstituted-[1,2,3]-triazolo-4',4'-dihydroxymethyl-3'-deoxy carbanucleosides were synthesized based on a "click approach." Various alkynes were introduced on a key azido intermediate by the "click" 1,3-dipolar Huisgen cycloaddition. Their antiviral activities and cellular toxicities were evaluated on vaccinia virus. None of the synthesized compounds exhibited a significant antiviral activity. 相似文献
74.
Background and Aims Many plants produce extrafloral nectar (EFN), and increase production following above-ground herbivory, presumably to attract natural enemies of the herbivores. Below-ground herbivores, alone or in combination with those above ground, may also alter EFN production depending on the specificity of this defence response and the interactions among herbivores mediated through plant defences. To date, however, a lack of manipulative experiments investigating EFN production induced by above- and below-ground herbivory has limited our understanding of how below-ground herbivory mediates indirect plant defences to affect above-ground herbivores and their natural enemies.Methods In a greenhouse experiment, seedlings of tallow tree (Triadica sebifera) were subjected to herbivory by a specialist flea beetle (Bikasha collaris) that naturally co-occurs as foliage-feeding adults and root-feeding larvae. Seedlings were subjected to above-ground adults and/or below-ground larvae herbivory, and EFN production was monitored.Key Results Above- and/or below-ground herbivory significantly increased the percentage of leaves with active nectaries, the volume of EFN and the mass of soluble solids within the nectar. Simultaneous above- and below-ground herbivory induced a higher volume of EFN and mass of soluble solids than below-ground herbivory alone, but highest EFN production was induced by above-ground herbivory when below-ground herbivores were absent.Conclusions The induction of EFN production by below-ground damage suggests that systemic induction underlies some of the EFN response. The strong induction by above-ground herbivory in the absence of below-ground herbivory points to specific induction based on above- and below-ground signals that may be adaptive for this above-ground indirect defence. 相似文献
75.
76.
Julián Alexander Mendivil Nieto Ranulfo González Obando Alfonso Neri García Aldrete 《ZooKeys》2015,(503):45-54
Two new species of Edmockfordia García Aldrete, from Valle del Cauca, Colombia, and the female of Edmockfordia
chiquibulensis García Aldrete, are described and illustrated. A key to the species of Edmockfordia is included; the genus was previously known only from Belize. The genus is re-diagnosed to include female characters. The distribution of the genus is considerably widened, from Belize to northeastern South America. 相似文献
77.
78.
The genome sequencing of Buchnera aphidicola BCc from the aphid Cinara cedri, which is the smallest known Buchnera genome, revealed that this bacterium had lost its symbiotic role, as it was not able to synthesize tryptophan and riboflavin. Moreover, the biosynthesis of tryptophan is shared with the endosymbiont Serratia symbiotica SCc, which coexists with B. aphidicola in this aphid. The whole-genome sequencing of S. symbiotica SCc reveals an endosymbiont in a stage of genome reduction that is closer to an obligate endosymbiont, such as B. aphidicola from Acyrthosiphon pisum, than to another S. symbiotica, which is a facultative endosymbiont in this aphid, and presents much less gene decay. The comparison between both S. symbiotica enables us to propose an evolutionary scenario of the transition from facultative to obligate endosymbiont. Metabolic inferences of B. aphidicola BCc and S. symbiotica SCc reveal that most of the functions carried out by B. aphidicola in A. pisum are now either conserved in B. aphidicola BCc or taken over by S. symbiotica. In addition, there are several cases of metabolic complementation giving functional stability to the whole consortium and evolutionary preservation of the actors involved. 相似文献
79.
Secanella-Fandos S Luquin M Pérez-Trujillo M Julián E 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(26):2821-2826
The profile of mycolic acids from Mycobacterium confluentis has not been adequately published. However, the definition of the composition of mycolic acids is a critical element for describing new mycobacterial species. Thus, an erroneously published profile can lead to confusing citations. The aim of this article is to make the protocols clear, by using thin layer chromatography as a tool, for defining the discrete pattern of mycolic acids of any newly reported mycobacterial species. By using this method, and corroborated using nuclear magnetic resonance analysis, we demonstrated that M. confluentis contains α-mycolates (type I) and epoxymycolates (type V mycolic acids). 相似文献
80.