Search

Your search keyword '"Jorge Luis Ávila Núñez"' showing total 4 results
Start Over Author "Jorge Luis Ávila Núñez" Search Limiters Full Text
4 results on '"Jorge Luis Ávila Núñez"'

1. Foliar exudates of Blakiella bartsiifolia (S.F. Blake) Cuatrec. (Asteraceae, Astereae). A Preliminary study of the Chemical Composition

Author

Maria Pia Calcagno-Pissarelli, Miguel Alonso-Amelot, Reynaldo Mora, Diego Rodríguez, and Jorge Luis Ávila Núñez

Subjects
Blakiella bartsiifolia, Asteraceae, exudates, flavonoids, labdane diterpene, Chemistry, QD1-999
Abstract

This is the first phytochemical study of Blakiella bartsiifolia, an endemic species of Mérida. From the foliar exudates two flavonoids ((5,4´-dihydroxy-3,6,7,3´-tetramethoxyflavone; 5,7,4´-trihydroxy-3,8,3´-trimethoxy-flavone) and a labdane diterpene (labda-7,14-dien-13(S)-ol) were identified by high field NMR spectroscopy. Plants naturally exposed to direct sunlight possessed a significantly higher specific absorbance coefficient in the UV region than plants growing in shaded areas.

Published
2010

2. Las exploraciones del naturalista Anton Goering en Mérida (1869-1870) y el establecimiento de una red de historia natural en los Andes venezolanos

Author

Jorge Luis Avila Núñez

Subjects
historia natural, Andes venezolanos, naturalistas, coleccionismo científico, Epistemology. Theory of knowledge, BD143-237, Science, History (General), D1-2009
Abstract

Durante el siglo XIX Venezuela recibió la visita de un número importante de naturalistas europeos, especialmente alemanes, quienes recorrieron el país con el propósito recolectar objetos de historia natural para los más importantes museos de Europa. Christian Anton Goering fue uno de ellos, visitando los Andes merideños entre 1869 y 1870 comisionado por la Sociedad Zoológica de Inglaterra. A partir de su relato de viaje, hemos podido conocer que además de su labor coleccionista, Goering estableció contacto con personajes nativos de Mérida, a quienes enseñó las técnicas de preservación de los especímenes biológicos. El propósito del presente trabajo es analizar estas interacciones y la trascendencia que tuvieron en la formación de una red de intercambio de conocimientos establecida en Venezuela a partir de la visita de este explorador.

Published
2024
Full Text
View/download PDF

3. Hydrogen cyanide release during feeding of generalist and specialist lepidopteran larvae on a cyanogenic plant, Passiflora capsularis

Author

Jorge Luis Ávila Núñez, Lisday Duarte, Miguel Enrique Alonso Amelot, and Alberto Oliveros-Bastidas

Subjects
Spinacia, Hydrogen cyanide evolution, Physiology, Cyanide, media_common.quotation_subject, Hydrogen cyanide, Passiflora capsularis, Generalist, Insect, Generalist and specialist species, chemistry.chemical_compound, Botany, Herbivory, Ecology, Evolution, Behavior and Systematics, media_common, Larva, Facultad de Ciencias, biology, Departamento de Química, Cyanogenesis, fungi, Tropics, Artículos, biology.organism_classification, Grupo de Química Ecológica, Escuela de Ciencias, Specialists, Kinetics, chemistry, Insect Science, Heliconius erato
Abstract

Hydrogen cyanide release during feeding of generalist and specialist lepidopteran larvae on a cyanogenic plant, Passiflora capsularis. (Alonso Amelot, Miguel; Avila Nuñez, Jorge Luis; Duarte, Lisday y Oliveros Bastidas, Alberto) Abstract The hydrogen cyanide-based interaction of a strongly cyanogenic plant, Passiflora capsularis, and larvae of two insect herbivores, a generalist (Spodoptera frugiperda) and a specialist (Heliconius erato), is examined in terms of the combined kinetics of the feeding process and the simultaneous hydrogen cyanide (HCN) liberation, as compared with the natural kinetics of hydrogen cyanide evolution by plant-leaf tissue. There are marked differences in acceptance of P. capsularis by third-instar larvae of specialist and generalist species. The former, H. erato, display a parsimonious ingestion rate of 0.74 ± 0.15 mg (fresh weight) min-1 comprising 18% active feeding time, whereas S. frugiperda larvae show a more erratic and restrained feeding involving 4% of the time at 0.45 ± 0.14 mg min-1. These S. frugiperda larvae ingest 124.4 ± 8.3 mg (fw) of the non-cyanogeneic Spinacia oleracea leaves in 24 h compared with only 74.7 ± 20.1 mg of P. capsularis in the same period. The total hydrogen cyanide released naturally from wild specimens of P. capsularis plants is in the range 326 - 3901 µ g g-1. Hydrogen cyanide evo lution from macerated P. capsularis leaves takes place along a hyperbolic function with time and initial velocities of cyanide evolution are a linear function of total hydrogen cyanide. When feeding on P. capsularis leaves, H. erato releases only a minor fraction relative to total hydrogen cyanide (0.09%) and to the anticipated cyanide from the initial velocity (7%). By contrast, S. frugiperda evokes 5.8-fold more than the anticipated hydrogen cyanide release from the plant. The findings are interpreted as diverging strategies by generalist and specialist insects in the utilization of hydrogen cyanide in cyanogenic plants. alonso@ula.ve jlavila@ula.ve aloliver@ula.ve Nivel monográfico

Published
2006
Full Text
View/download PDF

4. Herbivory on bracken (Pteridium spp.) by Bolax palliata Burmeister (Coleoptera: Scarabaeidae), a poliphagous beetle of the Venezuelan Andes

Author

Jorge Luis Ávila Núñez, Maria P. Calcagno-Pisarelli, L. Daniel Otero, and Marlene Naya

Subjects
chemistry.chemical_classification, Scarabaeidae, Herbivore, biology, Geniatini, biology.organism_classification, Neotropical Rutelinae, Venezuela, Bolax, Coleoptera, Food Preferences, chemistry, Sympatric speciation, Insect Science, Botany, Feeding preference, Pteridium caudatum, Animals, Condensed tannin, condensed tannin, Bracken, Pteridium
Abstract

Herbivore attack by Bolax palliata Burmeister is reported on two sympatric bracken species: Pteridium caudatum (L.) Maxon and P. arachnoideum (Kaulf.). Laboratory and field observations revealed a preference for the last of the two species. Available phytochemical information suggests it could be based on differences in concentration of condensed tannins.

Published
2008

Catalog

Books, media, physical & digital resources
See catalog results