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2 resultados encontrados para: AUTOR: Jackson, Doug
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1.
- Artículo con arbitraje
A positive association between ants and spiders and potential mechanisms driving the pattern
Marín, Linda ; Jackson, Doug (coaut.) ; Perfecto, Ivette (coaut.) ;
Contenido en: Oikos Vol. 124, no. 8 (August 2015), p. 1078–1088 ISSN: 0030-1299
Resumen en: Inglés |
Resumen en inglés

Biotic interactions play a central role in determining species distribution and abundance. Some ants act as keystone species affecting the distribution and abundance of other species, including spiders. In coffee plantations Pocobletus sp. spiders are significantly more abundant in coffee plants patrolled by the aggressive arboreal ants Azteca sericeasur. However, it is unknown if other ant species influence this ant–spider association, how these associates are spatially distributed, and which are the potential drivers of this association. Here we examine the influence of ants, Azteca sericeasur and Pheidole synanthropica, and coffee branch density on Pocobletus abundance in a coffee farm in southern Mexico. We also analyze the spatial distribution and abundance of Pocobletus sp., in relation to the spatial distribution of A. sericeasur and P. synanthropica. Finally, we examine prey availability and enemy-free space as potential mechanisms underlying this ant–spider association. Results show that Pocobletus abundance is positively correlated with coffee branch density and A. sericeasur and P. synanthropica presence. Furthermore, the spatial distribution analysis shows that in 20  20 m plots Pocobletus is strongly associated to A. sericeasur, but not to P. synanthropica. Results show that insect abundance in both Pocobletus’s webs and sticky traps was significantly higher in the presence of A. sericeasur whereas the abundance of the predators of Pocobletus decreased in A. sericeasur’s presence; suggesting positive direct and indirect effects of A. sericeasur on Pocobletus. Overall, this study highlights the strong influence of ants and plant characteristics on the abundance and spatial distribution of spiders as well their indirect effects on other taxa.


2.
- Artículo con arbitraje
Occurrence in the soil and dispersal of Lecanicillium lecanii, a fungal pathogen of the green coffee scale (Coccus viridis) and coffee rust (Hemileia vastatrix)
Jackson, Doug (autor) ; Zemenick, Kate (coaut.) ; Huerta Palacios, Graciela (autora) ;
Disponible en línea
Contenido en: Tropical and Subtropical Agroecosystems Vol 15, no. 2 (2012), p. 389-401 ISSN: 1870-0462
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Resumen en: Español | Inglés |
Resumen en español

Dos importantes plagas del café, la escama verde (Coccus viridis) y la roya del café (Hemileia vastatrix) son atacadas por el hongo Lecanicillium lecanii. Por consiguiente, conocer la epizootiología de este patógeno es importante para un exitoso control natural de estas plagas en agroecosistemas de café. Con este objetivo, evaluamos la presencia de propágulos viables de L. lecanii en el suelo, que es un potencial reservorio natural para este hongo. Para ello utilizamos dos diferentes carnadas: C. viridis y la carnáda estándar, Galleria mellonella. A lo largo de una parcela de 45 hectáreas, detectamos propágulos infecciosos de L. lecanii en muestras de suelo tomadas de sitios cercanos y lejanos a centros epizoóticos de L. lecanii. Para determinar el potencial de la lluvia y el viento para transmitir conidias de L. lecanii desde el suelo, colocamos plántulas de café infestadas con C. viridis cerca a tierra inoculada con L. lecanii. Luego sometimos las plántulas a tratamientos de lluvia y viento artificiales. Encontramos que la lluvia es un posible mecanismo de transmisión de las conidias. Adicionalmente, por medio de experimentos de exclusión en el campo y el laboratorio, evaluamos la capacidad de la hormiga Azteca instabilis para dispersar conidias de L. lecanii. Encontramos que, aparentemente, A. instabilis no es un importante medio de dispersión de las conidias en el campo.

Resumen en inglés

The fungus Lecanicillium lecanii attacks the green scale (Coccus viridis), a pest of coffee, and is also a hyperparasite of coffee rust (Hemileia vastatrix). Knowledge of the epizootiology of this fungus is potentially important for conservation biological control in coffee agroecosystems. The presence of viable propagules of L. lecanii in the soil, a possible environmental reservoir, was assessed using two baiting methods: the standard Galleria mellonella bait method and a C. viridis bait method. Infectious propagules of L. lecanii were detected in soil samples taken from a 45 ha study plot, both nearby and far from recent epizootics of L. lecanii. To test the potential for the transmission of L. lecanii conidia from the soil via rain splash or wind, coffee seedlings with populations of C. viridis were placed near L. lecanii-inoculated soil and then subjected to artificial rain and wind treatments. Rain splash was shown to be a potential transmission mechanism. Dispersal of L. lecanii conidia by the ant Azteca instabilis was tested using field and laboratory ant-exclusion experiments. Azteca instabilis was shown to transport conidia of L. lecanii; however, dispersal by A. instabilis may not be important under field conditions.