Journal of Environmental Biology

Galls and host occurrences along a forest gradient

in Sierra Ju?rez, Oaxaca, Mexico

Viviana Rodr?guez-Rivera¹, Cecilia Alfonso-Corrado¹, Victor Aguirre-Hidalgo¹, Jorge E. Campos²,

Crystian S. Venegas-Barrera³ and Ricardo Clark-Tapia¹*

¹Instituto de Estudios Ambientales, Universidad de la Sierra Ju?rez, UNSIJ. Av. Universidad s/n, Ixtl?n de Ju?rez, 68725 Oaxaca, M?xico

²Laboratorio de Bioqu?mica Molecular-Unidad de Biotecnolog?a y Prototipos (UBIPRO), FES?IZTACALA-UNAM, Av. de los Barrios # 1,

Col. Los Reyes Iztacala, 54000 Tlalnepantla, Estado de M?xico

³Instituto Tecnol?gico de Ciudad Victoria, Blvd. Emilio Portes Gil No 1301, Cd Victoria, Tamaulipas, M?xico. C.P.? 870010

*Corresponding Author E-mail: rclark@unsij.edu.mx

Key words

Ecological niche,

Forest gradient,

Gall occurence, Oak, Pine,

Regional distribution

Publication Data

Paper received : 18.12.2015

Revised received : 13.04.2016

Re-revised received : 20.07.2016

Accepted : 12.09.2016

Abstract

Aim : This study evaluates the abundance and environmental factors that regulate the regional distribution (hosts and study sites) and specific distribution (microhabitat oviposition) of the galls in the Sierra Ju?rez, Oaxaca, Mexico.

Methodology: During dry and wet periods, eleven sampling sites, the presence and abundance of galls were examined. . Ecological niche analysis was performed to relate gall niche occurrence/breadths with geographical and climatic gradients at two levels: regional distribution and specific distribution.

Results: Oak had the highest number of galls as compared to pines. Among the oaks, the Quercus section recorded twice the amount of galls (9 ? 2.14) than the Lobatae section (4.7 ? 2.19). As for the specific distribution level, over 70 % of the galls were located both at the underside of leaves and at primary stem.

Interpretation: We believe that abundance and distribution of galls and hosts could be associated with climatic factors. It was found that galls are highly sensitive to climatic and geographical changes. Galls are also attached to specific host structures for their survival. Climatic changes and structural disturbance can generate a crisis of co-extinction.

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