Abstract

CLARK-TAPIA, Ricardo et al. Abundance and distribution of leaf-shaped galls in Quercus resinosa Liemb. (Fagaceae) in Aguascalientes, Mexico. Polibotánica [online]. 2013, n.36, pp.129-145. ISSN 1405-2768.

Galls are abnormal morphological structures in tree leaves created by the parasitic activity of the arthropod group of animals. Currently only a few works focus on the description of leaf-shaped galls as a protection chamber against environmental changes for larva. This study describes the oaks' leaf-shaped gall structure at three levels: foliage, individuals and population, in order to identify the ecological patterns that restrict their abundance and distribution. It was found that these leaves' galls are specific of Quercus resinosa Liemb., and they are produced by a wasp of the family Cynipidae. A gall starts growing once the insect oviposit on young leaves of the tree. The principal ovi-position season is spring, with an adult wasp emerging in autumn. The number of galls per tree varies from one to more than ten, (4.88±2.4). Gall abundance was significantly different among the three local oak populations (χ²=14.78; P<0.001). While there was a low survival rate of wasps (<35%) there was a positive relationship between gall size and wasp survival. Our findings suggest that climate and physiography can directly restrict the abundance and distribution of leaf-shaped galls.

Keywords : leaf-shaped gall; wasp; Cynipidae; distribution; survival.