SPECIES COMPOSITION OF ROOT-FEEDING MACROARTHROPODS IN A SUBALPINE GRASSLAND ASSOCIATED WITH PINE FOREST IN MEXICO

Below-ground herbivores have been poorly studied regardless of their importance for the establishment and composition of plant communities. In a subalpine grassland associated with a 3200-m-elevation pine forest in central Mexico, the composition and vertical and horizontal distribution of the macroarthropod root-feeding community was studied for 14 months. The root-feeding community included six species of Coleoptera and one species of Diptera. The dominant species were Phyllophaga spp. (subgenus Phytallus , "macrophylla" group) and Trachyploeomimus aff. spurcus Champion. Mean density and biomass of this community were 101 individuals and 3 g per square metre, respectively. These values were low when compared with those reported for other communities. Species were most abundant in the first 10 cm of the soil all year around. Dominant species showed a clumped horizontal distribution most of the year.