2014 年 22 巻 4 号 p. 169-177
The present study aimed to examine the influence of termites (Isoptera) on soil clay mineralogy. To this end, we analyzed the clay mineralogy in the mound structures of Macrotermes bellicosus (Macrotermitinae) and in the adjacent natural (termite-free) soil horizons along an inland valley toposequence in central Nigeria, and compared them using differential X-ray diffraction approach. The results indicated that: (i) M. bellicosus modified soil clay mineralogy to minor extent regardless of the substantial enrichment of clay particles in the mound structures; (ii) the mound structures generally had a decreased abundance of quartz balanced with an increased abundance of phyllosilicate minerals such as smectite and/or kaolinite when compared with the adjacent near-surface (Ap2) horizons; and (iii) there was a subtle difference in clay mineralogy between the mound wall and the hive in spite of a large disparity in particle-size distribution. These findings suggest that soil clay mineralogy is not linked to the ecological requirements of M. bellicosus and the apparent change in the clay mineralogy in mound structures is caused by the preferential selection of fine soil particles during the mound construction rather than by a preference among clay mineral species.
