Suparoek Watanasit and Sopark Jantarit

pp. 723 - 730

Abstract

     Nests of the ant Crematogaster rogenhoferi (Mayr, 1879) were investigated at Tarutao National Park, Satun Province. Fifteen ant nests were selected at random along Phante Malacca Bay between the 2-7 March 2004. They built their nests from leaf and stick debris on branches of trees, at between 248-469 cm above the
ground level. The vegetation on which nests were built was composed of 5 species: Vitex pinnata L., Olea salicifolia Wall, Syzygium gratum (Wight), Ardisia elliptica Thum and one unknown species. The physical features of each nest were recorded. The average dimensions of the nest width and length were 10.65±2.57cm and 22.10±1.22 cm, respectively.

     Each nest was cut into small pieces for counting the numbers of each caste and developing stages. The results showed that the average number of queens, winged females, males and workers in each nest were 1.53±0.38, 1,753.33±506.55, 4,970.67±2,227.00, 15,577.93±2,637.84 respectively, while the developing stages of pupae, larvae, eggs were 1,589.93±480.37, 4,113.20±1,469.49 and 1,942.80±741.67 respectively. Thus the total number of ants in the population in each nest was 29,949.40±5,358.31. 

      The relationships between the number of castes, developing stages and physical features of the nests were explored. The Spearman Rank Correlation indicated that the width of nest positively correlated with the number of queens (r_s= 0.862, p = . 000), winged females (r_s = 0.691, p = 0.004) and workers (r_s
 = 0.667, p= 0.007). A comparison of the effects of vegetation types on the number of castes and development stages, showed that vegetation type did have an influence but only on the number of the worker caste (F = 7.712,
P = 0.011, one-way ANOVA). Most workers were associated with nests from Vitex pinnata. No nests were found on the dominant tree species of the area probably due to its ability to produce an insect repellant oil.