Species Diversity of Mosquito Larvae (Diptera: Culicidae) in the wild Pitcher Plants Nepenthes spp. in Surat Thani, Trang and Songkhla provinces

Abstract

This study was investigation of larval mosquito species in pitcher plants Nepenthes species; Nepenthes thorelii, Nepenthes mirabilis var. globosa, and Nepenthes mirabilis var. mirabilis in three sites; Surat Thani, Trang, and Songkhla province Southern Thailand. 50 pitchers, 25 upper pitchers and 25 lower pitchers, in cach Nepenthes species or each study site were collected two times during rainy and dry season. Mosquito larvae 5 species following 3 genus and 1,155 individuals were identified. The higher abundance of larval mosquitoes was Tripteroides tenax (85%, 991 individuals) and following Uranotaenia demeillori (13.33%, 154 individuals), Tripteroides species.1 (4.59%, 53 individuals), Toxorhynchites albipes (1.65%, 19 individuals), and Uranotaenia bicolor (1.3%, 15 individuals). Both principal component analysis (PCA), which used for reducing variables of pitchers, and multiple linear regression used to find out significant correlation between pitcher's variables and abundance of larval mosquitoes. The results of PCA showed pitcher size, active zone of pitchers, actual fluids in pitchers, dry detritus, and electrical conductivity in pitchers were positively correlated with abundance of larval mosquitoes. Whereas, pH, protozoa abundant, and rotifer abundant correlated negatively with abundance of larval mosquitoes. Multiple linear regression showed 21% influence of pitcher variables to predict on mosquito larvae abundant. Spearman rank analysis for influence pitcher environmental conditions on larval mosquito species indicated pitcher environmental conditions seemed to have less impacting on larval mosquito species. Actual fluid in pitchers was positive correlated slightly with larval mosquito Tripteroides tenax (r = 0.33, P = 0.003) and electrical conductivity correlated slightly positive with Tripteroides species.1 (r = 0.12, P = 0.03) but electrical conductivity correlated negative with Uranotaenia demeillori (r = -0.12, P = 0.02). Mean larval mosquito abundant were compared between seasons by using one-way ANOVA and mean larval mosquito abundant were found significant difference between rainy and dry season (one-way ANOVA, P<0.05). One-way ANOVA analysis compares mean of abundance larval mosquito between lower pitchers and upper pitchers and the significant difference were not detected between larval mosquito abundant in lower pitchers and upper pitchers (one-way ANOVA, P > 0.05). However, all explanations for those finding are discussed.