Aquatic insect emergence is strongly influenced by season. Most of Asian countries are affected
by the monsoon and seasonal rainfall, and monsoon behavior is nearly unpredictable (Gopal 2002).
Moreover, most tropical rivers have an annual cycle, which is governed by the pattern of rainfall (Payne,
1986). Precipitation plays a major role in changing the benthic community (Robinson and Minshall,
1986) in the tropical rivers (Silveira et al., 2006). In this study, the diversity and seasonal distribution of
caddisflies of a stream at Champathong waterfall in northern Thailand were described. Adult caddisflies
were identified to the species level and their species richness evaluated for conservation value in a
stream. Factors that could influence the temporal distribution of adults were investigated.