Species Diversity of Some Larval Chironomidae (Diptera) Communities in Two Rivers

Species diversity and equitability were measured using the Information Statistic and the Hill's Ratio. Six larval chironomid communities in two rivers were investigated. These communities were found to undergo a seasonal variation with high equitability and diversity in winter and low diversity and equitability in summer. Low equitability was due to high dominance caused by abundance of two Cricotopus species. The species-abundance relationship was suggested to be under the control of water temperatures. High larval production was associated with low diversity and high dominance. Continuous recruitment was seen as a strategy for reducing intraspecific competition whilst maintaining high populations. The role of predation in controlling diversity was explored.