Abstract: Chiromantes dehaani is one of the dominant benthos in the middle and high tidal flats of the Yangtze Estuary. Its population behavior has important consequences on the salt marsh. In this study, we conducted systematic analyses on the intraspecific competition behavior of C. dehaani and corresponding influencing factors through laboratory experiments, considering the effects of sex, body size, temperature, and space size. The results showed that there was a positive correlation between temperature and intraspecific competition intensity and a negative correlation between space size and intraspecific competition intensity. At the condition with same temperature and space size, the intraspecific competition intensity was higher among the larger body sizes and among the males. Temperature and body size interacted to affect the intraspecific competition intensity. Temperature had a stronger effect on C. dehaani with larger body size. Effects of different factors on the intraspecific competition of C. dehaani were not independent. It is necessary to carry out comprehensive analysis by fully considering the thresholds of related factors.

Key words: salt marsh, Chiromantes dehaani, Yangtze Estuary, intraspecific competition.