Effects of amino acids and light on the behavior of miracidia of Schistosomatium douthitti (Cort 1914)

Abstract

Behavioral responses of miracidia of Schistosomatium douthitti to chemicals were tested using amino acids similar to those excreted by the schistosome intermediate host, Lymnaea palustris. Amino acids suspended in agar plugs were placed in one or more arms of a four-arm test chamber and responses of miracidia placed in the center well were recorded. Under optimum conditions (20C and 10 000 lux) 84% of the miracidia were found in side arms containing an amino acid mixture after 120 min. Miracidia moved towards glycine, leucine, and valine.The combined effects of amino acids and light on the response of miracidia were tested. After 120 min at 20C with illuminance from 4800 to 32 000 lux, 93 to 100% of the miracidia were found in side arms containing 0.83 μM/ml of amino acids exposed to light.