The responses of two species of blood-sucking leech to light flash and water stir stimuli

A temperature-controlling apparatus and some electronic equipments for the responses of two species of blood-sucking leech to light flash and stirring water stimuli were used in a dark room. The light-flash stimulus were given by a lamp controlled by a silicon-control-led oscillator and the stirring water stimulus by a relay and a plastic plate, controlled by a silicon-control-led oscillator. Five individuals of each weight range per species were tested five times. The experimental results were expressed by the average creep distances in one minute. The results of statistics and analysis indicated that Hirudo nipponia to illumination of light has very well positive relationship at 16 degree C, while negative relationship at 22 degree C ; individuals of 0. 2g weight to illumination of light are more sensitive than those of 0.5 - 0.6g and 1.0 - 1.3g weight at two temperatures. Poecilobdella hubeiensis to illumination of light has positive relationship at both temperatures; individuals of 0. 5g of the species to illumination of lighy are more sensitive than those of 1.0-3.3 g at 16 degree C ; individuals of 9. 5-11.0 g weight to illumination of light are more sensitive than 0.5g and 1.0-3.3g at 22 degree C. According to a single factor, the responses of these two species of the leeches to stirring water stimulus are not obvious. In sum, the responses of the two species to light stimulus fit in a linear model, the formulae for both species as follow: Hirudo nipponia d = 2.31 - 0.040 H-z + 24. 61W, R-2 = 0.7149, P lt 0. 0001; Poecilobdella hubeiensis d = - 47.26 - 0.34 Lx + 3. 35Temp + 2.45W, R-2 = 0.8186, P lt 0. 0001; among them d-average distances (cm) creeping for one minute, H-z-frequency of light flash, Lx -illumination of light, Temp -water temperature, Wt-body weight. The results obtained provide a ecological basis for repelling and trapping these two species of blood-sucking leeches