AN INVESTIGATION ON THE STARVATION METABOLISM OF FOUR GASTROPODS

Benthic gastropods,a major group of aquatic fauna, play an important role in the material cycle and energy flow in a water ecosystem. In recent decades,interest in the bioenergetics of this group has grown rapidly. Aspects of the bioenergetics of many gastropod species have been reported aboard. But in China there are few studies published. In order to investigate the ecological significance of benthicgastropods in freshwater lakes in China,the author studied the production and energy metabolism of the predominant species.The relationships between starvation metabolism(SM)and temperature,body weight of four common gastropodswere carefully examined. Patterns of metabolic compensation to six seasonal oracclimatization temperatures (AT =5,10,15,20,25 and 30 ℃ )were examined with a modified Winkler's method. Six collections were made from April,1996 to March,1997,when lake water temperature was approximately 5,10,15,20,25 and 30 ℃at the sampling days. Specimens were collected,sorted to species and starved for 2 days in aerated filtered lake-water at appropriate AT. Twenty one or fifteen gastropods of different sizes for different species wereintroduced into twenty one orfifteen tightly stoppered vials. Experimental temperatures(ET) were held within ±0. 1 ℃ of the AT. The measurement lasted 24 h. To avoid the occurrence of anaerobic respiration,DO of thewater in the vials must con-stantly be kept over half the saturation of oxygen during the measuring period. Regression equations were computed for log metabolic rate(R) vs log mg wet or dry weight(Ww or Wd) at each AT.Based on the above data gained, the comprehensive relationship of the three parameters was computed, that is, for Bellamya. Aeruginosa,the relationship was R =0.044Wd0.537e0.061T; for Parafossarulus striatulus, R =0.004Wd1. 072e0. 091T; for Alocinma longicornis,R=0. 0004Ww0·9405e0. 0735T; and for Semisulcospira sp,R=0. 023Wd0. 777e0. 042T. The results showed that the SMs of the four species have logistic positive relation with their environmental temperature,and have a moderate positive relation with their body weight.