Meeting Abstract

P3.36  Tuesday, Jan. 6  The effects of feeding on medicinal leech swimming performance CLAFLIN, SB; PIEN, CL; RANGEL, EN; UTZ, KE; WALTHER, HV; WRIGHT, AN; ELLERBY, DJ*; Wellesley College dellerby@wellesley.edu

The locomotor system of sanguivorous leeches is presented with a unique challenge: how to maintain mobility while coping with a greater than 500% increase in body mass during feeding. A meal of this size is likely to disrupt the function of the muscular hydrostat during swimming, reducing speed and increasing predation risks. We quantified the effects of feeding to satiety on swimming kinematics, and the time course of recovery of swimming performance post-feeding in the medicinal leech Hirudo verbana. There was a 5.07 fold increase in mass during feeding. Despite this, leeches were able to swim immediately after feeding, reaching 27% of their pre-feeding speed. Reduced speed was a consequence of a reduction in both swimming cycle frequency and stride length to 69 and 42% of the pre-feeding values respectively. Recovery of swimming ability was rapid, despite a prolonged increase in body mass. 50% restoration of swimming speed was achieved in approximately 1 hour while body mass was still 4.2 fold greater than before feeding. Rapid mass and volume reduction immediately post-feeding, and the properties of the obliquely striated swimming muscles appear to aid recovery of swimming performance. Such features that aid post-feeding recovery of mobility may have been important in the evolution of leech sanguivory.