ABSTRACT
T he p rob lem s re la ted to survival for parasites are alm ost the opposite o f those faced by free-living anim als. Parasites are su rrounded by (they live w ith in o r on) the ir food and do n o t need to spend energy to find food; w hereas free living anim als are continuously searching for food. Free living anim als have few er p roblem s than parasites in rep ro d u c tion and d is tribu tion . D uring the d istributive phase o f its life-cycle, the probability o f a parasite m aking con tac t w ith a new host is relatively low .
