COMPARATIVE PATTERNS OF THERMAL ACCLIMATION OF LARVAL TREMATODES AND THEIR HOST

Abstract

This chapter discusses the comparative patterns of thermal acclimation of larval trematodes and their host. Different patterns of thermal acclimation occur for the two species of trematodes and for the molluskan host. According to Prossers classification, thermal acclimation curve of the bird parasite is clearly Type II A, the cold-acclimated larvae had significantly higher respiration rates at each temperature than did the warm-acclimated larvae. The M-T curve for cold- and warm-climated Z. rubellus larvae presented a totally different pattern. In this species, the warm-acclimated larvae showed a plateau between 18° and 24° C, whereas in the cold-acclimated larvae this was entirely missing. The patterns of thermal acclimation obviously differ in these trematode larvae and their host. The response of the larvae sharing the same thermal environment differs so greatly that this suggests that this is a genetically predetermined response which is not markedly influenced by thermal environment of the intermediate host.