Host-induced phenotypic differences in Egyptian Heterophyes [digenea: heterophyidae]

ABSTRACT

A comparative morphometric study identified host-related variations in Heterophyes heterophyes. In one study, variations in adult H. heterophyes obtained from different definitive hosts were examined. Significant differences were in size and dimensions of body organs of adults collected from dogs, cats and albino-rats experimentally infected with encysted metacercariae [EMC] from mullet [Mugil cephalus]. Hypotheses on the sources of host-dependent variations were interpreted in terms of adaptation to conditions created by the host. In a second study, comparative morphometric analysis of adults recovered from puppies experimentally fed on EMC isolated from five sympatric fish species was done. No significant differences were in adults H. heterophyes recovered from puppies feed on EMC of different fishes. Constancy in morphological characters of adults reared in the same host, independent of a change of fish was seen. So, the variations depend upon host species where worms develop, and host selection may determine the worm morphology and phenotypic plasticity