Molecular interactions between male and female schistosomes - a role for remote communication?

Persistent physical interaction between male and female schistosome adult worms has long been shown to be crucial for their development and sexual maturation, particularly for the female. Although not fully understood, worm pairing promotes local molecular communication between sexes, driving gonad and vitellaria differentiation. In this opinion article we (i) summarise evidence concerning molecular interactions underlying the physical pairing, and (ii) propose a new paradigm whereby remote male-female molecular communication may play an overlooked role in parasite sexual maturation. In this context we discuss recent research that supports both physical and remote male-female interactions driving differentiation of the gonads/vitellaria. This remote communication between sexes may be mediated by excretory-secretory products (ESPs). Integrated hypotheses are presented to stimulate research in this important and emerging field.