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

Schistosomes are human-infective blood flukes characterised by their unique sex biology with genetically determined male and female individuals. The worms must physically couple heterosexually to enable the full maturation of their gonads, particularly of the female, and must remain paired to sustain maturation and egg production. Recent studies have highlighted that soluble molecules could provide a previously overlooked means of inter-sex communication, including over distance, which promotes development/maturation. We argue that developing a deeper understanding of the tentative remote molecular interactions between sexes is essential given: (i) the remarkable sexual biology of schistosomes, and (ii) the requirement to develop novel control strategies for human schistosomiasis. 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. [ABSTRACT FROM AUTHOR]