Highly divergent neuropeptide - non-coding RNA regulatory networks underpin variant host-finding behaviours in Steinernema species infective juveniles.

We conducted a transcriptomic and small RNA analysis of infective juveniles (IJs) from three behaviourally distinct Steinernema species. Substantial variation was found in the expression of shared gene orthologues, revealing gene expression signatures that correlate with behavioural states. Ninety-seven percent of predicted microRNAs are novel to each species. Surprisingly, our data provide evidence of a new family of non-coding transcripts that overlap with neuropeptide gene loci, which are predicted to influence microRNA regulation of neuropeptide genes. These data suggest that differences in neuropeptide gene expression, isoform variation, and small RNA interactions could contribute to behavioural differences within the Steinernema genus.