On the basis of the similarities in neuropeptide actions between insects and vertebrates, we assume that neuropeptides such as tachykinin-related peptides (<i>TRP</i>s) regulate insect immune responses and are themselves modulated following infection.<h4>Methods</h4>In this study, we examined how immune activation affects the expression of genes encoding TRP precursors and receptors (<i>TRP</i> and <i>TRPR</i>) and whether TRPs directly modulate selected immune mechanisms in the pest species <i>Tenebrio molitor</i>. This evidence concerns the gene WARS1 and infection.