Competes for binding at site 3 of the insect voltage-gated sodium channel (Nav) (PubMed:12860384). Insecticidal neurotoxin (PubMed:12860384, PubMed:29247580). Causes temporary paralysis to lepidopteran larvae (10.3 nmol/g) or to crickets (doses from 0.93 to 119 ug/g) (PubMed:12860384, PubMed:29247580). Is not toxic to mice when injected intracranially (high doses) (PubMed:12860384, PubMed:29247580). Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Shows very weak inhibition on rat Nav1.4/SCN4A sodium channels (23% at 50 uM of toxin and 35% at 100 uM). Belongs to the neurotoxin 02 (plectoxin) family. 02 (plectoxin) subfamily.