Has antimicrobial, insecticidal, cytolytic and cytotoxic activity. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. The N-terminal part of the mature protein (59-100) probably forms an alpha-helix which acts as a membrane-active peptide. It is necessary and sufficient for the toxin's antimicrobial, insecticidal, cytolytic and cytotoxic activity. Belongs to the spiderine family. Cationic/spiderine subfamily.