This excitatory toxin inhibits insect calcium-activated potassium (KCa) channels (Slo-type). Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Belongs to the neurotoxin 11 (kappa toxin) family. This toxin has the prefix lambda in its name (instead of kappa), since lambda is the Greek letter attributed to calcium-activated potassium (KCa) channel impairing toxins (according to the nomenclature of King et al., 2008).