Insect-selective toxin causing rapid but reversible paralysis in crickets. Suppresses the excitatory postsynaptic potentials evoked in lobster neuromuscular synaptic preparations, possibly by blocking the presynaptic calcium channel (Cav). Induces instantaneous reversible paralysis when injected into crickets. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. PD(50) is 291 pmol/g of crickets. The primary structure of the mature peptide is identical to that of U2-agatoxin-Ao1a (Agelenin) from Agelena orientalis (AC Q5Y4Y5). This toxin does not inhibit mammalian Cav2.1/CACNA1A, Cav2.2/CACNA1B and Cav2.3/CACNA1E calcium channels. Belongs to the neurotoxin 01 (U2-agtx) family.