Nodulisporic acid is an indole terpene produced by Nodulisporium sp. first reported by researchers at Merck in 1997. Nodulisporic acid A is a more potent insecticide than paraherquamide, exhibiting an LC50 of 0.5 ppm against A. aegypti and 0.3 ppm against L. seracata. Like ivermectin, nodulisporic acid A targets glutamate-gated chloride channels of the filarial nematode, Brugia malayi. Structure-activity relationship studies indicate that modifications to the left-hand side of the molecule result in loss of activity against fleas, whereas modifications to the C8 chain resulted in similar or superior insecticidal activity.