This Penicillium species also causes mortality for the mosquito Culex quinquefasciatus. Specifically, the toxicity of nitenpyram on "Culex quinquefasciatus" or the southern house mosquito was tested. The other mosquito species on the island, "Culex quinquefasciatus," was not eliminated. In laboratory studies, the common "Macrocyclopsis" killed an average of 27 first-instar "Culex quinquefasciatus" larvae/copepod/day. Its main vector is the mosquito "Culex quinquefasciatus", introduced to the Hawaiian islands in 1826.