Blattella asahinai (Dictyoptera: Blattellidae): A New Predator of Lepidopteran Eggs in South Texas Soybean

Abstract

Abstract Large numbers of a cockroach that resembled the German cockroach, Blattella germanica (L.), were observed during winter 2005–2006 in home turf settings in Weslaco, TX, 11 km from the U.S. border with northeastern Mexico. In June and July 2006, this cockroach was observed at night on the foliage of soybean, Glycine max (L.) Merr., in numbers often exceeding 50 per m row. Because of its similarity to B. germanica, but with the characteristic of flying frequently, we suspected that our observations might be of the Asian cockroach, Blattella asahinai Mizukubo. Using a combination of morphological characters, cuticular hydrocarbons, and sequences of the mitochondrial cytochrome oxidase II gene, we definitively identified this cockroach as B. asahinai. B. asahinai was frequently observed feeding on sentinel eggs of Helicoverpa zea (Boddie) and Spodoptera exigua (Hubner). This cockroach was the dominant egg predator in soybean during 2006, making up 36.4% of all predators observed feeding on eggs. B. as...