The Mahanarva spp. (Hemiptera: Cercopidae) complex on sugarcane and the phylogeography of Mahanarva diakantha , a newly identified pest in Brazil

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Sugarcane (Saccharum L.) is an important crop in tropical and warm subtropical regions, and Brazil is the world's largest producer. Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) is reported as a key pest of sugarcane in Brazil. A recent taxonomic revision described a new species of spittlebug attacking sugarcane, Mahanarva diakantha (Carvalho & Paladini), which is morphologically similar to M. fimbriolata. This fact has raised urgent questions about which species are prevalent in and attacking sugarcane in the area and about the genetic diversity of their populations. Here, we employed partial COI gene sequencing to identify Mahanarva species across major Brazilian sugarcane regions and to assess mitochondrial diversity and population structure, with particular emphasis on M. diakantha. We analyzed 350 individuals, revealing 4 Mahanarva species: M. diakantha (N = 266), M. fimbriolata (N = 17), Mahanarva spectabilis (Distant) (N = 28), and Mahanarva posticata (Stål) (N = 39). Genetic distances among species ranged from 1.93% to 8.29%. In the Brazilian Northeast, we found only M. posticata, whereas the other 3 species were recorded in the center-south region. Genetic diversity in M. diakantha showed low haplotype diversity (Hd = 0.38) and moderate nucleotide diversity (0.0041). AMOVA indicated substantial genetic variation among populations (ФST = 0.44, P = 0.000), but we found no evidence of a correlation between genetic structure and geographic distance. Overall, the genetic diversity patterns suggest that anthropogenic activities have influenced the pest's movement and effective population size of M. diakantha in Brazil.

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