Acoustic recognition signals: barriers to hybridization in Homoptera Auchenorrhyncha

Abstract

The biological, or isolation, concept of species is compared with the recognition concept of Paterson. Specific-mate recognition signals are in practice equated with premating isolating mechanisms. Acoustic signals are dominant in specific-mate recognition systems of Homoptera Auchenorrhyncha. Recording and analysis of the signals give some of the best data for species discrimination in these insects. The morphological species Nilaparvata lugens, the brown planthopper, includes two morphologically indistinguishable biological species associated respectively with rice, Oryza, and the weed grass, Leersia hexandra. These planthopper species are sympatric over large areas of Asia and Australia. Populations of the two differ significantly in pulse repetition frequencies of male and female calls, but each also shows geographical variation for the same characteristics. These data are more consistent with theories of speciation involving sexual selection than with the recognition concept of species.