Cytology of Nilaparvata bakeri (Muir), a grass-infesting planthopper (Homoptera: Delphacidae)

Abstract

The genus Nilaparvata Distant comprises 14 determined and 2 undetermined species which have been recorded from tropical and temperate zones throughout the world (Okada 1977, Mochida and Okada 1979). About one-half of these are known in Asia and the Pacific region and the remaining in Africa and Central Amer ica. Two of these species-N. lugens (Stal) and N. bakeri (Muir), are particularly widely distributed and also occur in the Philippines. The former, commonly known as the brown planthopper, is a pest of rice whereas the latter is mainly a grass feeder. The two species can easily be distinguished from each other on the basis of genitalia. While the cytology of N. lugens has been studied by several workers (Saitoh et al. 1970, Liquido 1978, Den Hollander 1982, Saxena and Barrion 1982a, b, 1983), there is barely any information on this aspect of other Nilaparvata species. We, therefore, investigated the cytology of N. bakeri which was found thriving on Leersia hexandra (Swartz) weed grass that grew abundantly in irrigation canals along rice fields at the experimental farm of the International Rice Research In stitute (IRRI) in the Philippines.