Spittle protein profile of Mahanarva spectabilis (Hemiptera: Cercopidae) fed various elephant grass genotypes.

An understanding of the interaction between spittlebugs and forage grasses is essential for establishing factors that favor productive pastures. In the present study, we evaluated the protein profiles of the spittle of Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cercopidae) fed various elephant grass genotypes. Each plant was infested with a single fifth-instar M. spectabilis. After 24 h, samples of the spittle produced by each nymph were collected and stored at -20°C, after which their protein profiles were analyzed. The exclusivity or interactions of the proteins present in the spittle produced by the insects revealed the susceptibility of the tested genotypes. The results indicate that groups of genotypes show identical spittle protein profiles when subjected to attack by spittlebugs. Resistant and susceptible elephant grass genotypes exhibited high similarity indices within each group. The similarity index was low for the resistance control species (Brachiaria brizantha) compared with that of the tested elephant grass genotypes. Qualitative and quantitative studies of the proteins expressed in the most promising materials will be performed in an ongoing genetic improvement program seeking to develop genotypes resistant to spittlebugs, which are the main biotic pests of elephant grasses.