THE VARIABILITY OF MATING SIGNALS AND PREFERENCES IN THE BROWN PLANTHOPPER, NILAPARVATA-LUGENS (HOMOPTERA, DELPHACIDAE)

Male and female brown planthoppers, Nilaparvata lugens (Stal) (Homopte ra: Delphacidae), exchange substrate-transmitted signals prior to mati ng. The pulse repetition frequency of the male song is known to be inv olved in mate recognition and also to vary among geographical populati ons. Here the variability of male signals, female signals, and female preferences has been examined within a population. Female preference v ariation has been partitioned into variation in mean preference and va riation in the window of preference of individuals. The genetic compon ent of variation has been examined using isofemale lines. Male signal variation was limited (CV = 8%) and was mainly within individuals. Fem ale signal variation was greater (CV = 15%). Female mean preference va ried little (CV = 10%) and was closely matched to the male signal mean , but the preference window was wide (> 4 male signal standard deviati ons on average) and variable (CV = 56%). There was evidence for geneti c variation only for preference window. These results are discussed in relation to theories of signal system evolution.