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

Male and female brown planthoppers, Nilaparvata lugens (Stal) (Homoptera: Delphacidae), exchange substrate-transmitted signals prior to mating. The pulse repetition frequency of the male song is known to be involved in mate recognition and also to vary among geographical populations. Here the variability of male signals, female signals, and female preferences has been examined within a population. Female preference variation has been partitioned into variation in mean preference and variation in the window of preference of individuals. The genetic component of variation has been examined using isofemale lines. Male signal variation was limited (CV = 8%) and was mainly within individuals. Female signal variation was greater (CV = 15%). Female mean preference varied little (CV = 10%) and was closely matched to the male signal mean, but the preference window was wide (> 4 male signal standard deviations on average) and variable (CV = 56%). There was evidence for genetic variation only for preference window. These results are discussed in relation to theories of signal system evolution.