Repeated copulation in the brown planthopper, Nilaparvata lugens Stál (Homoptera; Delphacidae)

Abstract. 1. Mating of the brown planthopper, Nilaparvata lugens , was investigated in relation to oviposition. Females became unreceptive immediately after mating and showed various types of repelling behaviour to courting males. As a result, females usually did not mate repeatedly in quick succession, but after ceasing to lay fertilized eggs they behaved as virgins and mated again before producing more fertilized eggs.
2. Copulation, followed by deposition of fertilized eggs, occurred twice, or in a few cases three times, throughout the adult stage. Copulation lasted about 2 min at the first mating and about 1 min at the second or third mating.
3. When the number of fertilized eggs began to decrease rapidly, oviposition rate also decreased, but it increased again immediately after re-mating. Repeated copulation was also related to the potential rate of population increase. In the present experiments, the estimates of net reproductive rate ( R ₀) in brachypterous females was 287.7 (first mating), 88.3 (second mating) and 7.2 (third mating) and in macropterous females 286.8, 120.6 and 3.6 respectively.
4. In a patchy environment, repeated copulation following an invasion may contribute to the increase of a population.