| This study aims to clarify the factors influencing the superparasitism, development and reproduction of parasitoid wasp Coccophagus japonicus. The superparasitism of C. japonicus was observed in laboratory under the conditions of different parasitoid densities, female residence time, female residence interval and host age. Also, the development, longevity, adult emergence and body length of offspring wasps were assessed, when four different stages of host, Parasaissetia nigra, facing high superparasitism condition (1 parasitoid: 5 scales). The result showed that the superparasitism rate of C. japonicus decreased with the decrease of parasitoid density. The highest superparasitism rate (91.03%) was found when the wasp-host ratio was 1:5, and the lowest superparasitism rate (11.61%) was found when the wasp-host ratio was 1:30. For female residence interval of C. japonicus, the highest rate of superparasitism was 57.72% at 6 d interval. When the female residence time of C. japonicus was in the range of 0-48 h, superparasitism rate increased with residence time increasing, and the highest superparasitism rate was 30.41% at a residence time of 48 h. The effect of host age was also observed, and the highest superparasitism rate (54.40%) was found when using 3rd instar P. nigra as hosts. In addition, high superparasitism rate condition could affect the development, survival, adult emergence and body length of C. japonicus offspring. In general, the wasps had longer developmental time, shorter longevities and shorter body compared to control condition, whereas more adult emergence were recorded under high superparasitism rate. There are two exceptions: the wasp developmental time was shorter under high superparasitism rate compared to control condition when using the 2nd instar P. nigra as hosts, and less adult emergence was observed when using the early adult stage of P. nigra as hosts. Therefore, the study has shown that the parasitoid density, female residence time, female residence interval and host age are important factors influencing the occurrence of C. japonicus superparasitism. Under superparasitism condition, it seems that the wasp development is prolonged and the offspring quality is reduced, whereas the adult emergence is slightly increased. |
