| Coccophagus japonicus Compere,which is a dominant parasitoid of Parasaissetia nigra Nietner,belongs to a kind of bisexual reproductive parasitoid.The mating success rate of parasitoid is one of important factors that restricted the population growth and indoor mass rearing of C.japonicus.The mating behaviors and copulatory factors of C.japonicus,the mating ability of male C.japonicus,the effects of mating on ovary development,lifespan and fecundity of female C.japonicas were examined to provide some techinal supports for the mass rearing of C.japonicus.The results summarized as follows:1 Mating behavior of C.japonicusThe mating process of C.japonicus can be divided into three stages,including pre-mating behavior,mating,and after-mating behavior.It took 76.15 ± 47.70 seconds for whole mating process,and 20.6 1s ± 11.78 seconds for mating.2 Mating ability of male C.japonicusThe male C.japonicas can copulate from their neweclosion.The mating ability weakened with the increase of age.The one-day-old males had the highest mating ability(6.3 times per parasitoid).The males can averagely mate 36.94 times in a lifetime.With the increasing age of male,the pre-mating progress significantly be longer.3 The copulatory factors of C.japonicusThere are four factors(temperature,photoperiod,age of male parasitoid,sex ratio)for impacting the mating rate of C.japonicas.The results showed that:(1)The mating rate(93.25%)was highest at 24?.At 18? and 15?,the mating rate were 71.5%and 43.25%,respectively.No significant differences were found among these temperatures ranged from 24? to 30?.(2)At the photoperiod of 12 L:12 D,the mating rate was highest,which was 91.75%.The lowest mating rate(13.5%)was observed at the photoperiod of 0 L:24 D.(3)The results also showed that the mating rate decreased with the age of male parasitoid increased.The mating rate of newly emerged males was 91.75%,the mating rate of thirteen-day-old males was only 48.5%.(4)In this study,male-female ratio within 5?:1?-1??5?had no significant effects on mating rate.At sex ratio of 1 ?:3? and 1 ??5?,the mating rate reached maximum(73.25%)and minimum(65.0%).4 Reproductive system of female C.japonicusThe reproductive system of female C.japonicus consisted of a pair of avaries,a pair of lateral oviducts,one median oviduct,one spermatheca and genitalia and so on.The ovary of 95.78%female C.japonicus had six(3+3)ovarioles,2.78%females had five(2+3)ovarioles,1.22%females had seven(4+3)ovarioles,and 0.22%females had four(2+2,1+3)ovarioles.One few females had only one ovary,which contained three ovarioles.The ovum of C.japonicus can be divided into four grades.Grade ?,egg yolk deposition part<1/2 egg chamber.Grade ?,egg yolk deposition part ?1/2 egg chamber.Grade III,egg is matured,egg yolk deposition is full of egg chamber.Grade ?,egg is degenerated,egg yolk deposition is thin.5 Effects of mating on ovary development of C.japonicusThe fecundity of mated and virginal female parasitoids were firstly ascended and then descended with the increase of age,but the maximum fecundity on mated females were earlier than those on virginal females for two days.There were no significant differences in the maximum of fecundity.The maximum fecundity were 143.57 ± 2.49 eggs for the mated females and 139 ± 12.86 eggs for virginal females,respectively.The retained time of male parasitoids was a significant effect on the number of fecundity.The fecundity were 137.78 ± 6.56without male C.japonicas.The fecundity were 101.8±6.84 when the male parasitoids retained 6 days.6 Effect of mating on lifespan and oviposition of female C.japonicusThe mating significantly affected the lifespan of female C.japonicus.The females can survive 25.87 ± 0.55,21.6 ± 0.60 and 16.43 ±0.35 days after mating 0,1 and multiple times,respectively.The delayed copulation of female C.japonicus had a significant effect on its fertility.When the female C.japonicus delayed 0,2,4,6 days for mating,the number of eggs were 256.5 ±25.7,194.67 ± 10.58,173.5 ± 5.00 and 146 ± 10.97,respectively.Different day old male C.japonicus had no significant effect on the oviposition of C.japonicus.When the male parasitoids were in 1,3,5,7 day-old,the number of eggs were up to 256.5 ± 25.7,232± 17.15,229 ± 7.47 and 236.17 ± 11.17,respectively.In conclusion,temperature,photoperiod,male C.japonicas age significantly affected the mating rate.The 0 to 8 day-old male(1 day-old female)C.japonicas reared at the range of 24? to 27? withl2 L:12 D photoperiod can significantly enhance the mating rate and egg production and mass-rearing efficency of C.japonicas. |
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