Effect Of Marking With Acridine Orange On Trichogramma's Biological Characteristics

Insects marking played an important role in insectcontrol.For example,mark-release-recapture method could be used to study the population dynamics,so as to provide reliable basis for forecasting;marking natural enemies of insectpest can effectively evaluate the control effect.Trichogramma are egg parasitoids,belong to Hymenoptera,Trichogrammatidae.According to incomplete statistics,genus of Trichogramma includes species that can parasitize insects of more than 40 families from Lepidoptera,Coleoptera,Diptera,Hymenoptera and Neuroptera,.The wasps are mainly used for the prevention and control of corn borer,sugar cane moth,and apple leaf moth pests.In China,using Trichogramma to prevent and control the corn borer has obtained remarkable achievement.Application scope expands unceasingly,and it has become a very important measure for the prevention and control the corn borer in recent years.This article selected three commonly used Trichogramma species(Trichogramma ostriniae,Trichogramma dendrolimi,Tricho-gramma japonicum),aiming at marking of these wasps,to study the impact of the markers on the biological characteristics.The results are as follows:(1)Using acridine orange as fluorescent markers,and according to the gradient added in artificial diet.By feeding to mark three Trichogramma species,we found that after 24-h feedingthe green fluorescent was detectable under the fluorescence microscope.After 24-h feeding diet containing markers green fluorescent of acridine orange could be detected throughout life of wasps.The resuls suggested that the acridine orange could be used to mark these three Trichogramma species.(2)Compared with control,the average longevity(5.49 days)of Trichogramma ostriniae feeding low density acridine orange was longer,life span(4.59 days)of wasps incontrol group was the shortest among all groups.The longest average longevity of Trichogramma dendrolimi happened to wasps incontrol group,the average life expectancy is 5.49 days.The shortest life span is feeding high density acridine orange,the average life expectancy was 4.47 days.For Trichogramma japonicum,the results were different from aboves,the longest longevity happened to wasps feeding low density acridine orange diet,the average life expectancy is 5.34 days,andthe shortest life span happened to wasps feeding middle density acridine orange diet,the average life expectancy was 4.67 days.Life span of Trichogramma dendrolimi of control groupwas the longest among all groups.(3)The number of egg laid after marking is different.During 6-h parasitization,for Trichogramma ostriniae,wasps fed with high density produced the most eggs,35.1 eggs per three wasps,followed by the control group,the 34.9 eggs.Trichogramma dendrolimi wasps fed with middle density group produced the most eggs,32.7 eggs per three Trichogramma dendrolimi wasps.For Trichogramma japonicum,wasps fed with high density produced the most eggs,20.2 eggs per three wasps.During 12-h parasitization,for Trichogramma ostriniae,wasps fed with high density diet produced the most eggs,46.1 eggs per three Trichogramma ostriniae wasps.For Trichogramma dendrolimi,wasps fed with control diet produce the most eggs,40.3 eggs pery three Trichogramma dendrolimi wasp.For Trichogramma japonicum,wasps fed with high density diet produced the most eggs,22.6 eggs per three Trichogramma japonicum wasps.Taken together,during 6-h parasitization,Trichogramma ostriniae wasps fed with high density diet produced 35.1 eggs,which was the mostamong all wasp species,and T.japonicum wasps from control gave the lowest reproduction,18.2 eggs per three wasps.During 12-h parasitization,Trichogramma ostriniae wasps fed with high density diet produced 46.1 eggs,which was the most among all wasp species,and T.japonicum wasps from control gave the lowest reproduction,21 eggs per three wasps..This shows that acridine orange under certain conditions can improve the spawning quantity.(4)The highest parasitism rate of single parasitic wasp happened in control group of Trichogramma japonicum,the rate is 89.33%;and the lowest(73.76%)in Trichogramma ostriniae wasps fed with middle density diet,.The highest emergence rate(88.67%)of wasps happened to Trichogramma japonicum of control group,and the lowest emergence rate(71.67%)happened to Trichogramma japonicum,emergence wasps fed with middle density diet.The highest emergence offspring number 21.4 per female wasp,happened to Trichogramma ostriniae wasps of control group,and the offspring number(15.2)of Trichogramma japonicum wasps fed with middle density diet,was the lowest.The highest female offspring ratio happened to Trichogramma dendrolimi fed with low density diet,the female ratio was 81.10%;the lowest female offspring ratio happened to Trichogramma japonicum wasp fed with middle density diet,the female ratio was 64.4%.Thus it can be seen that different density of acridine orange have a different impact on different Trichogramma species.By dissceting moth eggs,Trichogramma ostriniae eggs and the offspring were obtained and observed under fluorescence microscope,we found acridine orange can be detected throughout the development process of Trichogramma individual.