Studies On The Biology And Ecology Of Tetrastichus Brontispae Ferrière

The biology and ecology of Tetrastichus brontispae Ferrière, the harmony of releasing Tetrastichus brontispae with other control measures was systematically studied in this article. The results are briefly summarized as below.1.Biological characteristics of Tetrastichus brontispae FerrièreTetrastichus brontispae Ferrière, an important endoparasitoid of the coconut leaf beetle Brontispa longissima (Gestro) at pupal stage. Morphology, behavior, development, survival and reproduction of the parasitoid were studied under laboratory conditions. The results showed that T. brontispae female was bigger than male in size, with obvious ovipositor. The number of parasitoid emerged from each host was averaged 21.5 with 77.4% females. The wasps could mate soon after emerging, and the mating behavior last 1~2 min.2 . Effect of temperature,humidity and photoperiod on the parasitism and development of Tetrastichus brontispae FerrièreThe effect of temperature,relative humidity and photoperiod on the parasitism and development of Tetrastichus brontispae Ferrière was studied in the laboratory.The results showed that the temperature and relative humidity had significant effect on the parasitism and development of Tetrastichus brontispae,while photoperiod had almost no effect on the parasitism and development of the Tetrastichus brontispae.The development duration of Tetrastichus brontispae decreased as temperature increased ,the developmental threshold and effective accumulated temperature of Tetrastichus brontispae were 10.93℃and 298.79 day-degrees respectively at constant temperature. the developmental threshold and effective accumulated temperature of Tetrastichus brontispae were 10.48℃and 315.61 day-degrees respectively at variable temperature.Under constant temperature,parasitism rate was 69.48% at 30℃,but the adults could not emerge from the mummies.The parasitism rate,emergence rate,successful parasitism rate, number of wasps per mummy and the intrinsic rate of natural increase (rm) of Tetrastichus brontispae increased with the rise of temperature from 18℃to 28℃;while development duration and female ratio decreased as temperature increased. Under variable average temperature from 18℃~28℃,the parasitism rate,emergence rate,successful parasitism rate, number of wasps per mummy of Tetrastichus brontispae increased with the rise of temperature from 18℃to 24℃,while decreased with the rise of temperature from 24℃to 30℃.The minimum female ratio was (72.08%) at 24℃.The shortest development duration was (18.73) and the highest rm was (0.1363) at 28℃.The parasitism rate , number of wasps per mummy and rm were highest within 65%~95% RH ,while decreased significantly with the relative humidity descend from 50% RH to 20% RH.The successful parasitism rate and emergence rate were significantly higher within 65%~95% RH than within 20%~35% RH.The development duration and female ratio were decreased with increasing relative humidity.Photoperiod had no influence on the parasitism rate,emergence rate,successful parasitism rate and number of wasps per mummy .The longest development duration was (20.54)and minimum rm was (0.1322) at L:D=0:24h,there were no significant difference at other photoperiods. The result from the integrated analysis on parasitism rate and rm indicated that 24℃~28℃,65%~95%RH and L:D=8:16 to L:D=24:0 were the most suitable for Tetrastichus brontispae rearing and propagation.3.Effect of cold storage on the population quality of Tetrastichus brontispaeThe present paper investigated the effect of cold storage of the Brontispa longissima (Gestro) pupae and parasitized B.longissima pupae on the population quality of Tetrastichus brontispae Ferriere.The 1~4 days old B.longissima pupae were stored at 10℃for 10 days. Results showed that the highest parasitisation rate,highest emergence rates of per mummy, highest emergence rate,highest number of wasps per mummy and highest parasitic ability was found in 1 day old pupae,which was followed by that in 2~3 days pupae,while the lowest in 4 days old pupae. The 1day old pupae biological qualities decreased as the period of cold storage increased from 5 days to 20 days,while the pupae cold storage 5 days and 10 days had no differences compared with the control.The mummies were stored at 10℃for 10 days after they were formed 1~11 days. Results showed the longest adult life,highest highest emergence rates of per mummy,highest number of wasps per mummy and highest parasitic ability was found in 8 days mummies.The 8 days mummies biological qualities decreased significantly compared with the control as the period of cold storage increased from 5 days to 20 days.4.Effect of Different Nutritional Resources on the Longevity, Parasitic Ability and Oviposition of Tetrastichus brontispaeEffects of sucrose,honey, glucose,pollen and water on the longevity, parasitic ability,oviposition,female ratio and offspring quality of Tetrastichus brontispae,influences of parasitic behaviors on female's longevity and survival rate were studied in the laboratory.The results showed that the longevity of Tetrastichus brontispae was obviously extended by feeding sucrose,honey, glucose,pollen and water.The parasitic ability of female feeding honey,sucrose and glucose were obviously higher than that in control group,while feeding coconut pollen , water and the control group was no significant difference.The parasitic ability of female feeding (bee pollen + water) 24h and the control group was no significant difference,while feeding (bee pollen + water) 48h obviously higher than that feeding 24h.The oviposition of Tetrastichus brontispae feeding honey,sucrose,glucose and bee pollen 48h were significantly higher than that in control group,while there were no difference between feeding above nutrition source 24h ,coconut pollen , water and control group.There were no difference between the oviposition of feeding coconut pollen ,water and control group.The parasitic ability and oviposition of female feeding honey,sucrose,glucose and bee pollen increased as its feeding time prolonged,while feeding coconut pollen and water decreased as its feeding time prolonged.No significant difference were found on ovipostion, development duration and female ratio between all nutrition source and control group.Parasitic behaviors decreased female's longevity and survival rate .The maximum oviposition and highest ovulatory female rate of female was at 1-day-old when feeding bee pollen + water,water and control group,then dropped with the female age.The maximum oviposition and highest ovulatory female rate of female was found at 3-day-old when feeding glucose.Daily female allocation remained at a stable level when feeding glucose,water and control,while feeding bee pollen + water vary to a large extent.The accumulate oviposition rate of female feeding on water and control group was 92.63% and 100% during the first 2 days . The accumulate oviposition rate of female feeding bee pollen + water was 90.33% during the first 4 days,feeding on glucose was 93.70% during the first 6 days.5. Tetrastichus brontispae and other control measuresThe comparative toxicity of the four insecticides carbosulfan, beta-cypermethrin, acetamiprid and yejiaqing on the Brontispa longissima and its pupa parasitoid Tetrastichus brontispae was determined in the laboratory . The selective toxicity were 3.8646,2.3884,0.5485 and 0.08311.When giving effective control to the Brontispa longissima,the safety of 4 inesecticides to the natrural enemy Tetrastichus brontispae was yejiaqing> beta-cypermethrin >acetamiprid>carbosulfan.Yejiaqing and beta-cypermethrin could be applied effectively in the integrated pest management program. The safe-time for acetamiprid,beta-cypermethrin,carbosulfan and yejiaqing were 33,91,91 and 110 days, respectively.The results showed that Metarhizium anisopliae had significant effect on Tetrastichus brontispae egg and larvae.The successful parasitism rate, emergence rate and number of wasps per mummy of Tetrastichus brontispae egg and larvae treating Metarhizium anisopliae were obviously lower than that in control group.The development duration of Tetrastichus brontispae egg and larvae treating Metarhizium anisopliae was significantly longer than that in control group.There was no difference between the Tetrastichus brontispae pupae of treating Metarhizium anisopliae and control group.