Study On Reproductive Biology Of Spalangia Endius Walker

The Spalangia endius Walker is an important pupal parasitoid of many Diptera pest species,has a great potential for biological control.To determine host preference and suitability of S.endius,a six host range test was conducted using a no-choise arena and temperature-dependent development studies at 16,20,24,26,28 and 32?.Statistical influence on the intrinsic rate of increase of S.endius on difference temperature and hosts was conducted using re-sampling technique,with aims of providing technological theory for improving artificial-rearing the parasitoid.The ovarian development of S.edius was also observed.The results were listed below:1.The observation of ovarian development of S.edius was studies.The results showed that S.edius belong to synovigeny parasitoid,the larvae of S.edius,which was composed of 1 pair of ovaries,1 pair of lateral oviducts,median oviduct,spermatheca,spermathecal gland and so on.O varies developed fastly after emergence,while ovary index increased from 0.34 mm² to 0.48 mm²,with the number of eggs from 37.67 to 42.67.4 days after emergence,ovaries became shorter,ovary index and number of eggs decreased.Research shows that two-day-old females'fecundity was best.2.To analyze the receptors on the ovipositors and copulatory related to the oviposition and mating behavior of S.edius,the ultrastructure of genitalia and genitalial sensilla of S.edius was studied by the scanning electron microscopy.Five sensilla were observed on the ovipositors of S.edius,including triochoid sensilla 1?TS1?,triochoid sensilla 2?TS2?,chaetica sensilla?CS?,volcanic sensilla?VS?,slight surface depression?SD?.Three receptors were found on the copulatory organs,including styloconic sensilla 2?SS2?,campaniform sensilla?CAS?,volcanic sensilla?VS?.3.Laboratory studies were conducted on certain aspects of biology of S.endius courtship,mating and oviposition behaviors,when the humidity was from 60%-70%and temperature was 26?.The process of courtship and mating behavior include finding and chasing,positioning the females,courtship,mating,resting or continuing courtship.The female layed after mating.The process of oviposition behavior includes positioning host and host test,oviposition puncture and spawning,oviposition and combing.4.The effects of 6 temperatures?16,20,24,26,28 and 32??on development and reproduction of the parasitoid on B.cucurbitae were studied.The results showed that the developmental duration of S.endius varied from 22.9 d at 32?to 109.45 d at 16?.The developmental threshold and effective accumulated temperatures for an entire generation were 5.24?and 417.3 degree-day,respectively.At 16?,the longevity of adult males and females averaged 46.9 d and 38 d,respectively,but declined to 9.4 d and 8.4 d at 32?.At26?,fecundity is maximum,the intrinsic rate of increase?r_m?was the highest at 26 and28?,which were 0.1389 and 0.1408,respectively.The net reproduction rate?R₀?was the highest at 24 and 26?,which were 35.38 and 31.75,respectively.It could be concluded that 26?is the best suitable temperature for the development and reproduction of the parasitoid.5.Experiments were confucted to evalute the impact of three different hosts on the development and reproduction of S.endius.The generation development time of S.Endius varied from 30d?B.cucurbitae?to 30.9d?B.dorsalis?.The sex ratio of offspring did not differ significantly between parasitoid reared from B.cucurbitae,B.dorsalis.and B.tau.?above 0.68?.Females wasps obtained from the tested host species were larger than male wasps.The longevity of female wasps was not significantly different when they were detected from B.cucurbitae,B.dorsalis to B.tau,and male wasps lived 11 to 12.2d.Intrinsic rate of natural increase?r_m?of S.endius on B.cucurbitae,B.dorsalis and B.tau were 0.1454,0.1273 and 0.1513 respectively.The net reproduction rate?R0?was the highest on B.tau,which was 37.96,and the lowest on B.dorsaliswhich was 23.The weekly growth rate and generational average duration were not significantly different on which ranged from B.cucurbitae,B.dorsalis to B.tau.The data revealed that S.endius was adapted to a wide range of host species.