Studies On Sense Organ And Parasitic Development Characters Of Three Parasitoids Of Bemisia Tabaci (Gennadius)

Eretmocerus sp., Encarsia sophia and Encarsia japonica are three dominant parasitoids ofBemisia tabaci (Gennadius), which play an important role in biological control of B. tabaci. Thispaper has investigated the characters of sensilla and reproductive system of the three aphelinids, andthe development, emergence behaviors and the functional response of the three aphelinids were alsostudied. The main conclusions are as follows:1.The sensilla of Eretmocerus sp., Encarsia sophia and Encarsia japonica were examined byscanning electron microscope. Six types of sensilla, namely sensilla trichodea, sensilla basiconica,sensilla placodea, sensilla chaeticum, sensillum ampullaceum, B hm bristles, were found on thesurface of antenna. Compound eye include only sensilla basiconica. Two types of sensilla, namelysensilla trichodea and sensilla chaeticum, were found on the surface of mouthparts. Sensillatrichodea and sensilla chaeticum were found on the surface of every leg, besides two organs namely“antenna-cleaning organs” and “wing-cleaning organs” on legs. Three types of sensilla, namelysensilla trichodea, sensilla pore and barb-like apophyses were found on the ovipositor.2. Reproductive system of the three aphelinids included internal reproductive system andexternal genitals. Internal reproductive system consisted of a pair of ovaries, a pair of lateraloviducts, a median oviduct and a spermatheca. External genitals had ventral valves, dorsal valvesand ovipositor sheath.3. Eretmocerus sp., Encarsia sophia and Encarsia japonica developed with four stages of egg,larva, pupa and adult. Larva stage consisted of1st instar,2st instar and3st instar. The pupa,s colourof Eretmocerus sp. was yellow, while Encarsia sophia and Encarsia japonica were black. Amongthe four stages, adult developed the longest one.4. The results of research on emergence, mating and oviposition behaviors of the threeaphelinids showed that emergence peak concentrated at8:00-10:00in the morning. The emergenceprocess could be divided into three procedures of biting, drilling and cleaning. The mating processconsisted of three procedures of testing, mating and cleaning. The oviposition process includedthree procedures of host location and examination, puncture and oviposition, and cleaning.5. The quantity of B. tabaci parasitized by three aphelinids increased with the increasingdensity of B. tabaci. The parasitic functional response of three aphelinids to B. tabaci belonged toHollingⅡdisc equation. The functional coefficient of Eretmocerus sp., Encarsia sophia andEncarsia japonica were0.9747,0.9720,0.9816, and the most hosting number of them were23.3100, 22.5225,26.1780per day theoretically. The searching efficiency of three aphelinids declined withthe increasing of their density.