Mouthpart,Ovipositor Morphology And Oviposition Behavior Of Cyrtorhinus Lividipennis Reute(Hemiptera:Miridae)

Little information is available on the oviposition behaviour of Cyrtorhinus livdipennis(Reute)(Hemiptera: Miridae),an important predator of rice planthopper and rice leafhopper.Before oviposition,C.livdipennis female explores the substrate with her mouthparts,performing ‘probing' behaviour which eventually leads to a choice of oviposition site.In this study,morphological and behavioural observations were carried out in order to define the mechanisms through which female mirids recognize suitable oviposition sites.The results were listed below:1.To better understand the oviposition behaviour of C.livdipennis,the mouthpart stylets and sensilla of nymph and adult were investigated with scanning electron microscopy.The stylet bundle of the mirid consists of two mandibular stylets and two maxillary stylets.The maxillary stylet has two rows of recurved barbs.The two pairs of maxillary stylets are pressed closely together and the separate salivary and food canals pass between them.The maxillary stylet has two rows strongly serration on the inner surface pointing away from the head.It was found that the mouthpart had trichoid sensilla ?(TS I),trichoid sensilla ?(TS II),basiconica sensilla(BS)and multiporous peg sensilla(MPGS).At the terminal of the labium,there are close-set basiconica sensilla(BS).There is no difference in type of sensilla among nymphs and adult,but the number of sensilla increase along with the growth of age.2.The oviposition apparatus and oviposit sensilla of C.lividipennis were investigated with scanning electron microscopy.The oviposition device of C.lividipennis was located at the end of the abdomen of the female on ??? and ? uromere,which consists of two valvifer 1,(VL1)and two valvula 3(VL3).Five sensilla were observed on the ovipositors of C.lividipennis,including triochoid sensilla(TS),chaetica sensilla(CH),slight depression(SD),depression sensillum(DS)and spine-bearing scales(SBS).3.The mirid female examines the rice plant substrate by means of the labial tip and then probes into the tissue using her stylets.Once the substrate is suitable,the female inserts her ovipositor precisely in the point previously probed and lays an egg.The processes of oviposition behavior include positioning host,host test,oviposition puncture and spawning,oviposition and combing.When the mirid spawn,the penetration rate of the mouth needle was 1.8?0.16 times /s,the spawning frequency was 2.04?0.07 times/s,1 eggs took 50.3?6.55 s and 54.1?1.79 s after the oviposition.In stylets ablation experiment,the mean number of eggs laid by females after 48 h was significantly lower in the stylet ablation(4.86?1.51)than in the fed controls(7.63?1.06).These results imply that the stylets play an important role in mirid's oviposition and eggs protection,and the sensilla associated with the stylets are involved in the location of the oviposition site.The results will be of great significance for future study of artificial oviposition substrates for this predatory mired.