Studies On The Reproductive And Predatory Behavior Of Lasioseius Sugawarai Ehara

The predatory mite, Lasioseius sugawarai Ehara (Acari: Mesostigmata: Ascidae) is a potential biological control agent of pest mites and small arthropods living underground. Nowadays, the pest mites are increasingly becoming rampant, such as the spider mites (Tetranychidae), eriophyid mites (Eriophyidae) and tarsonemid mites (Tarsonemidae) which can cause damage to crops and forestry plants and acarid mites (Acaridae) which can harm plants both in storage and the field. With the development of consciousness of environmental protection, people realized the problems made by chemical pesticides. The concept of using beneficial natural enemies to control pests is becoming more and more acceptable.In order to evaluate the efficiency of L. sugawarai as a natural enemy to two acarid mites, Tyrophagus putrescentiae (Schrank) and Rhizoglyphus echinopus (Fumouze & Robin), the predaceous abilities on the developmental stages of the two prey species and to provide theoretical knowledge for using L. sugawarai, herein, we studied the development and reproduction, prey preference, and the predaceous ability at 25±1 °C, more than 90% RH and L: D = 0: 24. The result shows as the following:a. The virgin male of L. sugawarai behaved inactively and indolently hile searching for opposite sex to copulate. During the copulating course, male stayed on the dorsal shield of female for 3-34 seconds (13.7±2.8) andthen moved to the ventral side of female. The copulate modality was indirect.b. Developmental durations of premature stages of L. sugawarai fed on two preys were not significantly different. The life spans of adult females of L. sugawarai fed on R. echinopus were 46.5 days, which was significantly longer (p < 0.05) than those fed on T. putrescentiae. The mortalities of larvae and deutonymphs of L. sugawarai fed on R. echinopus were little higher than those fed on T. putrescentiae. However, there was no significant different on premature stages and the emerging rate of adults of L. sugawarai fed on two preys. Adult females of L. sugawarai fed on R. echinopus had obviously longer oviposition period (39.7±6.7 d) and longevity (46.5±6.9 d) than those fed on T. putrescentiae, but pre-oviposition period of L. sugawarai fed on both preys were similar.c. Adult females of L. sugawarai consumed significantly more R. echinopus (1.740 larvae/12 h) than T. putrescentiae (0.700 larvae/12 h). There was no significance (p > 0.05) between mortalities of eggs laid by L. sugawarai fed on mixed preys and each prey alone.d. All females of L. sugawarai attacked preys actively during the first hour regardless of the preys and the extent of hungry and then their attacking times gradually declined.Starved L. sugawarai significantly {p < 0.05) hunted long than replete ones. Replete L. sugawarai significantly (p<0.05) needed more time to prey on one prey than the other two treatments(hunger L. sugawarai preyed on T. putrescentiae or R. echinopus)e. The favorite prey stage of/?, echinopus is larva, and then nymph, egg and adult. The functional response pattern of adult female of L. sugawarai to larvae and nymphs of R. echinopus were Holling II. Thesugawarai to larvae and nymphs of R. echinopus were Holling II. The predaceous ability of adult female of L. sugawarai enhanced while the temperature was rising during 10-25°C, and then dropped when temperature exceeded 25 "C. The parameters of functional response were affected by temperature and starvation, but the types of equations were not changed.Using predaceous natural enemies to control pests have already been reported by many people. Our test had displayed that L. sugawarai has a big appetite and a active movement. So it is worthwhile to exploring and using L . sugawarai which as a natural enemy of R. echinopus.