Study On The Substitute Diet And Prey Preference Of Orius Minutus

Orius minutes(Linnaeus)(Hemiptera:Anthocoridae)is a major natural enemy of thrips,aphid,tetranychid mites,aleyrodid,egg and larva of lepidoptera with strong activity ability,long occurrence time and big population quantity.As one of the dominant species of the predator anthocorid bug in China,O.minutus has great development potential.At present,there are few reports on the artificial rearing and pest control of this tiny flower bug both domestic and abroad,and the artificial rearing technology is not mature enough,which makes it difficult to be used as biocontrol agent in large scale.The effect of 3 diets on development and reproduction of O.minutus were evaluated under controlled conditions in the laboratory,i.e.,a diet of the acarid mite Tyrophagus putrescentiae(Schrank),T.putrescentiae plus apple(Malus pumila)pollen grains,and T.putrescentiae plus corn(Zea mays)honeybee pollen.The preference of newly hatched nymph,newly molting 5th instar nymph and newly emerged female adult of O.minutus to 4 natural preys was compared,too.The tested preys were:adults of Tetranychus cinnabarinus(Boisduval),low-instar nymph of Myzus persicae(Sulzer),2nd instar nymph of Frankliniella occidentalis(Pergande)and 2nd to 3rd instar nymph of Bemisia tabaci(Gennadius).This study aims at researching a simple,nutritionally superior and cost effectiveness diet for rearing the predator bug,evaluating its effect on prevention and control of common agricultural and forestry pests,as well as laying the foundation for the artificial large-scale rearing of O.minutus.Main conclusions are as follows:1.when rearing on T.putrescentiae plus corn honeybee pollen and T.putrescentiae plus apple pollen,the development duration of nymph(13.26d and 13.66d,respectively)was both significantly shorter than that on T.putrescentiae alone(14 44d);the survival rate of 3rd,4th and 5th instar nymph(0.8593,0.8690,0.9052 and 0.8476,0.8524,0.8846,respectively)were all significantly higher than those on T.putrescentiae alone(0.8124,0.8153,0.8300,respectively),while the survival rate of 1st and 2nd instar nymph(0.8076,0.8069 and 0.8242,0.8088,respectively)were both significantly lower than those on T.putrescentiae alone(0.8786,0.8512,respectively);the longevity of female and male adults(15.97d,13.96d and 15.42d,13.07d,respectively)were both significantly longer than those on T.putrescentiae alone(13.87d,11.57d,respectively).When adding corn honeybee pollen to a diet of T.putrescentiae for rearing,the pre-oviposition period(3.08d)was significantly shorter than that on T.putrescentiae alone(3.86d),nevertheless,adding apple pollen to T.putrescentiae for rearing had no significant effect on the pre-oviposition period.The fecundity,intrinsic rate of increase(rm)and population trend index(1)were the largest when reared on T.putrescentiae plus corn honeybee pollen(52.17 eggs,0.0647,7.75,respectively),followed by those on T.putrescentiae plus apple pollen,and all were the smallest when reared on T.putrescentiae salone(40.21 eggs,0.0533,5.22,respectively).However,addition of either pollen to T.putrescentiae for rearing had no significant effect on the egg developmental duration,egg survival rate,adult obtained rate,female ratio and effective mating rate.A combination of T.putrescentiae and corn honeybee pollen was more suitable for large-scale artificial rearing of O,minutus.2.In the no-choice texts of 4 kinds of prey,newly hatched nymph,newly molting 5th instar nyixph and newly emerged female adult of Orius minutus had the largest daily consumption of adults of T.cinnabarinus,which was 12.40,44.40 and 37.20 insect/d,respectively,followed by the daily consumption of 2nd instar nymph of F.occidentalis,which was 14.20、28.80 and 27.40 insect/d,respectively;newly molting 5th instar nymph had the largest daily consumption of preys among newly hatched nymph,newly molting 5th instar nymph and newly emerged female adult of Orius minutus.In the choice texts of 4 kinds of prey,newly hatched nymph,newly molting 5th instar nymph and newly emerged female adult of Orius minutus had the largest indexes of preference to 2nd instar nymph of F.occidentalis,which were all positive.In the 4 test preys,T.cinnabarinus was the prey having the largest daily consumption by O.minutus,while F.occidentalis was the most preferred prey of O.minutus.