Effect On The Growth And Reproduction And Predatory Ability Of Amblyseius Orientalis (Acari:Phytoseiidae) Feeding On Different Nutrient Sources

Amblyseius orientalis belongs to the genus Amblyseius of the family Phytoseiidae.It is an important predatory natural enemy in China.It mainly preys on the eggs of Tetranychus viennensis and Panonychus citri,as well as eggs of whitefly and some small insects.The mite has not yet achieved low-cost mass propagation,and can only rely on natural prey and pollen for food.In nature,the juice secreted by plant flowers and leaves,pollen and honeydew excreted by some small insects such as aphids can be used as a source of nutrition for insects and mites.Nutrients are the key to affecting the growth,reproduction,development and predation of insects and mites.Insects and mites ingesting these nutrients in nature can promote growth and development,mature reproductive organs,increase egg production,and facilitate population growth and reproduction.It is also beneficial to enhance the predation ability.Proteins and sugars are considered to be important nutritional regulation factors for the reproduction of insects and mites,and one of the important factors for the proliferation and application of predatory mites,which is of great significance to the development and utilization of predatory mites.In this paper,the spatial distribution pattern and population growth and decline of A.orientalis in citrus orchards in Jiangxi were investigated in the field.In the laboratory,the effects of different nutrient additions on the growth,development,reproduction and predation ability of A.orientalis were studied.The main results are as follows:1.Study on the spatial distribution and population growth and decline of Amblyseius orientalisIn order to understand the population dynamics of A.orientalis in the natural environment,a one-year field survey was carried out in the citrus orchard of Nanfeng County,Fuzhou City,Jiangxi Province.The number of A.orientalis was counted by the five-point sampling method and the clapper method at regular fixed points.Thus,the growth and decline of its population can be obtained,and the spatial distribution type of A.orientalis can be obtained by measuring the spatial distribution type index.The survey found that A.orientalis reached its peak in mid-April,and ushered in two small peaks in early June and early October.The spatial distribution indicators I,C_A,and m*/were greater than 0,greater than 0,and greater than 1,respectively, indicating that A.orientalis was clustered.Through the study of the spatial distribution and population growth and decline of A.orientalis in the wild,not only can we understand the population growth and change law of A.orientalis in the wild,but also can formulate reasonable control measures for pest mite through its change law.2.Effects of feeding Amblyseius orientalis with different nutrients on its growth,development and reproductionIn order to explore the effects of different nutrient additions on the growth,development and reproduction of A.orientalis,this experiment adopted the method of single-head feeding at a temperature of 25°C±1°C,a relative humidity of 65%±5%,and a photoperiod（L:D）of Under the laboratory conditions of 16h:8h,the age-stage sex life tables of A.orientalis were constructed for pollen group,pollen+yeast group,pollen+yeast+sucrose group.Statistically analyze the biological characteristics such as the development period,fecundity,lifespan and survival rate of each mite state,and use the TWOSEX-MSchart program to calculate and analyze the intrinsic growth rate r,the cycle growth rateλ,the net proliferation rate R₀,and the generation Period T and other population parameters.The experimental results showed that the total developmental duration of A.orientalis fed with pollen was 6.74 days,which was significantly longer than that of pollen+yeast group（5.27d）and pollen+yeast+sucrose group（5.36d）（P<0.05）.The lifespan of pollen group（19.05d）was significantly shorter than that of pollen+yeast group（28.13d）and pollen+yeast+sucrose group（31.00d）（P<0.05）.The oviposition period and fecundity of the pollen+yeast group were 21.86d and 25.86,respectively,and the pollen+yeast+sucrose group were 23.14d and 27.00,which were significantly higher than the pollen group（11.20d,13.50）（P<0.05）.From the perspective of population parameters,compared with the pollen group,there were significant differences in the net reproduction rate（R₀）and gross reproduction rate（GRR）of the pollen+yeast group and the pollen+yeast+sucrose group（P<0.05）,and the pollen+yeast group The net reproduction rate（R₀）and gross reproduction rate（GRR）were 12.06 and 17.98,respectively,and the pollen+yeast+sucrose group were 12.60 and 18.11,which were higher than the pollen group.It shows that pollen+yeast and pollen+yeast+sucrose are more conducive to the population growth and reproduction of A.orientalis.3.The effect of feeding Amblyseius orientalis with different nutrients on its predation abilityIn order to explore the effects of different nutrient additions on the predation ability and prey-finding ability of female adults of A.orientalis,so as to evaluate which nutrient supplement feeding is more suitable for the application and production of A.orientalis,this paper uses different nutrient supplements to feed Amblyseius orientalis and set different prey densities（4,8,12,16,20）and different generations（G3,G5,G7,rejuvenation G1,rejuvenation G3,rejuvenation G5）,record its response to Panonychus citrus within 24 hours Predation amount of adult female mites.The experimental results showed that the functional response of A.orientalis to Panonychus citrus under different nutrient additive treatment conditions belonged to the Holling type II.The predation ability of pollen+yeast+sucrose group in each generation was higher than that of pollen group and pollen+yeast group,and the recovery of predation ability after rejuvenation treatment was also the best.In addition,the seeking effect value of the pollen+yeast+sucrose group in each generation was also higher than that of the pollen group and pollen+yeast group,and the value of the seeking effect began to rise significantly in the rejuvenating G1generation,and finally the seeking effect of the rejuvenating G5 group reached the maximum（0.917）.These results indicated that the female adults of A.orientalis fed with pollen+yeast+sucrose group had the strongest predation ability,which provided a theoretical basis for the application of A.orientalis in the field after indoor propagation.In summary,compared with the pollen group and the pollen+yeast group,feeding adult females of A.orientalis with the nutrient supplement combination of pollen+yeast+sucrose showed better performance in terms of promoting their growth,development,reproduction and predation ability.These experimental results provide a theoretical basis and basis for the indoor breeding and propagation of A.orientalis and further application of biological control.