A Preliminary Study On The Growing Development And Predatory Ability Of Cheyletus Malaccensis(Oudemans)

Biological control have the advantages of low cost,long period of validity,no pollution to the environment,safety to humans and animals,and resistance to pests.Cheyletus malaccensis(Oudemans)is a kind of predatory mite,which is widely existed in grain storage,and is a potential natural enemy for stored-product pests.Mainly studies three parts: the growth and development of C.malaccensis under different conditions of temperature and humidity,the predation function response of different stages of C.malaccensis on different stages of Cryptolestes turcicus(Grouville)and Liposcelis bostrychophila(Badonnel).The results of the study are as follows:The growth and development of C.malaccensis have five stages: egg,larvae,protonymph,deutonymph,and adult,deutonymph was absent in males.The developmental duration at 24°C was longer than that at 28°C.The development of female was mean 16.3~18.6 days,and males 12.6~14.7 days,under 24°C.At RH(85±2)%,females have the shortest duration from egg to adult,with an average of 16.3 days.At RH(95±2)%,the developmental duration of males from egg to adult was shortest,which was 12.6 days.The developmental duration of females was the longest at RH(75±2)%,which was 74.3 days,and the longest at RH(95±2)%,reaching 95.8 days.When the relative humidity was(85±2)% at 28°C,the duration of development from the egg to the adult was the shortest,with an average of 13.2 days,while the male was the shortest at RH(95±2)%.8.1 days.The development duration of all stages was the largest at RH(75±2)%,which females were 80.1 days and males were 31.2 days,respectively.At 24°C,relative humidity RH(85±2)%,the number of eggs per female,oviposition period,and number of eggs laid by each female per day in C.malaccensis were the highest,493.0,46.2,and 10.3 grains/day,respectively..At 28°C,the total oviposition and oviposition period of female were maximal at RH(75±2)%,557.1 grains and 54.3 days,respectively,and the number of eggs laid by each female per day was the highest at RH(85±2)%.It was 11.7 grains/day.The predation of C.malaccensis feed on A.siro under different temperature and humidity.At 24°C and humidity RH(65±2)%,female adult can prey on 285.5 clams,and the longest predation period was 36.8 days at RH(85±2)%.The average predation of female and male was the highest at RH(65±2)%,which was 11.7 heads/day and 9.4 heads/day,respectively.At 28°C and RH(75±2)%,females can prey on 259.1 heads,and the longest predation period of males was 20.3 days.The average predation of male was 20.3 days.The maximum was at RH(65±2)%,which was 11.9 heads/day and 3.7 heads/day,respectively.When preying on the larvae of C.turcicus,the search rate(a)of the different stages of C.malaccensis was the highest(0.886),and the male was the smallest(0.776),in the following order: female > larvae > male;the handling time and the largest catching numbers of female was largest.The handing time was 0.028 days and the maximum prey consumption was 35.584 heads per day.The handing time and the maximum prey consumption of predation were 0.054 days and 18.667 heads/day,respectively.At the end of the survey,the handing time and the maximum prey consumption were 0.054 days and 18.667 heads/day,respectively;the predatory efficacy(control ability)of female was the highest,being 31.547 heads/day,followed by 17.53 heads/day.The following order was female > protonymph > male.The predatory ability of was strongest in females.When preying on the larvae of L.bostrychophila,the search rate(a)of the different stages of C.malaccensis was the highest(0.996),and the protonymph was the smallest(0.665),in the following order: female > male > protonymph;the handling time and the largest catching numbers of female was largest.The handing time was 0.025 days and the maximum prey consumption was 39.217 heads per day.The average processing time and the upper limit of predation were 0.047 days and 14.768 heads/day,respectively,the last was protonymph,the handing time and the maximum prey consumption were 0.136 days and 7.359 heads/day,respectively;the predatory efficacy(control ability)of female was the highest,being 39.063 heads/day,followed by male,was 17.53 heads/day,the last was protonymph.The following order was female > male > protonymph.The predatory ability of was strongest in females.