Effects Of Volatile On The Mating And Feeding Behavior Of Sitophilus Zeamais And Sitophilus Oryzae

Sitophilus zeamais Motschulsky,maize weevil,and Sitophilus oryzae Linnaeus,rice weevil,are two bored pests,whose feeding behavior can not only cause loss of weight and quality of stored grains,but also create favorable conditions for the occurrence of powdery feeding pests such as Tribolium castaneum Herbst.Therefore,the research of feeding behavior and mating behavior was of great importance to reduce its occurrence.What's more,the analysis of the volatile components of food in paddy,maize and wheat and their effects on their mating and feeding behavior were of great significance for the study of their behavior difference,monitoring of insect pests and comprehensive prevention and control.(1)In order to understand the mating regularity and mating preference of maize weevil and rice weevil,the mating behavior of maize weevil and rice weevil was observed at different day age under(28 ± 5)°C and(60 ± 5)% RH.The results showed that the peak mating age of maize weevil and rice weevil were 15 days and 15-20 days after emergence,respectively.Under the dark conditions,it is more conducive to increase the mating duration and the mating rate.The males with heavier weight are more likely to obtain mating opportunities.(2)Fifteen-day-old unmated maternal and maize weevil males and rice weevil males were tested using immersion solid-phase micro-extraction(DI-SPME)and gas chromatographymass spectrometry(GC-MS)to analyse cuticular hydrocarbons.The maize weevil males and rice weevil males cuticular hydrocarbons were classified into hydrocarbons,alcohols,esters and acids.The content of esters in maize weevil males than others,while that of rice weevil males were alcohols.Among them,?-sitosterol acetate,cholesterol acetate,?-sitosterol and ?-sitosterol existed in rice weevil males and could be used for identification of species.(3)Head-spaced solid-phase micro-extraction(HS-SPME)coupled with gas chromatography-mass spectrometry(GC-MS)was used to analyze volatiles of virgin maize weevil males and rice weevil males at 15 days of age.The volatiles of maize weevil males and rice weevil males were classified into hydrocarbons,aldehydes,alcohols and ketones.Fifteen volatile components were both found in the two species,but the relative percentages of them were different.(4)Four-arm olfactometer was used to test the preference of maize weevil and rice weevil to paddy,maize and wheat volatiles.The maize weevil preferred maize,followed by paddy and wheat,and the attraction rate were 33.00%±1.29%,24.50%±1.17%? 15.50%±1.91%;The attractivity of wheat on rice weevil was stronger than maize and paddy,and the attraction rate were 33.50%±1.71%,19.50%±1.71% and 17.00%±2.08%?.(5)Headspace solid-phase microextraction(HS-SPME)technology combined with gasmass spectrometry(GC-MS)was used to analyze the volatile components of paddy,maize and wheat.The volatile components of paddy,maize and wheat mainly include hydrocarbons,aldehydes,alcohols,ketones,acid esters,and benzene homologs.The contents of limonene and(+)-?-cadiene in paddy were higher than others,and the content of 2-ethylhexanol and piperonone were higher in maize,while the content of cubene and 2-ethylhexanol in wheat were higher than others.(6)The Y-type olfactometer was used to observe the behavioral responses of food volatiles of maize weevil and rice weevil,as well as the appropriate concentration range.3.5 mmol/L 2-ethylhexanol,0.35 mmol/L of(+)-?-cadiene,and 3.5 mmol/L of piperonone had significant attractive effects on maize weevil.35 mmol/L 2-ethylhexanol,35 mmol/L(+)-?-cadiene,35 mmol/L of piperonone and 3.5 mmol/L of limonene were better than other concentrations of the compounds.(7)The Y-type olfactometer was used to evaluate the behavioral responses of maize weevil females and rice weevil females to food volatiles with males.The combination of 3.5 mmol/L 2-ethylhexanol with maize weevil males had stronger attraction to maize weevil females than combinations of 350 mmol/L of piperonone with maize weevil males and 0.35 mmol/L(+)-?-cadiene with maize weevil males.The combination of 35 mmol/L(+)-?-cadiene with maize weevil males.The combination of 35 mmol/L 2-ethylhexanol with rice weevil males has stronger attraction on rice weevil females than combinations of 35 mmol/L pepperone with rice weevil males and 3.5 mmol/L limonene with rice weevil males.(8)Using 24-well cell culture plates to observe the effect of volatile constituents from three grains on the mating behavior of maize weevil and rice weevil.In the presence of 3.5 mmol/L 2-ethylhexanol and 0.35 mmol/L(+)-?-cadiene,the mating rate of 15-day-old maize weevil increased significantly.In the presence of 35 mmol/L 2-ethylhexanol,35 mmol/L(+)-?-cadiene,and 3.5 mmol/L limonene.There was a significant increase in the mating rate of 15-day-old rice weevil.