The Effect Of Wheat Flour Volatiles On The Orientation Behavior Of Tribolium Castaneum (Herbst)

Tribolium castaneum(Herbst)is an important pest in stored wheat flour.A two-choice pitfall bioassay was used to detailedly investigate the behavior response of T.castaneum adults and larvae to wheat flour volatiles.The wheat flour volatiles components were collected and indetified by SPME-GC-MS.The results are as follows:The approach behavior of T.castaneum larvae and adults with experiencing different starvation times to intact wheat kernels,broken wheat kernels,and wheat flour volatiles were different.With the increasing starvation times,the selection coefficients of T.castaneum adults and larvae to intact wheat kernels decreased.The selection coefficients of T.castaneum adults and larvae to wheat flour were higher than to intact wheat kernels,and broken wheat kernels.The highest selection coefficient to wheat flour were 70% for the adults,and 83.3% for the larvae.The selection coefficients of T.castaneum larvae to intact wheat kernels,broken wheat kernels,and wheat flour were higher than that of T.castaneum adults under the same conditions.After experiencing the odor of wheat flour for 0,24,48 and 96 h,the selection coefficients of adults and larvae of T.castaneum decreased with increasing experience times.The results showed that the adults and larvae of T.castaneum had a habituation to wheat flour odor source.Headspace solid-phase microextraction(HS-SPME)coupled to gas chromatography-mass spectrometry(GC-MS)was used for analysis of the volatile constituents emitted from the selected 5 samples.There were 54 kinds of main volatiles of wheat flour were identified including alkanes,aldehydes,aldehydes and alcohols,among which alkanes and alkenes occupied the largest proportion,and esters and heterocyclic contents were less.All the samples of wheat flour,the composition and varieties of numbers content of volatile components were similar.Five compounds were 5 components of wheat flour:1-Hexanol,Limonene,Nonanal,Dodecane,and Tetradecane.Four kinds of wheat volatiles standards including 1-Hexanol,Limonene,Nonanal,Tetradecanel were selected for the further testing of T.castaneum approach behavior.The results showed that Tetradecane and Nonanal standard had repellent effect on adults and larvae of T.castaneum,and1-Hexanol had attractant effect.After starvation for 0 and 6 h,the selection coefficients of the adults and larvae of T.castaneum to Tetradecane decreased along with increasing concentrations,while the selection coefficients of T.castaneum with 24 h starvation increased with increasing concentrations,and the larvae were more sensitive than the adults.After 0,6,and 12 h of starvation,the selection coefficient of adults and larvae of T.castaneum to the 1-Hexanol increased with the increase of standard concentration,but the selection coefficients of insects with 24 h starvation decreased.The adults and larvae of T.castaneum without starvation to 1-Hexanol decreased along with the increase of standard concentration,while the adults and larvae of T.castaneum with 6,12 and 24 h starvation increased.After experiencing the odor of wheat flour for 0,6,and 24 h,the selection coefficients of the adults and larvae of T.castaneum to Tetradecanee decreased with increasing experiencing times,the insects had a habituation.After experiencing the odor of wheat flour for 0 and 12 h,or 6 and 12 h,the adults and larvae of T.castaneum selective coefficien to 1-Hexanol or Nonanal increased with increasing experience times,the the insects had a induction of preference behavior to 1-Hexanol and Nonanal.