The Calling Behavior And Sex Pheromone Identification Of Sylepta Derogata Fabricius(Lepidoptera:Pyralidae)

The cotton leaf roller,Sylepta derogata Fabricius,belongs to the Lepidoptera Pyralidae family,which mainly damages cotton,okra,sycamore and other agricultural and forestry plants.Insect sex pheromone has the advantages of species specificity,high efficiency and eco-friendly,and thus has been widely used in the monitoring and management of some major pests at home and abroad.However,sex pheromone of cotton leaf roller has not been studied.In this study,firstly,the courtship behavior and dynamics of female moths of cotton leaf roller were studied to clarify the peak calling period of the insect;Then,the gland extracts of the female cotton leaf roller were analyzed by gas chromatography combined with an EAG detector(GC-EAD)and gas chromatography-mass spectrometry(GC-MS),the retention times of the standard solutions were analyzed by gas chromatography(GC),and the main pheromone component of the cotton leaf roller was putatively identified as(E10,Z12)-hexadecadienal(E10,Z12-16:Ald).The main results are as follows1 The courtship behavior of femaleUnder indoor conditions with a temperature of 25±1 ℃,a relative humidity of60±10%,and a photoperiod of 14L: 10 D,the calling behavior and dynamic changes of the female cotton leaf roller moth was observed systematically.The results showed that when the female cotton leaf roller was calling,the antennae trembled rapidly,the wings vibrated,and the ovipositor continued extending out.The calling behavior occurred only in the dark period,peaking at 4 h-7.5 h into the dark period;the female moths did not call on the day of emergence,and the 3-day-old females showed the highest calling rate of 70%;as the age of female moths increased,the peak calling time was slightly delayed,and the average duration of courtship was also slightly shortened.Comprehensive analysis shows that the courtship behavior of virgin female moths of the 3-4 day old cotton leaf roller was the most active.2 Identification of the female sex pheromone componentsThe glands of the virgin female cotton leaf roller moths were extracted by solvent hexane at the calling peak time,and then the gland extracts were analyzed by GC-EAD and GC-MS.The GC-EAD results demonstrated that the male moth antennae of cotton leaf roller moths showed strong electrophysiological responses to two components of the gland extracts;further GC-MS analysis identified one of the components as a hexadecanal unsaturated aldehyde(10,12-16:Ald)with double bonds at the 10 th and 12 th positions.In order to verify the specific configuration of this component,GC and GC-EAD analyses were performed on the mixture of several standard 10,12-16:Ald components(containing four fractions of E10,E12-16:Ald,Z10,E12-16:Ald,Z10,Z12-16:Ald,and E10,Z12-16:Ald)available in our laboratory,and the results showed that the main sex pheromone components of cotton leaf roller was E10,Z12-16:Ald,which needs to be confirmed by further field trapping experiments.