Location: Biological Control of Pests Research
Project Number: 6066-22320-010-004-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2019
End Date: Sep 30, 2021
Objective:
1. To identify pheromone attractants of elaterid beetles, Conoderus spp.
2. To investigate response of elaterid beetles to host plant volatiles.
Approach:
Adult click beetles will be collected from the field by sweep nets and purple funnel traps and brought to the laboratory. The paired pheromone reservoirs of individual live females will be collected intact by forcibly extruding the ovipositor and placing them in 300 µl of CH2Cl2. Extracts will be stored at -20 °C until analysis. Alternatively, the pheromone gland will be pierced carefully with a fine glass capillary and the liquid inside will be collected into the capillary. The liquid samples then will be dissolved in analytical grade hexane. An improved freeze-thaw method will be applied to click beetle samples before the HS-SPME-GC-MS analysis. Insect samples will be placed in 20 mL borosilicate glass volatile organic analysis vials and sealed with an open-top cap with EPA standard septa. The vial with the sample will be tightly capped and sealed with paraffin film and placed in a -80 °C freezer for 10 min. After removal from the freezer, the sample will be allowed to thaw for 5 min by dipping the vial in a water bath maintained at 25 °C. SPME extraction will be performed for 10 min, 1 h, or 2 h at 25 °C. Compounds on the SPME fiber will be analyzed by using GC-MS. The identified compounds will be screened by using electroantennogram (EAG) and eletropalpgram (EPG). The EAG/EPG positive compounds will be subjected to attractant/repellant and feeding stimulant bioassays. The EAG/EPG negative compounds will be subjected to single sensillum recordings (SSR) analysis. SSR positive compounds will be subjected to the same behavioral assays. SSR negative compounds will then be subjected to screening by measuring the responses of olfactory receptors. We will also investigate response of click beetle to volatiles of their host plant(s). Headspace collections from host plant leaves will be subjected to test methods described above.
