Larvae were disturbed in the search for food and ester volatiles by GmolCXEs silencing
The relative expression levels of GmolCXEs decreased mostly by 50.83% for 24 h (GmolCXE13 ), 75.23% for 48 h (GmolCXE14 ) and 58.33% for 24 h (GmolCXE21 ) after injected with 5 μg corresponding dsRNAs of GmolCXEs (Figure 7 A-C).
Our behavior assays showed that the numbers of larvae choosing ripe fuji apples or crown pears declined significantly after GmolCXE14 and GmolCXE21 silencing respectively (Figure 7 E and F). Besides, the larvae injected with dsCXE14 and dsCXE21 spent much time finding food compared to larvae injected with dsEGFP (Figure 7 H and I). However, after knocking down GmolCXE13 , there was no significant change on larvae searching for food compared to control group (knocking down GmolEGFP ) (Figure 7 D and G).
Ethyl butanoate and ethyl hexanoate were detected from ripe crown pear by GC-MS analysis (Figure S4). The 4th instar larvae of G. molesta exhibited attracting behavior response to these two ester volatiles (Figure 8 A). However, the attraction of two ester volatiles to larvae decreased significantly after the GmolCXE14or GmolCXE21 silencing (Figure 8 B and C).