Aggregation Pheromone (2E,6E)-Farnesyl Acetate Drives Attraction and Reproduction in Megalurothrips usitatus

The bean flower thrips, Megalurothrips usitatus, is a destructive pest that affects leguminous crops. Males release aggregation pheromone (2E,6E)-farnesyl acetate (abbreviated as E,E-FOAc) to attract conspecifics of both sexes. Here, we identified 105 olfactory-related genes in the female antennal transcriptome and found that MusiCSP7 was significantly upregulated in female antennae upon brief E,E-FOAc exposure. RNA interference (RNAi) showed that dsMusiCSP7-treated females significantly reduced behavioral attraction and electroantennogram (EAG) responses to E,E-FOAc. Competitive fluorescence binding assays confirmed a high binding affinity between MusiCSP7 and E,E-FOAc. Notably, a brief 30 s exposure to E,E-FOAc significantly increased offspring production and synchronized oviposition in females, accompanied by an increase in vitellogenin receptor (MusiVgR) expression. Our findings reveal a new role of E,E-FOAc in linking behavioral aggregation with reproductive modulation. This dual function enhances mating efficiency and accelerates population growth after host plant localization, conferring an adaptive advantage to M. usitatus.