A Farnesyl Pyrophosphate Synthase Gene Is Expressed in Fat Body Regulates Cantharidin Synthesis in Male Blister Beetle.

Blister beetles of have attracted attention because they contain a large amount of cantharidin (CTD). To date, however, the synthesis and transfer of CTD in adults of are largely unknown. Here, we showed that the larvae are capable of synthesizing CTD and they consume CTD during pupation. Before sexual maturity, both male and female adults synthesized a small amount of CTD, while after sexual maturity, males produced larger amounts of CTD, but females did not. The newly synthesized CTD in males first appeared in the hemolymph and then accumulated in the reproductive system. During the mating, the males transferred CTD to the reproductive system of females. In addition, a farnesyl pyrophosphate synthase (FPPS) gene was identified in male . RNA-seq analysis, quantitative RT-PCR, and RNA interference analyses were conducted to investigate expression patterns and the functional roles of FPPS (). Our results indicate that is highly expressed in the fat body of males. Moreover, the knock-down of led to a significant decrease in CTD synthesis. The current study indicates that is expressed in the fat body to regulate CTD synthesis in male blister beetles.