Sterile Rhynchophorus ferrugineus males efficiently impairs reproduction while maintaining their sexual competitiveness in a social context.

The Red Palm Weevil Rhynchophorus ferrugineus, recently spreading all over the world outside its native range, is one of the most dangerous pest for several palm species. A promising, environmentally friendly management technique for this pest is represented by the Sterile Insect technique (SIT). An essential prerequisite of SIT is that released irradiated males are as sexually competitive as their wild counterparts. Here, we evaluated the potential application of SIT on Red Palm Weevil males by investigating, under laboratory condition in a natural-like social context with a balanced sex ratio, the sexual competitiveness of gamma-irradiated (with a Cobalt 60 source at a dose of 80 Gray) males and by testing their efficacy in impairing female reproduction. Our results showed that irradiation did not affect any of the mating behaviour parameters considered for males sexual competiveness. On the contrary, irradiation strongly affected the reproductive potential of males, as fertility was drastically reduced in females mated with irradiated males. Our study provides evidence that 80 Gray irradiation dose represents a promising option under the SIT framework, allowing to obtain sterile but sexually competitive males even when tested in a natural-like mating context.