Claudia Benvenuti

Oscheius onirici sp. n. (Nematoda: Rhabditidae): a new entomopathogenic nematode from an Italian cave

Oscheius onirici sp. n. (Nematoda: Rhabditidae) was isolated from a karst cave soil of Central Italy. Molecular and morphological analyses were performed. Total DNA was extracted from individual nematodes and the mitochondrial COI, the ITS containing region, the D2-D3 expansion domains of the 28S rRNA gene and the 18S rRNA gene were amplified and sequenced. BLAST search at NCBI by using all molecular markers revealed that this taxon is similar to Oscheius species. Phylogenetic trees of ITS, 28S and 18S rDNA revealed that O. onirici sp. n. belongs to Dolichura-group. Oscheius onirici sp. n. is characterized by small body size and stoma rhabditoid type. Female reproductive system is amphidelphic. Males are rare with peloderan bursa, spicules slender and small, nine pairs of papillae of different lengths, arranged in a 1+1+1/3+3 pattern. Entomopathogenicity bioassay revealed that this nematode is capable of infecting larvae of Galleria mellonella and Tenebrio molitor.

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

The red palm weevil Rhynchophorus ferrugineus, recently spreading from its native range throughout the world, is one of the most dangerous pests for several palm species. The sterile insect technique (SIT) is a promising environmentally friendly approach for the management of this pest. An essential prerequisite of the SIT is that irradiated males released in nature are as sexually competitive as their wild counterparts. Here we evaluated the potential use of the SIT in red palm weevil males by investigating the sexual competitiveness of gamma-irradiated (Cobalt 60 source, dose 80 Gray) males in the laboratory in a natural-like social context with a balanced sex ratio and by testing their efficacy in impairing female reproduction. Our results showed that irradiation did not affect any of the mating behaviour parameters. However, the male reproductive potential was drastically reduced, as fertility was markedly decreased in females mated with irradiated males. Therefore, an 80 Gray irradiation dose is a promising option for the SIT in the control of the red palm weevil, producing sterile but sexually competitive males when tested in a natural-like mating context.