Guihong Lai

A comprehensive and precise evaluation of Arthropoda diversity in agricultural landscapes can enhance biological pest control strategies. We used Malaise traps and sweep nets to collect insects from three double-cropping paddy fields. DNA was extracted from the ethanol preservative of the Malaise traps and from tissue samples of selected parasitoid wasps. This was followed by amplification using DNA barcoding primers to prepare high-throughput sequencing libraries. We annotated a total of 4956 operational taxonomic units (OTUs), encompassing 174 genera and 32 families of parasitoid wasps. The ethanol filter method efficiently captured a wide range of information. However, the method has low resolution and may result in a reduced estimate of species abundance. Additional insect species were also identified in the parasitoid samples. This suggests that high throughput sequencing from adult parasitoid wasps can also detect host species, enabling a better understanding of host species and providing insights into food webs.

The modifications in planting structure and continuous land use adjustments have significant implications for the structure, diversity, and functioning of arthropod communities in farmland landscapes, particularly regarding the biological control of pest insects by natural enemy species. Therefore, there is an urgent need to comprehensively and accurately assess insect community diversity in croplands. In this study conducted between 2022-2023, we utilized Malaise traps and sweep netting to collect insects from three different double-cropping paddy fields. We extracted DNA from preservative ethanol of Malaise traps and tissue samples of selected parasitoid wasps, followed by amplification using DNA barcoding primers to prepare high-throughput sequencing libraries. As a result, we annotated a total of 4956 operational taxonomic units (OTUs) belonging to 174 genera and 32 families of parasitoid wasps. Our findings demonstrate that the ethanol filter method efficiently captures a wide range of information diversity. However, it demonstrates a lower resolution and may result in a reduction of species abundance. Furthermore, we have identified additional insect species in the parasitoid samples. This demonstrates that high throughput sequencing from adult parasitoid wasps can effectively detect host specie, enabling a comprehensive understanding of host species and providing novel insights into food web construction.