Identification of diet resources of big-eyed bug Geocoris ochropterus (Fieber) (Hemiptera: Geocoridae) by multiplex PCR and shotgun metagenomic approaches.

BACKGROUND

Big-eyed bugs (Geocoris spp.) are important generalist predators in agricultural ecosystems, playing a crucial role in natural pest control.

METHODS

To better understand their dietary sources, we assessed the plant and animal food sources in the gut of Geocoris ochropterus using multiplex PCR and shotgun metagenomic analysis. The PCR assays targeted genetic markers from both animal (COI) and plant (matK and rbcL) DNA.

RESULTS

Results revealed the presence of both animal and plant-derived DNA in the gut samples, indicating that Geocoris ochropterus feeds on a mixed diet. Additionally, the results of shotgun metagenomic sequencing of the gut microbiota showed a predominance of Eukaryota, with over 80% of sequences belonging to this domain, while a diverse range of taxonomic groups were identified, including arthropods, plants, bacteria, and fungi. Arthropods particularly insects from the orders Lepidoptera, Hemiptera, Hymenoptera, Coleoptera, Phasmatodea and plants belonging to the orders Brassicales, Cucurbitales, and Poales constituted the most abundant dietary components. At the genus level, notable taxa included Maniola (family Nymphalidae), Carposina (Carposinidae), Helicoverpa (Noctuidae), and Solanum (Solanaceae). Species-level analysis confirmed the dominance of several insect species, including Maniola hyperanthus, Carposina sasakii, and Bombyx mori, alongside plant species such as Cucumis melo, Gossypium hirsutum, and Digitaria exilis.

CONCLUSIONS

These findings provide a comprehensive characterization of the diet of Geocoris ochropterus, highlighting its role as a generalist predator with a diverse diet consisting of both insect and plant food sources. This study contributes to the understanding of Geocoris ochropterus as a potential biocontrol agent in agricultural systems.