Invasive and Native Non-Crop Plants Support Aphidophagous Insects in Chilli Pepper Agroecosystems

Understanding the complex interactions between aphids, their natural enemies and surrounding plants is crucial to effectively manage pest aphids in Capsicum crops. While it is known that aphidophagous communities can be found both within and around Capsicum crops, which specific plant species support these beneficial insects remains largely unknown. This study aimed to identify key plant species that could be conserved to promote natural pest control. We sampled and identified pest and non-pest aphids, as well as aphidophagous insects, for over 3 years in 30 Capsicum crops and surrounding non-crop vegetation in Colombian chilli pepper agroecosystems. By combining field observations with molecular techniques, we determined plant-insect associations and the trophic structure of the community. We found that the presence of crop flowers and fruits led to nestedness in plant-insect interaction networks, while flowering crops alone resulted in modularity in the plant-aphid network. A core group of plant and insect species, including Capsicum, the invasive weed Sorghum halepense, the native plants Parthenium hysterophorus and maize (Zea mays), and various aphid and generalist aphidophagous species, formed the most significant interactions within the network. These findings suggest that a diverse plant community, including both native and invasive species, can enhance aphidophagous insect populations and provide a foundation for sustainable pest management strategies in chilli pepper agroecosystems.