Intensified push-pull technology enhances above-ground arthropod assemblages and ecological balance

Abstract

Agroecological intensification aims to increase farm productivity, reduce dependency on external inputs, and enhance biodiversity conservation. However, the contribution of recent sustainable agricultural practices to arthropod assemblages and their ecosystem services remains underexplored. Through a 2-year multilocation trial, we investigated the response of above-ground arthropod assemblages and their ecological functions in cowpea and maize grown under monocropping systems and diversified systems (pure and intensified push-pull technologies). Using three sampling methods (visual observations, pitfall traps, sticky traps), a total of 65,307 arthropod specimens were collected. The most dominant arthropod taxa were Hemiptera (true bugs; 47%), followed by Thysanoptera (thrips; 17%), Diptera (true flies; 16%), Hymenoptera (ants; 9.7%), Trombidiformes (mites; 3.5%), Coleoptera (beetles; 2.2%) and Araneae (spiders; 1.5%). Familywise, grass spiders were most dominant in diversified systems, while wolf spiders and jumping spiders were more dominant in monocrops. Regarding the beetles, the highest abundance of ladybird beetles was observed in diversified systems, while ground beetles and rove beetles showed a high preference for monocrops. Tachinid flies showed a high preference for monocrops. Carpenter ants were more abundant in cowpea monocrops, while harvester ants were more abundant in diversified systems. Families of honeybees (pollinators), hoverflies (pollinators, predators) and wasps (parasitoids, predators, pollinators) occurred frequently in diversified systems. Regarding herbivores, noctuid moths/larvae were the most dominant pests in maize monocrops, while leaf miners, aphids, spider mites, thrips and leaf beetles were the most abundant pests in cowpea monocrops. The highest natural enemy-to-herbivore ratios were reported in diversified systems compared to monocrops. Diversified systems increased the crop yield by about two-fold compared to untreated monocrops. Our study demonstrates that diversified systems increase overall arthropod population and create a more balanced ecosystem in which beneficial arthropods are not dominated by destructive ones, which may have resulted in improved ecological resilience and crop productivity.