Long-term insect censuses capture progressive loss of ecosystem functioning in East Asia

• Published in: Science advances 2023-02, Vol.9 (5), p.eade9341
• Main Authors: Zhou, Yan, Zhang, Haowen, Liu, Dazhong, Khashaveh, Adel, Li, Qian, Wyckhuys, Kris A G, Wu, Kongming
• Format: Article
• Language: English
• Subjects: Animals; Asia, Eastern; Censuses; Earth, Environmental, Ecological, and Space Sciences; Ecology; Ecosystem; Food Chain; Insecta - physiology; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.ade9341

Insects provide critical ecosystem services such as biological pest control, in which natural enemies (NE) regulate the populations of crop-feeding herbivores (H). While H-NE dynamics are routinely studied at small spatiotemporal scales, multiyear assessments over entire agrolandscapes are rare. Here, we draw on 18-year radar and searchlight trapping datasets (2003-2020) from eastern Asia to (i) assess temporal population trends of 98 airborne insect species and (ii) characterize the associated H-NE interplay. Although NE consistently constrain interseasonal H population growth, their summer abundance declined by 19.3% over time and prominent agricultural pests abandoned their equilibrium state. Within food webs composed of 124 bitrophic couplets, NE abundance annually fell by 0.7% and network connectance dropped markedly. Our research unveils how a progressive decline in insect numbers debilitates H trophic regulation and ecosystem stability at a macroscale, carrying implications for food security and (agro)ecological resilience during times of global environmental change.