Abstract
<title>Abstract</title> <p> The age-stage two-sex life table resolves sex-specific developmental trajectories and enables accurate quantification of pest growth, survival and reproduction. As a subterranean herbivore, <italic>Bradysia odoriphaga</italic> (chive maggots) has undergone long-term coevolution with host plants, generating distinct host preference and adaptive differentiation; this study further quantifies such coevolutionary differentiation via age-stage two-sex life table parameters and interprets its theoretical implications for plant-insect coevolution. Field monitoring and laboratory life table assays were conducted on seven local vegetables of four families in cold Heilongjiang. Field data show temperature and precipitation jointly regulate seasonal population fluctuations, with three annual adult occurrence peaks. Laboratory assays reveal significant variations in developmental duration, survival, fecundity and intrinsic rate of increase among the seven hosts, with <italic>A. tuberosum</italic> , <italic>A. fistulosum</italic> and <italic>C. sativus</italic> supporting the highest population performance, whereas <italic>S. tuberosum</italic> severely suppresses population growth. Stage-specific analysis identifies early-instar larvae as the key stage for population regulation. This study fills gaps in cold-region research on its host adaptability, provides quantitative evidence for pest-plant coevolution, and offers theoretical support for ecological pest management and scientific rotation in organic chive cultivation. </p>