Monolepta signata is a polyphagous and highly destructive agricultural pest, currently only distributed in Asia. In its place of origin, it poses a serious threat to important economic crops, for instance, maize (Zea mays L.) and cotton (Gossypium hirsutum L.). Based on morphological and molecular data research, it has been found that M. quadriguttata (Motschulsky), M. hieroglyphica (Motschulsky), and M. signata are actually the same species. This discovery means that the range of this pest will expand, and it also increases the risk of it spreading to non-native areas worldwide. It is crucial for global agricultural production to understand which countries and regions are susceptible to invasion by M. signata and to formulate corresponding prevention, control, and monitoring strategies. This study uses the maximum entropy model, combined with bioclimatic variables and elevation, to predict the potentially suitable areas and diffusion patterns of M. signata worldwide. The results indicate that in its suitable area, M. signata is mainly affected by three key climatic factors: Precipitation of Wettest Month (bio13), Mean Temperature of Warmest Quarter (bio10), and Temperature Seasonality (bio4). Under the current status, the total suitable region of M. signata is 252,276.71 × 10⁴ km². In addition to its native Asia, this pest has potentially suitable areas in Oceania, South America, North America, and Africa. In the future, with climate change, the suitable area of M. signata will expand to high-latitude areas and inland areas. This study found that by the 2070s, under the SSP5-8.5 climate scenario, the change in the potentially suitable area of this insect is the largest. By identifying the potentially suitable areas and key climatic factors of M. signata, we can provide theoretical and technical support to the government, enabling them to more effectively formulate strategies to deal with the spread, outbreak, and invasion of M. signata.

Conogethes punctiferalis (Guenée, 1854) is a polyphagous pest with a wide host range and strong reproductive ability, and its potential threat to agricultural production cannot be ignored. Based on the optimized maximum entropy niche model, this study evaluated potential suitable habitats for C. punctiferalis in China and their dynamic changes under current conditions (Model 1: bioclimatic factors + elevation; Model 2: bioclimatic factors + elevation + human activity) and four different future climate scenarios (Model 3: bioclimatic factors + elevation + human activity). The results suggest that the potential suitable habitats for C. punctiferalis are mainly driven by a combination of temperature, precipitation, elevation, and human activity. Under current conditions, suitable habitats are mainly concentrated in southern Northeast China, North China, the Yangtze River Basin, and its south regions; highly suitable areas are primarily located in the main maize-producing regions of the Huang-Huai-Hai Plain. The area of suitable habitats predicted by Model 2 is smaller than that predicted by Model 1. Under future climate scenarios, the potential distribution range of C. punctiferalis will show an expanding trend, with the expanded area larger than the contracted area. Compared with Model 2, the suitable areas are expected to increase under Model 3 by approximately 91,799 km² to 723,711 km². This study provides an important basis for assessing the potential hazard risk of C. punctiferalis and is of major significance in guiding the formulation of targeted integrated pest management strategies and protecting the safety of agricultural production.