Predicting the expansion of Gephyraulus lycantha as a key pest of goji berry in China under climate change

Background The gall midge, Gephyraulus lycantha Jiao & Kolesik (Diptera: Cecidomyiidae), causes abnormal enlargement of goji berry, Lycium barbarum L, buds during its larval stage, forming galls and resulting in a significantly decrease in yield in China. Identifying the distribution of the midge in China under current and future climate change scenarios will provide guidance for the scientific prevention and control of this pest. Methods The MaxEnt model was used to predict the current and future potential suitable habitats for the midge in China based on the filtered 56 distribution points and 11 environmental factors, and the ArcGIS software was used to analyze the changes in its suitable region. Results The results showed that when the parameters were feature combination (FC) = HP and regularization multiplier (RM) = 1, the MaxEnt model was optimal, and the AUC and TSS values were greater than 0.90. The mean temperature of driest quarter (suitable range was -9.36–4.43 °C) was the most critical factor influencing the distribution of the midge. Under current climate conditions, the area of suitable habitat for the midge was 112.73 × 10 4 km 2 , primarily distributed in Xinjiang (29.03 × 10 4 km 2 ), Inner Mongolia (26.44 × 10 4 km 2 ), Gansu (18.36 × 10 4 km 2 ), Qinghai (10.46 × 10 4 km 2 ), and Ningxia (3.90 × 10 4 km 2 ) Provinces. Under the 2050s and 2070s climate scenarios, the area of suitable habitats was larger than current ones (except for SSP126), reaching its maximum under the SSP585 (119.06 × 10 4 km 2 ) and SSP245 scenarios (135.25 × 10 4 km 2 ), respectively. Conclusion In addition, climate warming would cause the suitable habitat of the midge to expand northeastward. Therefore, it is necessary to strengthen monitoring, early warning, and control measures for the pest to ensure the production of goji berry.