Invasive species pose a serious threat to biodiversity and result in significant economic costs. Although much effort is devoted to understanding invasive processes, some aspects are poorly understood, such as the early stages of invasions and the reasons for invasion failure. This study focuses on the spread of Trachymela sloanei, an Australian defoliating beetle, in the Iberian Peninsula. The species was first detected in southwestern Spain in 2014 and has spread significantly in recent years, recently reaching the semi-arid southeast. However, 4 years of population monitoring in this area since colonisation suggests a stagnation in its expansion. To explore the possible reasons for this stagnation, we investigated the main climatic characteristics of native and recently invaded areas worldwide, and the insect's tolerance to key climatic variables based on occurrence records. In particular, we compared climatic conditions in the southwest and southeast of the Iberian Peninsula. Our results suggest that this species is distributed in a wide range of climatic conditions and appears to exhibit a degree of ecological plasticity, as recently invaded areas differ from the native range in some key climatic variables. In general, the climatic characteristics of invaded areas in the Iberian Peninsula are similar to those of other invaded regions and the species' native range. However, notable climatic differences exist between the southeastern and southwestern invaded areas in the Iberian Peninsula, mainly related to precipitation. We suggest that frequent droughts in the semi-arid southeast of the Iberian Peninsula may be limiting the species' further expansion. These findings highlight the importance of improving our understanding of the survival of invasive species across different life stages and the flexibility of their ecological requirements.