Climate change and host plant drive the distribution of a specialized insect, Rhodostrophia jacularia (Lepidoptera: Geometridae), in the Palearctic region

The distribution and availability of host plants plays an important role in the dispersal of herbivorous insects, especially for the specialized species. In this study, we simulated the habitat suitability of a specialist species, Rhodostrophia jacularia, in the Palaearctic region based on environmental variables and host plant species (Goniolimon speciosum) and predicted its future distribution (2070) under RCP126 and RCP585 climatic scenarios using Maxent. For the host plant species, temperature related variables (bio2, bio3, bio5) were important, while for the moth species precipitation and vegetation related variables (including the host species availability) were critical for current and future distribution. Although wind did not play a major role in the dispersal of either species, the future direction of dispersal from eastern Kazakhstan to northwestern China was similar to the movement of the west wind. Under both climate scenarios, the size of suitable area for the host plant species will decrease by about 60% in the future. In contrast, the size of the suitable area for moth species tends to increase, but under the RCP585 scenario the increase would be small. In this study, we have shown that species living in arid and semiarid areas could shift their distribution following the distribution of their host plant species. However, in the future there could be a discrepancy between the distribution of the two species because they respond differently to climate change.