Predictions based on phylogeography and climatic niche modelling depict an uncertain future scenario for giant blister beetles (Berberomeloe, Meloidae) facing intensive greenhouse expansion and global warming

Abstract

Abstract Large‐scale agricultural and tourism development are the main threats to biodiversity in south‐eastern Spain. Species with low dispersal abilities, such as some endemic insects from this region, are particularly vulnerable to fragmentation and loss of genetic and morphological diversity. Here, we studied the current and future threat of climate and land‐use change on the intraspecific diversity of one such group of endemics, the giant blister beetles of the Berberomeloe insignis species group. Using a phylogeographic approach and morphometrics, we identified intraspecific variation within the B. insignis species group. These data were coupled with ecological niche modelling (ENM) to determine the effect of agricultural and climate change on the connectivity across phylogroups. We identified a marked geographic structure within B. insignis, with the time to the most recent common ancestor (TMRCA) of the two main mtDNA clades dating back to 2.1 Ma. Cyto‐nuclear discordances found across parapatric populations suggest past events of genetic introgression. B. insignis presents a head pattern that is geographically structured and mostly congruent with the four mitochondrial lineages. In contrast, diversification within Berberomeloe tenebrosus is more recent, dating back to less than 1 Ma. Future ENMs highlight the role of mountains as potential refugia under a climate warming scenario but predict extinctions in the lowlands. Based on our analyses, two lineages of B. insignis are threatened and should be urgently considered as independent conservation units, and their current geographic distribution areas protected to conserve, at the very least, a portion of the species' evolutionary heritage.