Climatic niche divergence in allopatry shapes the speciation among select scolopendrid centipedes in Peninsular India

Abstract

Deciphering the role of abiotic factors in the speciation process has been a major question in ecology and evolution. With its high spatial variation in geography and climate, peninsular India is an ideal setting to study the role of abiotic factors on the speciation process. Scolopendrid centipedes are a group of predatory soil arthropods with morphologically cryptic species pairs, indicating that abiotic factors could play an important role in their speciation process. This study assesses the geographic mode of speciation and the role of climate in two Scolopendrid genera, Ethmostigmus and Rhysida. Within these two genera, we ask if speciation has occurred via allopatry, sympatry, or parapatry and if we observe the signature of phylogenetic niche conservatism or niche divergence. We reconstructed robust species hypotheses for both genera using phylogenetic and species delimitation analyses. Based on the species trees, we selected four sister species pairs from Rhysida and a peninsular Indian clade of Ethmostigmus. We detected an allopatric mode of speciation within Ethmostigmus and three species pairs in Rhysida, driven by climatic niche divergence. These results are in concordance with the global pattern seen in small vertebrates. It will be interesting to test for the generality across clades and ecosystems.