Examining venom variation in a centipede species complex Scolopendra morsitans from Peninsular India

Abstract

Integrative taxonomic framework incorporates evidence from multiple sources including morphological, molecular, behavioural, and ecological characters to provide a robust species hypothesis. In this context, we employ the use of multiple molecular markers and the ecologically functional trait ‘venom’ to throw light on the evolutionary relationships within the cryptic widely distributed centipede species Scolopendra morsitans. We examine the morphologically cryptic diversity through molecular phylogenetic and species delimitation analyses. We also look at the interspecific variation in venom within the Scolopendra morsitans species complex distributed across peninsular India. We used mitochondrial and nuclear marker datasets to reconstruct the molecular phylogeny and delimit the putative species within the species complex. Our results show that S. morsitans species complex is paraphyletic lineage harboring multiple distinct species. We find a monophyletic clade of S. morsitans from peninsular India and Southeast Asia, another distinct clade of S. morsitans from Odisha, western India, and Himachal Pradesh, and a distinct clade of African S. morsitans. The S. morsitans clade from peninsular India and Southeast Asia is named S. morsitans 1 while the other distinct clade from India is named S. morsitans 2. Both clades had three distinct species from India. We further characterized the venom using a proteo-transcriptomic approach and performed various diversity and ordination analysis to study the venom variation between these putative species. There was significant difference in the venom composition between the two major clades, however less so among the putative species within the peninsular Indian clade.