Hemiscolopendra marginata, the eastern bark centipede, is a common species of centipede found in the Eastern United States and parts of Mexico. The species commonly shelters beneath loose bark on dead or fallen trees. H. marginata is the first centipede species shown to exhibit sexual dimorphism in venom composition.
Hemiscolopendra marginata is a moderate-sized scolopendrid centipede. Examined specimens have ranged from 27.8 to 54.8 mm in length and 2.7 to 7.8 mm in width. The species lacks the distoventral spur on the first tarsi of the ambulatory legs, a feature that distinguishes it from species of Scolopendra.
Hemiscolopendra marginata is a predatory species that primarily feeds on invertebrates, typically found beneath loose bark or within decaying wood. Like several other centipede species, females exhibit maternal care, guarding eggs and early juveniles.
Research has demonstrated that Hemiscolopendra marginata exhibits sex-based differences in venom composition. A 2019 study using chromatographic, transcriptomic, and proteomic analyses found that male and female individuals produce venoms with substantially different toxin profiles. Male venom was dominated by ion-channelâÂÂmodulating toxins and several previously undescribed toxin types, whereas female venom contained higher concentrations of ó-glutamyl transferases and CAP proteins (cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins). This study represents the first documented example of sexual variation in venom composition in a centipede.