Sex-based venom variation in the eastern bark centipede (Hemiscolopendra marginata)

Area of Science:

• Zoology
• Biochemistry
• Evolutionary Biology

Background:

• Sexually dimorphic traits are common in animals, often due to genetic or gene expression differences.
• Intersexual venom variation is known in scorpions and spiders, but not previously reported in centipedes.
• Centipede venom research has shown intraspecific variation, but sex-based differences remained unexplored.

Purpose of the Study:

• To investigate potential sex-based differences in the venom composition of the eastern bark centipede, *Hemiscolopendra marginata*.
• To identify the genetic basis for any observed sex-based venom variation using transcriptomic and proteomic analyses.

Main Methods:

• Reversed-phase high-performance liquid chromatography (RP-HPLC) was used to analyze venom from male and female *H. marginata*.
• High-throughput venom-gland transcriptomic and venom proteomic analyses were performed on male and female specimens.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to confirm identified toxins.

Main Results:

• Significant sex-based differences in venom composition were detected in *H. marginata*.
• 47 proteomically confirmed toxins and 717 nontoxin transcripts were identified in venom glands.
• Male venom showed higher abundance of ion channel-modulating toxins and unclassified divergent toxins, while female venom had more γ-glutamyl transferases and CAPs (cysteine-rich secretory proteins).

Conclusions:

• This study provides the first evidence of sex-based variation in centipede venoms.
• The findings highlight the importance of considering sex in venom composition studies and have implications for understanding venom evolution and function.