Oral Presentation The 16th Australian Peptide Conference 2025

Dynamic evolution of venom composition in slug moth caterpillars (128458)

Andrew A Walker 1 , Cheong Xin Chan 2 , Lucas Micheels 3 , Tabitha Taberer 4 , Marc E Epstein 5 , Glenn F King 1
  1. Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
  2. School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
  3. Department of Biological Sciences, George Washington University, Washington, Washington, DC, United States
  4. Department of Biology, University of Oxford, Oxford, United Kingdom
  5. California Department of Food and Agriculture, Sacramento, California, United States

Slug moth caterpillars (Lepidoptera: Limacodidae) produce defensive, pain-inducing venoms. Recently, we found that some limacodid species such as the painted wing cupmoth caterpillar Doratifera vulnerans1 and saddleback caterpillar Acharia stimulea2 produce venoms consisting mostly of bioactive peptides. In contrast, the Townsville electric caterpillar Comana monomorpha3 produces venoms dominated by aerolysin-like pore-forming toxins, which we previously thought occurred only in venoms produced by asp caterpillars in the related family Megalopygidae.4

To elucidate how venom composition has evolved in family Limacodidae, we resolved 16 additional venom proteomes from a wider phylogenetic breadth using venom spine transcriptomics and venom proteomics. We also sequenced, assembled, and compared the genomes of D. vulnerans (Limacodidae) and M. opercularis (Megalopygidae).

These data reveal that the ancestral state in Limacodidae is venom rich in aerolysin-like toxins and disulfide-rich peptides similar to von Willebrand factor and Kazal domain peptides. In the earlier diverging lineages “4” and “5”,5 aerolysin-like toxins are abundant, and disulfide-rich peptides are of either ancestral types or inhibitor cystine knots. Most species in the advanced “lineage 6”5 show reduced or absent aerolysin-like toxins, but massively expanded repertoires of inhibitor cystine knots and neurohormone-like peptides. Some atavistic species in lineage 6 possess aerolysin-like toxins, of which C. monomorpha is the most extreme. We are now producing a library of disulfide-rich peptides from limacodid venoms via chemical synthesis and recombinant expression, which we plan to pharmacologically test for their ability to modulate physiological processes related to pain, inflammation, and epilepsy.

References

1 A. A. Walker, S. D. Robinson, et al., and G. F. King. PNAS, 2021, 118, e2023815118.

2 M. H. Goudarzi, D. A. Eagles, et al., and A. A. Walker. Biochem. Pharmacol., 2023, 213, 115598.

3 M. H. Goudarzi, S. D. Robinson, et al., and A. A. Walker. Sci. Rep., 2024, 14, 14172.

4 A. A. Walker, S. D. Robinson, et al., and G. F. King. PNAS, 2023, 120, e2305871120.

5 Y-C. Lin, R-J. Lin, M. F. Braby, and Y-F. Hsu. Ecol. Evol., 2019, 9, 9827.