Toxin structure shapes palatability in a chemically defended butterfly
- 1University of Cambridge
Abstract
The toxicity of chemical defences is well studied, but the potential contribution of compound structure to predator deterrence remains largely unexplored. Whether predation acts more strongly on toxicity or unpalatability remains largely untested, partly because few systems allow toxin structure to vary independently of quantity. Heliconius sara larvae provide such a system: those reared on Passiflora auriculata sequester cyclopentenyl cyanogenic glucosides (CGs), while those reared on P. biflora biosynthesise comparable quantities of aliphatic CGs. Using two invertebrate predators, Camponotus floridanus ants and Hierodula membranacea mantids, we tested whether this structural difference affects palatability independent of toxicity. Mantids rejected larvae with cyclopentenyl CGs more often than larvae with aliphatic CGs, despite no detectable difference in total CG content. This pattern was mirrored in extract-based assays with ants, independently of cyanide release: extracts with cyclopentenyl CGs remained deterrent, while extracts with aliphatic CGs did not differ in deterrence from water. Live larvae, by contrast, elicited similar responses from ants regardless of CG structure. These results show that variation in toxin structure can strongly affect palatability, with some compounds conferring greater protection than others. This demonstrates the importance of chemical structural diversity in the evolution of chemical defences.
Related
- Elephant Presence Shapes Butterfly Communities in an East African Coastal Forest
- araucan regulates butterfly wing iridescence by coordinating scale structure and pigmentation
- Abundance-driven processes best predict plant-butterfly network structure across a forest-to-agriculture gradient
- Ecosystem community structure shapes carbon dynamics in the ocean
- Causal event structure shapes convergent reactivation signatures in human cortex and language model
BibTeX
@misc{todd2026toxin,
title = {{Toxin structure shapes palatability in a chemically defended butterfly}},
author = {E. Todd and A. Denton and D. Halali and G. E. Julian and A. LeBoeuf and C. Jiggins and E. C. P. de Castro},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.18.751997},
url = {https://www.biorxiv.org/content/10.64898/2026.09.18.751997v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Toxin structure shapes palatability in a chemically defended butterfly
AU - E. Todd
AU - A. Denton
AU - D. Halali
AU - G. E. Julian
AU - A. LeBoeuf
AU - C. Jiggins
AU - E. C. P. de Castro
PY - 2026
DA - 2026/09/18
PB - bioRxiv
DO - 10.64898/2026.09.18.751997
UR - https://www.biorxiv.org/content/10.64898/2026.09.18.751997v1
AB - The toxicity of chemical defences is well studied, but the potential contribution of compound structure to predator deterrence remains largely unexplored. Whether predation acts more strongly on toxicity or unpalatability remains largely untested, partly because few systems allow toxin structure to vary independently of quantity. Heliconius sara larvae provide such a system: those reared on Passiflora auriculata sequester cyclopentenyl cyanogenic glucosides (CGs), while those reared on P. biflora biosynthesise comparable quantities of aliphatic CGs. Using two invertebrate predators, Camponotus floridanus ants and Hierodula membranacea mantids, we tested whether this structural difference affects palatability independent of toxicity. Mantids rejected larvae with cyclopentenyl CGs more often than larvae with aliphatic CGs, despite no detectable difference in total CG content. This pattern was mirrored in extract-based assays with ants, independently of cyanide release: extracts with cyclopentenyl CGs remained deterrent, while extracts with aliphatic CGs did not differ in deterrence from water. Live larvae, by contrast, elicited similar responses from ants regardless of CG structure. These results show that variation in toxin structure can strongly affect palatability, with some compounds conferring greater protection than others. This demonstrates the importance of chemical structural diversity in the evolution of chemical defences.
ER -