Cardenolides in the defensive fluid of adult large milkweed bugs have differential potency on vertebrate and invertebrate predator Na+/K+-ATPases
Rubiano-Buitrago P, Pradhan S, Aceves AA and others. Royal Society open science, June 2024.
Read the paper Free to read · doi:10.1098/rsos.231735
What this paper is about
Large milkweed bugs squirt a defensive fluid when attacked, and it contains several different cardenolides rather than one. The authors measured which compounds are in the fluid and tested each against the sodium-potassium pumps of different predators.
The compounds were not equally toxic to all of them, which suggests the mixture is doing more than one job.
Summarised here from the abstract below. Not the authors’ words.
Abstract
Aposematic animals rely on diverse secondary metabolites for defence. Various hypotheses, such as competition, life history and multifunctionality, have been posited to explain defence variability and diversity. We investigate the compound selectivity hypothesis using large milkweed bugs, Oncopeltus fasciatus, to determine if distinct cardenolides vary in toxicity to different predators. We quantify cardenolides in the bug's defensive secretions and body tissues and test the individual compounds against predator target sites, the Na+/K+-ATPases, that are predicted to differ in sensitivity. Frugoside, gofruside, glucopyranosyl frugoside and glucopyranosyl gofruside were the dominant cardenolides in the body tissues of the insects, whereas the two monoglycosidic cardenolides-frugoside and gofruside-were the most abundant in the defensive fluid. These monoglycosidic cardenolides were highly toxic (IC50 O. fasciatus probably provide consistency in protection against a range of predators and underscore the need to consider predator communities in prey defence evolution.
Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.
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title = {Cardenolides in the defensive fluid of adult large milkweed bugs have differential potency on vertebrate and invertebrate predator Na+/K+-ATPases (listing)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/research/cardenolides-in-the-defensive-fluid-of-adult-large-milkweed-2024/},
note = {Accessed DATE}
}