The price of defence: toxins, visual signals and oxidative state in an aposematic butterfly



Blount, Jonathan D, Rowland, Hannah M, Mitchell, Christopher, Speed, Michael P ORCID: 0000-0001-8162-2052, Ruxton, Graeme D, Endler, John A and Brower, Lincoln P
(2023) The price of defence: toxins, visual signals and oxidative state in an aposematic butterfly. PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 290 (1991). 20222068-.

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Abstract

In a variety of aposematic species, the conspicuousness of an individual's warning signal and the quantity of its chemical defence are positively correlated. This apparent honest signalling is predicted by resource competition models which assume that the production and maintenance of aposematic defences compete for access to antioxidant molecules that have dual functions as pigments and in protecting against oxidative damage. To test for such trade-offs, we raised monarch butterflies (<i>Danaus plexippus</i>) on different species of their milkweed host plants (Apocynaceae) that vary in quantities of cardenolides to test whether (i) the sequestration of cardenolides as a secondary defence is associated with costs in the form of oxidative lipid damage and reduced antioxidant defences; and (ii) lower oxidative state is associated with a reduced capacity to produce aposematic displays. In male monarchs conspicuousness was explained by an interaction between oxidative damage and sequestration: males with high levels of oxidative damage became less conspicuous with increased sequestration of cardenolides, whereas those with low oxidative damage became more conspicuous with increased levels of cardenolides. There was no significant effect of oxidative damage or concentration of sequestered cardenolides on female conspicuousness. Our results demonstrate a physiological linkage between the production of coloration and oxidative state, and differential costs of sequestration and signalling in monarch butterflies.

Item Type: Article
Uncontrolled Keywords: aposematism, cardenolides, Danaus plexippus, honest signalling, oxidative lipid damage, resource competition
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology > School of Life Sciences
Depositing User: Symplectic Admin
Date Deposited: 21 Apr 2023 09:11
Last Modified: 21 Apr 2023 09:11
DOI: 10.1098/rspb.2022.2068
Open Access URL: https://doi.org/10.1098/rspb.2022.2068
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3169834