How do signals evolve and why do they vary?
Oncopeltus fasciatus on Asclepias tuberosa. Image Martin LaBar
Aposematic prey advertise their toxicity with conspicuous warning signals. Aposematic animals often have variable warning signals and differ in the quantity and the profile of specific defensive chemicals. Despite over 150 years of investigation, the evolution and maintenance of this variability is still described as paradoxical. In research funded by the International Max Planck Research School, we have studied the warning signals, the composition of chemical defences, and the effectiveness of these defenses against different predators using the large milkweed bug Oncopeltus fasciatus. This research combines chemical, behavioural, and ecological explanations for the evolution of aposematism.
Publications
Rubiano-Buitrago, R., Pradhan, S., Aceves-Aparicio, A., Mohammadi, S., Paetz, C., Rowland, H. M. Cardenolides in the defensive fluid of adult large milkweed bugs have differential potency on vertebrate and invertebrate predator Na+/K+–ATPases. Authorea https://doi.org/10.22541/au.169658664.45852491/v1
Rubiano-Buitrago, P., Pradhan, S., Grabe, V., Aceves-Aparicio, A., Paetz, C., & Rowland, H. M. (2023). Differential accumulation of cardenolides from Asclepias curassavica by large milkweed bugs does not correspond to availability in seeds or biological activity on the bug Na+/K+-ATPase. Frontiers in Ecology and Evolution, 11, 1175205.
Heyworth, H. C., Pokharel, P., Blount, J.D., Mitchell, C., Petschenka, G., Rowland,H.M. Antioxidant availability trades off with warning signals and toxin sequestration in the large milkweed bug (Oncopeltus fasciatus). Ecology and Evolution, 13, e09971. https://doi.org/10.1002/ece3.9971