There are various hypotheses as to how the Pitohui, I. kowaldi, and dendrobatid frogs acquired their toxicity. What is one unifying theory?
According to the cited reference, “It is proposed that melrid beetles may be a source of batrachotoxins as they are observed to be part of the diet of Pitohui and I. kowaldi. In addition, melrid beetles are also found in Colombian rainforests, which could link the similarities in toxicity with these birds and poisonous dendrobatid frogs despite being indigenous to different continents. An alternative theory is that both birds and beetles acquire toxins through a plant source, however, the Pitohuis are omnivorous making this plant theory less likely.”
Yeung KA, Chai PR, Russell BL, Erickson TB. Avian Toxins and Poisoning Mechanisms. J Med Toxicol. 2022 Oct;18(4):321-333. doi: 10.1007/s13181-022-00891-6. Epub 2022 Apr 26. PMID: 35474563; PMCID: PMC9492810.