Harlequin frogs, a group of brightly colored, small-sized amphibians found in the rainforests of Central and South America, have a unique and intriguing relationship with fungi, particularly in the context of combating the devastating infectious disease known as chytridiomycosis. These frogs are known for their striking coloration, which serves as a warning signal to potential predators due to their toxic skin secretions. What makes their connection to fungi fascinating is that many species of Harlequin frogs rely on specialized skin bacteria that produce potent antifungal compounds. In the face of the deadly chytrid fungus (Batrachochytrium dendrobatidis), which has decimated amphibian populations worldwide, these frogs' skin microbiota, particularly the beneficial fungi-fighting bacteria, help protect them from infection. This symbiotic relationship highlights the intricate ways in which nature's partnerships can provide essential defenses against environmental threats.
Interestingly, bullfrogs (family: Ranidae) can also carry the chytrid fungus but do not typically develop the disease. As a result, they act as vectors for the pathogenic fungi, spreading it to other types of amphibians that are vulnerable. A study reported in 2006 found that introduced bullfrogs in every country except Japan carried the chytrid fungus[1].
