Mimicry is a form of deception employed by some animals to resemble other, more dangerous or unpalatable species, thereby reducing their chances of being preyed upon. In the case of butterflies, certain species have evolved to mimic the warning signals of toxic or unpalatable butterflies, thereby deterring predators that have learned to avoid these dangerous insects.
The researchers, led by Assistant Professor Marcus Kronforst from the NUS Department of Biological Sciences, focused on two closely related species of butterflies found in Southeast Asia, Hypolimnas bolina and Hypolimnas misippus. These species exhibit different mimicry patterns, with H. bolina mimicking the toxic Danaus chrysippus butterfly, and H. misippus mimicking the unpalatable Euploea core species.
To understand the genetic basis of this mimicry difference, the researchers conducted a series of experiments involving genetic crosses between the two butterfly species. They identified a single genetic locus, known as the "mimicry supergene," that controls the expression of mimicry genes. This supergene contains a cluster of genes that are involved in wing patterning and coloration, and its activation or repression determines the specific mimicry pattern displayed by the butterfly.
Further analysis revealed that this mimicry supergene is regulated by a genetic switch—a small DNA region that controls the expression of the supergene's genes. This switch acts as a master regulator, determining whether the butterfly adopts the H. bolina or H. misippus mimicry pattern.
The findings of this study provide important insights into the genetic basis of mimicry in butterflies and highlight the role of genetic switches in controlling complex phenotypic traits. The researchers suggest that similar genetic mechanisms may be responsible for mimicry patterns in other animal species, opening up new avenues for exploring the evolution and diversity of mimicry in nature.
