Over time, birds and other predators of butterflies have learned which are poisonous and which are not based on the patterns of their wings. While their enemies were making rules, however, safe-to-eat butterflies were compromising them by developing patterns similar to ones known for their toxicity.

With birds so fooled they don't even know it, it is up to scientists to make sense of the complicated process by which butterflies mimic the patterns of their poisonous counterparts -- and why 75 percent of female common Mormon butterflies, or Papilio polytes, express wing patterns resembling more toxic species and none of the men do.

A new study published Wednesday sought to find and analyze the gene or genes responsible for color patterns in Mormon butterflies, the Los Angeles Times reported.

Researchers expected to discover a "cluster of tightly linked genes" (or a similar cluster to the one past researchers found in another species of butterfly capable of mimicking) where "each individual gene was doing some sub-set of that color pattern, but they were so close together that they would all be inherited as a single unit," according to University of Chicago evolutionary biologist Marcus R. Kronforst

Instead of a cluster, Kronforst and colleagues deemed a single gene responsible, known as "doublesex" for its typical role in other insect species as the signifier of sex differentiation. In the Mormon, it serves another purpose.

Doublesex acts similarly to gene clusters by controlling thousands of different mutations. A better understanding of how it works will be the subject of future research. Locating it was the primary objective of the current study.

Kronforst hopes that further analysis of doublesex sheds light on why only females are capable of mimicry.

"If mimicry is helping these females survive, why on Earth aren't the males getting the same advantage?" Kronforst asked. "We simply do not understand the answer to that question."

Researchers wonder if there are hidden, adaptive features to the classic wing pattern -- similar to the malaria immunity for those with sickle cell anemia. Also, the fact that males can only recognize females of traditional patterns might in some way add to the explanation.