Seeing UV colors is common for butterflies, but in some species, it is a female-only power

So, you may or may not know that many butterflies can actually see in UV light. It is very cool and I'm definitely not jealous that they get extra colors. It's helpful to them because many flowers have UV patterns on them (invisible to us) that let the butterflies know that they're a good source of food. The plants get pollinated and the butterflies get to eat. Everybody wins. This is a simulated version of what butterflies might see when they look at a flower.

Some butterflies, such as the zebra longwing pictured above, only display this trait in females. Because of this, male and female butterflies will tend to visit different types of flowers. But scientists have just recently figured out how this difference came to be, evolutionarily speaking.

Obviously many species have sexually dimorphic traits, some more prominently than others. There are also cases in which one sex develops a trait that is just... less useful than the other, like this case with the UV vision. Almost all butterflies can see in the UV spectrum, so it follows that at some point in the evolutionary line the male zebra longwing butterflies lost that particular ability. There are multiple ways that this sort of thing can happen, and the article covers them briefly, but after sequencing the genome for these butterflies they found that none of those previously seen explanations were the case.

Basically, we already know the gene that causes UV vision in butterflies. It is called the opsin gene. In zebra longtail butterflies, this gene occurs on the chromosome W, which is the female sex chromosome. That means that sometime in history, this gene just jumped from a normal chromosome onto the female-only chromosome, and has locked the male butterflies out of this ability ever since. This is the first time we have seen a gene do a jump like that, and it is pretty cool.

But anyway, appreciate the girlpower of zebra longwing butterflies getting all the UV vision, and take a look at the study! It's free to read, which is really nice to see.