Nature never ceases to hypnotize us with its beautiful creations. The dry leaf butterfly ( Gastropacha quercifolia) , for example, is among these natural wonders. It is a kind of moth that, when you look at it, looks like a dry leaf when it closes its wings . Contemplating it is simply spectacular. The inner part of its wings is full of color; but, if we see it closing its wings, the resemblance to a fallen leaf is amazing. It is difficult to differentiate them. It is a perfect camouflage.
Camouflage is a common defense mechanism within the animal kingdom, but it is undeniable that some animals do it better than others. This insect is a moth of the Lasiocampidae family that leads a kind of double life . On the one hand, it features vibrant shades of blue and burnt orange with black tips, and on the other side … they look like a dead leaf. Its wingspan is 50–90 mm and females are larger than males. We can locate it in Europe and North and East Asia.
How can a pretty butterfly look like a dead leaf at the same time? Its mimicry has been the subject of research, among others, by naturalist Alfred Russel Wallace who, according to Charles Darwin’s theory of evolution, wrote in the Westminster Review in 1867 that he suspected that butterflies developed this leaf-like appearance of life as an adaptation to evade the attention of hungry birds ; But exactly how they did it was a mystery in its day.
What is perhaps most striking is that their wings change according to the season. During the dry season, when they are less active, they are brighter and more like the dry leaves that would be found in the region. In the rainy season, these moths appear in duller hues and even develop “eye spots” on the lateral wings of the “leaves.” This is extremely useful because it deters birds, ants, and wasps from recognizing them as food. They go unnoticed in the animal world.
Specifically, the scientists found evidence of four different intermediate forms of this moth before this mode of camouflage evolved. By observing the small changes in the wings of these butterflies over time, as well as in those of 45 closely related species, they were able to put together the most complete evidence of gradual evolution by introducing a means of mimicry. They found that several related species shared an irregular plane of their wings, suggesting that the patterns observed in leaf mimicry have been inherited across species.
“The mimicry of the leaves in the wings of butterflies provides a striking example of complex adaptive characteristics and has led to speculation about how the wing patterns evolve into a close resemblance to the leaves in an ancestral way that did not resemble the leaves ”, comment the authors in their study published in the journal BMC Evolutionary Biology. “The imitation leaf patterns evolved gradually, rather than suddenly, from a non-mimetic ancestor [exhibiting no mimicry].”
Referencia: Suzuki, T.K., Tomita, S. & Sezutsu, H. Gradual and contingent evolutionary emergence of leaf mimicry in butterfly wing patterns. BMC Evol Biol 14, 229 (2014). https://doi.org/10.1186/s12862-014-0229-5
