The 14th of March is ‘Learn About Butterflies Day’ and to that, we say “YES, PLEASE!” There are innumerable facts and fascinating titbits we could delve into about how these mystical creatures use beauty as a lure, a temperature regulator, a disguise, and even a weapon. As this is a blog and not a book, let’s zoom in on one: how these butterflies use colour as a weapon.
Photographs © Adrianna Calvo & Cindy Gustafson (pexels)
Colour Defence & Camouflage
While undeniably exquisite, the bright and attractive colouration of butterflies is not solely for aesthetic appeal. It is a crucial and multifaceted aspect responsible for guaranteeing the survival of these iconic insects. One value of striking colour is to warn potential enemies against harming them. The scientific term for this is ‘aposematic colouration’ and it serves to alert any predators that this creature is unpalatable and should not be ingested.
To survive in the wild, different creatures possess different methods of colour defence. The one most widely understood is the camouflage tactic. By making use of cryptic colouration, an animal aims to disguise its appearance and blend into its surroundings. Think of the rosettes of a leopard and how they serve to conceal the animal as it moves through dappled light. Or the interrupted stripes on a kudu, that break the outline and enable it to move, in a ghostlike fashion, through the bush. Butterflies make use of camouflage at times, but they also make use of a strategy known as mimicry. Where camouflage aims to make an animal appear as an inanimate object, mimicry aims to make one species resemble another. Of this, the butterfly is an expert.
There are several ways in which butterflies use mimicry to deter potential predators. Let us have a look at three forms of mimicry used by the various butterflies of the Lowveld:
- Batesian mimicry is when one nontoxic species (known as the mimic) imitates the aposematic markings of another toxic species (known as the model). In the butterfly world, we see this most commonly with the African Monarch butterfly and the female Common Diadem butterfly. The Common Diadem is non-toxic, making it a delicious snack for opportunistic predators. The African Monarch, in contrast, is toxic and highly unpalatable to those who are seeking a butterfly snack. By mimicking the colouration of the African Monarch, the Common Diadem deters predators by giving the illusion of being toxic without actually being toxic.
Photographs © Sandy Millar & Tanuj Dargan(Unsplash)
- Mullerian mimicry differs from Batesian mimicry in that both the model and the mimic (the term used is ‘co-mimics’) are unpalatable. The benefit of using mimicry in this instance is to increase the survival rate of each species. If every toxic species looked vastly different from the next, predators would not be as proficient in associating certain colours with unpleasant rancidity and thus would be inclined to ‘test taste’ more frequently. The effectiveness of Mullerian mimicry is that the predator only needs to taste one individual before it realises that all those that appear a certain way, are not to be consumed.
- As if mimicking different species is not ingenious enough, some species of butterfly practice a mimicry known as ‘self-mimicry’. Self-mimicry is slightly different from Batesian and Mullerian mimicry as it is the process of misleading a predator’s attack by putting the ‘bull’s eye’ on a less threatening part of the body. Markings that resemble eyes on the wings or flimsy ‘tails’ on each hindwing that resemble antennas are two adaptations some species implement to confuse predators by detracting from the head. A butterfly has a much better chance of surviving an attempted attack to the wings than it does of surviving an attack to the head.
Photographs © Gayatri Malhotra & Anne Lambeck (Unsplash)
Beauty & Grace
Butterflies are synonymous with beauty and grace, this is why little girls accessorise with them, why artists use them as a muse, and why certain cultures associate them with a graceful departure into the afterlife. As we dive into the ornate nature of butterfly colouration, we discover that a butterfly is so much more than just a pretty face. Having barely skimmed the surface of functional beauty in the world of butterflies, we think it might be handy to have a ‘Learn About Butterflies Month’ but for now, we’ll take what we’ve been given and celebrate butterflies!
About the Author:
Victoria Craddock a past apprentice Field Guide student of EcoTraining and freelance Blogger.