In my post of August 10, we saw the marvel that the chrysalis of a butterfly is, and in my article of August 11, I described the anti-predatory measures of the caterpillar of the Common Mormon butterfly (Papilio polytes). If the caterpillar is so ingenious at fooling predators, can the butterfly that emerges from the chrysalis formed by it be far behind? No; in fact, the butterfly ratchets it up a notch higher!
The female of the Common Mormon has four forms or morphs and three of these forms display Batesian mimicry (a harmless organism ‘the mimic’ impersonating a harmful or toxic organism ‘the model’). The forms theseus and polytes mimic the Common Rose butterfly while the form romulus mimics the Crimson Rose butterfly. Both the Common Rose and Crimson Rose butterflies are toxic and unpalatable to predators as their bodies have toxic alkaloids accumulated from the host plants on which their caterpillars have fed off. Hence imitating these noxious butterflies saves the day for the harmless Common Mormon! Interestingly the fourth form, cyrus – which is non-mimetic, is mostly abundant where the Common Rose or the Crimson Rose do not occur.
There is much debate on why only the female of the Common Mormon exists as morphs and mimics for survival and not the male. There may be three reasons for this: 1) The female is more precious – she’s the one carrying the eggs! 2) The female is slightly slower than the male because she is slightly larger and heavier (think – larger wings to carry the heavy load of eggs) making her an easier prey. The wider abdomen of the female also makes her appear as sumptuous food to the predators. 3) The female identifies a male by certain physical traits to recognise the species before approaching him. If the male would also exist in numerous forms it would mean confusion in recognition and lesser chances of mating. It’s all so logical in nature!
Now, as promised, here are the pictures of the female Common Mormon butterfly (Papilio polytes romulus) that emerged from that chrysalis!
– Narendra Nayak © 2018