Do you know that the availability of the butterfly's "host plant" is a butterfly species only chance of existence? The reason is the caterpillars of a butterfly can only survive by feeding themselves on very specific plant species.
Normally, a female butterfly will only lay its eggs only after looking for that particular plant. Sometimes in the wild, a female butterfly has to look very hard and even fly for many miles in order to find their "host plant". In an urban area, most butterfly host plants are hardly to be found anywhere therefore we will not see a variety of butterflies except for a few very common ones whereby their host plants are also commonly found.
Have you seen a caterpillar on your plants at home? That's usually its host plant.
As you come to understand better about butterflies, you would've also realised that the Yellow Birdwing butterfly can hardly be seen at all in the highly developed areas of Penang. Today, it is hard to believe that anyone has spotted a Yellow Birdwing in Georgetown, Bayan Lepas, Air Itam or other developed areas of Penang. But about 30 years ago, it was still so commonly sighted. So now what do you think has actually happened?
Here's a fact: The Yellow Birdwing has to lay its eggs on a plant called Aristolochia tagala in order for its caterpillars to stay alive and complete its life cycle. Today, this particular butterfly food plant is hardly found in any major developed areas of Penang (for sure), but what's worrying is that the plant is also hardly found in Penang's forest reserves (although some may still classify it as a common plant).
What do you think? Should we wait for both food plant and butterfly to dissappear? If there is one thing you can do to save this species from dissappearing from Penang, it is simply by planting more of this butterfly host plant...
The Aristolochia tagala
The Aristolochia tagala is also known as the Indian birthwort or Dutchman's pipe. The plant is a climber plant that survives well under normal sun. It is also well known for its medicinal values, and can be found in many countries. Its flowers are bisexual and it bears fruits all year long. Its fruit which is globular capsule in shape also produces plenty of seeds. It can be propogated by seed and through stem cuttings.
In fact, caterpillars of a few local butterflies feed on the leaves of this plant, namely the Yellow Birdwing, Common Rose and Batwing Butterfly. Therefore the Aristolochia tagala is also a host plant for these butterflies. So if we can plant more of this plant, we not only have the chance to save the Yellow Birdwing from being wiped out from the necessary developments in Penang but we get to save a few other swallowtail butterfly species as well.
Host Plant Fun Facts
- Caterpillars can only survive on a few specific plants known as host plants or food plants, and all other plants are poisonous or not very useful as food to them.
- Caterpillars of the Yellow Birdwing enjoys munching on the Aristolochia tagala but finds the Aristolochia elegans quite toxic!
- The adult Yellow Birdwing butterfly does not feed on its host plant, but on other flowering plants with nectar.