On 1 May, a sizable population of caterpillars (Fig. 1) was discovered at the balcony area. A total of 26 were observed feeding on a Malayan Mistletoe (Dendrophthoe pentandra). The mistletoe was growing on a potted Indonesian Bay Leaf (Syzygium polyanthum). These caterpillars are from the Painted Jezebel (Delias hyparete metarete) butterfly.

1 May 2025	7 May 2025	12 May 2025	16 May 2025
Fig. 1: Observations of caterpillars of Painted Jezebel butterfly over time

In March 2015, I observed eggs of this butterfly on a Malayan Mistletoe growing on a potted Calabur Tree (Muntingia calabura) at the same balcony area. Unfortunately, I noticed them only after cutting down the small tree with the mistletoe on it, and had to dispose of them as I did not have the resources to raise them.

Fig. 2: A branch of mistletoe procured to feed the caterpillars

This occasion is distinct. I am prepared to host them on my mistletoe plant in the pot. After 17 days on May 17th, the mistletoe on the Indonesian Bay Leaf plant had depleted its leaves. At that time, six final (5th) instar caterpillars remained. It appeared they would need to feed for another day or two before pupating. Fortunately, I was able to procure a fresh branch of mistletoe (Fig. 2). I hung the mistletoe on the Indonesian Bay Leaf plant close to the caterpillars. Two of them proceeded to crawl onto the new mistletoe branch and consumed a few bites of the leaves. The remaining caterpillars did not exhibit any appetite.

Fig. 3: A pre-pupatory stage caterpillar under the leaf of the Vitis vine	Fig. 4: A pupa under the leaf of the procured mistletoe plant

The following day, I observed four stationary caterpillars in the pre-pupatory stage (Fig. 3) distributed at four different locations along the balcony area. Each caterpillar had positioned itself on the underside of leaves: one on the new mistletoe branch, another on the Indonesian Bay Leaf, and the remaining two on a Vitis species (family Vitaceae). The Vitis species is likely a grape vine. It is an abandoned potted plant that I have rehabilitated from a leafless root stock. Initially, when it began to produce its first few leaves, I mistook it for a Begonia species (family Begoniaceae).

On 19 May, three of the four caterpillars transformed into pupae (Fig. 4). On 21 May, it was observed that the pupation of the last caterpillar did not succeed, and the carcass attached to the Vitis species attracted several Ghost Ant (Tapinoma melanocephalum).

(a) Leafy mistletoe at the start of the invasion	(b) Leafless mistletoe at the end of the invasion
Fig. 5 (a-b): Appearance of the mistletoe plant on the Indonesian Bay Leaf at the start and end of the caterpillars' invasion

By 20 May, the leaves on the new mistletoe branch had begun to dry up and fall off. I salvaged the leaf where the pupa was attached and placed it in an open transparent container. According to a publication from 2017 [1], the transformation of the pupa into a butterfly takes approximately 9 days. Thus, for my cohort of three, this event is expected to occur around 29 May. Regarding the mistletoe on the Indonesian Bay Leaf (Fig. 5) that has been significantly consumed, I am hopeful it will recover from the attack and produce new leaves.

The life cycle of the Painted Jezebel butterfly has been documented on the Butterflies of Singapore website and described in the 2017 publication [1]. The publication referenced a source from 2001 [2] which listed several plants such as bilimbing (Averrhoa bilimbi), coconut (Cocos nucifera), mango (Mangifera indica), rambutan (Nephelium lappaceum), and sweet sop (Annona squamosa) as food plants for the caterpillar of this butterfly. However, there is no similar documentation supporting these plant species as host plants. It is possible that these plant species hosted the Malayan Mistletoe, which is the actual host plant for this caterpillar, and the mistletoe may have been mistaken to be a branch of those mentioned plant species.

Reference:

[1] Wee YC, Ng A. Life history of the painted jezebel, Delias hyparete Linnaeus, 1758 (Order Lepidoptera). Nature in Singapore 2017;1:103-108. | Read article |

[2] Robinson GS, Ackery PR, Kitching IJ, Beccaloni GW, Hernandez LM. Hostplants of the moth and butterfly caterpillars of the oriental region. Natural History Museum, London and Southdene Sdn. Bhd., Kuala Lumpur. 2001. 744 pp.