Chin’s Butterfly Gallery
Julia Heliconians mating (1) Julia Heliconians mating (2)
Dryas julia is an alien species introduced into Southeast Asia from the Neotropic Region through human agency.
The aliens have landed in my garden...
By Chin Fah Shin

THOSE TWO WERE making out in my garden when I found them on a sultry afternoon in September 2017. In an earlier time or age, one might have said the couple were caught in flagrante delicto. I must have startled them when I stumbled upon them thus engaged in the privacy of a mulberry bush, and they took off, one hanging onto the other, and then clung onto the garden's chain-link fence.
 I hurried indoors to fetch my camera and got a few shots of them before they flew off again. So I backed away and waited for them to settle down. Without disengaging, they returned to the leafy, shady mulberry bush to carry on what they were doing. I crept up to the bush and got another series of shots.
 While taking their photos, I had a good look at them and they truely pricked my curiousity. Their long and narrow forewings (compared to what the locals are equipped with) suggested that they were heliconids (from Family Heliconiidae). If they were, those two were really a long, long way from home. Later, after I have downloaded the images from my camera to a computer, I quickly flipped through some of my butterfly books and learned from one reference that has a photo match that they were of the species Dryas julia (also spelled iulia).
 Those two were indeed a very long way from their native "home" range in South and Central America, on the other side of the Globe from Puchong, Selangor, where my garden is located. My initial thoughts were that the parents or ancestors of those two, had escaped from or enroute to a butterfly park (or garden, or farm) in Malaysia and started to breed here where the climate and environment are similar to those in the Neotropic Region.
 All this remained a puzzle to me until early this year (2018) when I came across the Butterflies of Singapore blogsite and found two articles that deal directly with the subject of these illegal emigrants on wings.
 The first article, "Discovery of a new butterfly species on Pulau Langkawi" (dated 30 September 2009), details how some butterfly-watchers from Singapore found a couple of unfamiliar and tattered butterflies and managed to photograph one of them. It was later confirmed by Malaysian butterfly expert Dr. Laurence Kirton that the species was Dryas iulia (also spelled julia), new to Malaysia.
 The article mentions the possibility that this species might have escaped from a butterfly garden on the Thai resort island of Phuket as one of the Singaporeans had seen and taken photos
of the butterflies inside the "garden" and outside, near the hotel where they were staying. The article mentions two practices that might have contributed to this, releasing butterflies at weddings (instead of showering the newly-weds with rice confetti) and releasing butterflies at religious or other public events in Thailand. You can read the article here.
 The second article, titled "The Julia Heliconian's sambha continues" (dated 9 May 2015), features photos, taken by a Malaysian butterfly-watcher in Subang Jaya, of full-grown larvae, adults and ovipositing females indicating that the migrant species was thriving in Subang Jaya (which is just "next door" to Puchong). Also shown was the larval food plant Passiflora suberosa, an "invasive" weed. The article compares the recent southward migration of the Tawny Coster (Acraea terpsicore) and the Leopard Lacewing (Cethosia cyane) from Thailand through Peninsular Malaysia to Singapore with that of the Julia Heliconian. It posses the question when the alien species will arrive in Singapore and be added to its butterfly check-list. You can read the second article here.
 In my opinion, there is a vast difference in circumstances. Without human agency, the Julia Heliconian wouldn't have made it so far to this part of the world. The butterflies are airflown in the form of pupae or chrysalis from farms in South America over vast oceans and landmass. The adults which emerged from these imported pupae or chrysalis are released in large numbers without forethought or understanding or regard to the native fauna and flora and environment. IMHO that is unnatural; it is contrary to Nature's scheme of things.
 On the other hand, the Tawny Coster and Leopard Lacewing, with or without human intervention, were spreading within the zoogeographical zone where their habitats exist, just as some other species have done in the past, for example the Striped Albatross (Appias libythea) ... and that I believe is natural.
 A scientific study has been done, using DNA sequencing techniques, to determine the origin of the alien species which have now become naturalised over a wide area in peninsular Thailand. Comparative tests were carried out on genetic materials taken from specimens from that particular butterfly garden in Phuket with those taken from naturalised specimens in south Thailand and specimens from the species' natural range in South America. The study indicated that the naturalised butterflies and those from the butterfly garden are the same subspecies, modesta, found in Costa Rica. You can read about the scientific study here. ~ CFS, May 3, 2018.