This week's butterfly is rare. It may always have been rare. Pachliopta (or Papilio or Menelaides or Atrophaneura) oreon has been found in nature only on some of the smaller islands in Indonesia, the Lesser Sunda group. It's not on the endangered species list because nobody knows for sure how rare it's meant to be.
Photo donated to Naturalista.mx by James Lambo. Most web sites show images of museum specimens; it's instructive to compare these photos from Insecta.pro, which show how rapidly and drastically these butterflies fade. Even living Atrophaneuras often fade from iridescent black to subtle shades of brown and gray, and discussions of this species in Spanish describe the main color as pardo, fusco, and oscuro rather than negro.
Butterflies really need to be "collected" alive in order to look like anything, and fortunately most of them now are collected by camera...but oreon has seldom been seen by anyone who had a camera.
Oreon is big, with a wintspan between four and five inches, and showy. In 1891, W. Doherty described it as "a local form of P. liris." He observed no obvious difference between males and females. It:did not occur to him to take the dead bodies apart and examine the proportions of their inner parts under a microscope, which is how scientistis identify some similar-looking moths and butterflies today. As with the other Red-Bodied Swallowtails, females are usually a little bigger than males, sometimes much bigger, but individuals vary enough that both of a couple may be the same size.
In 1895 Walter Rothschild reported that he'd seen oreon, too, and believed they were a distinct species, though he admitted they looked like a sort of combination of features from pandianus nad liris. The shape and markings were consistently different enough from liris to justify calling it a separate species, he reasoned--quite wrongly. Some butterflies that look like completely different species, including some of the swallowtails, are the same species as its development is influenced by its environment.
The Rothschilds, as meddling Europeans who wanted to divide and conquer the United States, were the leading villains in the history of the American Civil War so it's pleasant to note that even Walter, the peaceful naturalist in the family, was wrong. He seems to have been correct, though, in guessing that oreon would be a distinct species. So far nobody has found that oreon can morph into a closer resemblance to another species under different environmental conditions, nor that it's apt to crossbreed with another species. It behaves like a distinct species. If it really is one, it's always been rare.
Doherty also observed that, while being exposed to this rarity and also to butterflies in the Birdwing and Monarch groups, the islanders regarded these butterflies as ordinary. Another big, dark Swallowtail, Papilio memnon, which is still listed in the genus Papilio today, was the one they considered most interesting. The Memnon, or Mormon, or Great Mormon, was considered sacred--though not so sacred that the islanders interfered with Doherty killing a few specimens for his collection. Money has always been of great benefit to science.
Perhaps because he wasn't sure it was a distinct species, Doherty gave oreon a name that's unusual in the Atrophaneura group--neither a living person's name, nor the name of a character in ancient literature, nor the name of a specific place where it was found. Then again, he might have been thinking of Orion. Both oreon and "Orion" mean "of the mountains." Pachliopta oreon lives among wooded hills. Like the other Red-Bodied Swallowtails it thrives in the deep shade of the rain forest, where their subtle, greyscaled dark wings can look wonderfully mysterious, a patch of shade that seems indefinably more mobile than the shade around it.
Last week's butterfly was a somewhat rare species about which a Blogspot blogger may have been the first to document information about its life cycle. That story illustrated the importance of private blogs. This week's butterfly research brings up a reminder of the need to read things on the Internet with a certain skepticism. A blogger, who shall be nameless here, posted this picture on Pinterest and labelled it Pachliopta oreon.
An excellent picture, clear enough to show all the field marks of the more common Crimson Rose, P. hector. They are similar enough that scientists assume they could be forced to hybridize (though I'm not finding any indication that anyone's done it), but the complete double border of red spots is typical of hector; oreon has a single border.
The life cycle of Pachliopta oreon may have been documented for the first time in 2022, by Trevor Lambkin, in a paper that is free for the downloading from ResearchGate. The PDF version uses formatting that's easy to view, but copy-resistant, in Chrome. Other programs can probably copy Lambkin's pictures but I think they're new enough that he has a right to feel possessive about them. His photos show that at all stages of its life this animal is easily recognized as a Pachliopta with only slight visible differences from others of its species.
Lambkin found that, although the forest on Flores island had lost its big old trees and been invaded by a non-native vine, the forest was still supporting about eighty different kinds of butterflies, including the island's specific subspecies of P. oreon, godmani. (A hundred years ago, naturalists thought Godman's Rose was a different species from the Mountain Rose, but they're now regarded as two of several subspecies.) Pachliopta oreon godmani flies in the wetter season, November to April. It is a pollinator species, attracted to lantana flowers. Males often fly high, probably thinking they are patrolling their territory. Females tend to fly lower, spending more time looking for unused vines on which to place their eggs.
The egg is a little round bead, slightly flattened at the top, with the usual droplets of aristolochic acid adding texture at the sides.
The caterpillar is reddish-brown to black, with pale orange to red tubercles. It looks designed to say to birds, nonverbally, "Another bird already ate me and it was very sorry. You do not want to eat me." Viewed head-on, its actual face--eyes, mouth, tiny proto-antennae--is turned down in line with its feet, but the back of its head and upper body suggest a sort of false face with bright red glaring eyes. The false-eye spots are on the upper segment that widens behind the head--where the upper thorax of the butterfly is going to be, or what would be its shoulders, if caterpillars had shoulders. It's large for a caterpillar, up to three inches long with a head about a quarter-inch across.
Lambkin didn't find pupae. He may not have looked in the right places, or it may turn out that the pupae look different from the typical Pachliopta pupa, which is pale brownish orange, flattened, with some tubercles remaining and making it look from a distance like a tattered dead leaf/
In 2015 the late Danny Burk and Mark Goode reportedly described another island's sbspecies, P. oreon batuata, in a paper that's not available on the Internet:
Burk maintained a web site, while living, where he discussed his studies of primarily Delias butterflies (he used "deliasfanatic" as a screen name). His web site apparently still exists but is not open to the public.
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