This week's butterfly is found in Australia. Scientists call it Graphium choredon; Australians call it the Blue Triangle. Some also call them Bluebottles, after a British species of fly, not butterfly, that shows a similar color. Then there's Peacock, not because they have any resemblance to Europe's Peacock Butterflies (which we'll discuss in a few years; they're pretty) or Peacock Moth but because the actual peacock has blue and green spots on his tail feathers, and Wanderer, because they fly far and fast and high and can travel long distances.
Why choredon? It sounds like one of those names of heroes of Greek literature that were given to so many other Swallowtails, but Google does not find a character in ancient or modern literature with this name. Greek translation sites suggest chorodia, a choir, and chorizo, to separate, which can mean "to separate oneself, to be aloof," which does seem appropriate. It was given this name by the Felders in 1864, so it's too latet to ask them whether the butterfly's tendency to keep to itself was what they had in mind.
The butterfly was known before 1864 but was presumed to be a subspecies of Graphium (then called Papilio) sarpedon. The Felders' argument for recognizing it as a distinct species has been preserved...in Latin.
Photo by Coelacanths. As with many species, this butterfly's color depends considerably on lighting. At some angles to the light the triangle may look white rather than blue.
It is one of the smaller butterflies in the Swallowtail family, with a wingspan only two to two and a half inches, and no "tails" on its hind wings; but it catches the eye.
Photo by Richard1251, showing that some individuals do show vestigial tails. But only vestigial.
It is what some scientists call a charismatic species. It inspires artists. For example, in this video its movements have been synchronized to music:
This piece of scientific speculation considers its prospects if some versions of global warming theory turn out to be correct:
Before considering anything written about "global climate change" this web site remembers that (1) this web site has seen several "climate change" theories come and go, and (2) local warming really is happening, and (3) people who seem emotionally attached to "global climate change" also tend to be attached to unsustainable political ideas that would be unlikely to stop "global climate change" if it happened. But those three facts don't mean that global climate change CAN'T happen. That all theories and theoretical models of "global climate change," so far, have predicted changes that have not happened, does not mean that no change will ever happen. It merely means that we don't know whether local warming effects will aggravate global warming, some day, or offset global cooling. We do know that "cap and trade," "let's just move the pollution somewhere else and say we've fixed the problem here," and similar socialist ploys are very effective ways of aggravating discontent, but not effective ways of reducing local warming. We know that, if we want to reduce local warming's effect on local ecosystems, nothing that can be left for bigger government to do can accomplish as much as twenty private people walking wherever they can.
Photo by Jamesbenny, who notes that it was taken in March--late summer in Australia.
Asian sources describe the Blue Triangle as living at lower elevations. This might give US readers the wrong idea. Relative to the towering Himalayas, altitudes below 5000 feet above sea level are considered "fairly low." In the US, any altitude high enough to affect the boiling point of water is called a "higher elevation." These butterflies live in flat land and on some of what might be called big hills or small mountains, not on snow-capped peaks. They fly high, too, usually sailing above the treetops.
Denis Wilson observed that, in a butterfly garden where more gregarious Graphium macleayanus were feasting on his buddleia bushes, the macleayanus chased the choredon away. They can't physically fight. They can knock each other down, but some butterflies do that in courtship; they are too light to hurt each other. What can they do to drive other butterflies away from food or leks? No human can really know. Possibly they exude scent at each other, finding each other's scents disgusting enough to destroy their appetites.
Blue Triangles are said to smell like camphor, which most insects don't like. Macleayanus may smell even worse.
Though what do humans know? Maybe Graphium macleayanus sell insurance...Right. That was a joke. But the Internet contains sillier ideas about these butterflies. In indigenous Australian tradition butterflies may have been seen as psychopomps because they flew away into the sky, or as symbols of resurrection or reincarnation because they survive metamorphosis, but New Agers and Neo-Pagans who want people to send them money have set up web sites claiming that these butterflies bring love, luck, joy, and all wishes granted. Let's see...do Australians file for divorce? Do they seek treatment for depression? Right.
The various Inaturalist pages, which have collected almost 2000 photos of Blue Triangles (nearly all from Australia), reveal some interesting trivia about the species. While another page noted that the easiest way to photograph male Swallowtails (of most species) in dry country is to find where a large animal's urine is soaking into the ground, Blue Triangles also show an interest in surfaces with a color close to their distinctive color markings.
Photo by Renee_A. I'll stop here. There are a lot of these pictures. The butterflies don't seem particularly keen on sweaty or beach-salty human skin, but they do flutter around turquoise-blue clothing, bags, etc. Whether they feel curious about things that seem to match their distinctive color, see them as rivals and want to drive them away, or think they are pretty and admire turquoise-colored objects, the attraction is not an appetite for food. The flowers they pollinate are usually pink or white.
Or, in some cases, pink
and white. Photo by Peterwatts165.
They occasionally join mixed flocks but are usually found alone or in pairs. It will be interesting to observe whether prolonged human cultivation of cinnamon trees, expanding their food supply, makes this species more gregarious, in the way large groves of pawpaw trees reportedly make our Zebra Swallowtails more gregarious. Mother butterflies place one egg on a leaf, and caterpillars are found one on a leaf.
Males and females look similar, although males have furry scent folds on the inside edges of their hind wings. For many Swallowtail species it's possible to say that females have larger wings with less contrasting color, whether this means that females are black while males are yellow, that males are black and red while females are brown and orange...For Graphium choredon it's possible to find photos of couples where one butterfly has bigger wings, or one butterfly has dark brown borders around bluish white triangles while the other has black borders and bright turquoise triangles, or both, or neither. They don't seem to care. They recognize each other by scent.
Photo by Billybaracus. Formal studies don't seem to have been done, but the little chap displaying his scent folds (above) may well be able to smell what the female thinks of him, even through his own scent.
Courting couples spend some time flying about together before mating back to back. Several people have snapped three or more good clear photos of one pair's courtship flight. This site, with a side view showing just how long the male Blue Triangle's scented hairs can grow, documents that butterflies can mate in the usual animal position. Most don't, since other positions are less likely to damage their wings, but they can.
Blue Triangles are widespread and abundant because they can eat leaves of any of about two dozen plant species. The species was found wild in damp areas. Its host plants, all of which are shrubs and trees in the laurel family, grew wild in damp areas. They originally ate leaves of native trees like brown laurel, blush walnut, wilga, bollywood, and bollygum. The butterflies are content with host plants reared and watered by humans, so they have spread into dry parts of Australia and can become a nuisance on cinnamon trees, avocado trees, or camphor laurels. They are often found in suburban gardens. They seem to be only occasional visitors, not residents, in New Zealand--so far.
For people who want to rear these butterflies, this site has a fuller list of native Australian host plants:
They seem to have a few other abilities other butterflies lack. Several photos suggest that couples can fly while mating, and one at Inaturalist, showing a butterfly curling itself under as it sips fresh orange juice, suggests that Blue Triangles may be one of the butterfly species that can eat, excrete, and reabsorb nutrients they've excreted all in one slurping session. (Butterflies really don't "poop" but they do excrete some liquid.)
Eggs resemble tiny round white beads, less than a millimetre across. Like other Swallowtail eggs, they're normally laid on the undersides of fresh young leaves.
Photo by Rodedmonds. Rodedmonds, however, also observed a mother butterfly apparently placing about a dozen eggs on the top side of an older, thicker leaf. Something must have gone wrong.
Caterpillars are usually some shade of green, with humped backs and flattened tail ends. Hatchlings are about 1.5 mm long. The green color is mottled with tiny lines and dots of yellow, black, and white. In some individuals the black or white predominates over the green; in some black and yellow predominate and the caterpillar looks brown.
For Blue Triangles as for other Graphiums, the earliest caterpillar skins have extremely humped backs and several little prickly points that make them less fun for birds to eat. The later caterpillar skins have smaller prickles and an almost conical shape, resembling the pupa, which is usually well camouflaged in green (sometimes brown)/
Photo by Nadsyg. Mature caterpillars have a yellow stripe across the hump. This is not the osmeterium, which is stored inside the hump. As the large hump suggests, these caterpillars have large osmeteria. The osmeterium is displayed under stress; making a peaceful, solitary caterpillar "put out its horns" is probably cruel, though some species seem to extrude their osmeteria far more readily than others.
The inner workings of the osmeterium are in the hump, but, when displayed, the osmeterium protrudes a few segments ahead of the stripe across the hump. Photo by Nicklambert.
Photo by Lianaj. This caterpillar has one of the more complex color patterns sometimes observed, with a yellow or even orange head and a patch of darker color on the front side of its hump, and paler color behind. It had that pattern even on the pale dull skin it has just cast off and is now tidily eating.
When caterpillars normally live alone and eat their cast-off skins, we know by now what this means for anyone trying to rear butterflies. They are not committed vegetarians. Siblings may tolerate each other or even huddle together to confuse predators, while they have plenty of fresh leaves to eat, but they should be kept one to a cage or sleeve.
In the context of rearing butterflies, someone on Reddit mentioned a fun fact that apparently some people who try to rear butterflies don't know beforehand. Caterpillars can't drink, and butterflies can't eat. Caterpillars get all their water from the fresh leaves their mouths are adapted to chew up. If the leaves they find are too dry, they can die of thirst beside a dish of water, which is useless to most caterpillars (although a few caterpillars like to go paddling on a hot day). Butterflies, conversely, get all their nutrients--primarily sugar for flying, though they also need mineral salts for successful reproduction, which is why so many males of pollinator species do some composting. They can starve to death beside a piece of fruit if it's not juicy. In the wild state they will go and forage, successfully or not, for what they lack. If kept in a cage they must be supplied with what they need.
In about three weeks, the butterfly ecloses.
Photo by Rosemary Robins.
Photo by Sylvia Felicity Ann Haworth, who snapped eleven recognizable photos of a courting couple of Blue Triangles.
