Humans don't know everything. We don't know as much as we often think we do. When we consider moths and butterflies, some of the gaps in human knowledge are obvious. While scientists have documented most of the life histories of most of the Macrolepidoptera (the ones big enough to be easily watched) in the English-speaking countries, we still don't know even what some Asian, African, South American, and Eastern European butterflies eat.
However, progress has been rapid. When I was a young gardener it was hard to get information about what all but the most common caterpillars in the garden were going to grow up to be, or which ones were actually a threat to any crops.
Most of them aren't. When you see a caterpillar in the garden, if it's a pest it's probably either devouring leaves or resting on a stalk it's stripped of leaves. There are exceptions, notably the Dreaded Gyps or "spongey" moth larvae, who wander about during the eating-and-growing phase of their lives, but most caterpillars stay near one source of food until they've reached their full size. Generally the caterpillars that let themselves be seen while they are not eating leaves are wandering about, usually exploring plants they don't eat, looking for a place where predators will not be looking for them. Once you learn to recognize the few pest species in your area, it's almost always safe to leave other caterpillars alone.
In the mid-twentieth century, when the first books I consulted were being published, American gardeners were paranoid about insects. My grandparents' generation did not understand how the Vicious Poison Cycle had worked to make formerly insignificant nuisance species like corn earworms and codling moths into major pest species. Who knew what harmless little animal might threaten the whole nation's supply of some food product next year. If it was an insect other than a ladybug or a Monarch Butterfly, the phrase people had learned was "Kill it before it multiplies!" And when the method of killing chosen was DDT or some other poison spray, that did lead directly to harmless animals becoming pests, people becoming ill, and bird populations becoming extinct.
Now we know that even when caterpillars can eat some things in the garden, it's always best not to try to poison them. Nature prevents most of the large, ominous-looking species from ever becoming pests; predators and diseases balance the populations of native species if we don't unbalance by introducing new chemicals. Some caterpillars do attack garden plants. When you go out to the garden and find a whole branch of a flower bush or tomato vine defoliated, nature probably intended that you do what you probably feel inclined to do. Why else would most caterpillars be so easy to kill? But leaving unpoisoned dead bodies in the garden, anywhere out of the way, actually encourages natural predators to prevent a population irruption that might make a species into a local pest. Some insects even have survival instincts that warn them that avoiding the places where their relatives have been killed might be healthy for them. And most of the time, even when a caterpillar takes a bite of a garden plant, no real harm is done.
This week's butterfly is Atrophaneura dixoni, a rare Batwing (large tropical member of the Swallowtail family) found only on Sulawesi island. Most of the pictures of this species were taken in museums. A gallery of pictures of living, flying butterflies, none really in the perfect pose for field guides, is online at https://uk.inaturalist.org/taxa/1060848-Atrophaneura-dixoni/browse_photos .Those pictures are not available free of charge. Use the link.
Here is a male doing what male Swallowtails often do--slurping up mineral salts at a shallow puddle.
Like the other Batwings, dixoni have wingspreads of five inches or more, up to 15 cm. Fore wings are black; hind wings have pink or red spots. Females are more likely to show more red than males; some males are all black. Wings look faintly striped in darker and lighter, or denser and thinner, shades of black scales following the shape of the wing veins. They don't have tails. Though living butterflies usually keep their fore and hind wings together, the wings of museum specimens can be coaxed out into an X shape that some nickname "windmill."
Little information is available about the life cycle of this butterfly. Apparently it's always been rare. DNA studies have been done, and it is thought to be a distinct species, but nobody is claiming to have reared living specimens or to know exactly what they eat. It is believed to be somewhat threatened, in a general way, but not known to be endangered.
You can buy dead bodies of this species online, and several Google hits for "Atrophaneura dixoni" are sites advertising their dead bodies and parts. This web site does not recommend ever paying for any part of a dead butterfly. If you have a use for butterfly carcasses, it's easy enough, and it's better science, to rear the animals in captivity and exclude unknown variables. People who don't know how rare or valuable a living thing may be will always think they need the money, and there must be more specimens somewhere else, if they can destroy the last individual of a species for extra cash.
While the first Atrophaneura species to be officially documented were given names with what we might now call a Halloween theme, some of the less common, later documented species were simply named after the scientists who first described them and presented evidence for regarding them as distinct species. Atrophaneura dixoni was named after Frank Dixon.
Due to disagreement even among informed sources about which species belong on the list, Atrophaneura dixoni is out of alphabetical order here. Our next butterfly will be Atropnaneura coon.
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