This week's butterfly is sometimes seen as an example of "disruptive coloration," in which a prey species is so brightly colored that it disrupts its predators' view in a way that shuts down their appetite. Graphium kirbyi has mostly black wings with a stripe across each wing that reflects light and can look white, blue, green, yellow, orange, or even pinkish. It can even gleam with a fluorescent white look reminiscent of Graphium codrus, if photographed in just the right light. This stripe is visible on both sides of each wing, and reddish spots are visible on the underside of the hind wing. It catches the eye, and has been much better documented than last week's well camouflaged butterfly, though kirbyi, too, is most often seen in Tanzania. It lives near the coast and is also found in Kenya. A report of it in Nigeria is now thought to have been an error.) It is described as "uncommon and local," though it doesn't seem terribly hard to find at the right times and places.
Photo from Tanzaniabirds.net. The wingspan is typically between three and four inches.
It likes coastal habitat where the males can get brackish water. It is usually found in forests, or along forest roads--males sipping from puddles, females sipping flower nectar in the morning--between September and November.
In English it is also called the Pale-Banded Swordtail. It was identified as distinct from other specimens, and officially described, by W.C. Hewitson in 1872. Exercising the right of the first scientist who describes a species to name it, Hewitson said he wanted to name this butterfly after "Mr. Kirby, the author of a "Synonymic Catalogue of Diurnal Lepidoptera," in admiration of the great accuracy which is displayed in its production, and in gratitude for the many weary hours of research he has spared to me by the labour he has bestowed upon it."
Graphium kirbyi looks very similar to some other Swordtails, especially Graphium policenes. Specimens of these two species that are photographed for display in field guide books and web sites are easy to recognize; policenes has numerous white spots in addition to a fragmented white band across the wings, while kirbyi's upper wings are black with a clear stripe of white. Apparently in real life they're not always so clearly distinguished.
Photo by Zarek. Lower-contrast colors--palpating a leaf--is this one female?
Another photo by Zarek, catching the fluorescent-white effect.
In males, the appearance of fluorescence may be enhanced by the white hairs in the scent folds. Many male Swallowtails have these folds at the inside edge of each hind wing. In flight the folds are opened and release a species-specific scent that may or may not be noticeable, or be considered pleasant, by humans. Sources don't mention this butterfly's odor, though it does have scent folds.
Its food plants are in the tropical genera Annona, Uvaria, and Uvariodendron, and include Uvariodendron mbagoi, an endangered small tree species only recently named in honor of Frank Mbago at the University of Dar es Salaam. Photos of Uvariodendron leaves, fruits, and flowers illustrate this article:
Although the butterflies can live on any of several plants, some of their hosts are endangered, and since this seems to be one of the large butterflies that nature intended to be sparsely distributed, loss of one host plant could endanger local populations.
Males gather at puddles, and may join mixed flocks, which may include Graphium policenes.
Photo by Clamsdell. The one in the center is kirbyi. As a guess the one at the center left is policenes but this is a question for experts to answer. When male Swallowtails drink at the same puddles this does not indicate that they belong to the same species. Some Swallowtails want to be the only individual of their sex and species in a neighborhood, and will keep moving on until they are...and, if male, these butterflies often get the safety-in-numbers benefit of sharing a puddle with lots of other butterflies of different species.
Photo by Titi-uu. Plastic waste is on the ground at this puddle...blue-green and green-blue litter. How much of an attraction is the blue-green color for this species?
Photos of larval and pupal stages of this species have been printed, but apparently have yet to be digitized. The species is said to pupate with its head down.
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