This week's butterfly has an unfortunate name. As you probably knew, the leech or bloodsucker is a sort of worm that attaches itself to people who wade or swim through infested water. People used to hope that diseases could be cured by draining out the infected blood--bleeding did seem to bring down fevers and subdue extroversion--so doctors used to keep leeches and carry them around to apply to sick patients. Though this treatment probably didn't cure anyone and may have killed some people, at the time it was considered an honest living, and "Leech" became a respectable family name. Eventually an obscure butterfly found in China and Vietnam was named after a naturalist called J.H. Leech--Graphium leechi. The butterfly does not suck blood. It's not even especially eager to lick sweat.
Photo by Rosefan2, taken in July in China.
Photos of living butterflies do not often show whether the males have furry scent folds along the inside edges of the hind wings. Museum specimens show this feature better. It is one of the ways naturalists can tell Graphium leechi from some similar-looking species; Graphium evemon have small scent folds, Graphium bathycles have no visible scent folds, and Graphium leechi have large conspicuous scent folds. Museum images for many Graphiums, including leechi, are available at Yutaka-it:
What it does eat is unknown. That is, adults sip nectar, apparently preferring white flowers, and caterpillars eat leaves, but nobody has published an official document identifying which species. Because China and Vietnam have not paid researchers to study butterflies, much remains to be learned, although Graphium leechi is not hard to find and photograph. Its genome has been mapped, but has anyone documented its life cycle?
Photo by Yzcitic_zj. This looks like a pregnant (some prefer "gravid" for egg-laying insects) female, whose coloring conforms with the general tendency for female Swallowtails to have bigger, stronger wings with better camouflaged colors than males of their species. Is she choosing a food plant for her offspring? If so, Graphium leechi may be able to live on a different kind of leaves than any other Graphium species. Graphiums generally live on the indigestible leaves of plants in the Annonaceae family, but some Swallowtails can eat the less toxic leaves of plants in the Rutaceae family--mints, which have shapes like the plant shown above.
Photo by Kaivictor, also taken in July in China.
We can see that males, as in many Swallowtail species, need mineral salts and spend some time composting polluted water. Algae and litter in the water are probably part of the attraction for these butterflies. In gregarious species, where males spend a lot of time hanging out in flocks at puddles, females often hang out on the edges of the male groups. Instincts tell the male butterflies that they need to slurp up a certain amount of minerals in order to be able to mate, and the females that they can meet their need for minerals by mating so that all they have to drink is flower nectar and clean water.
A photo at Inaturalist, not included here, documents a male Graphium leechi's attraction to a puddle in which a toad had been run over. Some Wikipedia editor has, for reasons of per own, chosen to use this as the main photo for this species on Wikipedia, though dozens of prettier and more informative photos are available. Many photos document the species' attraction to wet pavement--with residues of oil and lead from motor traffic and possibly still manure from animal-drawn traffic. There are reasons why the Bible classified the butterfly as an unclean animal. Photos do not show this species clinging to sweat-soaked shirts or socks, as some Graphiums have been caught doing, but do show it licking people's fingers...and two photos at Inaturalist show a naturalist who had obviously observed what else the butterfly had been licking, holding it up to pose on a rubber glove!
Photo by Nj_sam, taken in July in China. They'd really rather be pollinating.
Photo by Xuc, taken in April.
Three subspecies are recognized: aprilis, leechi, and yunnana. The subspecies aprilis is the one that flies in April.
Photo by Yixianshuiesuan, taken in July in China.
Photo by Xiaodoudou, taken in September. At this early stage the caterpillar resembles other Graphium caterpillars. Some species flatten out a bit as they grow up, while others beome more humpbacked. The host plant looks more typical for this genus, too.
Photo by Seventeennature, taken in September in China.
Photo by Jishenwang, also taken in September in China. This one's two pairs of false eyes may give predators pause. The working eyes are, of course, facing the surface on which it crawls. In order to see further than an inch ahead caterpillars rase their heads and look about in a shortsighted way. When tested, caterpillars seemed to be shortsighted, though Vincent Dethier, who took the trouble to test caterpillars' vision, was studying US moth caterpillars.
Photo by Jueming641, taken in September. The caterpillar's eye spots resemble the effects of a fungus infection on the leaf.
Photo by Dqk, taken in July in China. The pupa seems to be attached with an extravagant amount of silk, enough to have spun a cocoon, to a straight pin. Normally, of course, they pupate outdoors, on the undersides of leaves:
Both photos by Yzcitic_zj, taken in September in China. (One shows a single pupa close up; the other shows two pupae together, photographed further from the camera.)
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