This week's butterfly is sometimes called the Spot Swordtail. Nomios means "of the pastures" in Greek; it was the name of a few obscure men and of a nature spirit, similar to Pan, but identified with open grassland. Graphium nomius is found in forest land in India and southeast Asia, sometimes visiting islands even as far away as Australia; the males, like so many other male Swallowtails, hang out in groups at puddles, sometimes in pastures. Common in some places, these butterflies are also found in flocks around flowers and flowering trees.
Photo from Wikipedia. The hind wings always start out with long, thin, pointed dark tails but the tails may be lost by misadventure. This individual's plump shape and interest in a leaf bud suggest that it's a female looking for a place to lay her next egg.
Photo by Pam-Piombino. Though often photographed alone, males sometimes share puddles with large mixed flocks of other butterflies.
Photo by Gehan de Silva Wijeyeratne. They are liquid composters. They drink brackish liquid (sometimes from dead or dying animals), store and use mineral salts, and excrete more nearly pure water.
Photo by Antonio Giudici at ThaiButterflies.com. If you magnify the photo you can see the tiny stream of clear water being excreted.
Two subspecies are recognized: Geaphium nomius nomius, which is common in much of India, and G.n. swinhoei (or pernomiums), which is not common anywhere. A subspecies hainana, reported from China, is not mentioned by most sources. Swinhoei is said to be the subspecies found in Hainan. Rothschild described its difference from G.n. nomius in terms of slight variations in the proportions of spots on the wings, and of swinhoei having little or no white hair along the inside edge of each hind wing while nomius nomius has an inner border of thick white fur. Both subspecies can look black and white or pale blue-green, or yellowish brown and light yellowish green, depending partly on the angle at which their wings catch light.
Their resemblance to Graphium aristeus is strong, and in some places the species fly together, but no intermediate or hybrid form has been identified.
The wingspan is about four inches, more or less. Females often measure more and males less, and in some places (colder places?) they reach only two and a half to three inches. This species does not show a consistent visual difference between males and females. The ones who look egg-stuffed or are seen laying eggs are female. They average a little larger than males, but the difference is not obvious in every couple.
Photo by Saravanaraja_Vicky. There is not a consistent color difference in every couple, either.
Photo by Rajivthanawala. If the female weren't so full of eggs, could anyone tell them apart?
For Swallowtails this species seem "shy and wary" of humans. This may be because they fly closer to the ground, rather than up among the treetops, and are likely to be crushed. They will fly higher, though, to get at the nectar of their favorite flowers. They like a flowering tree called gamhar, or Gmelina arborea, which resembles the paulownia but has yellowish brown flowers.
Photo from Wikipedia. Humans don't eat the gamhar tree but prize honey made from its blossoms.
They are most often seen in March or April. Individuals sometimes fly as early as February or as late as June, and in some places they may fly as late as October.
Eggs are laid by ones, and look like little yellow beads stuck to the undersides of leaves or buds. The host plant is usually Miliusa tomentosum, but this species can also use M. velutina and Polyalthia longifolia. The eggs take three or four days to hatch.
Caterpillars have "glossy green" osmeteria rather than the usual orange or yellow. They have the humpbacked shape typical of Swallowtail caterpillars, sometimes so pronounced that the caterpillar seems cone-shaped. Bristles near the head of the young caterpillar are lost in the first molt. Bristles at the hump and at the posterior end shrink down to little spikes, harmless to humans but probably scratchy and disagreeable to caterpillar-eating birds.
Photo by Shivan Bhatt. This is a young caterpillar.
Photo from Vivekvaidyanathan. This is an older caterpillar. Its head is upward.
Photo from Ygurjar. This species does not seem as hard to provoke to put out its osmeterium, or "stink horns," as some Graphium caterpillars are. In older caterpillars lengthwise stripes break up the outline in a variety of ways that seem likely to confuse predators about what they might be trying to grab.
Photo by Maxncharlie. This black and white pattern on top sometimes accompanies green bands along the sides.
Phoro by Anil Kumar Verma. The stripe almost looks as if it were a separate animal and the main body of the caterpillar were only a rolled-up leaf.
Photo by Prajwal Ullal. This neutral-colored individual might have lived in the shade where it would have been well camouflaged. The caterpillars are most active, or least inactive, late in the evening. (Swallowtail caterpillars are not very lively animals. The less they move, the less they're noticed and the more likely to live to grow up.)
Caterpillars gobble their way through five skins, usually in less than three weeks. If conditions are unfavorable it may take 22 days for a caterpillar to be ready to pupate.
Pupae are shaped like others in this genus, and are usually brown. This species does not normally pupate near its host plant, but usually finds a crevice near or in the earth.
Photo by Rajiv Thanawala. Some pupal shells are green, but brown is more common. The pupal stage lasts twelve or thirteen days.
In places where their food plants are producing new, tender leaves all year, this species can have eight generations in a year. Adult butterflies usually fly for a week to ten days.
No comments:
Post a Comment