Lepidoptera – Don't hold your breath

Tigers and crows

Common tigers (Danaus genutia) are among the commonest of Indian butterflies. I’ve seen it in traffic islands in Mumbai and, across the country, in patches of weeds. When I first saw photos of the Monarch butterflies (Danaus plexippus) of north America (and parts of Oceania) I was surprised by the resemblance to that well-studied species. Both are milkweed butterflies, a group of conspicuous larger butterflies which are distasteful to predators and mildly poisonous even to humans.

These butterflies harbour poisons which they gather by feeding on a variety of plants which have toxins called pyrrolizidine alkaloids. These are a class of chemicals which The Family calls bra-shaped molecules because of the fact that their chemical formula is shaped like one. You can see the formulae for several of these alkaloids in the picture here; only the straps change. You can see many varieties of milkweed butterflies in India. They go by the generic names of tigers and crows. Examples are Danaus genutia, the Dark-blue tiger (Tirumala septentrionis) and the Double-branded crow (Euploea sylvester), all of which are illustrated here.

A well-known facts about Monarch butterflies is that they migrate in mass. At the time I got my first electronic camera and started to read about the butterflies that I was photographing, I was puzzled by this. The milkweeds of India had been catalogued and described two centuries ago, and widely studied by amateur naturalists. But there was no record of Monarch-like migratory behaviour among Common tigers, or any of the milkweeds. The only evidence for mass migrations was an obscure report of a mass of Indian butterflies suddenly appearing in the Arab peninsula in 1983 CE after a monsoon storm, from which observation two scientists deduced migratory behaviour.

This sounded intriguing to me, but a bit of a leap. So it must have seemed also to a generation of butterfly experts, but some began to search for direct evidence. Finally during 2012 to 2015, Milind Patil, a lecturer in a college of forestry in Maharashtra, finally located a site in the Western Ghats where enormous numbers of butterflies congregated annually before the monsoon to prepare for migratory flights. His paper was published in 2016. Now several other sites have been found and further work is being done on the migration of the milkweed butterflies of India.

Today is Holi, an appropriate day to read about these colourful creatures.

Marigold and Tiger

Marigolds were in bloom when I walked out to the garden. February is a good time for butterflies. Many of them fluttered around the flowers. I got a Glassy tiger (Parantica aglea) sitting on one. Mission accomplished. I went back to the lectures. I can’t sit for long stretches in a cold lecture hall. I know it looks impolite, so I try to make my breaks short.

Scalewinged

Our gardeners have decided to put in beds of lantana and tuberoses in a sunny patch at the back of the building. Late in the morning this is a magnet for butterflies. For a few days now I’ve been waiting for the scaly-winged fliers after 10 in the morning.

In an earlier post I’d described how hard it is to take a photo of a tailed Jay (Graphium agamemnon). This attractive flier, with bright green spots on a dark background is so active that you can barely ever get it sitting on a flower. When it settles for a few seconds, its wings move too fast to capture in detail. Now I decided to change my strategy and catch it in flight just before it descends on flowers. I focused on a bunch of flowers and waited for it to descend. The braking maneuver as it lands makes it slow its wing beats. In this bright sunlight I could get a few clear shots, as you can see here. I’m happy to have this new technique under my belt. I’ll have to work on it.

Another common visitor in this patch is the very common skipper called a small branded swift (Pelopidas mathias). It prefers tuberoses to lantana; must be something to do with the anatomy of its proboscis. The caterpillar of this species is one of the major pests which feed on rice (a few of these otherwise unrelated species are rolled into a group called rice leaf bundlers, for their habit of rolling leaves into a bundle before feeding). I wonder which of the garden plants they feed on.

The common baron (Euthalia aconthea) is another butterfly I saw here often. It is pretty nondescript when you see it in the shade, the colour of dust with marked out in grey soot. Here, in the bright sun, it glows with colour, the brown and olive markings coming alive with brightness. I suppose its caterpillars and pupae must infest the mango tree around the corner of the building.

Proboscis

This moth was probably a football fan. It flew in while we were watching one of the World Cup matches, and hid behind a curtain all night. Although this type is common in Mumbai, like most moths it has no common name. So I’m forced to call it the Pygospila tyres. I’ve seldom noticed the proboscis of moths, but here the coiled organ was so visible that the photos I took are concentrated on this. The proboscis is a tube which combines the functions of a drinking straw and a sponge for mopping up fluids. Ray Cannon has a very nice blog post on the proboscis of butterflies.

Scientists love to group all moths and butterflies together and call them Lepidoptera. This is useful because they have many features in common. All Lepidoptera which have proboscis are called Glossata. I didn’t think there was any need to have a new word for this; don’t all Lepidoptera have proboscis? After all, since the time of Darwin, people have studied how flowers and proboscis have shaped each other. You might be as surprised as me to read that there are some, although very few, moths without this organ. Some of them have mouths designed to masticate pollen, and some finish all their eating while they are caterpillars!

The proboscis is weirder than I’d ever thought about. Once it is uncoiled, Lepidoptera suck up fluids using muscles analogous to those in our cheeks and throats, so a drinking straw is not a bad description of it. Uncoiling uses a mechanism similar to erectile tissue in our bodies, in the sense that body fluids are pumped into the organ to flex it. Moreover, the adult stage of the insect forms the proboscis after it has emerged from its cocoon by fusing together two different appendages. But the oddest thing is that there are flexible sensory organs all along it (think of sensitive fingers) which give the insect a clear picture of the shape of the flower that it is probing.

Further searches led me to even stranger information. It seems that fossils of Glossata have now been found which are 212 million years old. This was a time when flowering plants had not yet evolved, so what use would there be for this organ? It seems that the era during which the newly discovered fossils lived was a time of ecological crisis. The ancient super-continent of Pangaea was beginning to break up and the atmosphere was full of greenhouse gases from the volcanoes which were tearing apart the continent. In this hot dry atmosphere water loss from the body would have been a major issue, and proboscis could be used to lap up even minute quantities of fluids. Even today Glossata ingest fluids from puddles of mud, mammalian sweat and avian tears.

The football fan was not interested in my tears or sweat. When I opened the window and flicked it off the curtain it disappeared into vegetation with strong beats of its wings.

Four butterflies and a moth

A decade back Mumbai was full of butterflies. You could see the bright grass-yellows fluttering in and out of traffic wherever there was an island with some greenery. If you stopped near one at a traffic light, you could see the fluttery flight of a Psyche or the almost invisible motion of small grass-blues. The potted plants in our balcony would be visited regularly by a host of larger butterflies, and on a Saturday afternoon I would take my camera and go for a half hour walk in the garden to take photos of a variety of these delightful animals. Then with the rise of mosquito-borne diseases, everyone decided to pump huge amounts of insecticides into our cities, and the butterflies suddenly vanished. The fluency which I had picked up in identifying butterflies also faded away.

Now, when I see butterflies during a walk in a forest, I feel like I can barely remember a few words of a language which I once knew well. The lemon pansy (Junonia lemonias)in the featured photo brought back a quick memory. I realized that when you have forgotten names, you see fewer butterflies. During our trip to the jungles around Thattekad I tried to train my eyes again to spot Lepidoptera, and I did manage to catch a glimpse of many Nymphalids (brush foots), Lycaenids (blues), Pierids (yellows), and Papilionids (swallowtails), from the little grass-blues to a fleeting glimpse of the yellow-and-black Southern Birdwing, India’s largest butterfly.

Butterflies are an undemanding pastime. You don’t have to wake up at unearthly hours to see them. They become active in the middle of the morning. The six-lineblue (Nacaduba kurava)that you see in the photo above is a typical low-level butterfly. The upper surface of its wing is a shimmery greyish blue. It hovers usually in bushes and undergrowth at the level of your knees, but comes to frequent stops to perch on a sunny leaf. If it settles on a chest-high leaf, grab the chance to take a photo. It will usually wait for you to take several shots.

The common bluebottle (Graphium sarpedon), like most larger butterflies, inhabits a higher world in the forest, often flying at a level above my head. It is harder to photograph, since it perches for a very short time. I managed to take the photo that you can see above because around noon it decided that it had had enough sugars, and needed some of the minerals that it can only suck up from wet mud. Such mud-puddling butterflies give you a great opportunity to take photos.

The butterfly which you see above is the Psyche (Leptosia nina). It is so common and widespread that think of it as the sparrow of the butterfly world. You can see its weak and fluttery flight everywhere there is some grass or some low bushes or herbs. I noticed this butterfly as far afield as in the Andamans and Myanmar, and it spreads well beyond that to the east. Like the lineblue, this is another small butterfly which flutters among vegetation below your waist.

There are very few experts on moths. These are vast families of Lepidoptera which defeat an amateur. The relatively smaller number of butterflies are easier for amateurs to recognize because they are well-differentiated by wing colours and patterns. Moths are often drab, well-hidden, and requires finicky attention to differentiate from each other. I took this photo of a day-flying moth perched on a leaf. You can tell that it is a moth and not a butterfly by its antennae. All butterflies have the thin antennae with a club-head at the end which you can see in the other photos. Moths have a wide variety of antennae: the extremely feathery antenna of this one probably means that it is male. Some day I must make a trip with an expert on moths.

After monsoon

After the monsoon ends the weather turns unbearably hot again; that’s what an Indian summer is. In the sweltering heat of October it is a minor disaster if you forget to water plants. The rose bush has been putting out flowers through the monsoon, because the rains keep it from drying up. Today I saw that two days of not watering it has begun to affect it.

Many plants are beginning to bud. I look at the methi (fenugreek) shrub. Every stalk is budding new leaves. The hairy surfaces of the leaves catch every piece of lint which floats by. You have to carefully wash the leaves before you use them in the kitchen.

But really this is the time of the year for insects. The hibiscus bush is beginning to push out flower buds. As soon as one opens, ants swarm over it. Soon they will bring their aphid cows up the stalks. The vegetation below the spectacular flower will be thick with aphids, as ants run up and down their farm milking them.

Moths have pupated too. I saw this lovely October visitor on the wall today, sitting out in full sight. The lore about bright and visible butterflies and moths is that they are poisonous. Many birds would see this yellow on the wings of the moth more brightly than we do, so it is definitely signaling that it is inedible.

Well back on the wall I found a few green lacewings. They are nocturnal and have probably come here to eat the aphids from the ant farms. Lacewings are not poisonous: birds and bats will happily eat them. That’s the reason this one was sitting far back on the wall, under an overhang. In another month all these showy insects will be gone. That’s when migratory birds begin to arrive.

Breakfast and butterflies

In Valparai breakfast was always late and large. Our mornings started a little before sunrise. We would gulp down a quick cup of tea and a couple of biscuits before leaving for a round of bird-watching. The real breakfast would start at about nine, after we got back. It always began with a ritual serving of fresh fruits. I was really amazed at the skill with which the kitchen produced bananas sliced into two precisely equal longitudinal halves. I tried this at home, and failed miserably. Then there were idlis with the famous Tamil gunpowder and coconut chutney, perhaps dosas or adai with sambar or appams with stew, and any amount of toast with eggs. Everything was very well done. Even the bread was surprisingly good.

On our second morning we arrived at breakfast to find a dark butterfly fluttering around our table. The Family asked me for an identification, and I was a little stumped. I hemmed and said it was not a moth but a butterfly, one of the variety called skippers. The only way to be certain is to look at the antennae: skippers have ones which are shaped like hockey sticks. But I couldn’t get beyond that. Very tentatively I said “rice swift”, knowing this was wrong. I took a photograph for later identification. ID wasn’t so easy: it could have been the weirdly named “restricted demon” except that it had too few spots. After a couple of other false leads I finally saw the pefect match. It is the Tamil spotted flat. It is common in the Nilgiris.

It fluttered repeatedly against the window glass, so I decided to do a good deed and opened the window to let it out. It fluttered on to the flower bed just outside. A bulbul darted in, picked it up and flew off. The Family and I looked at each other, and settled in for breakfast.