Arthropoda

Spiders, beetles, millipedes, for sure. Moths? Maybe. Butterflies, like the lemon pansy (Junonia lemonias) in the photo above? A stretch. Crabs and lobsters. Certainly not; that’s food! Have we reached the limits of the folk classification of visible bugs? Consider. Spiders are perhaps more closely related to horseshoe crabs than to beetles. And if you think sea lice are bugs, then their close relatives, the shrimps shouldn’t be exempted. So let me go with arthropods instead: those invertebrates with an exoskeleton and jointed legs and segmented bodies. (Ands are powerful things, easily lifting fifty times their weight in sentences. After all we have jointed limbs, and segmented vertebrae. But we are not arthropods, because we are not invertebrates.) I’ll go with this, because it gives me a reason to finally read two papers (this and this) that I’d been meaning to for a while.

When did arthropods come into being? Darwin noted an uncertainty: “For instance, I cannot doubt that all the Silurian trilobites have descended from some one crustacean, which must have lived long before the Silurian age, and which probably differed greatly from any known animal.” Darwin’s intuition has been vindicated by the discovery of new fossils which pushed the origins of arthropods beyond the Silurian period (445-420 million years ago) into the Cambrian (535-490 million years ago). I took this photo of a fossil arthropod, a trilobite, in Shanghai’s Museum of Natural History. That bug was the size of my hand! The species, Sinoptychoparia tuberculata, is known from this single specimen from 515 million years ago, preserved in a sheet of stone from China’s Guizhao province. The oldest fossils of arthropods that we know of are not more than about 550 million years old, embedded in the proliferation of animal forms that is called the Cambrian explosion. This roughly agrees with genetic information.

Of all the forms of living beings known and recorded, arthropods are the most varied. But the living species of arthropods are just a small fraction of all their extinct cousins. All of today’s arthropods are either crustaceans, insects, myriapods (millipedes, centipedes and their relatives), or chelicerates (spiders, hermit crabs, and related species). But there are many groups of animals which seem to be closely related: tardigrades (which recently failed to colonize the moon) and velvet worms certainly, but also roundworms. In Darwin’s time it was expected that arthropods must have evolved from the much older group of roundworms, the annelids. The biggest discovery since Darwin’s days is that genome analysis shows that arthropods do not come from annelids. I think that is my biggest take-away from the first paper. These genomic studies have completely rearranged the branches of the tree of life around arthropods into a form that Darwin would not have suspected.

Insects evolved from cave-dwelling crustaceans about 480 million years ago, late in the Cambrian period (that’s the headline of the second paper). Beetles began to develop about a 130 million years later. They have had time to evolve into a variety of shapes. So many, in fact, that J.B.S. Haldane remarked that “If one could conclude as to the nature of the Creator from a study of creation it would appear that God has an inordinate fondness for stars and beetles.” All insects have a pair of antennae to smell with, but the one I saw on the beetle on the wall outside my flat was really spectacular. This photo was taken in October 2019, and I saw another specimen in November 2022. So, whatever it is (help me if you can, as the Beatles implored), it is not uncommon. There are many ideas, but no certainty yet, about how antennae developed.

If you wander through the fossil section of a museum, you are likely to see insect fossils similar to today’s lacewings and dragonflies. All have two pairs of wings like modern insects. The earliest known fossils of winged insects are a little more than 300 million years old, but genomic studies now show that insect flight arose about 400 million years ago. So, one should expect fossil hunters to discover even older specimens. I’ve written earlier about how a butterfly is grounded by a predator taking a bite from its forewings, but it can continue to fly with reduced manoeuvrability even after losing large parts of its hindwings. Flies seem to have only one pair of wings, because the hindwings are reduced to small appendages called halteres. They lose control over their flight paths if the halteres are lost. Beetles have converted one pair of wings into a hard cover, and still retain an ability to fly. I wonder whether dragonflies and damselflies can also keep aloft without using their hindwings.

Ants are fascinating. With the wonderful cameras that many of us carry in our pockets, I’ve been looking at ants in detail for some years now, without being able to identify them. These have elegant striped bodies which were quite hard to see at first because of the lack of contrast with the flower they are clambering over. When we think of pollinators, ants are not the first to pop into our heads. We think first of bees and butterflies. Interestingly, both these families have their origins before the rise of the flowering plants. Their spectacular diversity, however, comes with the explosion of flowers about a 140 million years ago. Ants also date from that time.

The origins of spiders and related groups of animals still remains to be understood fully. Early ancestors of today’s spiders are visible in the fossil record in the middle Cambrian. Animals that we would perhaps recognize as spiders may have lived about 400 million years ago. They have had time to evolve into the many lifestyles we recognize today: the orb weavers, the jumpers, or the ambush hunting crab spiders, like the one in the photo above. Arthropods are an old order of animals, filling a variety of niches across the world. Even insects are much older than flowering plants. So tales of the insect apocalypse are overblown. If we heat our world beyond our limits, we might carry some arthropods into extinction with us (lobster claws could become rare), but far from all.

Goa in the monsoon

Monsoon in Goa: an advertising catchline from the 80s and 90s, when the hoteliers decided to fill up the empty rooms left after the party crowd disappeared. Winter is a washout with all the music and booze on the beach, so you might as well try to see the other Goa in the magical months of monsoon. This is one time when there is a truth beyond the lies of advertising.

The year I took these photos I realized that Goa is a wonderful place to observe the monsoon as it comes in to the Western Ghats. The wonderful plants and insects, the frogs and the moths, straggle down to Goa, to meet the birds and crabs of the coast. You can go for long walks, or drive to lonely spots, with your camera and catch some of the beauties that you might otherwise see on treks through the Ghats. You can lead a solitary life if you wish, broken by exchanging passing greetings with the fisherfolk who are the original inhabitants of this place, or long conversations with the university types over a strongly Portuguese-influenced lunch.

Or you could just stay at home on rainy days, reading, eating the sausages or dried fish in boiled rice, stepping out into the garden on the beach between spells of rain to capture the play of rain and sun on vegetation. It is a life to dream about in these constrained years.

Fresh catch

Many years ago, on our first visit to Chilika lake, we stopped at a small and unremarkable looking eatery on a side road. Our guide and driver was clearly looking forward to the meal. One of the three tables was occupied, and we parked ourselves on one under a tree in the little yard. The lobster and crab were the freshest I’d ever had, and cooked lightly and with a delicate touch. I went back on every visit to Odisha which took me near Chilika, and it remained wonderful. The single soft-spoken owner-cook-waiter was later joined by a couple of assistants to wait on tables, but the kitchen remained the exclusive domain of the old man.

In early March, on my last trip before the lockdown, I passed near Chilika again. This is a huge lake, with a surface area of over a thousand square kilometers. This time I was on the end near Berhampur, not Puri. But I was told that there was a Chilika dhaba nearby. Late in the evening we dropped off the highway and detoured into something quite different. This was one of the large productions which cater to busloads of tourists.

Fortunately, in rural Odisha, freshness is a fetish, as a result of which I’ve seldom had bad food on the roadside. The dhaba was out of lobster, but crab and two varieties of fish were available. We decided to share one of each thing on offer. The ingredients were as fresh as I’d expected; they can’t be otherwise next to one of the biggest fishing grounds in this part of India. Although the cooking was uninspired, the freshness of the crab was good enough to keep us plodding through the meal. I resolved to go back to the other dhaba as soon as possible. Now this is a promise to oneself which seems hard to keep.

On the way out I passed this large image of Kali painted on one wall. I find the simplification of this image wonderful. In Odisha it is enough to draw the eyes to signify Kali, time, the goddess of death. Every other piece of this image is dispensable. The dhaba had emptied out, and it was time to hit the road again. Kali stared at us as we climbed into the car.

A cat’s heaven

“Get it over with,” was The Family’s verdict. “Let’s go to the beach and sea the fishing nets.” The fishing nets were much less impressive than icons of tourism have any right to be, but just before you reach them is heaven. At least a cat’s version of heaven: a sea food market with all the wonderful catch from boats pulled up between the shore nets. Everything you want is there: lobsters, squid in its own ink, octopus, shark, shrimp, shark!

A large fraction of the people at the beach were examining the fish with interest, but it didn’t look like much was being sold. There was much I couldn’t recognize, so I sent off the album to my family, large parts of which have dedicated their lives to fish. After the clamour died down there were IDs for four varieties of fish: small pomfret, rays, blue runner and the pearl spot. The many varieties of edible marine arthropods that you see in these photos remain unidentified down to the species. Sea food fans, if you have any further IDs, please leave them in the comments to the photo. Otherwise just enjoy, like the cat in the chair.

An untimely dinner

After buying my train tickets I found that I was quite hungry. It was about 5 PM local time, but my body was probably still two and a half hours behind. Maybe it was a late lunch that I needed. The first day in China could be a little confusing for one’s metabolism. I’d eaten a large breakfast before catching my flight out of Shanghai, and then skipped lunch. Whatever the reason, I was famished, and there was a food street I could walk through. I looked at the various things on display and my eyes snagged on some seafood.

The shrimps with Szechuan peppers looked very inviting. What crab was that next to it? Not the Shanghai hairy crab, I thought when I looked at it closely. That would have been good, but I wouldn’t mind other crabs. Next to it was a trayful of large lobsters, cooked in Szechuan style. Some gestural language established that I could take a mixture of things, and pay by weight.

While buying the food it struck me that eating crab and lobster with chopsticks would be a challenge. Fortunately this is a challenge for the locals as well, so you get a bunch of plastic gloves as well. Between chopsticks and gloved hands it was not at all difficult to work my way through a bowlful of mixed seafood.