Saturday, December 25, 2010

Itchy backs and tickly toons

Robert William Wood
Some years ago, I had been to the Brahmagiris in Coorg. The rolling sholas are spectacular and it has a way of bursting into view with special effect that is enhanced by the climb that one has to make. Anyway in the weeks after  my return returned, I developed an itch on my back with eruptions on the skin that kept made me miserable for almost two months. The dermatologist I went to tried out antifungals, antibacterials and when the right remedy was found it quickly subsided but it did raise doubts about the quality of medical diagnostics. When I mentioned this to my birding  physician friend Dr. NS Prashanth, he mentioned that it should have been quite easy to identify a fungal infection using a Wood's lamp, something that every doctor would apparently have in their kit. A Wood's lamp essentially produces ultraviolet light and some fungi glow in UV. The process is termed fluorescence - the fungi convert light in the UV range into light in the visible wavelengths - and should not be confused with bioluminescence which is also seen in some fungi. Wood's lamp is just like our everyday "tubelight" (technically a fluorescent tube - a glass tube internally lined with a fluorescent chemical) but made of a special glass called Wood's glass. Wood's glass is made of Barium silicate with nickel oxide - which makes it very opaque to visible light but letting UV through.
First published in 1907 the introduction reads:

For some are guided by tradition.
While others use their intuition,
And  even I make no pretense
Of having more than common sense
Indeed these strange homologies
Are in most flornithologies,
And I have freely drawn upon
The works of Gray and Audubon,
Avoiding though the frequent blunders
Of those who study Nature's wonders.

Looking up, thanks to Wikipedia for showing the connectedness of things , I found that this Wood was  Robert William Wood (May 2, 1868 – August 11, 1955), a physicist who had a keen interest in UV and IR photography. He also apparently was debunker of frauds and when the journal Nature sent him to investigate something called N-rays he did the little trick of removing a vital prism in the experiment and the discoverer of the rays was still able to produce unaltered results demonstrating plainly that the setup was fake.  Wood liked to amuse people and one trick was to carefully toss sodium into a pond and act as if he was spitting to shock onlookers with explosive  effect ! H L Mencken apparently called him the "wild man of Baltimore" ! Strangely however I had already bumped into his Lear-esque verse and cartoons, long before learning about his other achievements. Pure entertainment that he created to amuse his children, but may well reflect to some extent the poor opinion that physicists in that era tended to have of biology. Indeed one physicist famously compared biology of that time to stamp-collecting. Wikipedia has an article on the "Nature fakers controversy" where this work has been pointed out as a parody of a long controversy at around that time in the United States of America that arose from the conflict between science and sentiment in popular nature writing. The controversy was due to a large number of nature writers of the time conflating fact and fiction. For instance one writer talked about birds applying a mud cast to their legs and another wrote about wolves hunting caribou by tearing their hearts out. This was finally settled and even involved Theodore Roosevelt, their hunting President, who decided that such fake writing should not be included as part of the compulsory reading for children. One protester even wrote a letter to Roosevelt to remove other "fake natural history" such as that written by Charles Darwin !

A pick below of some of the pages (thanks  to the Internet Archive) from Wood's satirical book follows.























References

Tuesday, December 21, 2010

Great observers - Ernest Hanbury Hankin

Never heard of E H Hankin? You can be excused, for neither had I, until this morning when Colonel Ashwin Baindur dropped his name. Searching around, looking up some bits and pieces at the end of the day I have to decided that he belongs on a pedestal along with so many other lesser known greats.

To start with Ernest Hanbury Hankin (February 4, 1865 – March 29, 1939) studied medicine and came to India to work in the United Provinces (now still UP) and was perhaps among the first to detect the activity of bacteriophages - he noted (in 1896) that there was something in the river waters of the Ganges and Jamuna that passed through filters but was destroyed by boiling and seemed to kill Vibrio cholerae . He suggested that these may have been responsible in reducing the ravages of Cholera in that area. Phages were finally "officially" discovered by Felix D'Herelle in 1917.

Anyway, Hankin did not work further on that front and phages continue to be a field that has a lot of promise but is perhaps supressed by legal frameworks which in turn are perhaps supported by the pharmaceutical industry. Imagine having a drop of water with a few viruses instead of buying antibiotics ! If you have heard about the practice of adding Potassium permanaganate into wells, that was a technique popularized by Hankin to manage cholera and typhoid.This practice led to the emergence of an Anglo-Indian term of everyday usage "pinky pani".

Around 1911 Hankin took an interest in observing birds and the detail of his observation can be found in his careful illustrations. These were first published in Flight - the first aviation magazine and in 1914 he published a book on Animal Flight. He restricted himself to making insightful observations and comparing notes with what he knew on anatomy and noted that he was handicapped by his lack of knowledge on various aspects. He looked up specimens at the Bombay Natural History Society (that was in an era when that organization did allow interested people to study their collections!)

He begins his 1914 book with a quotation from someone who signs as A.O.H. (easily determined as A O Hume - and this was perhaps at a time when he was under the sway of the theosophists - although later separating himself after exposing Madame Blavatsky)

A writer who signs himself A. O. H. watched vultures in Simla at a height of about 7000ft. in the Himalaya Mountains. He states that these birds start their flight in summer between six and seven o'clock in the morning, but in winter not till nearly nine o'clock. Their usual speed of flight he estimates to be from twelve to fifteen  miles  an   hour, the  lowest speed of gliding to be seven to eight miles an hour, and the highest twenty-six to twenty-seven miles an hour. The species observed was Gyps himalayensis, a vulture of 9ft span. When gliding in a straight line for miles the only movement shown by this vulture was an occasional and gradual "shift " of the tail. He says that crows can soar rising in circles without flapping, but that they do so only when the air is quite calm. He states that soaring flight is due to "levitation." This is a miracle or conjuring trick in virtue of which a man can remain unsupported in the air. He says that it consists in "so altering the magnetic polarity of the physical frame that in lieu of being attracted it is repelled by the earth." This power is achieved by "living an absolutely pure life and intense religious concentration." Birds are endowed with this power, apart from such mental exercises, unless, it may be suggested, the hill crow finds it helpful to indulge in irreligious sentiments when trying to descend to earth without  the help of gravity.

Others, having a clearer idea of causation, have attempted to show mathematically how soaring flight could he explained if the wind has a certain upward trend, or if the air is subject to horizontal pulsations. Such theories have been put forward as possibilities. They are admittedly not based on facts of observation, although, by some, they have been mistaken for established doctrines. But, as will be seen, the study of soaring flight brings us face to face with an extremely complicated series of phenomena, and there it room for doubt how far these simple mathematical conceptions carry us towards an explanation.
A selection of illustrations
What captures ones attention is the careful attention, observation and illustrations that he made of soaring birds. He then goes on to compare certain actions and postures with the musculature involved. He notes for instance that there are no muscles in birds that allow the phalanges to be pressed down to enhance the camber. He notes that this is present in flying foxes. His area of research seems to be the exploration of what is today called dynamic soaring and is presumably much better understood. Indeed hang-gliding enthusiasts today have a feel for the subject that would be have been much the envy of Dr. Hankin. In March 1923 Time magazine noted:
People on a London common saw a strange sight—an elderly gentleman playing with a toy aeroplane. He was Dr. E. H. Hankin, M. A., D. Sc., author of Animal Flight (a book dealing with the science of living flight), and he was experimenting with a model glider.
A vulture coming in for landing - at the final stage the flapping is directed forward to brake

When Hankin returned to England, he was also amusing himself with geometrical patterns. He was especially interested in the patterns in the trellis work of Fatehpur-Sikri and Sikandra. And so this multifaceted doctor turned his attention to tesselations comparing Mughal, Arab and Saracen patterns. He especially seems to have taken an interest in non-repeating tile patterns (Penrose tilings) !

Hankin's works are not very well known, but it is clear that he had a lot of time to think. He seems to have spent a lot of time on thinking about education. In one study he noted the upbringing of Quakers and suggested that their emphasis on intuition rather than excessive conscious logic helped them in making scientific advances. His statistics for that time period indicated that one had a 46 times greater chance of being elected Fellow of the Royal Society if one came from a Quaker upbringing ! He later wrote several books :
The first I can only find a reference to (PS July 2014: now online and linked above) is referred to in a 1926 issue of the "Proceedings of the Stanford Conference on Business Education" where the author notes:
There is a little book which I think every business teacher ought to read, by a man named Hankin, in England. It is entitled The Mental Limitations of the Expert. A revision and enlargement of this book has just been published by E. P. Dutton, with the title Common Sense and Its Cultivation. Mr. Hankin is an expert himself, an expert chemist in the British foreign service in India. To have a thinking Englishman live in India is significant. He has time to sit down and think, and some excellent work by Englishmen has come out of India. Among the illustrations that Mr. Hankin gives of expert limitations is this.

He says that, in a certain section of India, a certain caste had developed a high degree of financial ability. The people of this caste had handled banking and financial affairs of that region continuously and almost exclusively. For many years it had been one of the standards of this caste that their children should not attend school. They learned the multiplication tables by units and quarters up to 50—as 49% times 23%. They had most accurate memories for this most complicated of multiplication tables. Everything else they got by intuition and apprenticeship.

Then the English came in, and English education became the vogue. About fifty years ago this tribe began to take to English education, formal education.  Today, Mr. Hankin says. they have almost entirely lost their place of dominance in finance, and it has been taken by another caste, which adheres to the old type of education. By their English education the former controllers of the financial situation lost their intimate contact with things, the intimate try-outs of experience, through which they had been getting something which had made them dominant; and when they lost it they lost their dominance.
Fortunately for us, Hankin died more than 70 years ago and so his works are now in public domain under most jurisdictions.

References
  • Alexander Sulakvelidze, Zemphira Alavidze, and J. Glenn Morris, Jr. (2001) Bacteriophage Therapy. Antimicrobial Agents and Chemotherapy. 45(3): 649–659. doi: 10.1128/AAC.45.3.649-659.2001.
Postscript
Anyone lucky enough to have access to the Cambridge archives might be able to find a portrait of the man  (H62) and perhaps someone will be able to persuade them to release at least a low resolution version into the public domain.
Hankin aged 35


February 2014 - an email to the Cambridge Antiquarian Society received a very prompt response and thanks to Dr John D. Pickles, Honorary Librarian, we now have a copy of perhaps the only portrait of the man. Here it is in full glory. A crop is available on the Wikipedia article.


Additional 
Apparently some people make use of this bacteriophage story to add "scientific" weight to the idea of the purity of the Ganga. This, naturally is a bit of a misrepresentation, and it may dismay them to note that  most bacteriophage hunters today find the choicest phages in hospital sewage (often including phages that kill antiobiotic resistant bacteria). This inappropriate understanding of research findings encourages the status quo attitude of governments and people to assume that it is fine to dump garbage and sewage into these undoubtedly wonderful rivers because of their "miraculous" ability to recover from such abuse.


Saturday, December 11, 2010

Life on a raft

A friend recently approached me for some mapping help and this led me to rediscover some old tools (DIVA-GIS is one of the best free map tools that I know of) and forced me to look back at some recent thoughts. Generating a false-colour altitude map of the Indian Subcontinent heightened my appreciation of some observations and recent readings.
Elevations of India (click to see detail and legend)

Most people, even birdwatchers, often do not appreciate the peculiarities of species distribution and those that do not have the fortune of having a training in biology miss out entirely on the joy of mental stimulation that one gets when one tries to ask more questions.

On the border between northern Bengal (Jaigaon) and Bhutan (Phuntsholing) one can see an interesting phenomenon. Just walk into Bhutan and you see (apart from fewer humans and orderly traffic) that there is a lot of grass and vegetation and after walking up the first bend of the road you will find the commonest sparrow to be the Tree Sparrow, a species that simply refuses to accept life in India a few 100 metres away ! Along the busy roads of Jaigaon, only the House Sparrow may be seen, although it is also found on the Bhutan side. There is a difference in their habitat preferences and the Tree Sparrow seems to be the more picky species. Tree Sparrow do not have the marked sexual dimorphism that is found in the House Sparrow. When the two species occur in the same place, there is little confusion, but hybrids are known although they perhaps need further study. For instance, the only place where they are said to hybridize in India is not in the main distribution area but in the Eastern Ghats of Andhra Pradesh. The hill forests here are perhaps the least studied of the numerous biogeographical islands within India. The evidence for this supposed hybridization is not even well known - P. C. Rasmussen in her Birds of South Asia (2005) mentions this (presumably based on a specimen that shows hybrid characters) while Clement et al. (1993) (full references can be found on the Wikipedia articles) suggests that the species was introduced by ship to this part of India !

A painting by Bhawani Das (c. 1777)

Looking at the false-colour altitude map one can see a sharply delineated region in the Gangetic plains of Bihar in the altitude range of 50-100 m which corresponds to the region with the most records of the most-likely-extinct Pink-headed Duck. Now we do not really know much about that species, it may have lived in dense swampy wetlands and may even have been crepuscular in habit. Now we do not know about the habitat choice, behavioural or ecological adaptations evolved by this species and sadly perhaps, we will never know.

Considering this, one would imagine that we are better off when it comes to species that are not endangered but this just is not the case. Indeed, few have even really looked at the information available, not so much because they cannot, but because much of the information is scattered and it involves considerable work and trouble to bring together the data in a single location to even begin to examine for patterns. Often the tools required can only be handled by specialists and getting them to work across disciplines can be  daunting given the splintered scholarly ecosystem where academics carve niches outside of which they fear to step. Like mixed-species flocks of birds, interdisciplinary associations must be a tricky balance. A pleasant surprise however comes in the recent work on the  isolation and speciation of two high altitude birds from Southern India - the Rufous-bellied Shortwing and the White-bellied Shortwing. - these birds, whose exact higher level relationships are still shrouded (the genus placement remains questionable with scientists merely guessing that it should be close to the Himalayan Myiomela),  appears to have had ancestors that were widespread when the climate was a lot cooler. With changes in climate, populations were pushed up into the higher reaches of the hills of Peninsular India. Not being strong fliers , these birds were restricted into breeding locally within their own little pools (or beanbags )  and over time, these populations diverged in form, shaped by accident and selective forces into forms that are very different in plumage.

Disjunct distribution of Nephenthes

Now this is not an isolated incident, it is the norm although the isolation mechanisms and forces are harder to identify in other cases. Looking at the islands formed by just plotting altitudes, it is clear that that numerous other studies of this kind could be made within India and naturally "islands" can be created by any kind of barrier. The effects depend on the mobility and the evolutionary history of the species under consideration. Look at this distribution of pitcher plants in the genus Nephenthes for instance. It is well accepted that the Indian Plate rafted away from Gondwana into Asia but lots of debate exist on the timing and presence of bridges. These debates are largely raised by fossil evidence or surprising discoveries like the Purple frog. A recent talk (and paper) at IISc by Prof. Ashok Sahni was particularly interesting - working in an isolated island of scholarship in northern India, his team has looked at insects in Indian amber dating to the Eocene  - apparently there are tons of these fossils in lignite mines and they are usually just destroyed. And the wealth of information trapped there is being looked at - by the worlds leading  paleo-entomologists including David Grimaldi . Apparently the endemism levels in insect are high for India as most of  the insect fauna got onto the raft from Gondwanaland. These fossils come from after the K-T incident (65 million years ago).

Coming back to thoughts of Bhutan - the White-bellied Herons, 36 or so individuals - that live on the edge in the lower valleys of the Himalayan rivers surely have an interesting specialization, found only on the  lower elevations on rivers running southwards along the edge of the Himalayas  they are seriously threatened by dams that are needed mainly to power the growing populations of India. The world population has been optimistically estimated at 200 and as the bird-folks in Bhutan say - one hopes that the supposed 150 more birds in Burma are safer. And Burma is also the the last hope for the Pink-headed Duck.

Further reading

Friday, November 19, 2010

Splinters from the Cambrian explosion

One would love to be in a number of places but sadly this cannot be. Fortunately India is filled with people and hopefully there is someone near where I want to be, reading this, who can do the research and share the joy. The place I want to be in now is Rotung on the Dihang River, in Assam, not for birding although I would certainly look at the birds of the region, but to lift up and look under some stones and rotting logs in shaded humid places covered with a lot of leaf-litter. What I would be looking for is an animal from our deep evolutionary past - an animal that belongs to a phylum that is hardly even mentioned in college-level biology textbooks.

Meet Typhloperipatus williamsoni - the only representative of the Onychophora in the Indian region. Discovered in 1913 by Stanley Wells Kemp the Superintendent at the Indian Museum at  Calcutta when he went on the Abor expedition, hardly anything is known about this "velvet worm". The expedition really came about due to a local revolt in which the political officer of Sadiya, a Noel Williamson commemorated in the species name,  was killed. Strangely it seems that even political mission in those days often had a zoologist on board !

Rotung in red ( http://geonames.nga.mil/ )
The expedition found it under rocks along the Dihang river near Rotung. Fortunately one can locate the location today - and I can share the map because it is published by the US military and is therefore in public domain. The irony is that tax-payer funded work of the Indian government has to be purchased and even if you do, it is copyrighted and you are not even allowed to make a tracing of it ! And to add to all this sadness, little has been known about this species thanks to the wonderful way in which Indian establishments keep useful material away under lock and key - away from any interested researcher and available only to feed the far more needy Dermestidae and Thysanura. So imagine the joy when I finally get to access (thanks to the Biodiversity Heritage Library - an effort that has zero support from Indian museums and libraries) the scanned versions of the Records of the Indian Museum with the original description of Typhloperipatus. The genus name is from typhlo for blind and peripatus, an existing major genus of velvet worms was given since these worms were completely blind. The word Peripatus itself is derived from a path around a school, the one in which Aristotle taught and walked in a peripatetic way.
Peripatoides sp. (photograph by Bruno Vellutini)


The velvet-worms or Onychophorans are a mysterious group. They are found across the tropical zone and it is believed that their origins were in Gondwana. They were among the early land pioneers and we know that for certain, as they continue to require high humidity conditions to survive. Their unique body plan consists of a soft worm like body without an exoskeleton or clear segments and their legs are soft and tubular. There are no joints, the legs move by hydrostatic pressure - in effect they move somewhat like a caterpillar with tubular balloon legs that are inflated and deflated to achieve movement. The ends of these feet have tiny claws - from which the group is name is derived (Gr. onyches = claw) and the ancestry of the group and relationships is still much debated. Some have considered them as the leggy link between the annelids and the arthropods and their ancient divergence makes them difficult to study even using genetic material. They moult to grow and this has been used to place them in a suggested clade called the Ecdysozoa with the arthropods and other groups. Onychophora are mostly nocturnal, they have antennae with which they feel for prey - mostly small invertebrates - and when prey is detected, they squirt a sticky fluid, spiderman style, which arrests the victim. They then inject digestive juices into the prey and wait for the food to liquify and then suck it up along with their sticky slime. 
Close ups from the description of Typhloperipatus

Almost nothing is known about our Indian species, indeed nothing has perhaps ever been published after its discovery around 1913. Almost all members of the Peripatidae are on the endangered list - the Indian species however has evinced almost no interest - which is not surprising given that most conservation is money-dependent and small fleshy invertebrates lack the glamour needed to support flight and hotel bills. If ever the species can be found at Rotung or nearby regions in Assam, hopefully by interested locals (hope there are students, teachers and zoology enthusiasts reading) - the regions should be well worthy of some protection.

The Indian species is probably restricted north of the Brahmaputra - a major biogeographical barrier. Any relative discovered in south-western India would be even more spectacular, for it would probably show affinities to species from southern Africa.

Here is an extract from the original description:
The camp at Rotung where the majority of the specimens were found was situated at an elevation of 1320 ft. on a small plateau above  the Dihang River, one of the few approximately level pieces of ground seen in the Abor country. The site was at one time occupied by a village of Minyong Abors; but this was demolished in the latter half of 1911 and the villagers put up temporary dwellings half a mile further to the north at a considerably greater elevation.

The country in the vicinity of the camp was overgrown with dense scrub-jungle interspersed with stones and large trees, mostly jack-fruit. Here, as in so many parts, the ground had at one time been cleared for cultivation and scrub, which as a rule was not more than ten feet high, probably represented some eight or ten years' growth.

It was on the eastern side of the camp on dry gently sloping ground immediately above the edge of the great gorge of the Dihang River that Peripatus was found.

....
Solitary individuals were occassionally met with, but more usually two to four adults accompanied by a numer of young (sometimes as many as six) were collected together.
Further reading

Some videos to see
 

Saturday, October 9, 2010

The parasite within

I came across this ant one day as it sat still, refusing to be disturbed, on a leaf looking upwards in a remarkable posture and passed it. Returning back two hours later, I found it in the exact same place and posture. It was not dead, for the antennae were mobile and the gaster appeared distended and she probably was a species of Camponotus.

Praying - a parasitized ant ?
Ants are puzzling and captivating. I have no clue what made this ant go into a meditative state, but ants are successful beyond any human definition. And behind every successful organism is a slew of piggy-backing hitchhikers that include parasites that live on individual ants and unwelcome house guests that live off the labours of the colony. Some better known parasites of individual ants are fungi and nematodes. Nobody has yet found the adaptive function of the mind-altering Psilocybin in mushrooms but fungi in the genus Cordyceps and Ophiocordyceps make ants go quite crazy. An ant in a late stage of infection climbs up a twig and sinks its mandibles into the plant, before going into terminal coma after which the fungus emerges to produce its own "fruiting body" - from which arise new spores that will infect another generation of ants. The behaviour of the ant is modified by the fungus to its own benefit. It was thought that "driving" the ant higher up into the vegetation helped the dispersal of the fungal spores but some later research showed that the height was related to the best humidity and temperature conditions for the spores to germinate !
Cordyceps emerging out of a caterpillar

Species of Cordyceps  infect a range of insects. Up in the Himalayas, one species infects caterpillars of an as yet undetermined Hepialid moth (or possibly multiple species of them). The moth caterpillars emerge in the spring on high altitude meadows and some of them get infected by the fungus and a grotesque horn-like fruiting body emerges from the body of the dying caterpillar. Whether the fungus alters the behaviour of the caterpillars is unclear but it makes young men in the mountains across South Asia go mad - Yaartsa Gumbu - as this is known is collected by fit young men who climb up into the high-altitude regions across the region to harvest the caterpillars which are then sold to Tibetan and Chinese traders for an amazing fortune to be used in Chinese medicine. Like parasites, governments, Maoist quasi-governments and mafia in the region attempt to get a share of the enormous money (transactions are said to be made right on the high altitude meadows!) made in the harvest.

Coming back to our ants, their long evolutionary history has allowed them to adopt counter-measures. In some colonies, workers detect behavioural abnormalities among their fellow nest-mates. Any ants that are detected having perhaps a peculiar scent (members of each colony have their own characteristic scent) are quickly sent out of the nest by "bouncers".

Steve Yanoviak and T M Mushtak Ali at UAS, Bangalore
In 2009, some of  us in Bangalore had the good fortune of meeting up and listening to Steve Yanoviak Steve does his research high up in the canopy of the forests of South America and has discovered ants that glide and a bizarre nematode that infects ants. This nematode turns the gaster of an ant from its normal black colour into a large red-cherry like structure. These infected ants walk around with their berry-like hind ends raised and get eaten by  fruit-eating birds. Other ants, foraging for seeds on the forest floor pick up the droppings of these birds and continue the cycle of the nematode.

One of the greatest evolutionary thinkers, W D Hamilton had a knack of thinking about the strategies of organisms by putting himself in their "shoes". A successful parasite for instance should perhaps never kill its host, but manipulate its host to aid its own multiplication and to that end it could even "enhance" the behaviour of its host. In that light, the strategy of a virus like Ebola that produces near 100% fatality has to be rather bizarre - suggesting that humans are not the species with which they evolved. In 2000, some researchers found that rats infected by Toxoplasma acted rather oddly making them more likely to be preyed on by cats, the primary host of the parasite. This got others thinking if human behaviours (particularly "disorders") are in any way manipulated by parasites and infections and some have pointed out that some anti-psychotic drugs actually had the ability to kill parasitic organisms, particularly Toxoplasma and others have found bad drivers to have latent infections !

Now I am not sure what parasite got me to write this, but if you have some "good" viruses of the mind, make sure you spread them.

Further reading

Friday, September 24, 2010

When life is shi#

A skipper on bird dropping
People using the phrase need to watch out for they may very well be describing a life of heavenly bliss ! There are a whole lot of animals that depend entirely on the excretions of others. Scatology must be one of those subjects that universities are not advertising about but there are lots of amazing questions out there waiting to be researched. In some habitats there are very few sources of nutrition available, particularly for organisms with limited locomotion. A cave salamander has been found to be dependent on bat guano. A 2008 article discusses the antiquity of coprophagy in the beetles of the family Scarabaeidae - the dung beetles. It seems like they only took to this diet after the rise of the mammals , making it a relatively recent trend, evolutionarily speaking. The paper notes that herbivorous dinosaur dung is unlikely to have supported dung beetles due to the high nitrogen content - the result of the urinary and excretory tract merging into a cloaca. The feature is present in the birds and a study of beetle fauna in an oil bird cave found just one Scarabaeid, but that one fed on decaying plant matter. Coprophagy is however shown by many other insect groups and interestingly it is rather rare among the lepidoptera (as a primary diet)- two pyralids are known to live on mammalian droppings. Interestingly many adult butterflies will visit animal faeces, but this is related to special functions and do not appear to be part of their regular diet. The uninitiated are usually shocked when they see some of the prettiest butterflies they have ever seen perched on poop. Entomologists  however use the attraction to get closer to some of the rarer butterflies by baiting them. Skipper butterflies (Hesperiidae) have a particular fancy for bird droppings and some South American species are known to follow army ants which in turn are followed by ant-birds to get to the bird droppings !

Painting by J B Fraser with Greater Adjutants
An exhibition of old illustrations of India at the National Gallery of Modern Art caught my attention recently. An old (1819) watercolour by James Baillie Fraser showed Adjutant storks sitting over buildings in Calcutta, While researching the subject, I decided to improve the Wikipedia article on the Greater Adjutant Stork and realized in the process that this rather ugly-looking bird is essentially endangered by improved sanitation. At one time, there were thousands of this bird all over northern India, particularly in the city of Calcutta. They were busy feeding on the dead bodies disposed into the Ganges and disposing off offal, animal and human excreta with such efficiency that the Calcutta Municipal corporation of that time decided to make them their mascot, two birds facing each other became a part of the corporation logo. Their populations however rapidly declined during the Nineteenth Century and kept dropping to become the endangered bird that it is today. The best places to see them in India now are apparently garbage dumps in Assam and the only major breeding areas are in the Brahmaputra valley.

Other scavengers have declined sharply too- the most famous being the vultures - once found along the avenues of Delhi and floating in thermals in large numbers, they are almost absent today and the cause  is usually attributed to the non-steroidal anti-inflammatory drug Diclofenac. Interestingly these hit the vultures of the genus Gyps the most. There is however a smaller vulture - the Egyptian Vulture (Neophron percnopterus) which has also declined across its range and some Spanish scientists have suggested that they might have been affected by antibiotics - which apparently depress their innate immune system. Now this black-and-white vulture has a bright yellow bare facial skin and it seems that the birds derive the colour from carotenoids derived from a diet of mammal excreta. The usual ideas is that the fitter males have a brighter face and females choose them as their mates and it seems like this might have the cost of exposing their immune systems to the onslaught of bacteria. And having a weak immunity could be bad under those circumstances - so it seems like antibiotics, pain-killers and sanitation are not without ill-effects for some.

As another aside one should note that the ancient Egyptians who revered both the dung beetles and vultures  introduced some innovations in sanitation and it is comforting to see that there are scholars looking at these aspects of daily human life.

Further reading
  • Arillo, Antonio & Ortuño, Vicente M. (2008) Did dinosaurs have any relation with dung-beetles? (The origin of coprophagy). Journal of Natural History 42(19): 1405-1408
Postscript
  • Another blog post on an allied theme 
  • Campos-Arceiz, A., 2009. Shit happens (to be Useful)! Use of elephant dung as habitat by amphibians Biotropica. 41(4):406-407.

Monday, September 20, 2010

The twisted tale of the Lycaenid

Rapala in my backyard (false head raised)
The hair-like tails of butterflies in the family Lycaenidae are quite well known. Many of these butterflies move their hindwings further drawing attention to the antenna-like hairs. These are frequently white-tipped and further enhanced by an eye-like spot at the base of the tail. In some species in the genus Spindasis, the markings on the wing appear to radiate from the false-head and even the posture of the butterfly may be altered to make the hind end look like a raised-up head. For a very long time, their role has been decided as being an anti-predation mechanism, to lure potential predators towards the non-vital end and allowing them to make an escape with minor loss. Some species will even make a quick 180° turn after landing or walk backwards a few steps to further this impression. This behaviour has been termed as "anticipatory deflection" !

Lines radiating from the false head (Spindasis)
But ideas like this can be dismissed as merely "anecdotal" these days and need to be demonstrated more carefully and several researchers have attempted this. In the 1980s R K Robbins looked at the old ideas from Victorian times. Some suggested that having two heads confused predators while others suggested that an eye would alarm predators. The evidence that Robbins looked at was the extent to which symmetrical hind-wing tips with damage were found in the wild population. He first had to decide if that kind of damage could be caused only by failed predator attacks, particularly by birds. So he first kept specimens in cages and looked at the frequency with which symmetric wing damage could be produced without predators. Convinced that this did not happen in his control population, he looked at the damage levels in the wild. He also looked at the ease with which breakage of the wing occurs and found that breakage happens more easily at the tail end. Van Someren in 1922 noted that lizards invariably attacked the hind ends of Lycaenids. Robbins found that most of the symmetrical damage was at the hind end. This was however pointed out as merely an indicator of the number of butterflies that escaped and not a clear difference in the value of the "false head" to their survival. Some later researchers took butterflies without spots and used false tails and paint to artificially add eye-spots to dead Pierids and then placed them in a cage with birds and checked out what the birds do and found that they indeed tended to peck close to these spots. The tale does not end here - in 2007 someone decided that the 1922 observations needed to be looked at more carefully and they found that there was no real evidence that caged Anolis lizards attacked eyespots on butterflies (not Lycaenids, but Bicyclus). The authors further question the evidence of bird beak marks that were used in the past as well ! Turns out that there is a renewed interest in these questions and one recent paper by Ullasa Kodandaramaiah et al. suggests that large eyespots may startle small predators. One of his fellow researchers further adds that this may be particularly effective in low-light conditions. False eyes are also found on caterpillars and in these cases, they are often on the front end of the caterpillar and these may not have the same kind of survival value as in the Lycaenids. Indeed the suggestion here is that they serve to startle potential predators by appearing like the eyes of a larger predator.

Now here comes another twist - Cordero in 2001 suggested that predators preferentially attack the rear ends of butterflies and that the false head served to deflect the attacker making them come into view and increasing the likelihood of timely evasive action !

In the Sunderbans, there was an idea of using a face mask behind the head to reduce the attacks on people by tigers, which typically ambush from behind. The idea was that the tiger would try to approach from the front giving more time and a chance for the person to make an escape. Apparently tigers are now beginning to discriminate the false face. It should be interesting to look out for and observe the behaviour of lynx spiders near Lycaenids.

Credits

Vijay Barve - photograph of Spindasis vulcanus (Creative Commons /Wikimedia)

Further reading


Wednesday, September 15, 2010

Turning over a new leaf

The hoi polloi views insects as pesky fellow passengers on this crazy ball in space and science degrees hardly have an effect on most people. However insects are perhaps one of the most interesting fellow passengers around and more than make up for the annoyance of a few biters and blood-suckers. They came out of the waters a long time before the branching of life-forms with internal skeletons. Which means that they have had that much more time encountering the problems of life and solving them using "evolutionary algorithms". What interesting answers and questions might they have figured out ? (apart from perhaps finding that the answer is 42!)

Galls on Pongamia leaves
How does one find food on a planet like this ? There is so much green stuff and yet humans in a forest find so little that is edible. What has gone wrong here ? For someone who thinks about insects and plants, the real questions are not about how to keep the insects away from plants but about how plants keep them away and stay green in spite of the onslaught. Not every plant-eating insect feeds on every plant species and the few that are found in numbers on any plant has evolved such an array of tools to deal with their dinner and dining table.

Here are some Pongamia pinnata leaves I found not so long ago. One usually finds little outgrowths on the leaves. These are mostly insect galls, but galls may also be formed by fungi. If you cut an insect-gall you will likely find a central hollow, perhaps an exit hole on the base or tip and if you are lucky, a tiny larva somewhere. That could most likely belong to one of numerous wasps or flies and you will surely be hard-pressed to find anyone who can identify the species. Galls are not always shaped like this - they can be spherical, formed at the tip of a branch and botanists have been known to sometimes describe the gall as the characteristic fruit of a new found tree species. What exactly is happening is something to consider - is the plant trying to isolate the insect like a cyst forms to engulf a foreign body or is the insect manipulating the biochemistry of the plant to make it produce tasty tissue around it ? Turns out that the latter is often the case and sometimes the gall-inducer seems to be capable of inducing galls with very specific shapes, colours and structures (this article with illustrations is particularly worthy of reading).

Ficus at Hebbal with leaves eaten away
Anyone who has worked with plant-tissue culture can tell you what a complex and sensitive cocktail of auxins, cytokinins and other compounds have to be delivered to get a bunch of cells to grow into something that resembles a plant. Now, given that the structure is essentially an insect induced "fruit", there must be a few that people can eat and after some research I came upon the "Mulga apple" (apparently on Acacia aneura) of Australia but the number of cases of edible galls seems rather low. I have a rather vague recollection of seeing swellings on nettles in the Uttaranchal Himalayas and some comments on their edibility (if anyone has eaten this or knows more please do let me know). Now plants are not taking such damage lying down and they have come up with their own defences. (some years ago some of us worked on this article on Wikipedia and hopefully it is still readable) Turns out that the biggest human use of galls is in the extraction of tannins - and tannic acid - a mixture of potent chemicals used to treat leather (tanning leather), at least in the past. And printing ink was once made by treating rust with gall extracts ! Tannins are essentially anti-insect chemicals and in some plants, the tannin content goes up rapidly when the plant is physically damaged by insects this can have an effect on the insects. Now if the insects are such experts in plant biochemistry, perhaps the plants have in turn figured out the most critical insect biochemical gears into which their molecular spanners should be thrown. Given that these are potent chemicals tailored through evolutionary time-scales, there must be something in these Chinese cocktails worthy of some serious scientific attention.

Leaf mine - note widening with age of miner
The birdwatcher's of Bangalore hold regular field outings at Hebbal and Lalbagh on the first and second Sundays of each month. On one of the Hebbal outings around June and July we came across this Ficus, the leaves with holes, the ground below covered in tea-like frass and you could hear the fall of caterpillar droppings. The caterpillars were extremely pretty, moving along the trunk in large numbers, presumably the last instars looking for a place to pupate. Unfortunately we have been unable to obtain any further identification of this lepidopteran caterpillar. With the monsoon rains, the tree has now shed all its leaves. Now leaf-shedding is actually a bit of a story of its own and there are numerous theories on when a tree "ought" to shed its leaves "if its purpose" was to achieve something and one such function, teleologically speaking, is to get rid of pesky insects. But surely dropping leaves is not a good strategy to get rid of that eat leaves . At least certainly not without withdrawing all the best nutrients.

The caterpillars on the Ficus (unidentified)
Perhaps the easiest insect targets to get rid off by leaf-shedding would be things like galls and leaf miners. Life miners, usually moth or fly larvae live in the layer of the leaf and feed under the protection of the leaf surface, no rain, no drying and perhaps some protection from parasites and predators.
So, next time you have something to ponder over when you see a fallen leaf...

Turns out that some studies suggest that leaf dropping does not kill many leaf-miners and so seems unlikely while others point out that gall infestation induces early leaf shedding.

Postscript

Also discovered Huitlacoche caused by Ustilago maydis

Sunday, September 5, 2010

Why look like an ant?

Aint an ant

This morning, I found this ant-like chap on the wall. Anyone who does not look carefully might pass it off as an ant but anyone who knows a bit about the elbowed antennae of the ant family would know it was not. But what was it ?

It had a slender neck and the long rostrum suggestive of a Reduviid of which this could have been a nymph but how wrong can one be !

Turns out that this is Dulichius inflatus, a bug of the family Alydidae. And it is not a nymph, but an adult and it is (nearly) wingless!

"Some ant like forms are the most remarkable, and Mr Wroughton recently exhibited to the London Entomological Society an Indian Coreid which associates with the Ant Polyrhachis spiniger and is furnished with spines on the pronotum &c., resembling almost exactly those possessed by the Ant" - W L Distant, Rhynchota, Fauna of British India
Elbowed antennae ?

Looking up the entry in the Fauna of British India, one learns that it was described by W F Kirby. And a later specimen produced by R C Wroughton of the now largely defunct Bombay Natural History Society was described as Dulichius wroughtoni which became a junior synonym. Wroughton notes that the species is commonly found under rocks along with colonies of Polyrhachis spiniger (which seems to be synonym of P. lacteipennis) and that the spine structure varies widely across individuals !

A real Polyrhachis
What can one do after obtaining an identification from the few taxonomists left in India and researching the literature using the name? One could create a Wikipedia entry for a start and that makes one learn a little more too, sometimes it can be a bit of a consolation, especially when one finds out that W F Kirby, entomologist who described the species also thought it was a Reduviid ! A later amateur entomologist and physician from Finland, Bergroth who saw a specimen from Wroughton described the species as Dulichius wroughtoni and then came across Kirby's own description and decided that Kirby's had priority. However his note on Kirby is quite interesting, particularly as it comes from an amateur evaluating a self-professed expert at a museum of that time-period:

Mr. Kirby has had the kindness to send me a copy of his work on the Heteroptera and Homoptera of Ceylon (Journ. Linn. Soc. XXIV, pag. 72—176, with 3 plates). The author says in the introduetion, that he has thought his paper „would be rendering a real service to science". I think no serious hemipterist will be of the same opinion. As the author is assistant in the British Museum, one schould expect to find informations on the real systematic position of the many dubious Hemiptera deseribed from Ceylon by Walker, and it is therefore with great regret we find Mr. Kirby's work to be entirely in Walker's style and almost without any scientific value Mr. Kirby further says, that he will not create many new genera, 'until those already proposed have undergone a thorough and much-needed revision, which at present I have no time to "attempt".' It is to be hoped, that Mr. Kirby never will find time to a such revision, as it seems to be unknown to him, that the genera of Hemiptera have already undergone a thorough and most excellent revision by Stäl.


Postscript
Happened to visit one of the websites where photographers dump their pictures and found some rather excellent photos in the chaotic pile. Interestingly one from Bangalore seems to have been taken around the same time. Seems like the rains might be important factor for some aspect of their life cycle:

Photo 1
Photo 2

Also discovered a photograph of a Polyrhachis that I had taken - here sitting, perhaps in a defensive posture, on the spadix of a pink Anthurium - now added above.