Archive for the 'Ecology' Category



Sunday Article: House Sparrow

Sunday article by Mohan Pai
 
 House Sparrow
 
Passer domesticus
 


 

…there’s a providence in the fall of a sparrow  -Hamlet (Shakespeare)

India’s foremost ornithologist Dr. Salim Ali published his autobiography in1985. He very aptly gave the title “The Fall of a Sparrow”.

Universally familiar in appearance, the widespread and once abundant house sparrow has become a mystery bird and is becoming increasingly rare all over the world. Perky and bustling, house sparrows have always been seen, mingling with finches in the fields in autumn and winter, but now weeks pass without a single one putting in an appearance.

They are vanishing from many big cities, but are still not uncommon in small towns and villages. India has seen a massive decline of sparrows in recent years and on the world map too. Once a commonplace bird in large parts of Europe, its numbers are decreasing. In the Netherlands, the House Sparrow is even considered an endangered species. Their recent decline has earned them a place on the Red List in the Netherlands. Similar precipitous drops in population have been recorded in the United Kingdom. French ornithologists have charted a steep decline in Paris and other cities. There has been an even sharper fall in the urban areas in Germany, the Czech Republic, Belgium, Italy and Finland.

History

It is thought that the House sparrow originated in the Mediterranean and expanded into Europe with the growth of civilization. At the insistence of man did the sparrow make its way across the Atlantic to the United States in 1850.
The house sparrow is an intelligent bird that has proven to be adaptable to most situation, i.e. nest sites, food and shelter, so it has become the most abundant songbird in the world.
 
Sparrows are very social birds and tend to flock together through most of the year. A flock’s range covers 1.5-2 miles, but it will cover a larger territory if necessary when searching for food. The sparrow’s main diet consists of grain seeds, especially waste grain and live stock feed. If grain is not available, its diet is very broad and adaptable. It also eats weeds and insects, especially during the breeding season. The parasitic nature of the house sparrow is quite evident as they are avid seekers of garbage tossed out by humans. In spring, flowers (especially those with yellow colours) are often eaten crocuses, primroses and aconites seem to attract the house sparrow most. The birds also hunt butterflies.

Housing

House sparrows are generally attracted to buildings for roosting, nesting, and cover. They look for any man-made nook or cranny to build their nests. Other nesting sites are clothes line poles with the end caps open, lofts, kitchen garden etc. The sparrow makes its home in areas closely associated with human habitation.

The House Sparrow (Passer domesticus) is a member of the old world sparrow family Passeridae. Some consider it to be a relative of the Weaver Finch Family. A number of geographic races have been named, and are differentiated on the basis of size and cheek colour.
Birds of the western hemisphere are larger than those in the tropical South Asian populations.

In India, it is popularly known as Goraiya in the Hindi belt. In Tamil Nadu and Kerala it is known as Kuruvi. Telugu language has given it a name, Pichhuka, Kannadigas call it Gubbachchi, Gujaratis call it Chakli where as Maharashtrians call it Chimani. It is known as Chiri in Punjab, Chaer in Jammu and Kashmir, Charai Pakhi in West Bengal, and Gharachatia in Orissa. In Urdu language it is called Chirya while Sindhi language has termed it as Jhirki.

Features

This 14 to 16 cm long bird has a wing span of 19-25 cm. It is a small, stocky song bird that weighs 26 to 32 grams. The male sparrow has a grey crown, cheeks and underparts, and is black at the throat, upper breast and between the bill and eyes. The bill in summer is blue-black and the legs are brown. In winter the plumage is dulled by pale edgings, and the bill is yellowish brown. The female has no black coloring on the head or throat, or a grey crown her upper part is streaked with brown. The juveniles are deeper brown, and the white is replaced by buff the beak is dull yellow. The House Sparrow is often confused with the smaller and more slender Tree Sparrow, which, however, has a chestnut and not grey crown, two distinct wing bars and a black patch on each cheek
The sparrow’s most common call is a short and incessant, slightly metallic cheep, chirrup.

Reproduction

The nesting sites are varied – in holes in buildings or rocks, in ivy or creepers, on houses or riverbanks, on sea-cliffs or in bushes in bays and inlets. When built in holes or ivy, the nest is an untidy litter of straw and rubbish, abundantly filled with feathers. Large well- constructed domed nests are often built when the bird nests in trees or shrubs, especially in rural areas.

The House Sparrow is quite aggressive in usurping the nesting sites of other birds, often forcibly evicting the previous occupants, and sometimes even building a new nest directly on top of another active nests with live nestlings. Eggs are variable in size and shape as well as markings. Eggs are incubated by the female. The sparrow has the shortest incubation period of all the birds, 10 -12 days, and a female can lay 25 eggs each summer. The reproductive success increases with age and this is mainly by changes in timing, with older birds breeding earlier in the season.
 

Causes of Decline

There are various causes for dramatic decrease in their population, one of the more surprising being the introduction of unleaded petrol, the combustion of which produces compounds such as methyl nitrite, a compound which is highly toxic for small insects, which forms a major part of a young sparrow’s diet. Other being areas of free growing weeds, or reduction in number of badly maintained buildings, which are important nesting opportunities for sparrows. Ornithologists and wildlife experts speculate that the population crash could also be linked to a variety of factors like the lack of nesting sites in modern concrete buildings, disappearing kitchen gardens, increased use of pesticides in farmlands and the non- availability of food sources.

The widespread use of chemical pesticides in farmlands has resulted in the killings of insects on which these birds depend. Seed-eating birds like sparrows have to depend on soft- bodied insects to feed their young ones. The other possibility could be increased predation by crows and cats, while crows have grown in number as a result of garbage accumulation in the city. Changing lifestyles and architectural evolution have wreaked havoc on the bird’s habitat and food sources. Modern buildings are devoid of eaves and crannies, and coupled with disappearing home gardens, are playing a part in the disappearing act.
 
Today, one sadly misses the sight of sparrows hopping from branch to branch in the bushes outside one’s house and their chirping.
 

 
House Sparrow -Native range in dark green and introduced range in light green
 
References: House Sparrow – Declining Population by Kalpana Palkhiwala, Wikiped
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Sunday Article: Seahorse – The Pregnant Male!!!

Sunday article by Mohan Pai

 
 
Seahorses
Hippocampus
 
 
 
 
The Pregnant Male !!!
Seahorses are among the only animal species on Earth in which the male bears the unborn young. Male seahorses are equipped with a brood pouch on their ventral, or front-facing, side. When mating, the female deposits her eggs into his pouch, and the male fertilizes them internally. He carries the eggs in his pouch until they hatch, then releases fully formed, miniature seahorses into the water.
When people first hear about seahorse male getting pregnant, the question that naturally follows is, “So what makes them male?” The simple answer is sperm. The distinction between scarce round eggs and prolific tadpole-like sperm is essentially all that separates woman from man. 
  
This delicate, diminutive creature (size of a tea cup) has enchanted people for thousands of years. It was Aristotle, the Greek philosopher who first wrote about the unusual habits of the Syngnathidae family in the third century BC..
In ancient Rome, the people believed that when Neptune, the god of the ocean, traveled, he swished through the water in a chariot drawn by gigantic, enchanted horses who could breathe underwater. When fishermen first saw the minute sea horses, they thought that they must be the offspring of Neptune’s horses, and they were fascinated with the little creatures.
Now we know that sea horses are, of course, not horses at all, they are merely a unique kind of fish. But these petite sea creatures with the elongated snout still seem as magical to us as they were to the ancient Romans.They are playful and graceful, and divers often stop to watch these marvelous creatures frolic around in the depths of the sea.
 
Habits
Sea horses don’t have scales the way that many other kinds of fish do. Instead, they have bony plates underneath their skin, like a small suit of armor to protect them from harm. There are numerous different kinds of sea horses, and they come in varying colors and sizes. Sea horses can be very tiny, and some are no larger than the length of the fingernail on your pinkie finger. Many types of sea horses have a unique way to camouflage themselves and hide from their enemies. Some can change colors, and chameleon-like, blend in with their surroundings. Some sea horses look so much like their surroundings that it is difficult to see them unless one is looking closely, and this helps to hide them from predators. One kind of sea horse even grows hair-like skin extensions so that they will blend in with the plant life whose fronds wave gently in the water of the ocean. Seahorses have no teeth and no stomach. Food passes through their digestive systems so quickly, they must eat constantly to stay alive

Breeding

It is the male, not female, sea horses who are impregnated, and they can have up to 1500 babies at one time. Males have a special patch or pouch on their belly that provides incubation for the female’s eggs. The female transfers the eggs to the male’s pouch, and they then attach to the wall of the male’s pouch. After the male fertilizes the eggs, they are retained within the brood pouch to develop. When the young hatch, the male expels them from the pouch and they emerge looking like miniature versions of the adults. During the entire pregnancy, a mated pair of sea horses will dance in the water together every day just after the sun has risen. Scientists have speculated for years on the reason for this, but no one really knows why the sea horses execute this peculiar, beautiful greeting dance.
 
 

Seahorse distribution map
They are found in shallow, coastal, tropical and temperate waters from about 45°S to 45°N. They inhabit many ecologically sensitive aquatic habitats, including coral reefs, sea grasses, mangroves and estuaries, with most species in the Indo-Pacific and western Atlantic regions. Sea horses primarily occupy inshore habitats in narrow strips along the coast and prefer shallow waters (< 15 m depth), but have been encountered in shallow rock pools. Many temperate and tropical sea horse species inhabit sea grass meadows, while others inhabit mangrove ecosystems and coral reefs.
 
In medicine

Ironically, it is their very popularity that places them in danger, as they are sought in large numbers for use in traditional medicine, aquarium fish and curios (souvenirs).

Seahorses are used as an ingredient in traditional medicine, particularly in southeast Asia where traditional Chinese medicine and its derivatives (e.g. Japanese and Korean traditional medicine)are practiced and have been used perhaps for about 600 years. Seahorses are credited with having a role in increasing and balancing vital energy flows within the body, as well as a curative role for such ailments as impotence and infertility, asthma, high cholesterol, goitre, kidney disorders, and skin afflictions such as severe acne and persistent nodules. They are also reported to facilitate parturition, act as a powerful general tonic and as a potent aphrodisiac.

It was conservatively estimated that at least 20 million sea horses (more than 56 metric tonnes) were caught for the traditional medicine market. In addition, more than one million live sea horses are caught for aquarium trade, mostly destined for sale in North America, Europe, Japan and Taiwan. The value of sea horses is quite high; the price of dried sea horses in Hong Kong markets ranges from Rs 11,500 to 50,400 (US$ 275 to 1200) per kg depending on the species, quality and size. About 50 countries are involved in sea horse exploitation.

Medicinal seahorse
India is one of the largest exporters of dried sea horses globally, exporting at least 3.6 tonnes (~ 1.3million sea horses) annually, and contributes to about 30% of the global seahorse trade. There is also a significant trade in sea horses as aquarium fishes,as supplements in some specialized cuisine and as curios. Sea horses are exploited both as an incidental catch (by-catch in trawl nets) and target catch, for export. Presently, the commercial exploitation of sea horses is being carried out from Tamil Nadu and Kerala coasts. Along Ramnad coast in Tamil Nadu, dried sea horse is used as a medicine to arrest whooping cough in children.

Goa– Maharashtra coast also indicated a similar usage. Demand for medicinal purposes has increased 10-fold during the 1980s and continues to grow at an annual rate of about 8–10% in China alone, predominantly due to China’s economic boom which promotes increased consumer-spending on traditional medicines.
 
Today, sea horse populations face an unpredictable future. They are not as yet on the endangered list, or even the potentially threatened list, but scientists and other experts are worried. Fishermen are catching far too many of them, and more of their underwater habitats are destroyed each day by pollution and other human carelessness. 
 

Population data for most of the world’s 35 seahorse species is sparse. However, worldwide coastal habitat depletion, pollution, and rampant harvesting, mainly for use in Asian traditional medicine, have made several species vulnerable to extinction.

In Mythology

The hippocamp or hippocampus in Greek and often called a sea-horse in English, is a mythological creature shared by Phoenician and Greek mythology, though the name by which it is recognised is purely Greek; it became part of Etruscan mythology. It has typically been depicted as a horse in its forepart with a coiling, scaly, fishlike hindquarter.

Hippocamp in Roman mosaic in the thermae at Aquae Sulis (Bath)
Homer described Poseidon, who was god of horses (Poseidon Hippios) as well as of the sea, drawn by “brazen-hoofed” horses over the sea’s surface, and Apollonius of Rhodes, being consciously archaic in Argonautica describes the horse of Poseidon emerging from the sea and galloping away across the Libyan sands In Hellenistic and Roman imagery. However, Poseidon (or Roman Neptune) often drives a sea-chariot drawn by hippocampi. Thus hippocamps sport with this god in both ancient depictions and much more modern ones, such as in the waters of the eighteenth-century Trevi Fountain in Rome surveyed by Neptune from his niche above.
Poseidon’s horses, which were included in the elaborate sculptural program of gilt-bronze and ivory, added by a Roman client to the temple of Poseidon at Corinth, are likely to have been hippocamp.
 
 
References: Wikipedia, National Geographic, essortment.com, National Institute of Oceanography, Goa.
 
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Sunday Article: Coral Reefs – “Living Organisms”

Coral Reefs
 
“The Living Organisms”
 

 
Some of the biodiversity of a coral reef, in this case the Great Barrier Reef, Australia
 
Called “rainforests of the sea”, coral reefs are living organism and the oldest, most productive ecosystems on earth.
 
Existing for more than 500 million years, Corals are marine organisms from the class Anthozoa and exist as small sea anemone-like polyps, typically in colonies of many identical individuals. The group includes the important reef builders that are found in tropical oceans, which secrete calcium carbonate to form a hard skeleton.
 A coral “head”, commonly perceived to be a single organism, is formed from myriads of individual but genetically identical polyps, each polyp only a few millimeters in diameter. Over thousands of generations, the polyps lay down a skeleton that is characteristic of their species. An individual head of coral grows by asexual reproduction of the individual polyps. Corals also breed sexually by spawning, with corals of the same species releasing gametes simultaneously over a period of one to several nights around a full moon.

Although corals can catch small fish and animals such as plankton using stinging cells on their tentacles, these animals obtain most of their nutrients from photosynthetic unicellular algae called zooxanthellae. Consequently, most corals depend on sunlight and grow in clear and shallow water, typically at depths shallower than 60 metres (200 ft). These corals can be major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the enormous Great Barrier Reef off the coast of Queensland, Australia. Other corals do not have associated algae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,000 metres (9,800 ft). Examples of these can be found living on the Darwin Mounds located north-west of Cape Wrath, Scotland. Corals have also been found off the coast of Washington State and the Aleutian Islands in Alaska.Corals coordinate behaviour by communicating with each other.
 
Globally, coral reefs are under threat from climate change, ocean acidification, overuse of reef resources, and harmful land-use practices. High nutrient levels such as those found in runoff from agricultural areas can harm reefs by encouraging excess algae growth.
 
Formations

Coral reefs can take a variety of forms, defined in following:

Fringing reef – a reef that is directly attached to a shore or borders it with an intervening shallow channel or lagoon.

Barrier reef – a reef separated from a mainland or island shore by a deep lagoon (Great Barrier Reef).

Patch reef – an isolated, often circular reef, usually within a lagoon or embayment.

Apron reef – a short reef resembling a fringing reef, but more sloped; extending out and downward from a point or peninsular shore.

Bank reef – a linear or semi-circular shaped-outline, larger than a patch reef.
Ribbon reef – a long, narrow, somewhat winding reef, usually associated with an atoll lagoon.

Atoll reef – a more or less circular or continuous barrier reef extending all the way around a lagoon without a central island.

Table reef – an isolated reef, approaching an atoll type, but without a lagoon.
Distribution
Coral reefs are estimated to cover 284,300 square kilometers, with the Indo-Pacific region (including the Red Sea, Indian Ocean, Southeast Asia and the Pacific) accounting for 91.9% of the total. Southeast Asia accounts for 32.3% of that figure, while the Pacific including Australia accounts for 40.8%. Atlantic and Caribbean coral reefs only account for 7.6%.
  
 
 

 
Location map of coral reefs
 
Locations of coral reefs.
Although corals exist both in temperate and tropical waters, shallow-water reefs form only in a zone extending from 30°N to 30°S of the equator. Tropical corals do not grow at depths of over 50 m (165 ft). Temperature has less of an effect on the distribution of tropical coral, but it is generally accepted that they do not exist in waters below 18 °C., and that the optimum temperature is 26-27° Celsius for most coral reefs. The reefs in the Persian Gulf however have adapted to temperatures of 13° Celsius in winter and 38° Celsius in summer. Deep water coral is more still exceptional since it can exist at greater depths and colder temperatures. Although deep water corals can form reefs, very little is known about them.

Famous coral reefs and reef areas of the world include:

The Great Barrier Reef – largest coral reef system in the world, Queensland, Australia;
The Belize Barrier Reef – second largest in the world, stretching from southern Quintana Roo, Mexico along the coast of Belize to the Bay Islands of Honduras.
The New Caledonia Barrier Reef – second longest double barrier reef in the world, with a length of about 1500 km.
The Andros, Bahamas Barrier Reef – third largest in the world, following the east coast of Andros Island, Bahamas, between Andros and Nassau.
The Red Sea Coral Reef – located off the coast of Israel, Egypt and Saudi Arabia. 
 Pulley Ridge – deepest photosynthetic coral reef, Florida 
 Numerous reefs scattered over the Maldives 
 Ghe Raja Ampat Islands in Indonesia’s West Papua province offer the highest known marine diversity.
 

 Anatomy of Coral Polyp
 
 References: Wikipedia
 
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Sunday Article: The House Crow

Sunday article by Mohan Pai
 
The House Crow
Corvus splendens

Photo courtesy: J. M. Garg
 
In India, the crow is considered a spirit of the ancestors. During Shraddha or death ceremony pinda (food) is offered and is considered accepted only if a crow arrives and eats it.
 
The house crow is a widespread resident of India and has a special place in Hindu society. During death ceremonies (shraddha) and Pitru Paksha, the practice of offering food or pinda to crows is still in vogue since crows are believed to represent our ancestors.
 
The House Crow, also known as the Colombo Crow is a common bird of the Crow family that is of Asian origin but now found in many parts of the world, where they arrived assisted by shipping. It is between the Jackdaw and the Carrion Crow in size (40 cm in length) but is relatively slimmer than either. The forehead, crown, throat and upper breast are a richly glossed black, whilst the neck and breast are a lighter grey-brown in colour. The wings, tail and legs are black. There are regional variations in the thickness of the bill and the depth of colour in areas of the plumage.
 
Distribution and habitat
It has a widespread distribution in southern Asia, being native to Nepal, Bangladesh, India, Pakistan, Sri Lanka, Maldives and Laccadive Islands, South West Thailand and coastal southern Iran. It has been introduced to East Africa around Zanzibar (around 1897[3]) and Port Sudan, and arrived in Australia via ship but has up to now been exterminated. Recently it has made its arrival in Europe, and has been breeding in the Hook of Holland since 1998. It is associated with human settlements in all of its range, from small villages to large cities.

Due to a human population explosion in the areas it inhabits, this species has also proportionately multiplied. Being an omnivorous scavenger has enabled it to thrive in such circumstances.
 
 

House Crow – distribution
The invasive potential for the species is great all over the tropics. It has as yet not established in the New World. This species is able to make use of resources with great flexibility and appears to be associated with humans and no populations are known to exist independently of human
 
Size: 42 cm Weight: 250-350 gm
Identification: Plumage is glossy black, except for the nape, sides of the head, upper back and breast, which are grey. Bill, legs, and feet also black. Sexes alike.

Food: Omnivorous. Diet includes seeds, fruit, grain, nectar, berries, bird’s eggs, nestlings, mammals, reptiles, amphibians, fish, insects, wide range of carrion.It is a highly opportunistic bird and given its omnivorus diet, it can survive on anything that is edible.

Call: Normal call a harsh qua qua or a nasal kaan kaan. It also has a couple of softer calls when resting or during courtship.

Habits: Highly vocal, gregarious birds, seemingly unafraid of humans. Aggressive, will attack and chase off any large bird of prey. Birds have been reported taking food from school children and killing chicks of domestic fowls. Breeding pairs will repeatedly dive bomb humans near the nest.

Habitat: Wholly dependent on human habitation; consequently found in villages, towns, and cities throughout its range. Resorts to altitudinal and seasonal local movements in colder northern areas in winter. Replaced by Large-billed Crows and Jungle Crows in mountains and forests respectively.

Breeding: Solitary nester except in areas of high population density. Will use trees, buildings, or other artificial structures for rough stick nest lined with coir or other fibre. Four to five pale blue-green eggs, speckled with brown. Breeding season March through July. Incubation 16–17 days; fledging 21–28 days.

Status: Not threatened. Abundant in its range to the point of being a pest and a threat to other bird species.

Photo courtesy Muhammad Mahdi Karim
 
References: Wikipedia, birding.in
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Sunday Article: The Fungi

Sunday article by Mohan Pai

 
 
The Fungi

 
Wild, edible mushrooms, especially the short-lived variety that blooms with the onset of monsoons is a much relished variety on the western coast.
The Fungi are large group of parasites and decomposers that include mushrooms, molds and yeasts. Fungi were once grouped along with plants but are now thought to be more closely related to animals and are treated as a separate kingdom.
A fungus is any member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. The Fungi are classified as a kingdom that is separate from plants and animals. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose. The discipline of biology devoted to the study of fungi is known as mycology, which is often regarded as a branch of botany, even though genetic studies have shown that fungi are more closely related to animals than to plants.Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil, on dead matter, and as symbionts of plants, animals, or other fungi. They may become noticeable when fruiting, either as mushrooms or molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange.
The fungi have long been used as a direct source of food, such as mushrooms and truffles, as a leavening agent for bread, and in fermentation of various food products, such as wine, beer, and soy sauce. Since the 1940s, fungi have been used for the production of antibiotics, and, more recently, various enzymes produced by fungi are used industrially and in detergents. Fungi are also used as biological agents to control weeds and pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, that are toxic to animals including humans. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Losses of crops due to fungal diseases (e.g. rice blast disease) or food spoilage can have a large impact on human food supplies and local economies.However, little is known of the true biodiversity of Kingdom Fungi, which has been estimated at around 1.5 million species, with about 5% of these having been formally classified.

Lichens are a symbiotic union between fungus and algae (or sometimes photosynthesizing bacteria). The algae provide nutrients while the fungus protects them from the elements. The result is a new organism distinctly different from its component species. Around 25,000 species of Lichens have been identified by scientists.
Medicinal mushrooms
The Kingdom Fungi includes some of the most important organisms, both in terms of their ecological and economic roles. By breaking down dead organic material, they continue the cycle of nutrients through ecosystems. In addition, most vascular plants could not grow without the symbiotic fungi, or mycorrhizae, that inhabit their roots and supply essential nutrients. Other fungi provide numerous drugs (such as penicillin and other antibiotics), foods like mushrooms, truffles and morels, and the bubbles in bread, champagne, and beer. Fungi also cause a number of plant and animal diseases: in humans, ringworm, athlete’s foot, and several more serious diseases are caused by fungi. Because fungi are more chemically and genetically similar to animals than other organisms, this makes fungal diseases very difficult to treat.
 
Edible mushrooms
Edible mushrooms are used extensively in cooking, in many cuisines (notably Chinese, European, and Japanese). Though mushrooms are commonly thought to have little nutritional value, many species are high in fiber and provide vitamins such as thiamine, riboflavin, niacin, biotin, ascorbic acid. Mushrooms are also a source of some minerals, including selenium, potassium and phosphorusMost mushrooms that are sold in market have been commercially grown on mushroom farms. The most popular of these, Agaricus bisporus, is generally considered safe for most people to eat because it is grown in controlled, sterilized environments, though some individuals do not tolerate it well.

The button mushroom (Agaricus bisporus), one of the most widely cultivated mushrooms in the world.

At present 3 mushrooms are being cultivated in India. These are : the white mushroom (Agaricus bisporus), the paddy-straw mushroom (Volvariella vovvacea) and the oyster mushroom (Pleurotus sajor-caju). Of these, A. bisporus is the most popular and economically sound to grow and is extensively cultivated throughout the world
Hallucinogenic mushrooms
Some mushrooms possess psychedelic properties. They are commonly known as “magic mushrooms” “mushies” or “shrooms” and are available in smart shops in many parts of the world, though some countries have outlawed their sale. Because of their psychoactive properties, some mushrooms have played a role in native medicine, where they have been used in an attempt to effect mental and physical healing, and to facilitate visionary states.
Amanita phalloides accounts for the majority of fatal mushroom poisonings worldwide.
 
Poisonous mushrooms
Of the many thousands of mushroom species in the world, only 32 have been associated with fatalities, and an additional 52 have been identified as containing significant toxins. By far the majority of mushroom poisonings are not fatal, but the majority of fatal poisonings are attributable to the Amanita phalloides mushroom.
 
Famous poisonings
Roman Emperor Claudius is said to have been murdered by being fed the death cap mushroom. Pope Clement VII is also rumored to have been murdered this way. Holy Roman Emperor Charles VI and Tsaritsa Natalia Naryshkina are believed to have died from eating the death cap mushroom. The composer Johann Schobert died in Paris, along with his wife and one of his children, after insisting that certain poisonous mushrooms were edible.

References: Wikipedia

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Indian Spiders

Sunday article by Mohan Pai

 
 
 
Indian Spiders
Arachnids
 
Pic courtesy: Sandilya Theurkauf
 
Cobwebs of deception
 
 
In the gathering light of dawn, an orb-web spider sits motionless in the centre of its web. The web is one of nature’s most ingenious traps – woven from at least six types of silks and constructed with mathematical precision. But spiders are so short-sighted that they can barely see their webs. Instead they build them by touch, and instinct guides their every move. Weight for weight, spider’s silk is stronger than steel. Even so, webs soon get damaged and need to be repaired. When the damage gets too great, a spider instinctively knows to give up on repair work, and start afresh. It eats up the old web so that it can digest and recycle the silk. Each kind of spider always makes exactly the same kind of web.
 
‘Come into my parlour…’
 
Spiders are generally regarded as predatory. The best-known method of prey capture is by means of sticky webs. Varying placement of webs allows different species of spider to trap different insects in the same area, for example flat horizontal webs trap insects that fly up from vegetation underneath while flat vertical webs trap insects in horizontal flight. Web-building spiders have poor vision, but are extremely sensitive to vibrations. Females of the water spider Argyroneta aquatica build underwater “diving bell” webs which they fill with air and use for digesting prey, molting, mating and raising offspring. They live almost entirely within the bells, darting out to catch prey animals that touch the bell or the threads that anchor it. A few spiders use the surfaces of lakes and ponds as “webs”, detecting trapped insects by the vibrations that these cause while struggling. Spiders (order Araneae) are air-breathing chelicerate arthropods that have eight legs, and chelicerae modified into fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms. Spiders are found world-wide on every continent except for Antarctica, and have become established in nearly every ecological niche with the exception of air and sea colonization. As of 2008, approximately 40,000 spider species, and 109 families have been recorded by taxonomists. However, there has been confusion within the scientific community as to how all these genera should be classified, as evidenced by the over 20 different classifications that have been proposed since 1900.
 
Spiders are abundant and widespread in almost all ecosystems and constitute one of the most important components of global biodiversity. Spiders have a very significant role to play in ecology by being exclusively predatory and thereby maintaining ecological equilibrium. Many spiders feed on noxious insects like houseflies and mosquitoes which are vectors of human diseases. A large number of spiders are found in agricultural fields and thus play an important role in controlling the population of many agricultural pests. Despite this importance, spiders are largely neglected mainly due to ignorance and fear and the subsequent dislike for them. Although more than 1400 species (quite a number is endemic) have been described from India (and many more to be documented), the study on the taxonomy, biology and ecology of Indian spiders remains neglected.
 
 
Anatomically, spiders differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax and abdomen, and joined by a small, cylindrical pedicel. Unlike insects, spiders do not have antennae. In all except the most primitive group, the Mesothelae, spiders have the most centralized nervous systems of all arthropods, as all their ganglia are fused into one mass in the cephalothorax. Unlike most arthropods, spiders have no extensor muscles in their limbs and instead extend them by hydraulic pressure.Their abdomens bear appendages that have been modified into spinnerets that extrude silk from up to six types of silk glands within their abdomen. Spider’s webs vary widely in size, shape and the amount of sticky thread used. It now appears that the spiral orb web may be one of the earliest forms, and spiders that produce tangled cobwebs are more abundant and diverse than orb-web spiders. Spider-like arachnids with silk-producing spigots appear in the Devonian period about 386 million years ago, but these animals apparently lacked spinnerets.
 
True spiders have been found in Carboniferous rocks from 318 to 299 million years ago, and are very similar to the most primitive surviving order, the Mesothelae. The main groups of modern spiders, Mygalomorphae and Araneomorphae, first appear in the Triassic period, before 200 million years ago. Most known species are predators, mostly preying on insects and on other spiders, although a few large species also take birds and lizards. Spiders use a wide range of strategies to capture prey: trapping it in sticky webs, lassoing it with sticky bolas, mimicking the prey to avoid detection, or running it down. Spiders’ guts are too narrow to take solids, and they liquidize their food by flooding it with digestive enzymes and grinding it with the bases of their pedipalps, as they do not have true jaws.Male spiders identify themselves by a variety of complex courtship rituals to avoid being eaten by the females. Males of most species survive a few matings, limited mainly by their short life spans. Females weave silk egg-cases, each of which may contain hundreds of eggs. Females of many species care for their young, for example by carrying them around or by sharing food with them. A minority of species are social, building communal webs that may house anywhere from a few to 50,000 individuals. Social behavior ranges from precarious toleration, as in the aggressive widow spiders, to co-operative hunting and food-sharing. Although most spiders live for at most two years, tarantulas and other mygalomorph spiders can live up to 25 years in captivity.While the venom of a few species is dangerous to humans, scientists are now researching the use of spider venom in medicine and as non-polluting pesticides. Spider silk provides a combination of lightness, strength and elasticity that is superior to that of synthetic materials, and spider silk genes have been inserted into mammals and plants to see if these can be used as silk factories. As a result of their wide range of behaviors, spiders have become common symbols in art and mythology symbolizing various combinations of patience, cruelty and creative powers.

References: Wikipedia, Spider information

 
 
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Vanishing Species: Indian Otters

Sunday article by Mohan Pai

 
Indian Otters
Mustelids
Photo: courtesy: K. Pichumani
 
Playful creatures, a group of Otters is called ‘romp’, being descriptive of their playful nature.
Otters are semi-aquatic, fish-eating mammals. The otter subfamily Lutrinae forms part of the family Mustelidae, which also includes weasels, polecats, badgers, as well as others. With thirteen species in seven genera, otters have an almost worldwide distribution. They mainly eat aquatic animals, predominantly fish and shellfish, but also other invertebrates, amphibians, birds and small mammals.An otter’s den is called a holt or couch. A male otter is a dog (otter), a female a bitch (otter), and a baby a whelp or pup. The collective nouns for otters are bevy, family, lodge or romp, being descriptive of their often playful nature, or when in water raft.
India is home to three species of otters: the Eurasian otter (Lutra lutra), the smooth-coated otter (Lutra perspicillata) and the small-clawed otter (Amblonyx cinerous). Just 50 years ago, the smooth coated otter, also referred to as the smooth Indian otter, was widespread in the country while both Eurasian and the small clawed otter (earlier called the clawless otter) were absent from central India, but found in broad bands in the Himalayas and the ghats in the south. It is essentially an otter of cold hill and moutain streams and lakes. Today, these elegant creatures are confined only to protected areas and zoos. If there are any unknown pockets outside, they are unlikely to survive.What happened to otters was quite simple. Found in rivers, lakes and other wetlands, they competed with human beings for fish, their main diet, and lost. Pollution poisoned their food and habitat. Lakes and wetlands were drained for agriculture. In fact the trade of otter skins has been going on for hundreds of years in South East Asia. According to a wildlife trade survey done in Thailand, an otter skin can be sold for $90-$100 to leather factories and considered the best leather to make jackets. It is also believed that otter fat was good for rheumatism, and dried otter penis can fetch up to $50 per inch in Mandalay, and in Myitkyina in the Kachin state. A researcher from the Centre for Ecological Sciences, Bangalore, V. Meena, found nomadic tribal herb collectors from Haryana trapping otters in the Palani hills of Tamil Nadu to sell the oil and skin and of course, eat the flesh, while they were at it.
Characteristics
Otters have long, slim bodies and relatively short limbs, with webbed paws. Most have sharp claws on their feet, and all except the sea otter have long muscular tails.They have a very soft, insulated underfur which is protected by their outer layer of long guard hair. This traps a layer of air, and keeps them dry and warm under water.Many otters live in cold waters and have very high metabolic rates to help keep them warm. In summer, in the Himalayas many otters go up the streams and torrents ascending to altitudes of 12,000 ft or more. Their upward movement probably coincides with the upward migration of carp and other fish for purposes of spawning. With the advent of winter they come down to the lower streams.For most otters, fish is the primary staple of their diet. This is often supplemented by frogs, crayfish and crabs. Some otters are expert at opening shellfish, and others will feed on available small mammals or birds. Prey-dependence leaves otters very vulnerable to prey depletion.Otters are very active, chasing prey in the water or searching the beds of rivers, lakes or the seas. Most species live beside water, entering it mainly to hunt or travel, otherwise spending much of their time on land to avoid their fur becoming waterlogged. The sea otter does live in the sea for most of its life.Otters are playful animals and appear to engage in various behaviors for sheer enjoyment. Different species vary in their social structure, with some being largely solitary, while others live in groups – in a few species these groups may be fairly large.

Range map of Otters (IUCN)

Major Threat(s): The aquatic habitats of otters are extremely vulnerable to man-made changes. Canalisation of rivers, removal of bank side vegetation, dam construction, draining of wetlands, aquaculture activities and associated man-made impacts on aquatic systems are all unfavourable to otter populations (Reuther and Hilton-Taylor 2004). In South and South East Asia, the decrease in prey species from wetlands and water ways had reduced the population to an unsustainable threshold leading to local extinctions. The poaching is one of the main cause of its decline from South and South East Asia, and possibly also from the North Asia. (IUCN Red List)
References: Wikipedia, IUCN Red List, S. H. Prater (the book of Indian Animals), Aniruddha Mookerjee in the Hindu.

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