Wednesday, 10 August 2022

A Kite for Mankind

National Geographic’s second president, scientist Alexander Graham Bell, had an estate on Cape Breton Island where he conducted experiments. Writer Catherine Dunlop Mackenzie remarked on the broad range of his research in a 1920 National Geographic article. Among his innovations: were a high-speed hydroplane boat (it went 70 miles/113 km an hour), an outlook tower composed of stacked tetrahedral cells, and special twin-bearing sheep stock.

But perhaps most remarkable, Mackenzie wrote, was Graham’s collection of huge, manbearing kite structures. Graham was an aviation pioneer, fascinated by the idea of mechanical flight since his boyhood. In 1907, he sent one of his giant kites 168 feet (51 m) aloft over Bras d’Or Lake on Cape Breton Island, with U.S. Army officer Lt. Thomas E. Selfridge attached. Though Selfridge survived that experiment, he died just months later in one of Orville Wright’s flying machines, earning him the grim distinction of modern aviation’s first fatality.


Thursday, 5 May 2022

What is Spirulina?

Spirulina is a genus of blue-green algae used as a nutritional supplement. Blue-green algae, microscopic fresh-water organisms, are also known as cyanobacteria. Their color is derived from the green pigment of chlorophyll, and the blue from a protein called phycocyanin. The species most commonly recommended for use as a nutritional supplement are Spirulina maxima and Spirulina platensis. 

These occur naturally in warm, alkaline, salty, brackish lakes, but are also commonly grown by aquaculture and harvested for commercial use. Spirulina contains many nutrients, including B vitamins, beta-carotene, gamma-linolenic acid, iron, calcium, magnesium,manganese, potassium, selenium, zinc, bioflavonoids, and protein. Spirulina is composed of about 65%protein. 

These proteins are complete, in that they contain all essential amino acids, plus some nonessential ones. In that regard, it is similar to animal protein, but does not contain saturated fats, or residues of hormones or antibiotics that are in some meats. Since spirulina is normally taken in small amounts, the quantity of dietary protein supplied for the average, reasonably wellnourished person would not be significant. 

However, it is a good source of trace minerals, some vitamins, bioflavonoids, and other phytochemicals. It also has high digestibility and bioavailability of nutrients. Purpose Spirulina has been used as a source of protein and nutrients, particularly beta-carotene, by the World Health Organization (WHO) to feed malnourished Indian children. The program resulted in a decrease of a type of blindness that results from inadequate dietary vitamin A. 

The dose used in this year-long study was 1 gram per day. Description There is a high vitamin B12 content in spirulina. For this reason, it has often been recommended as a supplemental source of the vitamin for vegans and other strict vegetarians, who are unlikely to have adequate dietary vitamin B12. Unfortunately, spirulina is not an effective source of the usable vitamin. 

Much of the vitamin B12 is in the form of analogs that are unusable for humans, and may even block the active forms of vitamin B12 consumed from other sources. Gamma linolenic acid (GLA) is present in significant amounts in a small percent of spirulina species. This essential fatty acid can be used in the body to form products that are anti-inflammatory and antiproliferative. 

It is potentially useful for individuals with rheumatoid arthritis and diabetic neuropathy. It may also play a role in lowering plasma triglycerides and increasing HDL cholesterol. Spirulina is a good source of available iron and zinc. A study done in rats found that those consuming spirulina had equivalent or better absorption than those given a ferrous sulfate iron supplement. 

A small human study of iron-deficient women had good response to iron supplementation with spirulina, although the amounts used were large (4 grams after each meal). Similarly, a study of zinc deficient children found that those taking spirulina had a superior response to those taking zinc sulfate, and had fewer side effects. In addition to serving as a source of nutrients itself, spirulina has been used in the manufacture of fermented dairy products to guarantee the survival of the bacteria used to ferment the milk. 

A stronger immune system is one claim made by boosters of spirulina. A number of animal studies appear to support stimulation of both antibody and cellular types of immunity. Immune function was markedly improved in children living in the areas surrounding Chornobyl. The measurements were made after 45 days, with each child consuming 5 grams of spirulina per day. 

The growth of beneficial intestinal bacteria, including lactobacillus, appears to be stimulated by the consumption of spirulina, based on a study of rats who consumed it as 5% of their diets. The absorption of vitamin B1 was also improved. Cholesterol, serum lipids, and low-density lipoprotein (LDL) cholesterol may be lowered by a small, but significant, percentage by the consumption of spirulina. 

One study group of men with high cholesterol took 4.2 grams per day of spirulina, and experienced a 4.5% decrease in cholesterol after one month. Spirulina is also thought to be helpful in the treatment of oral leukoplakia, a precancerous condition that is manifested as white patches in the mouth. It improves experimentally induced oral carcinoma (cancer in the mouth) as supported by studies done in animals. 

The evidence for the ability of spirulina to promote weight loss is not very strong. Results have been mixed, and the phenylalanine content does not appear to be an appetite suppressant as is sometimes claimed. Whether other components of the algae are beneficial for weight loss is uncertain and unproven. Spirulina has been recommended to alleviate the symptoms of attention-deficit hyperactivity disorder (ADHD), although evidence for this indication is lacking. 

Spirulina has the highest concentration of evercetin found in a natural source. It is a potent antioxidant and anti-inflammatory compound that can be used to alleviate the symptoms of sinusitis and asthma. Phycocyanin, the protein that gives spirulina its blue color, has also been shown to relieve inflammation associated with arthritis and various allergies. 

Preparations One recommended dose is 3–5 grams per day, but the amount used may depend on the product, the individual using it, and the indication for which it is being taken. Spirulina supplements are available in powder, flake, capsule, and tablet form. These supplements are generally expensive, and have a strong flavor that many people find unpleasant. 

Precautions Because spirulina is sensitive to pollutants in sea water, it can be used as a biosensor to measure the toxicity of a given body of water. Unfortunately, this sensitivity means that spirulina grown in water contaminated with heavy metals can concentrate these toxic substances. Mercury levels are of particular concern. Infectious organisms may also be present and contaminate harvested algae, so reputable sources of spirulina should be used. 

Phenylketonurics should avoid spirulina due to the potential content of phenylalanine. A number of varieties of blue-green algae, including Aphanizomenon flos-quae and Anabaena, have been found to sometimes produce toxins that may affect the nervous system or the liver. The potential side effects of spirulina are primarily gastrointestinal, and include diarrhea, nausea, and vomiting. Allergic reactions occur rarely, but can cause insomnia and anxiety.



Friday, 29 April 2022

The Raccoon Dog

The Raccoon Dog is native to East Asia; it was brought to European Russia at the beginning of the nineteenth century and has since spread to other parts of Europe. Because of the white area around its snout, it strongly resembles a Raccoon, but the black band on its face is broken into two parts. The forehead is light, and an even lighter, almost white area stretches over the entire neck. The ears have dark borders, and the back is mottled grey with dark stripes. 

The chest, belly, and legs are black, and the tail is unstriped and dark on top, light underneath. The legs are all the same length. Raccoon Dog is about 60–80 cm long, and the tail measures up to 20 cm. Its height at the shoulder is 20–30 cm, and it weighs up to 10 kg. The Raccoon Dog’s thick fur exaggerates its true size. Raccoon Dogs live in deciduous or mixed forests with thick underbrush, usually near water or swamps, and in open landscapes with wet areas and areas with bush cover. 

It is not a shy animal, so you might also see it near or in inhabited areas. Raccoon Dogs do not hibernate, but like Eurasian Badgers, they remain in their den for several days if there is a severe frost or heavy snow. The prints of Raccoon Dog always show four toes set an equal distance from the central pad print, as well as clear claw marks. The front footprint is 4–5.5 cm long and about 4.5 cm wide, the rear footprints are somewhat smaller, 4–4.5 cm long and about 3.5 cm wide; the stride is about 40–60 cm. 

The tracks can resemble those of a fox, although the latter are more elongated. There is essentially no visible difference between the tracks of a domestic dog and those of a Raccoon Dog, and the latter may also be confused with the tracks of a domestic cat, even though the cat’s footprints never show claw prints. A male and female often hunt together, and one often sees the prints of two animals in the same place. The footprints are often found on the muddy shores of lakes or streams or in marshy areas. 

At the water’s edge, one may often also find paths that are regularly used by the animals. A Raccoon Dog can dig its own den, but it will also use old Eurasian Badger and fox dens, or live in natural cavities: in hollow trees, under roots, or between stones and rocks. One will almost always find the remains of prey close by. Raccoon Dogs live in family groups in established territories, which are, however, not defended vigorously. 

Like Raccoons and Eurasian Badgers, Raccoon Dogs are omnivores, but they consume mainly small rodents. The scat is somewhat twisted, 5–8 cm long, 1.5– 2 cm thick, and often contains much hair. It resembles domestic dog scat but is left in piles—in latrines near the burrow or along the edge of the territory. Beware! Raccoon Dog scat should not be touched since it can contain eggs of the dwarf tapeworm (transmitted by foxes), which can be dangerous to human beings. In many places in eastern Europe, this is the reason mushrooms and berries are not gathered in the wild. 

The Raccoon was introduced from North America to Europe for the fur trade at the beginning of the twentieth century. Escapes over time have multiplied and the naturalized population in Europe has increased steadily. Raccoons are often confused with the Eurasian Badger, though Raccoons have a black stripe diagonally crossing the area above the eyes, as well as a dark blaze from the snout to the forehead. On the side of the snout, there are white areas, and the Raccoon also has white above the eyes. 

The ears have a light border, and the tail is striped diagonally with six or seven dark stripes which are longer than those on a Eurasian Badger. The coat is grey, brownish, reddish-brown, or almost black on the upper side. Raccoons are about 48–70 cm long, and the tail measures about 20–30 cm. Raccoons weigh between 5 and 15 kg. 

The hind legs are longer than the front, so they move with the hindquarters slightly raised. Raccoons prefer deciduous woodland or underbrush near lakes, streams, and rivers, but may also be found in other open areas such as parks or arable land. If it is not persecuted, the Raccoon may become quite confiding. Raccoons are normally solitary but—especially where they are fed by humans —may also live in groups. 

Raccoons are usually nocturnal; during the day they sleep in hollow trees, rock crevices, and other natural cavities, or even in abandoned Eurasian Badger or fox dens. Raccoons don’t hibernate but are noticeably less active in winter than in summer. Raccoons have long and dexterous fingers, especially those on the front feet. 

The tracks show the footprints of all five toes and the pads as well as the imprint of powerful claws. Raccoons are good climbers and can rotate their hind feet 180 degrees to maintain their hold, and they are able to climb down trees headfirst. The toes are widely splayed; the front footprint is about 7–7.5 cm long and 6.5–7 cm wide, the hind footprint 8.5–9 cm long and 6–7 cm wide.

Monday, 4 April 2022

Amber – A Precious Gemstone

Amber is fossilized tree resin, which is produced by some trees as a form of protection from disease and wood-burrowing insects. It was one of the earliest gems used for personal adornment. Of special interest to scientists are ambers containing insects, pollen, leaves, and occasionally frogs and lizards that were trapped millions of years ago as the sticky resin dripped down the tree trunk.

Ambers with inclusions provide a rare look at the plant and insect life of that time period. Most amber is brownish yellow to orange in color but it can also be blue, green, or red. Brownish colors are the least valued. The best quality amber is transparent and either has no flaws or else has very distinctive inclusions.

The majority of gem-quality amber is found along the Baltic coasts of Russia and Poland. Other significant sources are the Dominican Republic, Mexico, Myanmar, Sicily, and Romania. Beware that Amber is sometimes dyed to make it darker or a different color. The dye may fade. Be on the lookout for pressed amber (also called reconstituted amber). It’s made by heating small amber fragments and compressing them into larger pieces. It can be identified by magnification.

A lot of natural ambers are heated just to make it more transparent. Amber can be separated from imitations such as plastic by placing it in a saturated salt solution. Amber will normally float while imitations may sink. However, copal and polystyrene plastic have about the same specific gravity as amber, so amber experts find high magnification to be more useful in detecting imitations. One imitation that is harder to detect is copal, a young version of amber.

It has essentially the same chemical formula as amber but different physical properties. Copal contains liquids such as oils, acids, and alcohol, whereas in amber these liquids have evaporated, resulting in a more durable product. Besides its greater resistance to cracking and crazing, amber is much more rare and valuable than copal. 

A drop of acetone nail polish remover on the back of the material can help separate copal from amber. The acetone will make copal sticky but it will have no effect on amber. Amber scratches abrade and melt easily. If it’s left in the sun, it can dehydrate and crack. Avoid ultrasonic’s, all chemicals, brushes, and heat. To clean amber, wipe it with a soft damp cloth; or clean it in cool soapy water, rinse and dry with a soft cloth.


Monday, 10 January 2022

What is the Weight of the Human Soul?

Andrew Jackson Davis believed it to weigh about one ounce. Others say it does not weigh anything. However, being substance, the astral body must have some weight. ~ Sylvan Muldoon & Hereward Carrington, 1973 the idea of a material soul is not new. The Greek philosopher, Heraclitus, who lived in the sixth century BC, thought that the soul was composed of an unusually fine or rare kind of matter, such as air or fire. However, if it was material it had to have some weight. Barbara Brennan, the former NASA engineer and now world-renowned energy healer, observes that ‘aura’ appears to have weight.
 
Robert Monroe also believes that the ‘Second Body’ has weight, although much less than the carbon-based body. (The terms ‘aura, ‘astral body’ and the ‘Second Body’ refer to what is generally de- scribed as the ‘subtle body’ in the metaphysical literature. The subtle body has often been loosely identified as the ‘soul’) If the soul has weight, it means it has mass and is subject to Earth's gravitational force. This has motivated various researchers, including Noetic Science, to undertake experiments to weigh the soul. 
In 1907, Dr. Duncan McDougall weighed six patients, while they were in the process of dying from tuberculosis. When death was imminent, the entire bed of the patient was quickly placed on a highly sensitive industrial sized scale. In each case, when the patient expired, he noticed an extremely small sudden change in the weight of the deceased which could not be ac- counted for by other means. 
The missing mass, which this weight loss represented, was used to support his hypothesis that the body had a soul which had mass On the death of the visible body, the soul departed, and so did this mass. The weight of the soul, based on the average loss of mass in six patients, was measured by McDougall to be 21 grams A paper summarizing his findings appeared in the journal American Medicine in 1907. 
One critic quickly pointed out that the sphincter and pelvic floor muscles relax at death, and that the loss was perhaps due to ejected urine and or faeces. McDougall rebutted that if this were the case, the weight would remain upon the bed and, therefore, upon the scale. Someone else suggested that the dying patients’ final exhalation might have contributed to the drop in weight. 
To disprove this, McDougall climbed into the bed and exhaled ‘as forcibly as possible” while his assistant watched the scale. No change was observed. Another critic reasoned that body weight was being continually lost as water escapes into the air through.

 

An Estimate Based on Dark Matter Statistics — © BY JAY ALFRED —

Thursday, 23 September 2021

What Makes Bees Different?

Bees are unique in several ways. In their anatomy, they are like their carnivorous wasp ancestors, but in their biology, they have evolved into something completely different. Most honeybees do not have hardened mandibles (mouthparts) for chewing flesh. They sip nectar from flowers using a particular proboscis. Bees are not parasitic within other animals like some wasp larvae, but some are social parasites, rather like cuckoos.

Honeybees focus their diet on pollen and nectar and play a pivotal role in the pollination of numerous species of flowering plants. Furthermore, from a human perspective, what really makes bees unique is their significant agricultural, economic, and scientific importance.


AGRICULTURAL

Bees are amazingly effective pollinators, in part because of their sheer numbers. Honeybee colonies have tens of thousands of individuals perhaps up to eighty thousand per colony. It only takes one bee to visit, for example, one almond flower, and then a second almond flower, to make an almond. And there are well over a million honeybee hives in the handful of Californian counties that produce almonds for the entire United States and regions beyond.


Furthermore, multiply these numbers by the over 135 crops that bees pollinate worldwide, and then factor in all the countries around the world growing fruits and vegetables. Therefore, you will start to get a sense of the vital importance of bees to agriculture. These figures also demonstrate how massively effective bees are in driving our current agricultural practices. However, it is not just honeybees that are vital to our agriculture; many other types of bees are terrific pollinators too, including bumblebees, mason bees, and squash bees among others.


ECONOMIC:

In the USA, honeybees are estimated to contribute over $20 billion annually to the economy. However, the honeybee population has been declining severely since the 1980s. The main reason due to the onset of new diseases and pests, pesticides, and habitat loss. Hence, this decline has coincided with an increase in agricultural demand.

The result has been a significant rise in the price of food, especially in the case of almonds, which up to now have relied entirely on honeybees for pollination. The blue orchard bee (Osmia lignaria) has recently been introduced as a pollinator in commercial almond orchards, and other bee species are being studied as possible pollinators for this crop.

Moreover, the bumblebees, are too used for crop pollination and make a key contribution to the global economy. In China, a shortage of bees means that human laborers now pollinate some crops by hand. And even in the United States, some farmers are turning to human hands equipped with pollination wands and swabs a technique already used on at least one urban farm in Boston to guarantee crop yields.


SCIENTIFIC

The research value of honeybees is massive, and not only for their contributions in the field of agriculture. Even though honeybees can be trained, and the blue orchard bee is a focus of research to train the bees to a target fruit blossom scent for increased pollination efficiency.

 

Given that the life span of a worker bee is typically a few weeks to a few months, bees are also used in research relating to age-related disorders such as Dementia, Alzheimer’s disease (Memory loss), studying relationships between aging, memory, and behavior. Honeybees also act as research subjects in the study of epidemiology, conservation, communication, sociology, genetics, chemical ecology, and many more subjects.


Wednesday, 15 September 2021

THE FIELDFARE

THE FIELDFARE was in the past called the ‘snow magpie’. It was known for migrating late and arriving in the south in large flocks along with the first snow. The first thing we hear from such flocks is often clear short scraping ‘gih’ or ‘glih’ notes followed by a soft chattering ‘chaka-chak-chak’. Often flocks come in large, loose formations, like an armada. In Sven Nilsson’s nineteenth-century Scania, these flocks were the last chance of the year to gather in edible birds. Where I live on Gotland, the local birds often begin to move around in groups or small flocks from the end of September, but it is generally not until the end of October or in November that I see any bigger flocks on the move southwards. Rowan, Swedish whitebeam, hawthorn, and juniper bushes are thought to be the focus for their autumn foraging in my district, the berries provided in perfect portion-sized packages. 

In spring it is earthworms that are important: but apples and pears in gardens or in the open countryside are also consumed with great relish. The local birds have usually, with the help of crows, cleared most of the rowanberries when the northern thrush flocks arrive. They stop off, however, if there is food, but move on if gets cold and there is a shortage of fruit and berries. It is mostly solitary individual birds that turn up at the feeding stations in winter, even when larger flocks are present in the surrounding countryside. When it was time to paint a Fieldfare for this book, I started, as usual, to ponder over where in my numerous sketchbooks I have some field sketches. 

Then it suddenly struck me how rarely I have painted or drawn this species in the field – perhaps I have never done it. Certainly, I have painted newly fledged Fieldfare young several times, which I associate with my childhood. When I was small, perhaps ten years old, I always took home young birds barely able to fly in the belief that they had fallen out of the nest. Soon enough I realized that they often hopped out of the nest before they could fly, but my interest in keeping a bird was greater than my intellect. I fed them with worms and thought that they were happy, with their tufts of down on the head, big yellow gape flanges, and cocky expressions. 

They were in some way caricatures of themselves. I had a small menagerie with frogs, caterpillars, slow-worms, and every spring a Fieldfare young or Magpie young. But I cannot recollect having tried to create a picture of a full-grown Fieldfare. Fieldfares nest in my own garden almost every year, so it would have been natural that I had at some time made a drawing of them. All the other thrushes I have painted here in south Gotland, including the rare Ring Ouzel. Perhaps it is a manifestation of the fact that the Fieldfare is altogether too commonplace, but I know that such is not the case. 

Is it its appearance, its hard-to-interpret face with an unusual marking around the eye and black bags under the eyes and an odd blue-grey color and the seemingly irregular black spots? Is it quite simply because it is facially a little unattractive that I have never become absorbed in this bird? Despite that, one of the innumerable faces of Fieldfares should have inspired me to get out the watercolor pad, but I do not remember any such occasion. I think that, among birdwatchers, the Fieldfare ends up lowest of the thrushes in status, the species which produces the least feeling of excitement when we focus on it. 

In autumn we usually look through the flocks to see if any other, rare thrush has sneaked in – at best we find a Redwing, which at least raises the pulse rate a little. Birds that are somewhat uncommon are often accorded an unmerited aesthetical quality in addition; we imagine that we see beauty in what is uncommon. The Fieldfare is an out-of-tune singer, or in any case a very poor one. If somebody approaches their nests they attack by defecating on the intruder. That wonderful songster the Blackbird is Sweden’s national bird while its congener, the Fieldfare, is ignored or regarded as a berry thief. Fieldfare has never achieved a prominent place in Swedish nature-writing or nature-painting. 

Gunnar Brusewitz however, painted at least once, but perhaps several, watercolors of Fieldfares. I find it in his first large-format book, Skissbok (‘Sketchbook’) from 1970. It is the only picture I remember. After having hunted out photographs and brought out a traffic-killed bird from the freezer, I set to work. But I am empty, empty of anything to relate to. I do not have any of my own inner visions of the type which abound on the internet if one searches for photographs of the species where it is perched on a snowy or frosty berry-tree branch. I know that I have on some occasion seen a paler female which had an unusually gentle expression, was timider and had less black beneath the eye, but I do not have a drawing of it. I had to make a late hunt for observations of Fieldfares. 

The first thing I detected was its call. While other thrushes hardly converse in the autumn, the Fieldfare communicates quite frequently. It reverts to brief attempts at the song as if it were seizing the opportunity to rehearse its song; I think that it sounds pleasant at a time when the Blackbird sounds most like a chicken, ‘kuck’ and ‘pick’. And after several different attempts to draw the species, I begin to see the bird, recognize its face, understand which parts convey the character. I came to the conclusion that Fieldfare is, despite everything, both ugly and attractive at the same time. 

For comparison, one could perhaps wonder if the plumages of the other thrushes were designed in Milan or Paris, with black, buffy grey, brown, and a tinge of ochre, whereas the Fieldfare is an odd mixture from London and the 1970s. Yellow shirt with black stripes and squares, wine-red lumber jacket, grey flannel trousers, and black shoes. The Fieldfare is really unusual in its pattern, with an assortment of colors and markings which seem somewhat surprising in comparison with the more sober look of the other thrush species. 

It has, with varying degrees of saturation, a rusty-yellow breast, heavily streaked, changing into dark spade shapes on the side of the breast and then arrowheads or horseshoes over the flanks. The crown, nape, and rump are greys, while the rest of the upper side has a cold reddish-brown tone. The many varying patterns and color tones make it distinctive and easy to recognize. Males generally have a more intensively streaked throat and bigger black spots on the crown. 

Females have narrower, pointed spots on the crown which are difficult to see in the field. Young, during their first winter, often retain a few outer greater coverts, which contrast somewhat with the new coverts in color and pattern. If it is only a pair of the outermost, however, the difference is rarely visible. The juvenile coverts are, moreover, usually shorter than the new ones. Old males exhibit a strong contrast between the warm reddish-brown upper back (mantle), which often appears dark-spotted, and the pale grey lower back and rump. Young females sometimes have a markedly browner tail and can have a softer and more uniform brown color on the back and a more buff than grey rump. 

Some birds in autumn have an almost all-dark bill and this is the rule with young females. Some females have very little streaking on the throat and breast. I was surprised at how big the individual differences were when I finally began to see them with pencil and brush.


Monday, 30 August 2021

Anti-g flying Suit

 A fighter plane making a tight turn acts like a spin-dryer. The so-called “g” force drains blood out of the pilot’s brain, possibly Anti-g flying Suit By the 1950s, suits like this one by Dunlop were filled with air, not water. causing a blackout. When a team under Sir Frederick Banting, better known for his work on insulin, discovered this, US scientist Wilbur Franks started work on an anti-g suit. The design his team produced was made from two layers of rubber with water in between them. When the suit was laced tightly around the pilot, it kept the blood in place, allowing tighter turns. The Franks Flying Suit Mk II was ready by 1941. Sadly, on his way to Britain to demonstrate it, Banting died in an airplane crash.

Saturday, 24 July 2021

Hummingbirds and Pollination

 Most tropical plants rely on animals to transfer pollen from flower to flower. The most important animal pollinators are bees, but there are many others, including other insects, bats, and hummingbirds. Since flowers “want” to be pollinated, they have features that match the physical and sensory abilities of pollinators. To achieve pollination, flowers provide a reward, advertise it, and are constructed so that visitors come into contact with their stamens and stigma. The commonest reward is nectar, but others include pollen and less usual substances, such as waxes, oils, and perfumes (the latter is used by orchid bees as sexual attractants).

Nectar varies in the sugars it contains. Flowers pollinated by hummingbirds, butterflies, hawkmoths, and many bees secrete nectar rich in sucrose, whereas those pollinated by bats and by passerine birds (including American orioles and tanagers, Australian honeyeaters, and Old World sunbirds) have nectar-rich in glucose and fructose, sugars that are also found in fruits.

The significance of these intriguing differences is unknown, but they do not seem to matter much to hummingbirds and bats. Hummingbirds happily feed on leftover nectar in bat flowers, while bats routinely empty hummingbird feeders full of sucrose solution. Flowers have evolved a variety of adaptations to attract specific pollinators. Certain plant families are particularly important for hummingbirds, some of the most notable being the Heliconiaceae, Bromeliaceae, Ericaceae, Rubiaceae, Acanthaceae, and Gesneriaceae.

These flowers are ornithophilous, or bird-loving, and exhibit clear adaptations for pollination by hummingbirds. Most of them are either red or have red bracts or leaves that advertise their presence, red being a color that is conspicuous to hummingbirds but not to most insect competitors. In addition, the flowers are diurnal, have a tubelike corolla that fits the slender bill of a hummingbird, and lacks any scent (which might attract insects), and most also lack a landing platform that would provide easy access for insects.

Flowers aimed at other pollinators have other characteristics. Those pollinated by hawkmoths, for example, are nocturnal, white (to show up in the dark), fragrant, and also tubular (to fit a moth’s proboscis). Bat flowers are nocturnal and usually pale, with a strong musky odor, and some have “sonar guides,” which bats detect by echolocation. There are two main types of hummingbird flowers. One sort has long tubular flowers (mostly 30 to 40 mm long) that secrete copious nectar; these tend to be scattered and are usually visited by traplining hummingbirds. The other sort has short tubular flowers (mostly less than 20 mm long); these contain less nectar but are massed together in numbers great enough to be worth defending by territorial hummingbirds. These differences have consequences for the plants.

Trapliners tend to carry pollen from plant to plant, which results in cross-pollination and enhanced reproductive success. In contrast, territorial hummingbirds foster self-pollination. Sometimes a hummingbird visits so many flowers on the same plant that its face gets covered with white or golden pollen, making it look like a different species. Hummingbirds that intrude into territories to steal nectar are probably more useful to a plant than the territorial owner. Since these filchers visit flowers only briefly before being chased off, they perhaps deliver pollen to plants of the same species some distance away. Another point to be considered is why many flowers use hummingbirds as pollinators rather than insects.

After all, insects can be attracted with a smaller reward of nectar. The probable reason is that hummingbirds are more reliable as pollinators when the weather is bad, particularly at high altitudes. Bees and butterflies remain inactive when it is very wet or too cold, so flowers dependent on them fail to be pollinated. Hummingbirds are active in all kinds of weather, so it is no surprise that there are many more hummingbird-pollinated plants in the highlands than in the lowlands.

Thursday, 21 January 2021

The Oriental Rat Snake

The Oriental Rat Snake (Ptyas mucosa) is a medium-sized, active, diurnal snake associated with open habitats including agricultural systems; much of the diet consists of amphibians and commensal rodents. The species has a wide distribution through much of Asia, from Iran to China and Southeast Asia, and has been commercially harvested for the international skin trade since the early 20th century. From west to east, it occurs in Iran, Turkmenistan, Afghanistan, Pakistan, India, Sri Lanka, Nepal, Bangladesh, Myanmar, China, Thailand, Laos, Cambodia, Vietnam, Malaysia, Singapore, and Indonesia. The Oriental Rat Snake is not strongly associated with wetland habitats. In the wet season, the species shifts to drier areas that do not flood.

The species is also used in the illegal meat trade in China. Under Indonesian legislation, only the harvest of live specimens and skins of the Oriental Rat Snake is permitted – the trade in meat of this species is therefore illegal. During the 1980s most specimens in trade originated from Java (Indonesia) and Thailand. However, the trade has banned the harvest of the species in 1985, and the distinct decline in export volumes after 1986 from Indonesia was the result of a decreased market demand rather than any negative impact on populations of the Oriental Rat Snake.

General biological and life history characteristics of the species

  • The Oriental Rat Snake is a medium-sized, active, non-venomous, diurnal snake associated with open habitats including agricultural systems.
  • Medium-sized snake, reaching about 2.5 m in length and 5-10 cm in girth.
  • Males grow longer than females and have larger heads, longer tails, and greater body mass than females of the same length
  • Reaches maturity at 9 months 120 cm for females  
  • Clutch size average 13 
  • May lay 2 clutches per year.
  • Widespread generalist thrives in a human-modified environment
  • Unknown density and population trends
  • No major threats known

Arboreal behavior is believed to be largely associated with resting. Parts of the range of the Oriental Rat Snake overlap with the Indo-Chinese Rat Snake (Ptyas korros) and where they overlap both species may share the same habitat. Both species search paddy fields for prey and hide beneath dense vegetation along riverbanks. However, the Indo-Chinese Rat Snake is more closely associated with habitats along watercourses than the Oriental Rat Snake.

This species is a predator of rodents and amphibians, and to a lesser extent lizards, insects, birds, and even insects.  Rodents are reportedly the favored food, however; amphibians were the predominant prey of Oriental Rat Snake populations in Central Java.  Snakes are either captured by experienced harvesters or opportunistically by seasonal rice farmers. Snake capture is secondary to farming activities and appears to be carried out in an ad hoc manner. According to several traders, the harvesting activity levels increase with the onset of the wet season (the first heavy rains after the dry season).

In East Java the wet season typically occurs between December and April, and in Central Java between October and December and February to April, depending on the geographical location. During the dry season (May to August) the species is extremely scarce, and another collector estimated that the capture of the Oriental Rat Snake decreases by 50-60% in the dry season. 

During the dry season, the people work in the rice fields so that less manpower is available to capture snakes during the rice harvest, and so the study species is less common in trade during the dry season. The species occurs on other Indonesian islands, including Sumatra and Sulawesi. Furthermore, Increased enforcement is needed to reduce illegal trade.