Category Environtal Studies

HOW DO INSECTS PROTECT THEMSELVES?

          There are almost, as many different ways in which insects protect themselves from enemies as there are different insects. Some insects, such as wasps and ants, have powerful stings or are able to shower their attackers with poisonous fluid. The hoverfly does not sting, but its colouring is so like that of a wasp or bee that enemies are very wary of it! Other insects, such as stick insects and praying mantises use camouflage. They look like the leaves and twigs among which they feed.

          In the insect community there exist many different methods of hunting and killing. Some of these methods are short and quick, and others seem to be slow and painful. Some insects do not even have to fight by virtue of their spectacular camouflaged bodies. However, other insects are nearly always vulnerable to predators. Many insects sport particular colors that scare predators away and some insects use venom in order to subdue their prey before feasting on it. There are many more methods of attack and defense to be observed in the insect world, and even the few methods named above do not begin to touch upon the great variety of ways that insects attack others and defend themselves.

          Some insects use irritating sprays to subdue their enemies. For example, ladybugs, bombardier beetles, and blister beetles are just a few insects that are capable of deterring predators with unpleasant fluids. The bombardier beetle keeps a caustic substance within its abdomen at all times. When this beetle’s life is threatened by a predator, it will spray the invader with its caustic fluid. While the injured predator is occupied with the caustic substance, the bombardier beetle will make its getaway.

          Another interesting, and largely unheard of defense tactic employed by some arthropods involves the sacrifice of a limb. Many long-legged insects, such as katydids, walkingsticks and craneflies have easily detachable legs, which they are more than happy to give up to a predator if it means getting away alive. These legs have “fracture points” located at certain joints on the legs. When a leg is pulled by a predator, the leg will become detached, leaving the insect alive and the predator with a modest meal.

          This is different than mimicry or camouflage, though it uses the same principle. Some insects “hide in plain sight” by resembling objects in their environment. A thorn could really be a treehopper; a twig might be a walkingstick, an assassin bug, or a caterpillar; and sometimes a dead leaf turns out to be a katydid, a moth, or even a butterfly. Some caterpillars resemble bird droppings, and others have false eyespots on their wings or body to create an imitation of a predator’s head. Often, these guys are the coolest-looking… the details in their appearance astonishing in their accuracy and creativity.

          If there is one thing most of us have in common, it’s distaste for foul smells. And the really bad ones can be enough to make you recoil. Ever been at the epicenter of a skunk attack? It’s like someone is burning tires directly in your NOSE. Stink bugs have special glands that produce a foul-smelling reek. The caterpillar form of some swallowtail butterflies have glands just behind their heads that, when disturbed, will rear up and release a terrible stench. Darkling beetles will raise their big, black butt in warning when they are threatened, and if you don’t pay attention to the warning – will expel acrid, foul-smelling fluid.

          When stink and burning isn’t enough, some bugs will hit their attackers with sticky compounds that harden like glue and incapacitate. Some kinds of cockroaches guard their backsides with a slimy anal secretion (those are three words that are just terrible together) that cripples any ants that launch an attack. And there are types of soldier termites that have nozzle-like heads that can spays sticky, immobilizing toxic fluids at attackers as varied as ants, spiders, centipedes, and other predatory arthropods.

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Where are most bushfires in Australia?

Bushfires happen almost every year across the island-nation of Australia. However, this time around, it has been one of the worst-ever. What began in September 2019 has continued well into 2020. It has claimed more than 25 lives while reducing millions of acres to ash. And New South Wales was hit the hardest – in this State alone, more than half-a-billion creatures, including mammals, birds and reptiles, are feared to have perished. There are reports that thousands of kangaroos and koalas have been consumed by the fire across the country. The last few decades have seen an increase in the number of bushfires, and may be attributed to global warming. As for Australia, the bushfires season seems to be beginning earlier and lasting longer. In a chilling revelation, the U.K. scientists have said that the recent fires in Australia are assign of what the world will go through as temperatures increase.

 

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Why tiger population was reduced rapidly in India?

A telling identity of our planet’s biodiversity, the tiger is also a keystone species. And its population the world over, and especially in India, has been of particular concern. However, July 2019 brought with it some comforting news. The findings of the Tiger census, conducted in our country once in every four years, showed that the tiger population had increased from 2,226 in 2014 to 2,967 in 2018. With that, India is estimated to be home to around 70% of the world’s tigers. Following an alarming decrease in the tiger population since the early 20th Century, the government had put in place stringent laws in the 1970s to protect the national animals, and this seems to have been paying off over the last decade or two. However, human-animal conflicts continue, and conservationists have repeatedly called for an increase in protected areas for the tiger.

 

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HOW CAN YOU TELL HOW OLD A TREE IS?

In temperate climates, a tree makes rapid growth in the warm spring and summer months and much slower growth in the autumn and winter. This growth shows in the trunk as a light ring during times of fast growth and a darker ring for slower growth. It is therefore possible to count the pairs of light and dark rings to see how many years the tree has been growing.

If you are curious about the year that a tree was planted, then you are in luck, as there is an easy way to tell! You may have heard of how to identify the age of the tree by the rings within its trunk, but what’s inside the trunk can even tell us about the conditions/environment the tree was exposed to for its full life cycle.  A tree may have experienced drought, excessive rain, fire, insect plagues and disease epidemics, injuries, thinning or air pollution.  This can all be told by the trunk of the tree.

The only way to see the rings on a tree is for the entire horizontal surface of the trunk to be exposed.  After cutting horizontally through the tree, all you need to do is count the dark rings and you’ll know the tree’s age! You can also gain insight into environmental conditions affecting the tree based on the appearance of the rings. The rings could have some alteration to their shape, colour, and thickness.  For example, narrow rings may be due to insects or dry conditions. On the contrary, wide rings may indicate a wet-season or the death of neighbouring vegetation, permitting rapid growth. While this method may only work on dead trees, it is not impossible to date a living tree.

Bisecting a living tree will obviously cause it immediate and irreparable damage. It is often important to identify the age of living trees. Fortunately, this is possible, even if only in a rough way. To do this, you need to multiply the diameter of the tree by its species-specific growth factor. First, you measure the circumference of the trunk in inches.  Next, calculate the diameter and then multiply the diameter by the species’ average growth factor.  Now you will have a rough age of the living tree! Here is a chart for trees and their associated growth factor. Naturally, you will need to know precisely what species you are dealing with, for that you may want to consult a professional- like the highly trained arborists.

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HOW ARE YOUNG TREES PRODUCED?

Trees produce seeds just as smaller plants do. Their flowers or cones are fertilized by the wind, or insects or birds. But a parent tree takes up large amounts of water from the area around it, and its leaves prevent sunlight from reaching the ground beneath, so it is important that all the seeds do not fall directly beneath the tree. Some trees produce fruits that are eaten by birds or animals and carried far away in their digestive systems. Others bear seeds that have “wings” and can be blown far away by the wind.

Wind pollinator flowers may be small, no petals, and no special colors, odors, or nectar. These plants produce enormous numbers of small pollen grains. For this reason, wind-pollinated plants may be allergens, but seldom are animal-pollinated plants allergenic. Their stigmas may be large and feathery to catch the pollen grains. Insects may visit them to collect pollen, but usually are ineffective pollinators and exert little natural selection on the flowers. Anemophilous, or wind pollinated flowers, are usually small and inconspicuous, and do not possess a scent or produce nectar. The anthers may produce a large number of pollen grains, while the stamens are generally long and protrude out of flower. There are also examples of ambophilous (pollinated by two different classes of pollinators) flowers which are both wind and insect pollinated.

Most conifers and about 12% of the world’s flowering plants are wind-pollinated. Wind pollinated plants include grasses and their cultivated cousins, the cereal crops, many trees, the infamous allergenic ragweeds, and others. All release billions of pollen grains into the air so that a lucky few will hit their targets.

Water pollinated plants are aquatic. Pollen floats on the water’s surface drifting until it contacts flowers. This is called surface hydrophily, but is relatively rare (only 2% of pollination is hydrophily). This water-aided pollination occurs in waterweeds and pondweeds. In a very few cases, pollen travels underwater. Most aquatic plants are insect-pollinated, with flowers that emerge from the water into the air. 

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DO TREES HAVE FLOWERS?

Trees can be divided into two groups. Broad-leaved trees, which may also be deciduous, meaning that they drop their leaves in winter, are flowering plants. Sometimes their flowers are very small and difficult to spot. Conifers, most of which are evergreen, retaining their leaves all year round, are cone-bearers. They have small male cones and larger female cones instead of flowers.

If trees didn’t have flowers there would be no seeds, and if there were no seeds, new trees wouldn’t come up each year. And if new trees didn’t come up each year, there wouldn’t be forests.

Every single tree in the world has flowers, though sometimes they are too small to be seen or are buried so deep in the leaves that nobody can find them. Certain trees have flowers that come before their leaves, so people don’t notice the tiny blooms, which usually are not very colorful.

Certain trees have flowers that have no petals; others are green and appear to be buds of coming leaves unless you look very closely. There are even trees whose flowers are too small to see without a microscope.

Evergreen: Evergreen any plant that retains its leaves through the year and into the following growing season. Many tropical species of broad-leaved flowering plants are evergreen, but in cold-temperate and Arctic areas the evergreens commonly are cone-bearing shrubs or trees (conifers), such as pines and firs. The leaves of evergreens usually are thicker and more leathery than those of deciduous trees (those that shed their leaves in autumn or in the tropical dry season) and often are needlelike or scalelike in cone-bearing trees. A leaf may remain on an evergreen tree for two years or longer and may fall during any season. An evergreen forest may be needle-leaved, as the coniferous forests of the Northern Hemisphere, or broad-leaved, as the temperate rain forests of the Southern Hemisphere and the broad sclerophyll forests (with thickened, hardened foliage resistant to water loss) of coastal areas of the Northern Hemisphere. Most tropical rain forests contain broad-leaved evergreens.

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