Free Admission Tests GMAT Practice Exam with Questions & Answers | Set: 4

Parasitic wasps propagate by injecting their eggs into a caterpillar that then becomes paralyzed as the eggs inside develop into wasp larvae. The wasp larvae kill the caterpillar host as they feed on it, form cocoons, and finally develop into wasps. In attempting to discover how such wasps detect the presence of the caterpillar hosts that are so critical to the wasps' propagation, researchers have uncovered an intriguing defense mechanism developed by the plants on which the caterpillars feed.

When chewed on, many plants release volatile compounds from both damaged and undamaged tissues. When these compounds are toxic to the insects that feed on the plants, they can help defend the plants from such attacks. However, the plants on which the wasps' caterpillar hosts feed have evolved an even more complex defense: the caterpillar-infested plants appear to release volatile chemicals that attract parasitic wasps, which then prey on the caterpillars. Scientists originally suspected that the wasps were attracted by an odor, reminiscent of cut grass, that is released as the caterpillar feeds, but a recent study suggests that a different set of volatile attractants is involved. In this study, when researchers used a razor blade to mimic caterpillar damage on the leaves, only grassy odors were emitted, not the volatile compounds that attracted wasps. However, when oral secretions from the caterpillars were applied to these damaged leaves, the leaves released the wasp attractants several hours later. Further tests revealed that oral secretions placed on the razor-damaged leaves stimulated the release of such attractants, making the plants as attractive to wasps as plants that had suffered actual caterpillar damage. These results suggest that chemicals from the caterpillar must be present for these attractants to be released and that unlike the grassy scent, which emanates only as the caterpillar on the plant, the wasp attractants are produced several hours after the attack and persist for several hours, perhaps days. Researchers have launched additional studies to determine whether the wasps' capacity to prey on caterpillars can be enhanced to the extent that the wasps could be used as a natural pesticide to "police" plants and protect them from crop-destroying caterpillars.

Despite overall physiological bilateral symmetry, many species exhibit

lateralized biases, i.e., preferences for right- or left-oriented behavior. When

approaching prey, for example, some predator species favor their right eye; some

prey species respond more quickly when their left eye detects a predator. Similar

behavioral asymmetries occur in humans. Most notable is right- and lefthandedness; less notable is the tendency to turn right when entering a room.

Paul Farnsworth found that more successful students tended to choose seats near

the front, a little to the right. He arqued that external factors such as teacher

location might have affected this lateral bias. But it is now known that processing

differences between the two brain hemispheres can also contribute to behavioral

asymmetries.

George Karev found that when presented with a movie theater seating

diagram, right-handed people were more likely than left-handed people to choose

a seat on the right, facing front. But he hypothesized that, since the right

hemisphere processes visuospatial and emotional information, the people who

chose right-side seats did so because that would put the screen in their left visual

field, optimizing information flow to the right hemisphere.

Although the right hemisphere is thought to be dominant in processing

emotion, some evidence suggests that the left hemisphere plays a role. The

valence model proposes that the left and right hemispheres process positive and

negative emotion respectively, while the approach-withdrawal model posits that

the left hemisphere processes emotion expressed in approach behavior and the

right hemisphere processes emotion expressed in withdrawal behavior.

Victoria Harms and colleagues suggested that since a paper seating plan was

used in the theater-seating studies by Karev and others, the exhibited preference

might be due simply to handedness: people choose the same side of the paper as

their favored hand. Consequently, the Harms research was designed to study

choices in an actual movie theater. Also, hoping to distinguish between various

explanations, they studied seating choices for comedies (presumed to contain

positive emotional content), dramas (presumed to contain negative emotional

content), and documentaries (presumed to have balanced emotional content).

They found significant—though not universal—preference for seats on the right,

facing front, regardless of movie genre and of handedness.

Many policymakers adopt a macro approach to environmental problems in emerging markets (countries experiencing rapid economic growth): discussing ambitious regulations in global faums and looking to giant multinational companies and non-governmental organizations (NGOs) for insight. But examining what successful companies in these countries are already doing to make growth more environmentally sustainable may make more sense.

One study identifies several such firms that are turning eco-consciousness into a source of competitive advantage. The most salient quality of these highly profitable companies Is that they turn limitations (of resources, labor, and Infrastructure) into opportunities. An Indian cement company suffering water shortages developed the world's most water-efficient cement-making method, using air-cooling rather than water cooling. A Philippines utility reduced its water loss through wastage and illegal tapping from 63 percent (1997) to 12 percent (2010) by making water more affordable for lower-Income consumers. A Chinese company makes air conditioners powered with buildings' waste heat, reducing strain on the electric grid.

The companies also seek to shape their business environment to support sustainable objectives. Some lobby regulators: a Brazilian organic-sugar producer works with Brazil's government to establish an organic certification system. Some form partnerships: Kenya's Equity Bank allies with international groups to reduce its risks when lending to smallholders or single-family farms; a Brazilian cosmetics company works with suppliers to produce sustainable packaging. Some firms also work to reach and educate lower-income consumers, sacrificing short-term profits to create future markets: a Chilean forestry company organizes local carpenters into networks and connects them to low-income customers.

One could quibble with the study. Switzerland's Phil Rosenzweig has argued that management writers are prone to a halo effect: they treat a company's temporary success as proof that It has discovered some eternal principle of good management. That some successful companies have embraced environmental sustainability does not prove that It makes companies successful. Some firms, having prospered, can afford splurging on green Initiatives; some pursue eco-Initiatives for public relations purposes.

Nonetheless, the study Is thought-provoking. Critics argue that environmentalism Is a rich-world luxury, but such fears are overblown. When natural resources are scarce and consumers are cash-strapped, sustainability can be a lucrative business strategy.

Parasitic wasps propagate by injecting their eggs into a caterpillar that then becomes paralyzed as the eggs inside develop into wasp larvae. The wasp larvae kill the caterpillar host as they feed on it, form cocoons, and finally develop into wasps. In attempting to discover how such wasps detect the presence of the caterpillar hosts that are so critical to the wasps' propagation, researchers have uncovered an intriguing defense mechanism developed by the plants on which the caterpillars feed.

When chewed on, many plants release volatile compounds from both damaged and undamaged tissues. When these compounds are toxic to the insects that feed on the plants, they can help defend the plants from such attacks. However, the plants on which the wasps' caterpillar hosts feed have evolved an even more complex defense: the caterpillar-infested plants appear to release volatile chemicals that attract parasitic wasps, which then prey on the caterpillars. Scientists originally suspected that the wasps were attracted by an odor, reminiscent of cut grass, that is released as the caterpillar feeds, but a recent study suggests that a different set of volatile attractants is involved. In this study, when researchers used a razor blade to mimic caterpillar damage on the leaves, only grassy odors were emitted, not the volatile compounds that attracted wasps. However, when oral secretions from the caterpillars were applied to these damaged leaves, the leaves released the wasp attractants several hours later. Further tests revealed that oral secretions placed on the razor-damaged leaves stimulated the release of such attractants, making the plants as attractive to wasps as plants that had suffered actual caterpillar damage. These results suggest that chemicals from the caterpillar must be present for these attractants to be released and that unlike the grassy scent, which emanates only as the caterpillar on the plant, the wasp attractants are produced several hours after the attack and persist for several hours, perhaps days. Researchers have launched additional studies to determine whether the wasps' capacity to prey on caterpillars can be enhanced to the extent that the wasps could be used as a natural pesticide to "police" plants and protect them from crop-destroying caterpillars.