GMAT Exam Dumps : Graduate Management Admission Test (2022)

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.

According to the production-smoothing buffer stock model, inventories of a

firm’s products allow it to supply unexpected demand without having to adjust

Output immediately. When costs per additional unit produced are increasing,

using inventory to smooth production is efficient as long as the savings from not

adjusting production exceed the cost of holding inventory. Inventory acts as a

buffer stock, absorbing increases or decreases in demand while production

remains relatively steady.

If firms are smoothing production, then sales should vary more than

production. If inventories are used as a buffer stock, then high-frequency

changes in inventory should be in the opposite direction to sales. Empirical

research using aggregate data daes not confirm this expectation, however;

production varies more than sales, and changes in inventory and sales tend to

vary in the same direction. Thus either the production-smoothing buffer stock

model is incorrect, or other factors are preventing empirical confirmation of the

smoothing effect.

Most of the research that finds contradictions of production smoothing uses

seasonally adjusted aggregate data concerning inventory and sales. It is possible

that firms actually do use inventory to smooth production, but the research has

failed to detect signs of this activity because the data are too highly aggregated

over many firms. But even research at the level of individual companies has

failed to confirm the model.