Gut instinct
The last time you noticed a grasshopper in your garden munching away at leaves, did you think of the massive damage it causes to agricultural crops across the world? But getting rid of the pest is not an option because it plays a positive role in recycling nutrients by decomposing plant matter.
The feeding habits of herbivorous pests like grasshoppers have always been a matter of concern as well as interest to scientists. Just by the choice of food, they can alter the plant community of a region. Knowledge about their feeding habits can be important for control efforts and restoration of damaged areas. “Accurately determining the feeding preferences of grasshoppers can help us understand the magnitude of plant damage, and consequently, whether or not control of grasshoppers is needed in a given area,” says Alina Avanesyan, researcher at the University of Cincinnati, USA.
Her process involves dissecting the insect&’s gut and isolating DNA from the tissue. This DNA is a combination of the DNA of the grasshopper and that of the plants it has consumed. The plant DNA is then enriched in this mixture by an inexpensive and routine technique — Polymerase Chain Reaction.
The DNA obtained acts as a “bar code” for individual plants and can accurately mark out the plant consumed by the insect. It can be used for a variety of purposes, for example to determine how long food has been digested and to explore the sequence of multiple plant species consumed and feeding preferences. Scientists can also use it to compare specific feeding patterns of different grasshopper species and uncover behaviour that might lead to intensive crop damage in certain areas.
“The findings will help us understand the diet of a range of different insect species, and this information could be used to design cropping systems and landscapes to minimise pest damage,” said Hari Chand Sharma, entomologist with the International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh.

MANUPRIYA/CSE-DOWN TO EARTH FEATURE SERVICE

Saving a crushed egg
Conservationists in New Zealand are celebrating after an extremely rare kakapo chick hatched from a cracked egg held together by nothing more than tape and glue. The bird joins a global kakapo population of just 125 birds — but what makes these animals so unique and why are they worth saving?
   To describe a kakapo as concisely as possible you’d say that it is a species of flightless parrot, one that is ground-dwelling, nocturnal and thoroughly rotund. However, this barely even scrapes the surface of the kakapo&’s strangeness — a quality that is in no small way thanks to the fact they developed in the isolated environment of the islands of New Zealand. This evolutionary upbringing accounts for some the bird&’s odder physical characteristics, with the abundance of food and an absence of ground-based predators encouraging the kakapo (the name translates as “night owl”) to sacrifice the power of flight in favour of becoming more “thermodynamically efficient” — that is to say, they piled on the pounds and at two to four kilograms are the heaviest parrot around.
   However, kakapos compensate for their inability to fly with superb camouflage and a tendency to freeze completely when startled. These two traits combine to form a pretty good defence against the unwanted attention of eagles (who find their prey mostly by movement) but they unfortunately made the bird easy pickings for the cats and rats introduced by European settlers. These predators decimated kakapo populations and it&’s now the responsibility of the New Zealand government&’s Kakapo Recovery Plan to save the species.

JAMES VINCENT/THE INDEPENDENT