Insect Morphology and Classification Questions and Answers

Answer: A

‘Handbook of Economic Entomology for South India’ was written by T. V. Ramakrishna Ayyar, an Indian entomologist who worked in Madras. It is a standard reference on insect pests of South Indian crops.

M. S. Mani is known for his work on Indian high-altitude and gall insects, and T. Kumara Swami and K. K. Nayar are other Indian agricultural writers, so they are not the author of this handbook.

Ramakrishna Ayyar was an Indian entomologist who served in Madras (now Tamil Nadu) and wrote about insect pests of crops in South India. His handbook is a standard older reference on the subject.

Answer: C

The exotic bee Apis mellifera was successfully introduced in India in 1962, in Himachal Pradesh. Earlier attempts in 1880 and 1887 had failed, and the 1962 introduction established it for commercial beekeeping.

The years 1942, 1952 and 1972 are not the date of this successful introduction.

Earlier attempts to bring the European honey bee into India failed, and only the 1962 introduction in Himachal Pradesh at Nagrota Bagwan succeeded. After that, Apis mellifera spread to commercial beekeeping in Punjab, Haryana and other states.

Answer: A

Newton's bee hive is the most popular in South India. It was developed in the south to keep the Indian hive bee, Apis cerana indica, in a movable-frame hive.

The Langstroth hive is the standard for the European bee Apis mellifera, the Jeolikote hive is associated with Uttar Pradesh in the north, and a nucleus hive is a small hive used to start colonies, so none of them is the popular South Indian hive.

The Newton hive was designed for the Indian hive bee, Apis cerana, and is widely used in South India, where this bee is the main species kept. The Langstroth hive, by contrast, is the standard box for Apis mellifera.

Answer: C

Cantharidin is produced by the blister beetle (family Meloidae). It is a toxic compound that blisters skin and is used in small doses as a medicine to remove warts.

The cochineal insect gives carmine dye, the giant fly is not a source of it, and the lac insect gives lac.

Cantharidin is made by blister beetles and by some related beetles. The substance blisters the skin, which gives the beetle its name, and it has been used in medicine for warts.

Answer: B

Royal jelly is produced by the lateral pharyngeal glands, also known as the hypopharyngeal glands, of nurse bees. It is fed to the larvae and to the queen.

Mandibular glands add some fatty acids, while the cephalic and thoracic salivary glands are not the source of the jelly.

Nurse bees make royal jelly from secretions of their glands in the head. Royal jelly is the sole food of the queen larva and the adult queen.

Answer: B

The keyed answer is Incomplete lifecycle.

Thrips (order Thysanoptera) are generally classed with the hemimetabolous insects: the egg gives a nymph, the nymph feeds and moults, and the adult appears without a full larval-pupal-adult sequence. This is described as incomplete metamorphosis, and it is how the keyed answer reads.

They do have a distinct feature: after the two feeding nymphal stages come one or two non-feeding, pupa-like stages (the propupa and pupa), and some authors call this intermediate or neometabolous development. The pupa-like stages do not involve the internal reorganisation of a true holometabolous pupa, so the standard classification remains incomplete metamorphosis. 'Complete' would be wrong in either view.

Answer: B

The insect body is divided into Three regions.

The body of an insect has three distinct regions (tagmata): the head, which carries the eyes, antennae and mouthparts; the thorax, which bears three pairs of legs and usually two pairs of wings; and the abdomen, which contains most of the digestive and reproductive organs.

Two body regions, a cephalothorax and an abdomen, is the arrangement of spiders and other arachnids, and four is not the plan of any major arthropod group.

Answer: A

The monophagous pest among these is the Pink bollworm.

A monophagous pest feeds on a single host or a very narrow range of closely related plants. The pink bollworm, Pectinophora gossypiella, depends on cotton, feeding inside its flowers, bolls and seeds, and is the standard example of a monophagous pest in Indian entomology.

White grubs feed on the roots of many crops, and the pink stem borer, Sesamia inferens, attacks rice, maize, wheat, sugarcane and other grasses, so both are polyphagous. That also rules out "Both (A) and (C)".

Answer: B

The paper's answer is Malphigian tubules (Malpighian tubules).

The Malpighian tubules are the excretory organs of insects. They take up water, salts and nitrogenous wastes from the blood and pass them into the hindgut; in the rectum most of the water and useful salts are then reabsorbed, while the nitrogen leaves as nearly dry uric acid. This tubule-and-rectum system lets insects excrete wastes while losing very little water, and in some beetles and caterpillars the tubules are fused to the rectum (the cryptonephridial system) to draw out still more water.

Rectal gills are breathing organs of dragonfly nymphs in water. The crop stores food, and the proventriculus grinds and filters it; neither has a role in conserving water.

Answer: B

Thrips mouthparts are asymmetrical because the right mandible is absent.

Thrips have rasping-sucking mouthparts in a cone. Only the left mandible develops, as a stylet used to pierce the plant surface; the right mandible is reduced or lost during development. The paired maxillary stylets then suck up the sap from the damaged cells, which gives the silvery streaks typical of thrips damage.

It is the left mandible that is present, so 'Left mandible' is wrong, and since one mandible remains, 'Both' is also wrong. 'None of these' does not apply because the absence of the right mandible is the reason.