Economic Zoology: Sericulture, Apiculture and Lac Culture

The correct answer is B, Bombyx mori, the mulberry silkworm, the only fully domesticated insect of the silk group and the source of most of the world's raw silk. Option A, Antheraea mylitta, is the tropical tasar silkworm, which lives in the open on Asan and Arjun trees. Option C, Samia ricini, is the eri silkworm, reared on castor leaves, whose broken fibre is spun rather than reeled. Option D, Kerria lacca, is not a silkworm at all but the lac insect, a scale insect whose female secretes the resin called lac. The way to keep the four apart is to attach each to its host plant: mulberry for Bombyx mori, Asan and Arjun for tasar, castor for eri and Som for muga. Note also that this insect has been bred by people for so long that the adult moth can barely fly and depends entirely on rearers, which is what makes it the one truly domesticated silk insect.

The correct answer is C, Assam. Muga silk comes from Antheraea assamensis, reared on Som and Soalu trees of the Brahmaputra valley, and Assam's muga carries a Geographical Indication tag. Option A is wrong as an answer to this question although Karnataka leads the country in mulberry silk, which is a different variety; students who remember only the words largest silk producer mark it wrongly. Option B is wrong because West Bengal is known for mulberry silk and for the research institute at Berhampore, not for muga. Option D is wrong because Jharkhand is famous for tasar silk and, above all, for lac. Remember the pairing: mulberry with Karnataka, muga with Assam, tasar with Jharkhand and Chhattisgarh. One more fact from this topic is often paired with the state: muga is reeled into a golden yarn that needs no dyeing, and its natural colour is the reason it is prized.

The correct answer is B, castor. The eri silkworm, Samia ricini, feeds on castor leaves, and its silk is called ahimsa silk because the moth is allowed to emerge before the cocoon is used, leaving a broken fibre that is spun like cotton instead of being reeled. Option A is wrong because mulberry is the food of Bombyx mori, and growing mulberry for it is called moriculture. Option C is wrong because Arjun, along with Asan, is the host of the tropical tasar silkworm. Option D is wrong because Som, with Soalu, is the host of the muga silkworm of Assam. The examiner's favourite trick here is to offer two tree names from the tasar and muga groups beside castor. Castor is Ricinus communis, grown widely in Assam and the North-East, which is why eri rearing is concentrated there alongside muga.

The correct answer is C, Apis dorsata, the rock bee, the largest of the Indian honey bees, which builds a single huge comb on cliffs and tall buildings and yields the most honey per colony, yet is fierce and cannot be kept in hives. Option A is wrong because Apis florea, the little bee, is the smallest and gives the least honey. Option B is wrong because Apis cerana indica, the Indian hive bee, is the species traditionally kept in Indian hives, so it is domesticated. Option D is wrong because Apis mellifera, the Italian or European bee, is the species most used in commercial apiaries for its gentleness and high yield in managed hives. Note the contrast the question rests on: highest yield in the wild against the best bee to manage.

The correct answer is B, unfertilised eggs. The queen can lay both fertilised and unfertilised eggs; the unfertilised ones develop into haploid males called drones, a form of parthenogenesis, while fertilised eggs give rise to diploid females. Option A is wrong because fertilised eggs become workers or queens, not drones. Option C is wrong because although a laying worker can sometimes produce drones in a queenless colony, that is an exception and not the normal origin of drones, so it cannot be stated for all cases. Option D is wrong because royal jelly fed throughout the larval period produces a queen, not a drone; caste among the females is decided by diet, while the drone's sex is decided by the egg being unfertilised. Drones do no work in the hive, gather no food and have no sting; after the nuptial flight they are driven out of the colony, so their number falls sharply in a lean season.

The correct answer is A, Karl von Frisch, who decoded the dance language of bees: a round dance for a source near the hive and a waggle or tail-wagging dance for a distant one, in which the angle of the straight run shows the direction of the food relative to the sun. Options B and D are wrong as the answer to this question although Konrad Lorenz and Nikolaas Tinbergen shared the 1973 Nobel Prize in Physiology or Medicine with von Frisch for work on animal behaviour; Lorenz is remembered for imprinting in birds and Tinbergen for his experiments on instinct. Option C is wrong because Charles Darwin wrote on natural selection and did study comb building, but the dance language was not his discovery.

The correct answer is A, Kerria lacca, earlier named Laccifer lacca, a tiny scale insect whose female settles on the twigs of a host tree, sucks its sap and secretes the resin we call lac. Option B is wrong because Bombyx mori is the mulberry silkworm and secretes silk from a modified salivary gland. Option C is wrong because Apis dorsata is the rock bee, which makes honey and beeswax. Option D is wrong because Antheraea proylei is the oak tasar silkworm of the Himalayan belt. A further point often asked is that it is the female lac insect, and not the male, that produces the resin of commerce, and that the scraped lac is refined into seedlac, button lac and shellac. The lac insect belongs to the order Hemiptera, the group of sap-sucking bugs, and the lac of commerce is the hardened secretion that covers the female's body on the twig.

The correct answer is D, castor, which is the host of the eri silkworm and has nothing to do with lac culture. Options A, B and C are all genuine lac hosts: Palas, Kusum and Ber are the three chief host trees on whose tender twigs the lac insect is inoculated. Kusum carries the Kusmi strain, which gives the Aghani and Jethwi crops, while Palas and Ber carry the Rangeeni strain, which gives the Katki and Baisakhi crops, so four lac crops are taken over two years. India is the world's largest producer of lac and Jharkhand the leading state, and the research institute at Namkum near Ranchi, founded in 1924 as the Indian Lac Research Institute, now works as the Indian Institute of Natural Resins and Gums.

The correct answer is B, Bengaluru. The Central Silk Board was constituted under the Central Silk Board Act, 1948 and works under the Ministry of Textiles with its headquarters in Bengaluru, from where it runs the country's sericulture research and seed organisation. Option A is wrong, though Mysuru is the seat of a Central Sericultural Research and Training Institute, the other two being at Berhampore in West Bengal and Pampore in Jammu and Kashmir. Option C is wrong because Ranchi, or more exactly Namkum near it, is the home of the lac research institute, not of the silk board. Option D is wrong because Guwahati is in the muga belt but is not the board's headquarters. Keep the three cities separate: Bengaluru for silk administration, Mysuru for silk research and Ranchi for lac.

The correct answer is B, sericin. The silkworm's silk gland secretes a protein called fibroin, and over it a second protein, sericin, which acts as a gum and hardens the cocoon; boiling the cocoon softens the sericin so the filament can be reeled, and removing it afterwards is called degumming, which gives silk its lustre and softness. Option A is wrong because fibroin is the fibre itself and must not be removed. Option C is wrong because chitin is the material of the insect's own exoskeleton and of fungal cell walls, not of silk. Option D is wrong because keratin is the protein of hair, wool, nails, horns and feathers; wool is keratin while silk is fibroin, a distinction examiners like to test in a single question.

The correct answer is B, Jharkhand, the leading lac producing state of India, which also explains why the country's lac research institute stands at Namkum near Ranchi. Option A is wrong, although Odisha and Chhattisgarh are also lac producing states of the same forest belt and often appear as the distractor closest to the answer. Option C is wrong because Assam is associated with muga and eri silk, not with lac. Option D is wrong because Karnataka leads in mulberry silk and in sandalwood, not in lac. Hold the three leaders together for the examination: Jharkhand for lac, Karnataka for mulberry silk and Assam for muga silk, and remember that India itself is the largest lac producer in the world. The state's forests carry both strains of the insect, Rangeeni on Palas and Ber and Kusmi on Kusum, which is what allows four crops to be harvested over two years.

The correct answer is B, honey. The Sweet Revolution is the term used for the drive to raise honey production and beekeeping in India, supported by the National Beekeeping and Honey Mission. Option A is wrong because sugarcane and sugar do not have a colour revolution of their own in the usual list. Option C is wrong because milk is the White Revolution, associated with Operation Flood and Verghese Kurien. Option D is wrong because fruit production is called the Golden Revolution, which covers horticulture and honey in some lists, while the Yellow Revolution stands for oilseeds, the Blue for fish, the Green for food grains and the Pink for prawns or onions. These colour revolutions are asked almost every year, so learn them as one table.