BEST IELTS Academic Reading Test 127

BEST IELTS Academic Reading Test 127

ACADEMIC READING TEST 127 – PASSAGE – 2

ACADEMIC READING TEST – 127

READING PASSAGE – 2

Lepidoptera

Myths and Misnomers

A buttercup is a small, bright yellow flower; a butternut is a yellow-fleshed squash; and, there is also a butter bean. The origin of the word ‘butterfly’ may be similar to these plants – a creature with wings the colour of butter – but a more fanciful notion is that ‘flutterby’ was misspelt by an early English scribe since a butterfly’s method of flight is to flutter by. Etymologists may not concur, but entomologists agree with each other that butterflies belong to the order of Lepidoptera, which includes moths, and that ‘lepidoptera’ accurately describes the insects since ‘lepis’ means ‘scale’ and ‘pteron’ means ‘wing’ in Greek.

Until recently, butterflies were prized for their evanescence – people believed that adults lived for a single day; it is now known this is untrue, and some, like monarch butterflies, live for up to nine months.

Butterflies versus Moths

Butterflies and moths have some similarities: as adults, both have fur membranous wings covered in minute scales, attached to a short thorax and a longer abdomen with three pairs of legs. They have moderately large heads, long antennae, and compound eyes; tiny palps for smell; and, a curling proboscis for sucking nectar. Otherwise, their size, colouration, and lifecycles are the same.

Fewer than one percent of all insects are butterflies, but they hold a special place in the popular imagination as being beautiful and benign. Views of moths, however, are less kind since some live indoors and fast on cloth; others damage crops; and, most commit suicide, being nocturnal and drawn to artificial light. There are other differences between butterflies and moths; for example, when resting, the former fold their wings vertically above their bodies, while the latter lay theirs flat. Significantly. butterfly antennae thicken slightly towards their tips, whereas moth antennae end in something that looks like a V-shaped TV aerial.

The Monarch Butterfly

Originating in North America, the black-orange-and-white monarch butterfly lives as far away as Australia and New Zealand, and for many children, it represents a lesson in metamorphosis, which can even be viewed in one’s living room if a pupa is brought indoors.

It is easy to identify the four stages of a monarch’s lifecycle – egg, larva, pupa, and adult – but there are really seven. This is because, unlike vertebrates, insects do not have an internal skeleton, but a tough outer covering called an exoskeleton. This is often shell-like and sometimes indigestible by predators. Muscles are hinged to its inside. As the insect grows, however, the constraining exoskeleton must be moulted, and a monarch butterfly undergoes seven moults, including fur as a larva.

Temperature dramatically affects butterfly growth: in warm weather, a monarch may go through its seven moults in just over a month. Time spent inside the egg, for instance, may last three to four days in 25° Celsius, but in 18°, the whole process may take closer to eight weeks, with time inside the egg eight to twelve days. Naturally, longer development means lower populations due to increased predation.

A reliable food supply influences survival and the female monarch butterfly is able to sniff out one particular plant its young can feed off – milkweed or swan plant. There are a few other plants larvae can eat, but they will resort to these only if the milkweed is exhausted and alternatives are very close by. Moreover, a female butterfly may be conscious of the size of the milkweed on which she lays her eggs since she spaces them, but another butterfly may deposit on the same plant, lessening everyone’s· chance of survival.

While many other butterflies are close to extinction due to pollution or dwindling habitat, the global numbers of monarchs have decreased in the past two decades, but less dramatically.

Monarch larvae absorb toxins from milkweed that renders them poisonous to most avian predators who attack them. Insect predators, like aphids, flies, and wasps, seem unaffected by the poison and are therefore common. A recent disturbing occurrence is the death of monarch eggs and larvae from bacterial infection.

Another reason for population decline is reduced wintering conditions. Like many birds, monarch butterflies migrate to warmer climates in winter, often flying extremely long distances, for example, from Canada to southern California or northern Mexico, or from southern Australia to the tropical north. They also spend some time in semi-hibernation in dense colonies deep in forests. In isolated New Zealand, monarchs do not migrate, instead of finding particular trees on which to congregate. In some parts of California, wintering sites are protected, but in Mexico, much of the forest is being logged, and the insects are in grave danger.

Milkweed is native to southern Africa and North America, but it is easy to grow in suburban gardens. Its swan-shaped seedpods contain fluffy seeds used in the 19th century to stuff mattresses, pillows, and lifejackets. After milkweed had hitched a lift on sailing ships around the Pacific, the American butterflies followed with Hawaii seeing their permanent arrival in 1840, Samoa in 1867, Australia in 1870, and New Zealand in 1873. As butterfly numbers decline sharply in the Americas, it may be these Pacific outposts that save the monarch.

Questions 14-17

Do the following statements agree with the information given in Reading Passage 2?

In boxes 14-17 on your answer sheet, write:

TRUE – if the statement agrees with the information

FALSE – if the statement contradicts the information

NOT GIVEN – if there is no information on this

14.   One theory is that the word ‘butterfly’ means an insect the colour of butter.

15.   Another theory is that a ‘buttery’ was a mistake for a ‘flutterby’.

16.   The Greeks had a special reverence for butterflies.

17.   The relative longevity of butterflies has been understood for some time.

Questions 18-21

Classify the things on the following page that relate to:

A. butterflies only.

B. moths only.

C. both butterflies and moths.

Write the correct letter A, B, or C, in boxes 18-21 on your answer sheet.

18.   They have complex eyes.

19.   Humans view them negatively.

20.   They fold their wings upright.

21.   They have more pronounced antennae.

Questions 22-27

Complete the summary below using the numbers or words, A-I, below.

Write the correct letter A-I, in boxes 22-27 on your answer sheet.

The Monarch Butterfly

Monarch butterflies can live for up to nine months. Indigenous to (22)……………….., they are now found throughout the Pacific as well.

Since all insects have brittle exoskeletons, they must shed these regularly while growing. In the life of a monarch butterfly, there are (23)……………….. moults.

Several factors affect butterfly populations. Low temperatures mean animals take longer to develop, increasing the risk of predation. A steady supply of a specific plant called (24)……………….. is necessary, and a small number of eggs laid per plant. Birds do attack monarch butterflies, but as larvae and adults contain toxins, such attacks are infrequent. Insects, unaffected by poison, and (25)……………….. pose a greater threat.

The gravest danger to monarch butterflies is the reduction of their wintering grounds, by deforestation, especially in (26)………………….

Monarchs do not migrate long distances within New Zealand, but they gather in large colonies on certain trees. It is possible that the isolation of this country and some other islands in (27)……………..  will save monarchs.

ANSWERS ARE BELOW

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ANSWERS

14. TRUE

15. TRUE

16. NOT GIVEN

17. FALSE

18. C

19. B

20. A

21. B

22. G

23. I

24. F

25. A

26. E

27. H