Collecting Ant Specimens - IELTS Reading Answers & Explanations
From Cambridge IELTS 08 Academic Reading Test 4 · Part 3 · Questions 27–40
Reading Passage
You should spend about 20 minutes on Questions 27–40, which are based on Reading Passage 3 below.
Collecting Ant Specimens
Collecting ants can be as simple as picking up stray ones and placing them in a glass jar, or as complicated as completing an exhaustive survey of all species present in an area and estimating their relative abundances. The exact method used will depend on the final purpose of the collections. For taxonomy, or classification, long series, from a single nest, which contain all castes (workers, including majors and minors, and, if present, queens and males) are desirable, to allow the determination of variation within species. For ecological studies, the most important factor is collecting identifiable samples of as many of the different species present as possible. Unfortunately, these methods are not always compatible. The taxonomist sometimes overlooks whole species in favour of those groups currently under study, while the ecologist often collects only a limited number of specimens of each species, thus reducing their value for taxonomic investigations.
To collect as wide a range of species as possible, several methods must be used. These include hand collecting, using baits to attract the ants, ground litter sampling, and the use of pitfall traps. Hand collecting consists of searching for ants everywhere they are likely to occur. This includes on the ground, under rocks, logs or other objects on the ground, in rotten wood on the ground or on trees, in vegetation, on tree trunks and under bark. When possible, collections should be made from nests or foraging columns and at least 20 to 25 individuals collected. This will ensure that all individuals are of the same species, and so increase their value for detailed studies. Since some species are largely nocturnal, collecting should not be confined to daytime. Specimens are collected using an aspirator (often called a pooter), forceps, a fine, moistened paint brush, or fingers, if the ants are known not to sting. Individual insects are placed in plastic or glass tubes (1.5-3.0 ml capacity for small ants, 5-8 ml for larger ants) containing 75% to 95% ethanol. Plastic tubes with secure tops are better than glass because they are lighter, and do not break as easily if mishandled.
Baits can be used to attract and concentrate foragers. This often increases the number of individuals collected and attracts species that are otherwise elusive. Sugars and meats or oils will attract different species and a range should be utilised. These baits can be placed either on the ground or on the trunks of trees or large shrubs. When placed on the ground, baits should be situated on small paper cards or other flat, light-coloured surfaces, or in test-tubes or vials. This makes it easier to spot ants and to capture them before they can escape into the surrounding leaf litter.
Many ants are small and forage primarily in the layer of leaves and other debris on the ground. Collecting these species by hand can be difficult. One of the most successful ways to collect them is to gather the leaf litter in which they are foraging and extract the ants from it. This is most commonly done by placing leaf litter on a screen over a large funnel, often under some heat. As the leaf litter dries from above, ants (and other animals) move downward and eventually fall out the bottom and are collected in alcohol placed below the funnel. This method works especially well in rain forests and marshy areas. A method of improving the catch when using a funnel is to sift the leaf litter through a coarse screen before placing it above the funnel. This will concentrate the litter and remove larger leaves and twigs. It will also allow more litter to be sampled when using a limited number of funnels.
The pitfall trap is another commonly used tool for collecting ants. A pitfall trap can be any small container placed in the ground with the top level with the surrounding surface and filled with a preservative. Ants are collected when they fall into the trap while foraging. The diameter of the traps can vary from about 18 mm to 10 cm and the number used can vary from a few to several hundred. The size of the traps used is influenced largely by personal preference (although larger sizes are generally better), while the number will be determined by the study being undertaken. The preservative used is usually ethylene glycol or propylene glycol, as alcohol will evaporate quickly and the traps will dry out. One advantage of pitfall traps is that they can be used to collect over a period of time with minimal maintenance and intervention. One disadvantage is that some species are not collected as they either avoid the traps or do not commonly encounter them while foraging.
Questions
Questions 27–30 True / False / Not Given
Do the following statements agree with the information given in Reading Passage 3?
Questions 31–36 Matching Features
Classify the following statements as referring to
A. hand collecting
B. using bait
C. sampling ground litter
D. using a pitfall trap
Questions 37–40 Diagram Labeling
Label the diagram below.
Choose NO MORE THAN TWO WORDS from the passage for each answer.
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q27 | TRUE | For taxonomy, or classification, long series, from a single nest, which contain all castes (workers, including majors and minors, and, if present, queens and males) are desirable, to allow the determination of variation within species | Excerpt/Passage Explanation: The passage states that for naming and grouping ants, it is helpful to have many ants from the same nest. This allows scientists to see how much ants of the same kind change or look different from one another. Answer Explanation: The answer TRUE means that the text agrees with the statement that scientists who study the naming and grouping of ants (taxonomy) look at the differences between ants within the same group or home. Reason For Correctness: The correct answer is TRUE because the passage explains that for the purpose of taxonomy, researchers prefer to collect a large number of ants from one single nest. They do this so they can look at all the different types of ants in that group (like workers and queens) to see how they vary or differ. In this context, a 'single nest' represents 'one group,' and 'the determination of variation' involves 'comparing members' to see their differences. |
| Q28 | NOT GIVEN | The taxonomist sometimes overlooks whole species in favour of those groups currently under study, while the ecologist often collects only a limited number of specimens of each species, thus reducing their value for taxonomic investigations | Excerpt/Passage Explanation: The passage explains that people who classify living things (taxonomists) might miss certain species because they are focused on specific groups, but it does not give any information about how many new species are found or if this happens regularly. Answer Explanation: The answer 'NOT GIVEN' means the text does not say if taxonomists find new types of ants often or not. Reason For Correctness: The correct answer is NOT GIVEN because the passage discusses how taxonomists study ants and which ants they might ignore, but it never mentions the frequency (how often) they identify new species. Information about the timing or regularity of discovering new ant species is missing from the text. |
| Q29 | TRUE | For ecological studies, the most important factor is collecting identifiable samples of as many of the different species present as possible | Excerpt/Passage Explanation: The passage says that when scientists study how ants interact with nature, their main goal is to find and name every different kind of ant that lives in that area. Answer Explanation: The answer is TRUE because scientists who study ecology want to find as many different types of ants as they can in a specific place. Reason For Correctness: The correct answer is TRUE because the passage says that for ecological studies, the 'most important factor' is to collect 'as many of the different species' as they can find. In this context, 'range' means having many different types, and 'key criterion' means the most important goal. Therefore, the statement matches the information in the text. |
| Q30 | FALSE | Unfortunately, these methods are not always compatible | Excerpt/Passage Explanation: The passage states that the different ways scientists collect ants for different types of studies do not always work well together. Answer Explanation: The answer is "FALSE" because the text indicates it is usually not possible to use the same collection of ants for both naming/classifying them and studying their environment. Reason For Correctness: The correct answer is "FALSE" because the passage explains that the goals for taxonomy (classification) and ecology are different. Taxonomists want a large number of ants from a single nest to see variations, while ecologists want to find as many different species as possible. Because of these different goals, the text explicitly states that these two collection methods are "not always compatible," meaning they do not work well together for the same purpose. |
| Q31 | A | When possible, collections should be made from nests or foraging columns and at least 20 to 25 individuals collected | Excerpt/Passage Explanation: The passage explains that if it is possible, you should get your ant samples from their homes or from a line of ants searching for food, taking at least 20 to 25 ants at once. Answer Explanation: The answer A states that hand collecting is the recommended method when you want to take samples from groups of ants living or moving together. Reason For Correctness: The correct answer is A because the section on hand collecting specifically mentions that researchers should try to take ants from a nest (their home) or a foraging column (a line of ants walking together). Both a nest and a column are groups of ants. Doing this helps make sure that all the ants collected are the same type or species. |
| Q32 | C | This method works especially well in rain forests and marshy areas | Excerpt/Passage Explanation: The passage explains that the leaf litter sampling method is very effective in environments that are naturally very wet. Answer Explanation: The answer identifies the method called sampling ground litter, which involves collecting leaves and organic waste from the floor of a forest or field. Reason For Correctness: The correct answer is derived from the section discussing ground litter. The text mentions that using a funnel to extract ants from collected leaf litter is a technique that is very successful in specific wet environments. It mentions 'rain forests' (which receive a lot of rain) and 'marshy areas' (which are very wet, swampy lands). Therefore, this method is especially good for wet habitats. |
| Q33 | B | Baits can be used to attract and concentrate foragers. This often increases the number of individuals collected and attracts species that are otherwise elusive | Excerpt/Passage Explanation: The passage explains that putting out food (baits) helps bring together ants that are looking for food. This method is useful because it helps collectors find and catch types of ants that are usually very hard to find. Answer Explanation: The answer is option B, which refers to using food to attract ants. Reason For Correctness: The correct answer is B because the passage states that using bait helps to attract ant species that are otherwise 'elusive.' In English, the word 'elusive' is a synonym for 'hard to find' or 'difficult to catch.' While other methods are used for different reasons, baiting is specifically mentioned as a way to bring out those specific types of ants that collectors might normally struggle to locate. |
| Q34 | D | One advantage of pitfall traps is that they can be used to collect over a period of time with minimal maintenance and intervention | Excerpt/Passage Explanation: The passage explains that these traps are useful because they can keep working for a while without the collector needing to do much more work or check on them constantly. Answer Explanation: The answer means that using a pitfall trap is a method of catching ants that does not need much work or a person's constant attention. Reason For Correctness: The correct answer is D because the text mentions that pitfall traps can be left alone to catch ants over a long time. The passage uses the phrase 'minimal maintenance and intervention,' which means the person collecting the ants does not have to spend much time or effort looking after the traps once they are set up. |
| Q35 | A | Individual insects are placed in plastic or glass tubes (1.5-3.0 ml capacity for small ants, 5-8 ml for larger ants) containing 75% to 95% ethanol | Excerpt/Passage Explanation: The passage explains that when people catch ants by hand, they put each single ant into its own small container, like a plastic or glass tube, filled with alcohol. Answer Explanation: The answer is A, which identifies 'hand collecting' as the method that uses separate containers for individual ants. Reason For Correctness: The correct answer is A because the text about hand collecting specifically mentions using separate plastic or glass tubes to store single insects. In this context, 'tubes' are the containers, and they are used for 'individual' specimens to keep them safe and organized for study. |
| Q36 | D | The preservative used is usually ethylene glycol or propylene glycol, as alcohol will evaporate quickly and the traps will dry out | Excerpt/Passage Explanation: The passage explains that for pitfall traps, people use special liquids like ethylene glycol. These are used because alcohol dries up too quickly when the trap is sitting in the ground. Answer Explanation: The answer 'D' means that when using a pitfall trap, you should use liquids that do not contain alcohol to keep the ants in good condition. Reason For Correctness: The correct answer is 'D' because the text mentions that pitfall traps use liquids like ethylene glycol or propylene glycol instead of alcohol. These are different types of chemicals, so they are 'non-alcoholic.' The author explains that alcohol is not a good choice here because it will 'evaporate' (turn into gas and disappear) too fast, leaving the trap dry. |
| Q37 | heat | This is most commonly done by placing leaf litter on a screen over a large funnel, often under some heat. As the leaf litter dries from above, ants (and other animals) move downward and eventually fall out the bottom and are collected in alcohol placed below the funnel | Excerpt/Passage Explanation: The passage explains that to collect ants from leaf litter, you put the leaves on a mesh (screen) above a funnel and add heat. When the heat dries the leaves, the ants crawl down through the funnel and fall into a bottle of alcohol at the bottom. Answer Explanation: The answer "heat" refers to the high temperature or warmth used to dry out the leaves to make ants move. Reason For Correctness: The correct answer is "heat" because the passage explains a specific method for getting small ants out of piles of leaves (leaf litter). In this method, the leaves are put over a funnel and warmed up. The warmth makes the top of the leaves dry, which forces the ants to move downwards to avoid the dryness, eventually falling into a collection container. Keywords like "funnel" and "screen" are often used in diagrams for this process. |
| Q38 | leaf litter | This is most commonly done by placing leaf litter on a screen over a large funnel, often under some heat | Excerpt/Passage Explanation: The passage says that to catch ants, people put the leaves and debris from the ground on a mesh screen that sits on top of a big funnel. Answer Explanation: The answer is the layer of dead leaves, twigs, and dirt found on the ground where many small ants live and search for food. Reason For Correctness: The correct answer is found in the section of the text describing how to collect small ants from the ground. It explains a method using a screen and a funnel. To use this method, someone must put the "leaf litter" on top of a screen. Heat helps move the ants out of this material so they fall through the screen and can be caught. The term "leaf litter" describes exactly what is placed on the screen. |
| Q39 | screen | This is most commonly done by placing leaf litter on a screen over a large funnel, often under some heat | Excerpt/Passage Explanation: The passage explains that to find ants in old leaves, you put the leaves on top of a screen. This screen is placed over a big cone shape called a funnel. Answer Explanation: The answer is the word 'screen'. A screen is a material made of wire or plastic with many small holes in it, similar to a net or mesh. Reason For Correctness: The correct answer is 'screen' because the passage describes a specific tool used to extract ants from leaves and dirt (leaf litter). The text explains that this material is placed on a screen which sits on top of a funnel. This setup allows the ants to fall through the small holes while keeping the leaves on top, which is exactly what a diagram of this collection method would show. |
| Q40 | alcohol | As the leaf litter dries from above, ants (and other animals) move downward and eventually fall out the bottom and are collected in alcohol placed below the funnel | Excerpt/Passage Explanation: The passage explains that when the leaves dry out, the ants crawl down and fall into a liquid called alcohol that is waiting at the bottom. Answer Explanation: The answer is alcohol, which is a liquid used to catch and keep the ant specimens in good condition for studying. Reason For Correctness: The correct answer is alcohol because the passage describes a specific collecting method using a funnel and leaf litter. In this process, the ants move away from heat and fall through the bottom of the funnel into a container. The text explicitly states that this container holds alcohol to collect the ants. Key terms to notice are 'collected' and 'below the funnel'. |