次の英文を読み、下記の設問に答えなさい。

Professor: Good morning James. For homework, you're going to read about the connection of sex with smell, which is highly developed in insects. During this biology laboratory period, you will be offered an insight into both the importance and the disadvantage of reliance on smell in relation to sex in the insect world. So for today's experiment, we will separate the head of a green bottle fly from its body and connect the head with this wire to an oscilloscope^注1 that will display the wave」form of any changes in electrical voltage as a line on the screen. This is similar to the machine that displays the waveform of the heartbeat that you might have seen in a hospital.

Student: But if we cut off the fly's head, won't it simply die and then we won't be able to see anything on the oscilloscope?

Professor: Not at all. Even with their heads separated, most insects can still briefly function. One example is that the female praying mantis will often cut off the head of the male during mating. While this may seem strange and you may think that it should defeat the purpose of mating, nonetheless with the brain removed this actually encourages what is left of the body of the male to continue to mate.

Student: That is very interesting, but what is the advantage of removing the fly's head from its body?

Professor: By removing its head, I am able to gain access to the olfactory organ while it is still functioning. The olfactory organ is where the sense of smell and the ability to perceive orders is located. Now let's begin our experiment. With the head removed and hooked up to the oscilloscope, I will wave some tobacco smoke in front of it.... Notice that there is no movement of the line on the oscilloscope. Now, with alcohol...nothing.... Next I will try ammonia.... Once again, notice there is no visible movement. Now, let's try it with a very small quantity of the sex attractant^注2 released by the female of the species....

Student: Wow!!! Look, the line on the oscilloscope has really shot up! It is amazing that the fly could not smell anything except the female sex attractant. Even though only a small amount was used, the male fly could smell it very well.

Professor: Such ability to pick up the attractant by the female species is quite common in insects. For example, the male silkworm moth is able to detect the female's sex attractant molecule even if only one molecule reaches its antennae. A single female silkworm moth needs release only a hundredth of a microgram of sex attractant per second to attract every male silkworm nearby.

Student: To locate their mates only by their sense of smell sounds great, but couldn't it be used to trick the insects?

Professor: Yes, and one of the most curious aspects of the dependence on smell to find a mate and continue the species is found in South African beetles, which go into the ground during the winter. In the spring, as the ground thaws, the beetles emerge, but the male beetles come out of the ground a few weeks before the females do. In this same region of South Africa, a species of orchid has evolved which gives off an aroma identical to the sex attractant of the female beetle. The male beetles are exceedingly shortsighted^注3, and the orchids have evolved their petals so that, to a beetle, they (a)resemble the female in receptive sexual posture. The male beetles spend several weeks among the orchids before the females emerge from the ground.

Student: By producing and releasing the same molecule that the females produce, the orchids are able to trick the beetles into pollinating^注4 them; therefore both organisms survive. That is a very good (b)survival mechanism used by the orchids.

Professor: Yes, it is. But the orchids must be careful not to be too attractive; if the beetles fail to reproduce themselves, the orchids will also die out. As for the beetles, that is one limitation to purely olfactory sexual incentive. Another is that since every female beetle produces the same sex attractant, it is not easy for a male beetle to fall in love with that one special lady insect. While male insects may display themselves to attract a female, the central role of the female sex attractant in mating seems to reduce the extent of sexual selection among the insects.

Student: I'm glad we humans don't know that way of finding a mate. It would mean the end of romance, wouldn't it?

Professor: At its simplest level, that is true, but there are several studies that suggest that humans also use various toms of smell, sight and so on, when subconsciously choosing their mate. However, that area is much more difficult to understand, and we will cover it next time.

• 注1:オシロスコープ
• 注2:誘引物質
• 注3:近眼で
• 注4:受粉させる

問 英文の内容から判断し、(1)～(5)の質問に対する答えとして最も適したものをそれぞれ選択肢1～4の中から選びなさい。また(6)～(10)は書き出しに続くものとして最も適したものをそれぞれ選択肢1～4の中から選びなさい。

• (1) Which of the following does NOT have a correct meaning of the word “(a)resemble”?
  • 1. He is looking like his father more and more as the years go by.
  • 2. He looks like his sister in appearance but not in character.
  • 3. He takes his sister when they visit their grandmother.
  • 4. He takes after his grandfather as he got older.
• (2) Which of the following is closest in meaning to “(b)survival mechanism”?
  • 1. survival rate
  • 2. survival period
  • 3. survival technique
  • 4. survival kit
• (3) Which of the following is NOT mentioned as a way for orchids to reproduce themselves?
  • 1. Orchids have evolved to bloom in the same season as the female beetle emerges.
  • 2. Orchids have evolved to give off an aroma identical to that of the female beetle.
  • 3. Orchids evolved shape of their petals that resembles the female beetle.
  • 4. Orchids evolved at the same time as the female beetle.
• (4) Why is it that the female praying mantis will cut off the head of her own mate?
  • 1. to reduce competition after mating
  • 2. to reduce the chance of species survival
  • 3. to increase the chance of the species survival
  • 4. to increase the chance of her survival after mating
• (5) Which of the following groups would find it useful to have a sex attractant that can confuse male insects about the location of their female partners?
  • 1. fanners
  • 2. carpenters
  • 3. researchers
  • 4. educators
• (6) It can be inferred from the reading that
  • 1. the orchids as a species will die out in the near future.
  • 2. the orchids as a species will outlive the beetle species because they look better than the female beetle.
  • 3. the male beetles will mate with anything during the spring.
  • 4. the male beetles have bad eyesight but good sense of smell.
• (7) According to the reading, the key role of the female is
  • 1. to display themselves to attract other female beetles.
  • 2. to make babies for the species.
  • 3. to attract the weakest male.
  • 4. to live as long as possible.
• (8) According to the professor, two of the biggest disadvantages of the male beetles are
  • 1. they can't fall in love, but they can be tricked.
  • 2. they emerge from the ground weeks before the female.
  • 3. they don't fall in love and they don't care about the female beetles.
  • 4. they can't tell the difference between an orchid and the female beetle because the female beetles are also beautiful like the orchid.
• (9) It is implied in the last passage that humans and insects
  • 1. share some of the same methods for choosing their mates.
  • 2. sometimes choose their mates together.
  • 3. share some advantageous methods for choosing a mate.
  • 4. share some very different methods of choosing their mates.
• (10) The best title for the reading is
  • 1. “How Insects Rely on Sight to Find a Mate.”
  • 2. “How Nature Uses Evolution through Natural Selection.”
  • 3. “How Insects Can Briefly Function without their Head.”
  • 4. “How Nature Tricks Insects into Evolution.”