あるアリの女王は、500万年以上前に分かれた「別の種」の息子も産んでいた

Q1. What is the passage mainly about?

1. AA cat that has puppies
2. BAn ant queen that lays males of two species
3. CWhy worker ants live in southern Europe
4. DHow scientists keep ants as pets

「The queen of this ant lays males of her own species. She also lays males of a different species.」とあり、2つの種のオスを産む女王アリの話なので、正解は B。

Q2. When did the two species split?

1. ALast year
2. BAbout five hundred years ago
3. CMore than five million years ago
4. DWhen the queen was born

「The two species split more than five million years ago.」とあるので、正解は C。

Q3. In the passage, "split" in "The two species split" is closest in meaning to ___.

1. Aseparated
2. Bmet
3. Cgrew
4. Date

split は「分かれる」という意味。2つの種がずっと昔に別々になったことを言っているので、正解は A。

Q1. What is the passage mainly about?

1. AAnt queens that lay males of another species because they need them
2. BAnts that moved from Sicily to the rest of Europe
3. CHow worker ants choose a new queen
4. DWhy some male ants lose their hair in winter

女王が別の種のオスを産み、その理由は働きアリを作るのにそのオスの精子が要るからだと説明しているので、正解は A。

Q2. Why can't the queens raise workers without M. structor sperm?

1. ABecause M. structor sperm makes the workers bigger
2. BBecause every worker is a hybrid with an M. structor father
3. CBecause their own males cannot fly
4. DBecause M. structor ants bring food to the nest

「Every worker in their nests is a hybrid with an M. structor father, so the queens cannot raise workers without M. structor sperm.」とあるので、正解は B。

Q3. What can we guess about the queens in Sicily?

1. AThey have no worker ants at all.
2. BThey fly to other islands to find M. structor males.
3. CThey can make workers because they lay M. structor males themselves.
4. DThey only lay hairy males.

シチリア島の近くには M. structor の巣がないが、巣の中で M. structor のオスを産むので父親が絶えない、と書かれている。だから働きアリを作れると考えられ、正解は C。

Q1. What is the passage mainly about?

1. AA study showing that an ant queen lays males of another species, and what is still not known
2. BA plan to bring M. structor ants back to eastern France
3. CWhy hybrid workers live longer than other ants
4. DHow scientists counted all the ants in Europe

女王が別の種のオスを産む証拠と、仕組みが分からないことや数が少ないことなど、まだ分からない点を述べているので、正解は A。

Q2. How did the team know that the hairless males had an M. ibericus mother?

1. AThey watched the males fight with M. ibericus queens.
2. BThe males had M. ibericus mitochondria, which are normally passed down only from the mother.
3. CThe males had M. ibericus genes in their cell nuclei.
4. DThe males were found only in Sicily.

「had M. structor genes in their cell nuclei but M. ibericus mitochondria, which are normally passed down only from the mother」とあるので、正解は B。核の遺伝子は M. structor なので C は誤り。

Q3. Why does the writer mention that only seven eggs became winged adults?

1. ATo show that the queen was sick
2. BTo prove that M. structor males cannot survive in the lab
3. CTo point out that part of the evidence comes from a small number of ants
4. DTo explain why the workers are hybrids

「The lab evidence rests on few animals: only seven eggs from that colony became winged adults」とあり、証拠の一部が少ない数にもとづくことを示すためなので、正解は C。