10 . The cultivation of plants by ants is more widespread than previously realized, and has evolved on at least 15 separate occasions.
There are more than 200 species of ant in the Americas that farm fungi (真菌) for food, but this trait evolved just once sometime between 45 million and 65 million years ago. Biologists regard the cultivation of fungi by ants as true agriculture appearing earlier than human agriculture because it meets four criteria: the ants plant the fungus, care for it, harvest it and depend on it for food.
By contrast, while thousands of ant species are known to have a wide variety of interdependent relationships with plants, none were regarded as true agriculture. But in 2016, Guillaume Chomicki and Susanne Renner at the University of Munich, Germany, discovered that an ant in Fungi cultivates several plants in a way that meets the four criteria for true agriculture.
The ants collect the seeds of the plants and place them in cracks in the bark of trees. As the plants grow, they form hollow structures called domain that the ants nest in. The ants defecate (排便) at designated absorptive places in these domain, providing nutrients for the plant. In return, as well as shelter, the plant provides food in the form of fruit juice.
This discovery prompted Chomicki and others to review the literature on ant-plant relationships to see if there are other examples of plant cultivation that have been overlooked. “They have never really been looked at in the framework of agriculture,” says Chomicki, who is now at the University of Sheffield in the UK. “It’s definitely widespread.”
The team identified 37 examples of tree-living ants that cultivate plants that grow on trees, known as epiphytes (附生植物). By looking at the family trees of the ant species, the team was able to determine on how many occasions plant cultivation evolved and roughly when. Fifteen is a conservative estimate, says Campbell. All the systems evolved relatively recently, around 1million to 3 million years ago, she says.
Whether the 37 examples of plant cultivation identified by the team count as true agriculture depends on the definitions used. Not all of the species get food from the plants, but they do rely on them for shelter, which is crucial for ants living in trees, says Campbell. So the team thinks the definition of true agriculture should include shelter as well as food.
1. According to biologists, why is ant-fungus cultivation considered as a form of true agriculture?
| A．Because it occurred earlier than human agriculture. |
| B．Because it fulfills the standards typical of agricultural practices. |
| C．Because it redefines the four criteria for true human agriculture. |
| D．Because it is less common than previously thought. |
2. What motivated Chomicki and others to review the literature on ant-plant relationships?
| A．They determined on new family trees of the ant species. |
| B．They overlooked some tree-living ants that provided nutrients for the plants. |
| C．They never studied the ant-plant relationships within the context of agriculture. |
| D．They never identified any an t species that engaged in cultivation of fungi. |
3. Which of the following statements is supported by the team's findings according to the passage?
| A．Ants’ cultivation of plants is limited to a few specific species. |
| B．The cultivation of fungi by ants is considered the earliest form of agriculture. |
| C．True agriculture in ants involves only food-related interactions with plants. |
| D．Ants have independently cultivated plants on at least 15 distinct occasions. |
4. What is the passage mainly about?
| A．The evolution of ants in the plant kingdom. |
| B．The widespread occurrence of ant-plant cultivation. |
| C．The discovery of a new ant species engaging in agriculture. |
| D．The contrast between ant agriculture and human agriculture. |
