Which of the following statements is true regarding bats?

Bats play a crucial role in the ecosystem, particularly as natural pest controllers. They are known to consume a significant number of insects, including agricultural pests and other insects that can impact human health. By keeping the population of these insects in check, bats contribute to the balance of local ecosystems and can help reduce the need for chemical pest control methods, which can have harmful environmental effects.

The statement about bats serving no purpose in the ecosystem is incorrect, as their role in insect population management is vital. Although some bats do eat fruit, it is not accurate to describe bats primarily as fruit eaters since many species are insectivorous. Lastly, while some bats can occasionally be seen near crops, they are generally beneficial rather than harmful; they help protect crops by reducing the number of insects that may damage them. Thus, the statement about bats keeping down the number of insects accurately captures their significant ecological contribution.