Which of the following characteristics is true about Toxorhynchitis mosquitoes?

Toxorhynchites mosquitoes are indeed unique among the mosquito family for their feeding habits. Unlike many other mosquito species, the larvae of Toxorhynchites are predatory, feeding on the larvae of other mosquitoes and small aquatic organisms. This characteristic is significant because it positions them as natural biological control agents, helping to reduce populations of disease-carrying mosquitoes by preying on their larvae.

In contrast, the other options do not accurately depict the characteristics of Toxorhynchites mosquitoes. While they do breed in fresh water, the statement about females feeding on blood for egg production is not true; female Toxorhynchites do not require blood for egg development. Additionally, their activity pattern is mainly nocturnal rather than primarily daytime. Hence, option C captures the essence of Toxorhynchites mosquitoes' behavior and ecological role effectively.