What is a Gravid trap used for in mosquito control?

A Gravid trap is specifically designed to attract and capture adult female mosquitoes that are ready to lay eggs, known as gravid females. These traps utilize a combination of attractants, such as water mixed with organic materials or specific scents that mimic the conditions found in natural breeding sites. When a female is ready to lay eggs, she seeks out suitable environments, and the Gravid trap simulates such an environment, encouraging her to enter the trap.

By effectively capturing these gravid females, mosquito control programs can gather valuable data on mosquito populations and their breeding habits, which is essential for implementing targeted control measures. This information can help in understanding not only the abundance of mosquitoes but also their species composition, which is crucial for controlling diseases associated with specific mosquito types.

The other options do not align with the primary function of the Gravid trap; male mosquitoes are attracted to different stimuli and are not the target of this trap. Capturing larvae requires different methods, often focusing on water management and larviciding rather than adult trapping. Monitoring repellent efficacy typically involves techniques other than trapping gravid mosquitoes. Thus, the use of Gravid traps plays a vital role in effective mosquito surveillance and control strategies.