Evaluating Egg-Laying Preference of Individual Aedes aegypti Mosquitoes

Automated Egg-Counting Approaches for Aedes aegypti Oviposition Experiments

Egg-laying preferences of mosquitoes can reveal key neurosensory mechanisms informing the decision-making process for this critical behavior. A single blood meal results in a gravid female Aedes aegypti mosquito laying more than 100 eggs. Therefore, egg counting represents a potentially time-consuming and laborious component to behavioral assays, such as those that measure oviposition preference or fecundity. Automated algorithms that count eggs from images can dramatically reduce the time required for this step of data processing and analysis and increase reproducibility associated with having multiple human observers count the eggs. Here, we present two distinct approaches for counting melanized Ae. aegypti eggs laid on white filter paper.

Measuring Oviposition Preference in Aedes aegypti Mosquitoes

The female mosquito is endowed with the responsibility of gene transfer from one generation to another through careful delivery of her eggs to an appropriate environment. To guarantee a successful reproduction process, female mosquitoes use an evaluative approach to select an oviposition site that will ensure that their progeny successfully hatch and develop from larvae to pupa to adult. Specific conditions must be met during oviposition site selection before gravid females deposit eggs, including but not limited to appropriate temperature, salinity, and pH; the presence of nutrition; and a low risk of predation. Mosquito species exhibit a remarkable diversity in their oviposition site selection behaviors. For instance, Aedes aegypti, which is a vector for Zika, dengue, yellow fever, and chikungunya viruses, prefers to lay its eggs in natural depressions (e.g., tree holes) or artificial containers. In contrast, other mosquito species, like Anopheles, gravitate toward more open water bodies. Understanding the oviposition preference behavior of the Ae. aegypti mosquito will facilitate the development of surveillance and control efforts to hinder the successful progression of this vector. Here, we present information on some of the known behaviors and preferences of Ae. aegypti during oviposition site selection, techniques to measure these preferences, and some open questions.