Oviposition traps

Oviposition traps or ovitraps are quite simple and inexpensive tools used to obtain large amounts of data on the distribution density of some species of mosquito. These species are not very mobile and difficult to capture with other methods, especially when it is not essential to collect the adult individual. The monitoring method based on the use of ovitraps is widely used all over the world, especially when estimating the density of Aedes albopictus and similar species.

There are different models of ovitrap, but all essentially consist of a small container filled with water and a removable support for laying and collecting eggs. Black, plastic nursery pots, which are filled with dechlorinated water, are the most used. The dark color and the presence of water attract females from some mosquito species in search of small sites to depose eggs.

A strip of hardboard or Masonite is fixed vertically against the inner wall of the pot, which acts as a support for the female and the deposition of her eggs.

The water is restored, and the strip replaced periodically; it is then taken to the laboratory and “read” under a stereoscopic microscope. A careful "reading" of the strip allows us to identify the eggs and count them. The more eggs there are, the more females will have laid eggs; in turn, an idea is given regarding the number of mosquitoes present in each area and compares it with other monitored zones.

However, what is important is that the monitoring sites are similar to each other. In fact, shaded areas that are rich in vegetation, must always be chosen, otherwise the data collected would be strongly underestimated.

Last modified: Feb 2021