A User Friendly Method to Assess <I>Anopheles stephensi</I> (Diptera: Culicidae) Vector Fitness: Fecundity

Abstract

Fecundity, bloodmeal size, and survival are among the most important parameters in the overall fitness of mosquitoes. Impact of an intervention that affects fecundity can be assessed by directly counting the eggs laid by exposed mosquitoes, which is usually done manually. We have developed a macroinstruction, which can be used to count thousands of Anopheles stephensi Liston eggs in a few minutes, to provide an alternative and adaptable method to egg counting as a measure of fecundity. The macro was developed using a scanner and a computer running AxioVision Rel. 4.8 software, a freely accessible software compatible with Windows XP/7/Vista. Using this semiautomated method, it is possible to reduce time, avoid human error and bias, and obtain improved consistency in studies measuring mosquito fecundity.

Assessment of ICount software, a precise and fast egg counting tool for the mosquito vector Aedes aegypti

“…However, most of them require a scanner for egg sampling, which is not practical for field analysis [12, 14, 16, 22]. Moreover, images taken with scanners need complex image processing using ImageJ before automatic counting.…”

“…Moreover, images taken with scanners need complex image processing using ImageJ before automatic counting. Other studies suggest methods from camera images but automated counting is not straightforward and needs image segmentation before the number of eggs can be estimated [12, 14]. The technique described here requires only a camera, no complex image processing and has a user friendly interface.…”

“…ICount is also a free software which can be downloaded [18]. Similarly, “Egg-counter”, designed to automatically count eggs from Anopheles mosquitoes, was released in 2014 [12]. However, our attempts to process our “micro” or “macro” images with this free software, detected no eggs.…”

“…Methods have recently been developed for automatized counting of Ae. aegypti eggs via digital image analysis [12–16]. However, some of these techniques require prior knowledge of the algorithm and the image processing techniques employed [13, 15].…”

Impact of repeated NeemAzal®-treated blood meals on the fitness of Anopheles stephensi mosquitoes

“…Two days after each blood meal administration, gravid females were provided with wet filter paper discs for oviposition for 2 subsequent nights [ 35 ]. The number of eggs laid on the paper discs were then quantified by imaging analysis, as previously described [ 44 ]. The mean percent reduction in oviposition was evaluated using the equation below: …”