Effortless Counting of Sorted Culicoides (Diptera: Cerapotogonidae) from Light-Traps
Résumé
Introduction and Objectives : Culicoides biting midges are among the most abundant of haematophagous insects. They transmit a great number of pathogens, but it is as vectors of arboviruses, and particularly arboviruses of domestic livestock, that they achieve their prime importance. Counting sorted Culicoides from light traps can be time-consuming, especially with hundreds or thousands of specimens. Despite advancements in artificial intelligence (AI) and AI-based object counting applications, implementing these techniques can still be costly or challenging. The study aimed to develop a simple, cost-effective, and easy-to-implement method for counting sorted Culicoides from light traps.Materials and Methods : Culicoides, ranging from 10 to 1000, were accurately counted using a stereomicroscope and then photographed in alcohol on a white enameled plate with an Android cell phone. Subsequently, these samples were mixed to create various densities, up to several thousands, and photographed again. The IMAGEJ (FIJI) software was utilized to automatically count the specimens using a combination of simple commands based on the final “FIND MAXIMA” process. Optimal parameters for the command chain were estimated by comparing the results from several photographs of various insect densities with known exact counts.After defining the process, its agreement with exact manual counting using the stereomicroscope was evaluated through Bland-Altman analysis and Passing-Bablok regression.Results : The statistical analysis showed that the method is highly repeatable, and as precise as the standard manual counting. It can thus be used in routine analysis.Conclusion : The presented method is rapid and simple, and can even be implemented in a cell phone with the IMAGEJ. JS software. To simplify the process, particularly for the cell phone app where screen manipulation is challenging, an ImageJ MACRO containing all the necessary commands and parameters has been developed to simplify the process and is available from the authors.