Evaluation of ovitraps of different materials to monitor the seasonal activity of co‐occurring Aedes aegypti and Aedes albopictus

The selection of oviposition sites by a female mosquito is useful knowledge to monitor the frequency and activity of vector species such as Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) (Diptera: Culicidae). In localities where they co-occur, an additional complexity of monitoring is the species identification. As the eggs of both species are not morphologically distinguishable, the eggs must be induced to hatch, and the newly hatched larvae reared to the fourth instar, identified to species based on morphological characters. Thus, it is very important that eggs remain viable. The aim of this study was to evaluate the selection of ovitraps of different materials (glass, plastic and bamboo) by females of Ae. aegypti and Ae. albopictus in a city where both coexist, and to assess which type of ovitrap would allow better detection of each species. Mosquito eggs were collected weekly from June 2017 to May 2018 in the city of Eldorado (Misiones, Argentina), using the three types of ovitraps placed in urban areas. For each ovitrap, the eggs collected each week were counted and classified by condition (intact, collapsed and hatched eggs). Subsequently, eggs were immersed to induce the hatching of larvae, which were then reared under laboratory conditions, and fourth instar larvae were identified to species. Both species exhibited broadly overlapping seasonal dynamics, with reduced oviposition activity during winter and increased activity during warmer months. Aedes aegypti showed greater temporal persistence and higher overall abundance, whereas Ae. albopictus displayed a more fluctuating pattern with a short-lived peak during the warmest period. Ovitrap material significantly affected egg presence, while no significant differences were found in egg preservation among materials. Species detectability differed among ovitrap materials, with bamboo and glass ovitraps consistently outperforming plastic ovitraps. However, species identification was not possible in a substantial proportion of positive ovitraps, highlighting a methodological limitation of oviposition-based surveillance in sympatric areas. Overall, our results emphasize the importance of considering both seasonal variation and ovitrap material when designing surveillance strategies and provide practical guidance for improving the detection and monitoring of Aedes species in regions where they coexist.