The hidden world of Asian tiger mosquitoes: Immature Aedes albopictus (Skuse) dominate in rainwater corrugated extension spouts

Background: The primary sources of Aedes albopictus (Skuse) in its exotic range in North America are artificialcontainers in backyards, which vary widely in accessibility. In this study we examined their prevalence in twocontainer types that are difficult to inspect: catch basins and corrugated extension spouts (CES), the latterused to divert rainwater in downspouts away from house foundations.Methods: We conducted larval and pupal surveys in catch basins, CES and open containers such as buckets andplant saucers in three urban locations in Mercer County, New Jersey, USA.Results: We found that Ae. albopictus were rare in catch basins but prevalent in CES, and were often the onlyspecies collected in CES. Specific characteristics of the CES were not significantly associated with the presenceor number of Ae. albopictus in them, but those longer and closer to the ground were significantly more likelyto contain water, and therefore mosquitoes. During peak season (July-August), the abundance of immatureAe. albopictus was significantly higher in CES than open containers.Conclusions:We found that CES are an important source of Ae. albopictus in our region and propose that effectivecontrol strategies should be implemented to minimize mosquito populations from these cryptic habitats.