Fritz lab finds Washington DC mosquitoes are using belowground urban infrastructure as breeding and development sites

In spring of 2018 the Fritz Lab was asked to investigate a mosquito infestation on federal property in Southwest Washington, DC. So PhD student Arielle Arsenault-Benoit and Assistant Professor Megan Fritz headed off to the capital to scrounge around in dirty basements and look for mosquitoes. Could moderation of winter conditions make belowground urban structures a refugia for warmer-climate species, like Ae. aegypti and Cx. quinquefasciatus, allowing them to overcome assumed thermal barriers? To test their hypothesis they surveyed belowground levels of nearby parking structures for mosquitoes and standing water in the summer months of 2018 and 2019 and compared winter and spring temperatures  above and belowground. Their findings, published in the Journal of the American Mosquito Control Association, found several species using these structures as adults, but only a few species (and ones that can transmit disease) use them as breeding and development sties. Belowground urban infrastructure may allow populations to persist for longer and build up earlier in the spring, plus warmer temperatures can shorten the development and generational time, extending the breeding season, increasing population size, and potentially affecting disease transmission. Given these results, the authors suggest pest control operators and local public health officials incorporate surveillance of these structures into their integrated pest management programs. This article also includes new records of Aedes aegypti populations beyond the Capitol Hill neighborhood in Washington DC.