Since the introduction of Asian rock pool mosquito (Aedes japonicus) to the eastern USA more than 20 years ago, investigators have reported the decline of the native rock pool mosquito (Ae. atropalpus). The displacement, or reduction, of the native species by Ae. japonicus could have public health implications because while the native is not considered of significant public health importance, the invader is considered a potential vector of West Nile and La Crosse viruses. Previous research revealed that thermal ecology determines the distribution of these species across riverine rock pool habitats in the SE USA, with Ae. japonicus occupying cooler, and Ae. atropalpus occupying warmer pools, with a broad range of overlap. Beyond this, little is known about the biotic and abiotic factors related to the abundance of these taxa in habitats where the co-occur. Here we examine the relationship between native and invasive mosquito abundance and the environmental characteristics and aquatic community composition in 88 riverine rock pools from six different sites along an elevational gradient in the southern Appalachian Mountains. Specifically, we examine the relationship between patch characteristics (size, site, distance from forest edge), water quality (temperature, dissolved oxygen, chlorophyll), and potential species interactions (mosquito richness, predator diversity, & predator abundance) . The relationship between Aedes abundance and predictors was examined using poisson GLMs. Data were collected 17 - 20 June 2019 as part of a course-based research project based at Highlands Biological Station, NC.
Results/Conclusions
The native Ae. atropalpus was less abundant overall (425) but occupied more pools (36%) compared to the invader, Ae. japonicus (abundance: 1445, occupancy: 29%). Abundance varied across sites, however these differences were idiosyncratic with respect to site elevation. Accounting for differences due to site, Ae. atropalpus abundance decreased with increasing temperature, dissolved oxygen, and predator abundance, and increased with the number of mosquito species in a pool. Abundance of the non-native Ae. japonicus decreased with increasing predator richness, and increased with the number of other mosquito species present in a pool. Our results suggest that while temperature plays a role in determining the abundance of the native rock pool mosquito, interactions with other mosquitos and predators likely play and important role in shaping the larval abundance of both species across habitats. The negative relationship between the invasive mosquito Ae. japonicus abundance and aquatic predator species richness highlights a valuable ecosystem service of consumer biodiversity enhancing the suppression of a potential disease vector.