Prior Hydrologic Disturbance Affects Competition between Aedes Mosquitoes via Changes in Leaf Litter

Abstract

Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrologic conditions that containers are exposed to prior to mosquito utilization affect litter decay and associated water quality. We tested the hypothesis that larval competition between A. albopictus and A. triseriatus would be differentially affected by prior hydrologic conditions. Experimental microcosms provisioned with Quercus alba L. litter were subjected to one of three different hydrologic treatments prior to the addition of water and mosquito larvae: dry, flooded, and a wet/dry cycle. Interspecific competition between A. albopictus and A. triseriatus was mediated by hydrologic treatment, and was strongest in the dry treatment vs. the flooded or wet/dry treatments. Aedes triseriatus estimated rate of population change (λ') was lowest in the dry treatment. Aedes albopictus λ' was unaffected by hydrologic treatment, and was on average always increasing (i.e., > 1). Aedes triseriatus λ' was affected by the interaction of hydrologic treatment with interspecific competition, and was on average declining (i.e., < 1.0), at the highest interspecific densities in the dry treatment. Dry treatment litter had the slowest decay rate and leached the highest concentration of tannin-lignin, but supported more total bacteria than the other treatments. These results suggest that dry conditions negatively impact A. triseriatus population performance and may result in the competitive exclusion of A. triseriatus by A. albopictus, possibly by reducing microbial taxa that Aedes species browse. Changing rainfall patterns with climate change are likely to affect competition between A. triseriatus and A. albopictus, probably enhancing negative competitive effects of A. albopictus on A. triseriatus in areas that experience drought.

Effects of tire leachate on the invasive mosquito Aedes albopictus and the native congener Aedes triseriatus

“…Since its establishment in North America in the mid-1980s, A. albopictus has rapidly become the most common urban mosquito in many areas in the eastern United States. There are several explanations for this dominance; the most well documented being that A. albopictus is a superior competitor at the larval stage ( Juliano, 2009 ; Smith, Freed & Leisnham, 2015 ) and asymmetric reproductive competition ( Lounibos, 2007 ). Our study suggests that tire habitats may also facilitate the dominance of A. albopictus through this species’ superior tolerance to compounds that leach from tire rubber.…”

Interactive and sex‐specific life‐history responses ofCulex pipiensmosquito larvae to multiple environmental factors

“…For instance, one of the most important challenges faced by aquatic organisms is the drying of their aquatic habitat (Lounibos, ; Bradshaw & Holzapfel, ). This process is related to a range of environmental factors, including decreasing water volume, increasing solute concentration caused by evaporation, changes in food availability, and increased temperature fluctuations (Juliano & Stoffregen, ; Aspbury & Juliano, ; Jannot, ; Smith, Freed & Leisnham, ). In response to such changes in environmental conditions, development is usually accelerated, resulting in reduced adult survival, size, reproduction and immune function (Block & Stoks, ; Gervasi & Foufopoulos, ).…”

No detectable role for predators mediating effects of aquatic habitat size and permanence on populations and communities of container‐dwelling mosquitoes

“…Drying can have direct effects on larvae through desiccation and death but can also have indirect effects by altering life histories (e.g., Juliano and Stoffregen, 1994), quality of resources in the habitat (Aspbury and Juliano, 1998; Smith et al , 2015), or by altering biotic interactions such as resource competition or predation (Wellborn et al , 1996; Laurila and Kujasalo, 1999; Bridges, 2002; Turner and Montgomery, 2009; Murrell and Juliano, 2013). The species that occupy container habitats vary greatly in their abilities to withstand habitat drying.…”