Consumer–resource dynamics in Arctic ponds

Abstract

Population dynamics are shaped by species interactions with resources, competitors, enemies, and environmental fluctuations that alter the strength of these interactions. We used a food web approach to investigate the population dynamics of an abundant Arctic mosquito species, Aedes nigripes (Diptera: Culicidae). Specifically, we evaluated the importance of bottom-up variation in aquatic biofilms (food) and top-down predation from diving beetles (Colymbetes dolabratus, Coleoptera: Dytiscidae) on mosquito population performance. In spring 2018, we tracked mosquito and predator populations across eight ponds in western Greenland, measured biofilm productivity with standardized samplers, and estimated grazing pressure by invertebrate consumers with an in situ exclosure experiment. We also assessed the quality of biofilms as nutrition for mosquito larvae and evaluated pond attributes that might influence biofilm productivity and food quality. Our results indicated that mosquito population dynamics were more related to resource quality and intraspecific competition than to the density of predaceous diving beetles. Ponds with better quality biofilm tended to have more hatching larvae and those populations experienced higher per capita mortality. This aggregation of larvae in what would otherwise be the best mosquito ponds was enough to produce relatively low fitness. Thus, the landscape would support more mosquitoes if they instead distributed themselves to match predictions of the ideal free distribution. Although mortality rates were highest in ponds with the highest initial densities, the increased mortality was not generally enough to compensate for initial abundance, and 78% of the variation in the density of mosquitoes emerging from ponds was explained by the initial number of larvae in a pond. Resource quality was a strong predictor of consumer abundance, yet there was no evidence that biofilm grazing pressure was greater in ponds where mosquito density was higher. Collectively, our results suggest that mosquito ponds in western Greenland are a mosaic of source and pseudo-sink populations structured by oviposition tendencies, biofilm resource quality, and density-dependent larval mortality.

Spatial and temporal patterns in Arctic mosquito abundance

“…In 2018, emerging adults varied as much as tenfold among sites, for example, the average density of emerging adults was 244 versus 24 at ponds 1a and 4, respectively (Figure 1b). Ponds with more early instar adults tended to have the most emerging adults (Figures S2 and S3, DeSiervo et al, 2020). The sex ratio of emerging males and females was approximately 1:1, with little variation among ponds (DeSiervo et al, 2020).…”

“…habitats, selective pressure for strong flight capacity and long dispersal distances (Smith et al, 2009(Smith et al, , 2015. number of eggs for A. albopictus), (Costanzo et al, 2018, DeSiervo et al, 2020. A. nigripes females also have a larger body mass compared to A. albopictus.…”

“…First, we quantified the density of emerging adult mosquitoes at eight study locations representing a variety of available aquatic habitats, including ephemeral ponds, shallow lake margins, and thermokarst thaw ponds (Figure 1b). Only habitats suitable for mosquito larvae were chosen, and study locations were selected to capture a range of larval densities (DeSiervo et al, 2020). In 2018, at each aquatic habitat, we installed 3–5 circular emergence traps (surface area of 0.28 m 2 ) (Corbet, 1965) in the littoral zones (Figure 1b).…”

“…We focused on the single species of mosquito in this area, Aedes nigripes Zett (Kalaallisut: ippernaq), the most widespread and abundant mosquito species in the Arctic (Vockeroth, 1954). Previous research in this system suggests that population densities of immatures vary widely among aquatic habitats, with denser populations generally associated with habitats with better food quality for larvae (DeSiervo et al, 2020). Furthermore, aquatic habitats with relatively high and low densities of larvae tend to stay consistent across years (DeSiervo et al, 2021).…”

Assessment of mosquitoes larvae and their predatory aquatic insects in Taksebt Dam, Algeria

“…According to Schrama et al (2018), insect predator presence decreased mosquito larval survival and adult emergence by 20-50%. Many aquatic insects of the orders Coleoptera (DeSiervo et al 2020), Diptera (Moirangthem et al 2018), Hemiptera (Allo and Mekhlif 2019) and Odonata (Córdoba-Aguilar et al 2021) are known to be mosquito predators, commonly found with the mosquito immature in varied mosquito larval habitats including the wetland (Kumar 2009;Shaalan and Canyon 2009).…”