Biting the Hand that Feeds: Anthropogenic Drivers Interactively Make Mosquitoes Thrive

Distribution of Culex pipiens life stages across urban green and grey spaces in Leiden, The Netherlands

“…Culex pipiens egg rafts were collected weekly during two subsequent trapping nights at all 36 sites within the 6 paired locations using three 5-l (202 × 171 mm) round black buckets (Dijkstra Plastics, Haaksbergen, The Netherlands), which were placed under each adult mosquito trap. To attract gravid mosquitoes and outcompete local breeding sites, we mimicked the nutrient level of a hypertrophic land puddle (100 mg/l N-total) [ 18 , 50 , 51 ]. To each bucket we added 4 l ditch water and dried cow manure (2.4% N; 1.5% P 2 O 5 ; 3.1% K 2 O) to reach 100 mg/l N-total, which was then left to incubate for 1 week so that the microbial communities could stabilise [ 50 ].…”

“…To attract gravid mosquitoes and outcompete local breeding sites, we mimicked the nutrient level of a hypertrophic land puddle (100 mg/l N-total) [ 18 , 50 , 51 ]. To each bucket we added 4 l ditch water and dried cow manure (2.4% N; 1.5% P 2 O 5 ; 3.1% K 2 O) to reach 100 mg/l N-total, which was then left to incubate for 1 week so that the microbial communities could stabilise [ 50 ]. To ensure that egg raft collection coincided with the adult mosquito trapping, a lid was placed on the bucket and removed during the two trapping nights.…”

“…This method ensured that we only counted the breeding habitats that persisted long enough for adult Cx. pipiens to lay their eggs and for larvae to develop, which typically takes about 2 weeks under local climatic conditions [ 50 ]. For all 36 sites, we registered and sampled all potential breeding habitats within a 100-m radius using both larval dipping and eDNA collection methods.…”

Feeding the fever: Complex host‐pathogen dynamics along continuous resource gradients

“…Although transmission is often modeled as independent of resources, empirical examples in both animal (Johnson et al, 2007 ) and plant (Abro et al, 2013 ) hosts demonstrate that increasing nutrient supply can substantially alter the rate of pathogen production by infected hosts. For vector‐borne pathogens, increasing environmental resources can release vector populations from growth limitation, increasing population‐level transmission of both plant (Strauss et al, 2020 ) and animal (Boerlijst et al, 2022 ; Ostfeld et al, 2006 ; Pope et al, 2005 ) pathogens. For directly or environmentally transmitted pathogens, transmission can increase with host population density, a function of population size (next section), and aggregation (e.g., animal behavior or crop spacing; see Section 4 , below).…”