Habitat characteristics of larval mosquitoes in zoos of South Carolina, USA

To investigate whether the unique assemblage of habitats in zoos could affect mosquito oviposition behavior and to provide zoos with suggestions for mosquito control, larvae were sampled and associated habitat variables were measured in 2 zoos in South Carolina, USA. Fifty-nine sites were sampled from March 2008 to January 2009. A total of 1,630 larvae representing 16 species was collected and identified. The dominant species was Aedes albopictus (46.0%), followed by Ae. triseriatus (23.6%), Culex restuans (12.4%), and Cx. pipiens complex (9.7%). Principal components and multiple logistic regression analyses showed that across both zoos the distribution of Ae. albopictus larvae was predicted by ambient and site temperature, precipitation, dissolved oxygen, and container habitats. The distribution of Ae. triseriatus larvae was predicted by natural containers and shade height ≤ 2 m. Overall larval mosquito presence (regardless of species) was predicted by ambient and site temperature, precipitation, dissolved oxygen, presence of natural habitats, and absence of aquatic vegetation. Additionally, C₈ values of pairwise species associations indicated significant habitat-based relationships between Ae. albopictus and Ae. triseriatus, and Cx. pipiens complex and Cx. restuans. In general, species-habitat associations conformed to previously published studies. Recommendations to zoo personnel include elimination of artificial container habitats, reduction of shade sources ≤ 2 m over aquatic habitats, use of approved mosquito larvicides, and training in recognizing and mitigating larval mosquito habitats.