Fig. 5

Vector competence of field-collected and laboratory-reared Culex pipiens mosquitoes for West Nile virus. a Mean infection rates of laboratory-reared and field-collected Cx. pipiens mosquitoes collected at overwintering Sites 1 and 2, orally exposed to WNV. b Mean transmission rates of laboratory-reared and field-collected Culex pipiens mosquitoes collected at overwintering Sites 1 and 2, orally exposed to WNV. Sample size for laboratory-reared (n = 68), overwintering Site 1 (n = 14; remaining mosquitoes survival experiment), and overwintering Site 2 (n = 69). Error bars indicate the standard error of the mean. Data were analysed with Chi-square tests. No significant differences were found between infection or transmission rates of the three groups