Temporal Analysis of Feeding Patterns ofCulex erraticusin Central Alabama

Abstract

Host blood meals in seven mosquito species previously shown to be infected with eastern equine encephalitis virus at a site in the Tuskegee National Forest in southcentral Alabama were investigated. Of 1374 blood meals derived from 88 different host species collected over 6 years from these seven mosquito species, 1099 were derived from Culex erraticus. Analysis of the temporal pattern of Cx. erraticus meals using a Runs test revealed that the patterns of feeding upon avian and mammalian hosts from March to September of each year were not randomly distributed over time. Similarly, meals taken from the three most commonly targeted host species (yellow-crowned night heron, great blue heron, and white-tailed deer) were not randomly distributed. A Tukey's two-way analysis of variance test demonstrated that although the temporal pattern of meals taken from avian hosts were consistent over the years, the patterns of meals taken from the individual host species were not consistent from year to year.

Field Investigations of Winter Transmission of Eastern Equine Encephalitis Virus in Florida

“…Such a biphasic pattern of feeding has been seen in other studies of Cx. erraticus 50 and other mosquito species, [6][7][8] and has been hypothesized to play an important role in arboviral transmission and amplification. One reason for this shift may be an increased abundance of wading birds at our study sites in the winter months, caused by the in-migration of these species, which augments the year-round resident populations.…”

Vector Competence and Capacity ofCulex erraticus(Diptera: Culicidae) for Eastern Equine Encephalitis Virus in the Southeastern United States

“…erraticus may act both as the enzootic amplification and bridge vector for EEEV. Culex erraticus exhibits a shift in feeding behavior, frequently feeding upon avian species in the spring and summer and then shifting almost exclusively to feeding upon mammals in midsummer through the autumn (Burkett-Cadena et al 2011, Oliveira et al 2011. This pattern corresponds to patterns of EEEV infection observed in mammals (particularly horses) throughout most of the virus' range (Scott and Weaver 1989).…”

“…melanura feeds almost exclusively upon avian hosts, Cx. erraticus is a much more catholic feeder (Oliveira et al 2011). However, the longer incubation period and lower feeding rates on the enzootic reservoirs (birds) are balanced by the greater relative abundance of Cx.…”

“…Here, Culex erraticus (Dyar and Knab) is by far the most abundant mosquito species (Cupp et al 2003(Cupp et al , 2004Cohen et al 2009;Mukherjee et al 2012), and is also the mosquito species most commonly infected with EEEV (Cupp et al 2003, Mukherjee et al 2012. Culex erraticus feeds primarily on avian hosts in the spring and summer months, then switches to feeding primarily upon mammalian hosts in the summer and fall (Burkett-Cadena et al 2011, Oliveira et al 2011. It has been hypothesized that Cx.…”

“…Cs. melanura (source) M Relative population density 46 (Cupp et al 2003) 1 (Cupp et al 2003) A Proportion of avian bloodmeals 0.33 (Oliveira et al 2011) 0.94 ) P Daily survival probability 0.954 (this study) 0.961 (Cooper et al 2000) b Vector competence 0.105 (this study) 1.0 (Scott et al 1984) n Extrinsic incubation period 6 (this study) 3 (Scott and Burrage 1984) V Vectorial capacity 8.4 (this study) 19.2 (this study) Fig. 2.…”