1 Arboviral Disease Section, Ecological Investigations Program, Center for Disease Control, Health Services and Mental Health Administration, U. S. Department of Health, Education, and Welfare, P. O. Box 551, Fort Collins, Colorado 80521, and School of Public Health, University of California, Berkeley, California 94720
The blood meal source for 4,957 engorged mosquitoes collected from 1964 through 1968 was determined by a capillary precipitin technique. Culex tarsalis and Aedes vexans comprised most of the specimens tested; other species tested included Aedes nigromaculis, Anopheles punctipennis, Culex quinquefasciatus, Culiseta inornata, and Psorophora signipennis. The predominant feeding of Aedes, Anopheles, Culiseta, and Psorophora was upon mammals, and of Culex quinquefasciatus upon birds. The C. tarsalis feeding pattern varied widely, and the proportion that had fed upon birds ranged from 42% in 1966 to 83% in 1965. An analysis of forage ratios provided an index of host preference of C. tarsalis in 1966. The data reported further substantiate the role of C. tarsalis as the principal vector of western equine encephalitis and St. Louis encephalities in the western United States.
Arboviral Disease Section, Ecological Investigations Program, Center for Disease Control, P. O. Box 551, Fort Collins, Colorado 80521.
School of Public Health, Earl Warren Hall, University of California, Berkeley, California 94720.
Supported by U. S. Public Health Service Research Career Development 3-K3-AI, 427-035l.