Host switching in Culex mosquitoes: effects of photoperiod and aging on host choice
| Author(s) | Caranci, Angela | |
| Date Accessioned | 2011-05-18T12:08:49Z | |
| Date Available | 2011-05-18T12:08:49Z | |
| Publication Date | 2010 | |
| Abstract | Culex pipiens has long been recognized as an important enzootic vector of arboviral diseases throughout the mid-Atlantic U.S. Recently, the role of mosquitoes in the Cx. pipiens complex as bridge vectors has been debated. West Nile Virus has spread throughout the continental U.S. and the threat of arboviral introduction is a constant reality. Therefore, the determination of the vectorial capacity of Cx. pipiens as a bridge vector is vital to understanding local disease transmission cycles now and in the future. This study aimed to investigate the effects of aging and larval photoperiod exposure on the feeding behavior of Culex pipiens. This was explored in the lab using a host choice chamber with Japanese quail and golden Syrian hamsters as possible host choices. Mosquito cohorts were reared under specified photoperiod patterns to mimic naturally occurring seasonal changes in daylength: 15L:9D; 14L:10D; and 13L:11D. Larval mosquitoes reared at 15 hours of daylight, which was set to mimic the local peak summer daylength, showed a statistically significant preference for Japanese quail. This preference was not seen when evaluating mosquitoes reared at 14 or 13 hours daylight, which supports the hypothesis that early season mosquitoes show a preference for avian hosts which is lost later in the season. Adult mosquitoes were tested in the host choice chamber at different ages (measured in days post emergence). The tendency of mosquitoes to enter any side host chamber increased with greater number of days post emergence. There was no correlation with host choice over aging. Host-baited trapping was performed in the field using Japanese quail and golden Syrian hamsters resulting in a statistically significant preference for hamsters early in the season, which does not support the hypothesis that early season mosquitoes prefer avian hosts. It is important to note that large discrepancies in the probability of host choice were apparent among field sites and between seasonal years. A higher percentage of mammalian bloodmeals (69%) was found in late summer using ELISA analyses of bloodfed Cx. pipiens, which again supports the hypothesis that a preference for avian hosts is lost later in the season. The final objective was to evaluate the previously reported trend of Cx. pipiens feeding preference with relation to avian host abundance. Regression probabilities of ELISA showed elevated mammalian host positives coincided with periods of low bird species abundance, which corresponds with previously reported trends. Overall, these results support the overall influence of avian host availability on fluctuations in Cx. pipiens seasonal feeding trends. However, trends that correlate feeding patterns with aging and larval daylength exposure reported here have not been previously considered and therefore require further investigation to determine influence on Cx. pipiens populations in the field. | en_US |
| Advisor | Mason, Charles E. | |
| Degree | M.S. | |
| Department | University of Delaware, Department of Entomology and Wildlife Ecology | |
| URL | http://udspace.udel.edu/handle/19716/5894 | |
| Publisher | University of Delaware | en_US |
| dc.subject.lcsh | Culex pipiens -- Larvae | |
| dc.subject.lcsh | Photoperiodism | |
| dc.subject.lcsh | Host-parasite relationships | |
| dc.subject.lcsh | Japanese quail | |
| dc.subject.lcsh | Golden hamster | |
| Title | Host switching in Culex mosquitoes: effects of photoperiod and aging on host choice | en_US |
| Type | Thesis | en_US |