Spatial and Temporal Variation of Wolbachia in Aedes albopictus

1. Patrick R Murphy, Dr. Steven Juliano, Dr. Sabine Loew Introduction Methods Wolbachia is a group of bacteria that are inherited intracellularly. This group of bacteria affect a wide range of arthropods. The reason this group of bacteria have been able to remain within the mosquito populations is because they use a relatively novel evolutionary strategy which is reproductive parasitism. The Wolbachia infection has been able to spread because it changes the reproductive success of it’s host. Infected females gain a reproductive advantage over uninfected females because infected females can reproduce via insemination by either uninfected males or infected ones, but uninfected females can only reproduce via insemination by uninfected males. Eventually, one would expect to see a rise in Wolbachia infection because there are just not as many successful fertilizations in uninfected females. Genomic DNA was extracted from individual Aedesalbopictusmosquitoes. Following that process, the DNA was amplified under optimal Polymerase Chain Reaction conditions. The DNA was amplified for the primers Wsp 16S, Wlb A, and Wlb B. Once this was completed the amplified DNA was run on 1.5% agarose gel to determine what strain was present in each mosquito. The primer Wsp 16S was run first on each mosquito before the other two primers were run. This was done because Wsp 16S shows whether or not a mosquito is infected with any strain of Wolbachia. Following that, each mosquito was run using the primer Wlb A and Wlb B. These are both strains of the infection and the test showed us what type of Wolbachiawas present in each mosquito. The picture below is an example of what the gel would look like after DNA was run through it. The Wlb A strain is 470 base pairs in length and the Wlb B strain is 460 base pairs in length. In each run on the gel below, the top line represents Wlb A and the line underneath it represents Wlb B. Spatial and Temporal Variation of Wolbachia in Aedesalbopictus e) Objectives Significance The objectives of this study are: Analyze the frequency of Wolbachia infection within Aedesalbopictusacross three different years within the same localities. Obtaining multi-year frequency data of infections will allow me to determine potential temporal variation of the two strains of Wolbachia within a few mosquito populations. Analyze the frequency of Wolbachia infection within Aedes albopictus across several localities of the same time period. Obtaining frequency data for several localities within the same year will allow me to determine the spatial variation of the two different strains of Wolbachia within one year. This study has significance when it comes to pest control. Wolbachia limits a host population via the shortening of the life span in adults. This occurs because the different strains of Wolbachiahave different effects on the mosquitoes. If Wolbachia could be placed in a population, then it could reduce the fitness of the mosquitoes and drive down their numbers. Wolbachiahas also been reported to cause early death of male embryos. As the population of mosquitoes continues to breed, the dominant part of that population will be infected females who either are breeding and losing many of their embryos, or are not breeding because they cannot find any males to mate with. Wolbachiain a population of mosquitoes could really decrease the fitness and the frequency of mosquitoes. Study sites Results All of the sites that mosquitoes were collected from were in Tampa, FL. All of the sites were cemeteries in the area and the mosquitoes were collected in or near vases. Some of the cemeteries were: Woodlawn, Oak Hill, Austriano-Centurian, Rosehill, North 25th, and Myrtle Hill Cemetery. Most of the sites were sampled in 2003, 2005, 2006, and 2009. The results of this study show a relationship between the sex of the mosquito and the year. The Wlb B strain of Wolbachia rose in frequency from 2005 to 2006. The Wlb B strain declined in males however in the same time frame. The results also indicate that there is no significant difference between the frequency of Wolbachia, and the localities around Tampa. Conclusions References Acknowledgements The Wolbachia strain B seems to be killing off males while not affecting females. The females who have strain B tend to not lose fitness because of it. The males who have better fitness have Wolbachia strain A. While there does not seem to be a connection between the mosquitoes of different localities, there is a connection between the years 2005 and 2006. With the different strains of Wolbachiachanging between the sexes, the Wlb A strain is suited for male survival, and the Wlb B strain is suited for female survival. Barry, A. (2010, May 6). Bmore Scientific. Charm City Current. 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Retrieved September 23, 2010, from http://maps.statemaster.com/state/FL/1 Dr. Sabine Loew Dr. Steven Juliano Dr. KavithaDamal Dr. Erik Larson Dr. Rachel Bowden