Dr. Rui-De Xue and Dr. D.R. Barnard, Mentor
At the chilling table. Live mosquito specimens are taken from the rearing chambers seen in the background, and examined under the microscope. This ensures that no mutant individuals contaminate the strain under study.
John Profumo studied the behavior of three strains of Aedes aegypti mosquitos: normal, white-eye, and redeye This species is known to transmit yellow fever to people, and studies of the behavioral differences between various strains may lead to new methods of controlling their populations in the wild.
Testing host attack response using the WHO test kit. This is one of the behavioral experiments John conducted this summer. The mosquitos are placed in the top chamber of the cylinder, then allowed access to the lower chamber via the sliding door. Different strains' response times to attack the host (John) were measured and compared.
Using the dissecting microscope to count the number of mature eggs in the ovaries of the mosquito specimens.
Behavioral Study of Mutant Aedes aegypti
For years the populations of red-eye and white-eye mutant strains of Aedes aegypti were kept in quarantine, perceived as a possible genetic study population, but their behavior was never examined. The mutant mosquitoes might exhibit behavioral traits that would make them a viable method of bio-control against the potential disease vector and probable annoyance that wild mosquitoes have become. Such traits as inability to find hosts, reduced fecundity, or even increased effectiveness of repellents would all make these mutant mosquitoes an extremely attractive future method for population control. The redeye, white-eye, and normal strains of Aedes aegypti mosquitoes were used to perform different behavioral tests. The olfactometer was used to compare the ability of the mosquitoes to locate hosts through detection of human scent or attractant. The WHO test kits were used to test the rapidity with which each strain would begin feeding and become satiated from a blood meal. Mosquitoes were also dissected, and eggs laid were counted in order to compare the fecundity of the strains after blood meals. Standard repellency tests were performed to see if the strains had any effect on the duration of protection provided by various types of commercially available repellents. These experiments revealed that the normal strain was most adept at locating the host in the olfactometer; the redeye strain could also finds hosts, but only one of the white-eyed mosquitoes ever found its host. In the WHO test kit the red-eyed mosquitoes were significantly faster than the other two strains, which were similar in speed. There was no difference found in the duration of blood feeding amongst the three strains. Fecundity tests revealed that the white-eye strain produced significantly less eggs than the other strains. DEET repellent (7-15%) provided hours of protection from all strains and all strains reacted similarly to varying repellents. The behavior of the white-eye strain seems to lend itself to uses in bio-control, because the females cannot find hosts well and they do not lay many eggs even if they are able to bloodfeed.