Mosquito-borne pathogens are the cause of important, often deadly diseases worldwide; and, use of repellents is one of the components of mosquito control programs. The most effective mosquito repellent is N,N-dimethyl-m-toluamide, known as DEET. Speculation on the adverse effects of DEET have been on the rise since the 1980s, and manufacturers are searching for a safe and long lasting insect repellent that may be used on the skin as well as possess spatial applications. Olfactometers used in the bioassays for evaluating repellents usually do not measure repellency, but rather measure non-attraction. Therefore, I designed a novel olfactometer that divides host-seeking behavior of mosquitoes into attraction and repellency at close range. I compared my olfactometer with another similar olfactometer and found no difference when attraction was measured. However, the new olfactometer assesses true repellency. I also added a new term to the terminology of host-seeking behavior, that is 'inhibition'. Inhibition occurs in combination with at least two chemicals and causes failure of mosquitoes to respond to a previously attractant stimulus. I evaluated 80 inert and active ingredients of commercially available products on eleven volunteers and determined that four were true repellents. I unexpectedly discovered that DEET did not attract nor repel the mosquitoes when applied on skin. I conducted a series of experiments to elucidate the behavioral mode of action of DEET. Lactic acid was used as a control attractant. I demonstrated that DEET attracted mosquitoes in the absence of a host. When DEET was combined with lactic acid, it neither repelled nor attracted mosquitoes. I concluded that DEET works in combination with lactic acid on the skin by inhibiting lactic acid, rather than being a true repellent. In this study, I developed a novel device measuring attraction, repellency and inhibition. I contributed to the mode of action of DEET by proving that DEET is not a repellent but an inhibitor, and I identified five true repellents that are worth consideration. / Graduation date: 1998

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Entomology." Includes bibliographical references (p. 108-123).

Thesis (Ph. D.)--University of Florida, 1970. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 69-72).

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Geography." Includes bibliographical references (p. 76-79).

Thesis (Ph. D.)--Rijksuniversiteit te Leiden, 1935. / Folded leaf with six theses entitled "Stellingen" inserted. Includes bibliographical references (p. [246]-256).

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

No description available.

Larvae of Culex quinquefasciatus and Aedes aegypti were raised on five different diets and the effects thereof on various parameters was studied. The diets used were: A = Pronutro and Tastee wheat, B = Epo 1 rat cubes, C= Breeder's Dogmor puppy chunks, D = Vital Brewer's yeast powder and E (the control) = Vital dessicated liver. The following results were obtained. 1. Fecundity appeared not to be affected by diet in both species. 2. Fertility did not appear to be affected by diet either. 3. Diets C and D significantly shortened the duration of the larval stage in C. quinquefasciatus when compared with the control Diet E. In A. aegypti diets B, C and D produced larval periods that were significantly shorter than the control. 4. The pupal stage in C. quinquefasciatus in diets C and D was also. Significantly shorter than that of the control diet E. In A. aegypti only diet B produced a pupal stage that was significantly shorter than the control. 5. Larval mortality was significantly higher than the control diet E in C. quinquefasciatus in diet group A. There was no significant differences between the experimental diet groups A to D and the control, in A. aegypti. 6. Pupa 1 mortality appeared to be unaffected by larval diet in both species. 7. Larval diet did not affect adult mortality either. 8. In C. quinquefasciatus the size of the ovaries was significantly smaller than the control in diet group B. Ovary size appeared to be unaffected by larval diet in A. aegypti. 9. Sex ratio appeared to be greatly affected by larval diet. There were significantly more males than females in diets D and E in Culex quinquefasciatus and in diets C and E in Aedes aegypti. 10. Oogenesis also appeared to be affected by larval diet. In C. quinquefasciatus oogenesis was found to be slower from 36 hours PBM in diet A. In A. aegypti oogenesis was slower in diets A and B from 60 hours PBM. The rate of oogenesis in C. quinquefasciatus was also found to be slower, than that in A. aegypti. / Thesis (M.Sc.)-University of Durban-Westville, 1987.

No description available.

No description available.