Oviposition-Modifying Substances for Mosquitoes.
Annual summary rept. no. 2, Sep 79-Aug 80,
CALIFORNIA UNIV RIVERSIDE DEPT OF ENTOMOLOGY
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The objectives of this research project are to study the chemistry and the biology of oviposition-modifying substances for mosquitoes, to investigate the possibility of applying them in the management of mosquito populations, and to evaluate the role of oviposition attractants in sampling populations of female mosquitoes and ovipopulations. The study on the structure-activity relationship of homologous, straight-chain, aliphatic carboxylic acids as oviposition repellents revealed that octanoic, nonanoic, and decanoic acids were the most active against gravid females of Culex quinquefasciatus, Cx. tarsalis, and Aedes aegypti. Other types of compounds, such as skatole, 1-hexadecanol, and 2-methylnonanoic acid, were also repellent against Cx. quinquefasciatus. The semi-field evaluation of oviposition repellents in experimental field ponds with the use of metal-sheet cylinders demonstrated that octanoic acid, at the 15 and 30 ppm concentrations, suppressed gravid female mosquitoes from ovipositing. At a lower concentration, this acid did not show any repellency. The full-scale field evaluation of oviposition repellents in experiment field ponds showed that octanoic acid, at 10, 20, 25, and 50 ppm, failed to prevent gravid female mosquitoes from ovipositing in the ponds. However, nonanoic acid was able to repel ovipositing females for about two weeks at the 150 ppm concentration.
- Anatomy and Physiology