Abstract
The Methoprene-tolerant (Met) mutation of Drosophila melanogaster results in a high (100-fold) level of resistance to the insecticide methoprene, a chemical analog of juvenile hormone. Pest species that are under control with methoprene may therefore have the potential to evolve resistance via a mutation homologous to Met. To evaluate the potential of such mutants to persist in wild populations, we must understand the fitness of flies carrying Met. In the absence of methoprene, Met flies were outcompeted by a wild-type strain both in a multigeneration population cage and in single-generation competition experiments. To determine which fitness component(s) is responsible for the competitive disadvantage, the survival, time of development, and fecundity of flies homozygous for each of five Met alleles were compared with wild type. Small but significant differences were found between the pooled Met alleles and wild type for pupal development time, pupal mortality, and early adult fecundity. These differences result in a large competitive disadvantage. Although Met flies were found to have reduced fitness by these measures, the phenotype is not as severe as might be expected from a knowledge of the disruption of juvenile hormone regulation seen in Met flies. It is concluded that (1) although Met flies have a large advantage under methoprene selection, they will quickly become outcompeted upon relaxation of methoprene usage, (2) even a seemingly severe disruption of juvenile hormone regulation has no drastic effect on the vital functions of the insect and (3) small differences in fitness components can translate into a large competitive disadvantage.
Full Text
The Full Text of this article is available as a PDF (2.5 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bownes M. Hormonal and genetic regulation of vitellogenesis in Drosophila. Q Rev Biol. 1982 Sep;57(3):247–274. doi: 10.1086/412802. [DOI] [PubMed] [Google Scholar]
- Bownes M., Rembold H. The titre of juvenile hormone during the pupal and adult stages of the life cycle of Drosophila melanogaster. Eur J Biochem. 1987 May 4;164(3):709–712. doi: 10.1111/j.1432-1033.1987.tb11184.x. [DOI] [PubMed] [Google Scholar]
- Georghiou G. P., Taylor C. E. Genetic and biological influences in the evolution of insecticide resistance. J Econ Entomol. 1977 Jun 15;70(3):319–323. doi: 10.1093/jee/70.3.319. [DOI] [PubMed] [Google Scholar]
- Haymer D. S., Hartl D. L. The experimental assessment of fitness in Drosophila. I. Comparative measures of competitive reproductive success. Genetics. 1982 Nov;102(3):455–466. doi: 10.1093/genetics/102.3.455. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Prout T. The Relation between Fitness Components and Population Prediction in Drosophila. I: The Estimation of Fitness Components. Genetics. 1971 May;68(1):127–149. doi: 10.1093/genetics/68.1.127. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Riddiford L. M., Ashburner M. Effects of juvenile hormone mimics on larval development and metamorphosis of Drosophila melanogaster. Gen Comp Endocrinol. 1991 May;82(2):172–183. doi: 10.1016/0016-6480(91)90181-5. [DOI] [PubMed] [Google Scholar]
- Roush R. T., McKenzie J. A. Ecological genetics of insecticide and acaricide resistance. Annu Rev Entomol. 1987;32:361–380. doi: 10.1146/annurev.en.32.010187.002045. [DOI] [PubMed] [Google Scholar]
- Shemshedini L., Lanoue M., Wilson T. G. Evidence for a juvenile hormone receptor involved in protein synthesis in Drosophila melanogaster. J Biol Chem. 1990 Feb 5;265(4):1913–1918. [PubMed] [Google Scholar]
- Shemshedini L., Wilson T. G. Resistance to juvenile hormone and an insect growth regulator in Drosophila is associated with an altered cytosolic juvenile hormone-binding protein. Proc Natl Acad Sci U S A. 1990 Mar;87(6):2072–2076. doi: 10.1073/pnas.87.6.2072. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Simmons M. J., Crow J. F. Mutations affecting fitness in Drosophila populations. Annu Rev Genet. 1977;11:49–78. doi: 10.1146/annurev.ge.11.120177.000405. [DOI] [PubMed] [Google Scholar]
- Staal G. B. Insect growth regulators with juvenile hormone activity. Annu Rev Entomol. 1975;20:417–460. doi: 10.1146/annurev.en.20.010175.002221. [DOI] [PubMed] [Google Scholar]
- Sved J. A. Fitness of third chromosome homozygotes in Drosophila melanogaster. Genet Res. 1975 Apr;25(2):197–200. doi: 10.1017/s0016672300015603. [DOI] [PubMed] [Google Scholar]
- Williams C. M. Third-generation pesticides. Sci Am. 1967 Jul;217(1):13–17. doi: 10.1038/scientificamerican0767-13. [DOI] [PubMed] [Google Scholar]
- Wilson T. G., Fabian J. A Drosophila melanogaster mutant resistant to a chemical analog of juvenile hormone. Dev Biol. 1986 Nov;118(1):190–201. doi: 10.1016/0012-1606(86)90087-4. [DOI] [PubMed] [Google Scholar]