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Sterile Insect Technique(SIT)
[edit]The colonization and mass-rearing of mosquitoes and other insects that are then sterilized by gamma radiation or RNA interference and released into an area. These releases must contain large enough numbers of insects to overflood the wild population. After the release, sterile males will mate with wild females and transfer sperm with dominant lethal mutations. Embryogenesis will be prevented even though the wild females’ eggs were fertilized and no offspring will be produced. This causes a reduction, and in some cases, extinction, in the wild insect population. [1]
Some success stories of the SIT are the New World screwworm (Cochliomyia hominivorax), a livestock parasite, being eradicated from the southern United States, Mexico, and Central America to Panama, and the Mediterranean fruit fly (Cerititis capitata) being eradicated from Central America into southern Mexico. Pink bollworm moths (Pectinophora gossypiella), since 1967 have been released over cotton fields in the San Joaquin Valley of California to prevent their establishment and migration by moths from southern California. The SIT is also being used to reduce codling moth (Cydia pomonella) populations, a pest of apples and pears, in British Columbia, Canada.[2]
Genetically Modified Mosquitoes
[edit]Genetically modified mosquitoes are mosquitoes that are made resistant to pathogen infection. Mosquitoes are released into the wild to reduce of eliminate the transmission of pathogens.[3]
Environmental Impacts of Genetic Control
[edit]Loss of Genetic Diversity
[edit]The eradication of pest populations will inevitably lead to a decline in the genetic diversity of that species. It should be required that a certain level of genetic diversity be maintained in laboratory colonies of mosquitoes. The developmental stages of mosquitoes and information on both sexes must be stored in scientific collections for future exploration. Cryopreservation techniques for mosquito embryos can also be used to preserve insects for future research.[4]
Enhanced Pathogen Transmission
[edit]Before genetically modified mosquitoes can be tested in the real world as malaria or dengue fever vector control, more research needs to be conducted to examine the evolutionary and environmental costs of the release. Will mosquitoes that have been genetically modified to block malaria pathogen infections be more capable of transmitting other pathogens? There has been little research on the ability of vector borne pathogens to overcome the barriers placed by genetically modified mosquitoes. For instance, Plasmodium malaria parasites often evolve resistance to antimalarial drugs, and dengue fever viruses are mutable. [5]
Trophic Cascade
[edit]Mosquitoes act as competitors, prey, and predators within ecological communities. Decreasing the population of mosquitoes may increase the population of its prey, and decrease the population of its predators, such as fish, frog larvae, and dragonfly larvae, which are consumed by much larger organisms like humans and birds. The reduction of one target vector may cause a trophic cascade that could impede or enhance another vector’s transmission of a different parasite.[6]
Environmental Change
[edit]Changes in climate and the environment can sometimes facilitate the expansion of several vector species and intensify pathogen transmission. In several parts of the tropics, there has been an increase in the human-biting rate of formerly zoophilic vectors due to deforestation.[7] Rises in temperature have also enables malaria to spread into new habitats and regions.[8]
References
[edit]- ^ Vreysen, M.J.B., J.E. Carpenter, and F.Marec. 2010. Improvement of the sterile insect technique for codling moth Cydia pomonella (Linnaeus) (Lepidoptera Tortricidae) to facilitate expansion of field application. Journal of Applied Entomology 134 (3):165-181.
- ^ Dyck, V.A., J. Hendrichs, and A.S. Robinson. 2005. Sterile Insect Technique, Principles and Practice in Area-wide Integrated Pest Management. Dordrecht, The Netherlands: Springer.
- ^ Scott, T.W., W. Takken, Knols,B.G.J. and C. Boete. 2002. "The Ecology of Genetically Modified Mosquitoes." Science. 298:117-119. Print.
- ^ Dyck, V.A., J. Hendrichs, and A.S. Robinson. 2005. Sterile Insect Technique, Principles and Practice in Area-wide Integrated Pest Management. Dordrecht, The Netherlands: Springer.
- ^ Scott, T.W., W. Takken, Knols,B.G.J. and C. Boete. 2002. "The Ecology of Genetically Modified Mosquitoes." Science. 298:117-119. Print.
- ^ Ferguson,H.M., A. Dornhaus, A. Beeche, C. Borgemeister, M. Gottlieb, M.S. Mulla, J.E. Gimnig, D. Fish, G.F. Killeen. 2010."Ecology: A Prerequisite for Malaria Elimination and Eradication." 7(8):1-7.
- ^ Vittor,A.Y.,R.H. Gilman,J. Tielsch,G. Glass, T. Shields, et al. 2006. The effect of deforestation on the human biting rate or Anopheles darlingi, the primary vector of falciparum malaria in the Peruvian Amazon. Am J Trop Med Hyg 74:3-11.
- ^ Patz, J.A., S.H. Olson. 2006. Malaria risk and temperature: influences from global climate change and local land use practices. Proc Natl Acad Sci U S A 103:5829-5834.