Genetically Modified Insects
Science & Technology › Biotechnology – Applications · Topic 11.21
Genetically modified insects are insects whose genes have been changed to control pests, stop the spread of disease or improve useful species such as silkworms. The main approaches are the sterile insect technique, in which males made sterile by radiation or genes are released to mate with wild females that then produce no offspring, self-limiting insects whose young die before adulthood, population suppression by gene drives that spread a trait through wild populations, and engineering of beneficial insects. The pink bollworm, the Mediterranean fruit fly and Aedes aegypti mosquitoes have all been targets. Transgenic silkworms that make fluorescent or spider silk proteins show the use of the technology for materials.
5 min read · UPSC Prelims · Science & Technology · Biotechnology – Applications
At a Glance
- Main aim Pest and disease control
- Old method Sterile insect technique
- Newer method Self-limiting and gene drive
- Useful insect Transgenic silkworm
- Safety Biosafety rules apply
- Exam link UPSC Prelims, Science & Technology: Biotechnology – Applications
Where Does It Fit?
This topic follows xenotransplantation. Both involve gene edited animals, but here the targets are insects, which are small, breed fast and affect farming and health. Previous topic: Xenotransplantation: Animal Organs for Human Patients. Next topic: Food and Beverage Fermentations: Microorganisms as Food, Enzymes in Food Processing.
What Are the Main Methods of Insect Genetic Control?
| Method | How it works |
|---|---|
| Sterile insect technique | Millions of males are sterilised with radiation and released. They mate with wild females, which then lay eggs that do not hatch. Used against the screwworm and the Mediterranean fruit fly |
| Genetic sterile insects | Insects carry a gene that makes them sterile or their offspring unable to survive, avoiding the need for radiation |
| Self-limiting insects | Males carry a lethal gene that is passed to young, which die. The effect fades as the released males die, so it does not spread |
| Gene drive | A gene that is inherited by almost all offspring, so it spreads rapidly. It can reduce fertility or make mosquitoes unable to carry parasites |
| Population replacement | Insects are made unable to carry pathogens and spread that trait in the wild |
| Wolbachia method | Mosquitoes infected with a natural bacterium that blocks viruses. Not genetic modification of the insect |
| Transgenic useful insects | Silkworms and honey bees engineered for materials or resistance |
What Are the Examples and Concerns?
- Pink bollworm: United States agencies released sterile pink bollworm moths in cotton fields, helping to wipe out the pest in the country
- Aedes aegypti: Oxitec’s self-limiting mosquitoes have been released in Brazil, Cayman Islands and the United States to reduce dengue spread
- Fruit flies: sterile male releases protect orchards in several countries
- Diamondback moth: a self-limiting strain was tested in New York State and in Brazil to protect cabbage crops
- Transgenic silkworm: silkworms engineered to make spider silk protein or fluorescent silk
- Gene drive for malaria: Anopheles mosquitoes with drives to reduce fertility are tested in laboratories and cages
- Concerns: effects on ecosystems, escape of modified genes, effect on food webs and public consent
- Regulation: release needs approval from biosafety authorities
What Else Should You Remember?
- Sterile insect technique: developed by Edward Knipling in the United States, who used it to remove screwworm flies from the country in the 1950s
- Gene drive: uses CRISPR to bias inheritance, and scientists have warned that release needs careful rules because the spread cannot be called back
- Indian research: India has done work on genetically modified silkworm and on sterile insect techniques, and a 2010s field trial of Oxitec mosquitoes was planned with an Indian partner, but status should be checked
- Indian biosafety: release of genetically engineered insects in India needs permission under the 1989 Rules from the Genetic Engineering Appraisal Committee
- Cartagena Protocol: insects crossing borders are living modified organisms, so advance informed agreement applies, as in Biosafety Protocols
- Target Malaria: an international research consortium working on gene drive mosquitoes for Africa, with a focus on community engagement
- Resistance management: pests can evolve resistance to control methods, so monitoring is needed
- Beneficial insects: bees pollinate crops, and engineering them raises sharper ecological questions
- Cost effectiveness: the sterile insect method needs mass rearing, which is costly, so it suits high value crops and area wide programmes
- Sericulture: India is a major silk producer, and silkworm genetics is important for yield and disease resistance, as in work by the Central Silk Board
- Link: mosquito control is explained in Genetically Modified Mosquito for Vector Control
- Public acceptance: communities must be informed and consulted before releases
Why Does It Matter for the Exam?
- Methods: SIT, self-limiting, gene drive
- Examples: pink bollworm and Aedes
- Concern: ecological effects and consent
- Current affairs link: gene drive trials and dengue control
- Common errors: confusing Wolbachia mosquitoes with GM mosquitoes
As an analytical point, insect control by genes can cut pesticide use, but the effects on ecosystems are hard to reverse. Phased, transparent trials with local consent are the sound approach.
Why Is This Topic Important?
- Methods SIT and gene drive
- Examples Pink bollworm
- Safety Ecological risk
What Came Next?
The next topic covers fermentation in food and drink. Next topic: Food and Beverage Fermentations: Microorganisms as Food, Enzymes in Food Processing.
Key People and Terms
- Sterile insect technique Release of sterile males
- Gene drive Super-inherited gene
- Self-limiting Effect that fades
- Transgenic Carrying foreign gene
- Wolbachia Bacterium blocking viruses
- Refuge Unmodified area
Exam Corner
Points to Remember
- SIT pioneer: Edward Knipling.
- Self-limiting insects do not spread in the wild.
- Gene drives spread through populations.
- Wolbachia is a bacterium.
- Release needs GEAC permission in India.
Do Not Confuse With
- Self-limiting insects and gene drive Fades out versus spreads
- GM mosquito and Wolbachia mosquito Gene change versus bacterial infection
- Sterile insect technique and pesticide Mating control versus chemical kill
Memory Hook
Sterilise to starve the line, limit to let it fade, drive to spread it wide.
Mains Angle
Questions ask for methods, examples and risks. These points help.
- Benefit Less pesticide
- Risk Ecosystem effects
- Rules Consent and approval
A Question You May Face
An original practice question, not a past paper question.
“Examine the potential and risks of genetically modified insects for agriculture and public health, with reference to biosafety regulation.”
How to Answer
- Methods SIT to gene drive.
- Benefits Pest, disease control.
- Risks Ecology, consent.
- Way Phased trials.
GS Relevance
Frequently Asked Questions
What are genetically modified insects?
Genetically modified insects are insects whose genes have been altered, usually to control pests or the diseases they carry. Examples include self-limiting mosquitoes whose offspring die before adulthood, sterile moths released to control crop pests, and silkworms engineered to produce special proteins.
What is the sterile insect technique?
The sterile insect technique involves releasing large numbers of males that have been made sterile, usually by radiation, so that they mate with wild females which then produce no young. Edward Knipling developed it in the 1950s, and it has been used to eliminate or suppress pests such as the screwworm and fruit flies.
What is a gene drive?
A gene drive is a genetic system that causes a particular gene to be inherited by nearly all offspring instead of half, so it can spread quickly through a wild population. Using CRISPR, scientists are testing gene drives that reduce mosquito fertility, but release is controversial because the effect cannot easily be reversed.
How do self-limiting insects work?
Self-limiting insects carry a gene that causes their offspring to die before they become adults. Released males mate with wild females and the young do not survive, so the wild population falls. Since the gene does not persist when the released males die, the effect does not spread or last in the environment.
How are genetically modified insects regulated in India?
In India, work with genetically modified organisms, including insects, is regulated under the Rules of 1989 made under the Environment (Protection) Act, 1986. Research is overseen by the Review Committee on Genetic Manipulation, and release into the environment needs approval from the Genetic Engineering Appraisal Committee.
PYQ Practice — Statement Analysis
1 In the sterile insect technique, sterilised males are released to mate with wild females.
The eggs then do not hatch.
2 A gene drive is designed to spread through a population.
By biased inheritance.
3 Wolbachia mosquitoes are produced by inserting foreign genes into the mosquito genome.
Wolbachia is a natural bacterium.
4 Edward Knipling developed the sterile insect technique.
Used against screwworm.
Past Mains Questions on This Topic
This topic comes under Biotechnology – Applications. UPSC Mains questions asked on the matching syllabus topic, year-wise with marks:
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