Genetically modified fruit flies could save crops

Releasing genetically engineered fruit flies into the wild could prove to be a cheap, effective and environmentally friendly way of pest control, a new study has found.
New research by scientists at the University of East Anglia and Oxitec Ltd shows the release of genetically engineered male flies could be used as an effective population suppression method - saving crops around the world.
The Mediterranean fruit fly is a serious agricultural pest which causes extensive damage to crops.
It is currently controlled by a combination of insecticides, baited traps, biological control and releasing sterilised insects to produce non-viable matings, known as the Sterile Insect Technique (SIT).

Researchers simulated a wild environment within greenhouses and studied the impact of releasing Oxitec flies.
"The Mediterranean Fruit Fly infests more than 300 types of cultivated and wild fruits, vegetables and nuts. It is a real pest to agriculture and causes extreme damage to crops all around the world," lead researcher Dr Philip Leftwich, from UEA's school of Biological Sciences, said.

"The genetically engineered flies are not sterile, but they are only capable of producing male offspring after mating with local pest females - which rapidly reduces the number of crop-damaging females in the population," Leftwich said.
"When we tested the release of the genetically modified male flies, we found that they were capable of producing rapid population collapse in our closed system.

"This method presents a cheap and effective alternative to irradiation. We believe this is a promising new tool to deal with insects which is both environmentally friendly and effective," said Leftwich.
The method works by introducing a female-specific gene into the insects that interrupts development before females reach a reproductive stage.
Populations of healthy males and females can be produced in controlled environments by the addition of a chemical repressor.
If the chemical repressor is absent in the genetically engineered flies' diet, only males survive.
The surviving males are released, mate with local wild pest females and pass the female specific self-limiting trait onto the progeny resulting in no viable female offspring.

The research was published in the journal Proceedings of the Royal Society B.