text: A British biotechnology company called Oxitec has genetically engineered a new breed of olive tree fly that could stop their natural counterparts from ravaging olive trees in Spain. 
   
   The altered flies are implanted with a gene that causes female offspring to die in the larval stage. Males will grow old with the gene, and soon won't have anyone to mate with. In a controlled experiment conducted by the UK scientists, according to New Scientist, the population crashed in about 10 weeks. 
   
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   Olive tree fly larvae eat through 15% to 30% of the crop each year, making them much more than a nuisance to anyone whose income depends on the fruit. 
   
   For now, Oxitec is waiting for the go-ahead from the National Biosafety Commission in Spain. But in Brazil, a similar experiment is well under way in the wild. The scientists have engineered dengue-carrying mosquitoes around the city of Mandacaru to produce offspring that will all die before they can reproduce. 
   
   The company claims to have killed off 96% of the dengue mosquito, but there are those who believe their method of doing so is dangerous. 
   
   GeneWatch UK, a nonprofit dedicated to investigating how genetic science and technology affects everything from food to society in general, is concerned that this method of species control doesn't have enough oversight. They believe that the relationships this species of mosquito has with other mosquitoes have been oversimplified, meaning the insects could intermingle and cause other populations to deteriorate. 
   
   But Oxitec CEO Hadyn Parry says that its method is much more practical and safe than, say, using insecticide. 
   
   "Insecticides will kill many species — whether the target or a beneficial insect so they can have quite a broad impact in the environment," Parry wrote in an e-mail to Mashable. 
   
   He also suggested that his method is better for people, too. 
   
   "The mosquito lives and breeds very close to humans — so they live in and around the home," Parry said. "So with pesticides you need frequent and total access to people’s homes to spray or fog." Many people don't want those chemicals near where they live, of course. 
   
   Oxitec's main focus for now is on the mosquitoes, but they have developed a few more bugs for different purposes, including one that can control populations of cotton-eaters. 
   
   Does controlling populations through genetic tweaking sound safe to you? Let us know in the comments. 
   
   Image: Flickr, Reini68 ||||| GM insects are go. Genetically modified versions of a fly that decimates olive trees could soon be released in Spain in an attempt to control the pests. And in Brazil, GM mosquitoes are already at large as part of the biggest project yet involving engineered insects. The aim is to stamp out their natural counterparts, which carry dengue fever. 
   
   The techniques are opposed by anti-GM groups, but advocates say they offer a real alternative to spraying insecticides, and have the potential to provide a better and more precise tool to combat agricultural pests and insects that spread human diseases. 
   
   The olive fruit fly is a major pest to olive growers in the Mediterranean and California. Females lay their eggs in the fruit and the larvae destroy 15 to 30 per cent of the crop each year as they munch their way to freedom. To tackle this, Oxitec, a biotech company based in Oxford, UK, has submitted an application to the National Biosafety Commission in Spain to release a small contingent of male GM olive flies, in what would be the first field trial of its kind in Europe. 
   
   The males are equipped with genes that cause any female offspring they sire to die while they are still in the larval stage, before they have had a chance to reproduce. The idea is that the male offspring inherit the lethal genes and continue to propagate them through the population, until the number of females dwindles to zero and the species crashes. 
   
   In lab experiments, the designer flies successfully competed with non-GM males for mates and caused the population to nosedive within 10 weeks (BMC Biology, doi.org/nvd). To check this happens in the wild, the trial would involve releasing the engineered flies under six olive trees in the Tarragona province, draped in mesh netting to prevent escape. 
   
   As the Spanish authorities mull the application, Oxitec is continuing with an even bigger trial to combat dengue fever in Jacobina, a city of 50,000 people in the Brazilian state of Bahia. The aim: to run local mosquitoes that transmit dengue out of town. 
   
   The principle is almost the same as with the olive flies – send out an army of male mosquitoes equipped with genes that prevent any offspring, male or female, from reaching breeding age. "Our males are mating at the frequency we'd hoped," says Luke Alphey, co-founder of Oxitec. 
   
   In a preparatory field study elsewhere, the team showed its mosquitoes reduced the native population by between 80 and 96 per cent within six months. "The new programme is less about 'does this work?', and more about the first operational roll-out of this technology," says Alphey. 
   
   The main benefit of the GM insect method, says Tony Nolan from Imperial College, London, is that it is "strictly species-specific" as the insects only seek out mates of the same species. Controlling the pests with insecticides wouldn't be so discriminating. 
   
   However, opponents, such as GeneWatch UK, say there are unanswered questions about the insects, whether they will spread unpredictably, for example. They also point out that sites cleared of insects would eventually be reinvaded. Alphey counters that similar work using males sterilised with radiation has shown that reinvasions can be controlled for decades by simply releasing more insects. 
   
   This article appeared in print under the headline "Designer insects join fight against pests and disease" 
   
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target: – How do you get rid of a population of bugs destroying your crops? Scientists are trying out a controversial method: spreading a gene that prevents females from reproducing. Males can live with the lab-inserted gene, but females die in the larval stage—which doesn't leave a lot of options for reproduction or the future of the species, New Scientist reports. In a lab experiment, this decimated the population in 10 weeks. Scientists at English firm Oxitec want to try their method in Spain, where they're awaiting the OK from Spanish authorities to kill off certain fruit flies that destroy some 15% to 30% of the olive tree crop each year. But genetic science watchdogs have concerns about the method, fearing, for instance, that altered populations could affect creatures outside their own species, Mashable reports. A similar experiment is already happening in the wild in Brazil, where the Oxitec team has altered males of a population of dengue-carrying mosquitoes. Some 96% of dengue mosquitoes around the city of Mandacaru have been destroyed, the company says.