An international team of scientists have combined their expertise to complete the whole genome sequence of the Mediterranean fruit fly, Ceratitis capitata. This insect pest attacks more than 260 fruit, vegetable and nut crops worldwide, including Europe and Australia, causing billions of dollars annually in direct harm, export sanctions, lost markets as well as treatment and prevention expenses. The biggest threat is from egg-laying females. Once a female fruit fly has mated, she’ll deposit 1 to 10 eggs just below the skin of the host fruit or vegetable. Maggots then emerge, damaging the fruit or vegetable and exposing it to rotting. The maggots later pupate in the ground and emerge as adult flies, ready to mate in a few days and start the cycle all over again.
Reported in Genome Biology, researchers now have an edge in understanding how this insect’s genetics enable it to be such a successful invasive pest. Genes control many important traits such as its ability to reproduce, withstand pathogens, find host plants, and break down environmental toxins.
Researchers are now working with the wider international community to identify how to improve the effectiveness of the Sterile Insect Technique (SIT). An approach used worldwide, SIT involves mass-rearing insects in the lab and sterilizing the males for release into the wild to mate with the females found in nature, resulting in eggs that don’t hatch. Combining SIT releases with baits and other measures sustainably suppresses or eventually eradicates the targeted population but it can also be used as a preventative measure to avoid the establishment of introduced populations, notes Dr Al Handler, a Research Geneticist with the USDA’s Agricultural Research Service.
Dr Handler, with Prof Marc Schetelig from the Justus-Liebig-University Giessen, Germany, has served as the project leader for a group of 64 scientists from 25 research organizations throughout the world that contributed to the “Mediterranean Fruit Fly Whole-Genome Sequencing Project”. It’s one of the genome projects being coordinated by Prof Stephen Richards from the Baylor College of Medicine’s Human Genome Sequencing Center as part of the 5,000 Arthropod Genome Initiative (i5k), a worldwide USDA-led effort to create more genomic resources for insects and other arthropods.
With the medfly’s genome sequence decoded, scientists can begin to explore new ways of breaking the reproductive cycle, as well as gain critical insight into how the pest invades and adapts to new habitats in tropical and subtropical regions of the world. This work is just the beginning of using genetics with invasive species: as the lead author of the study, Dr Alexie Papanicolaou (the Hawkesbury Institute for the Environment of Western Sydney University), says that this has been a “breakthrough moment in building the capability to generate very high quality genome resources rapidly and accurately, our work here has enabled us to use genomics for other insect pests and support the work of industry such as Australia’s SITPlus and Plant Biosecurity CRC initiatives”.
For further reading:
The Stressed Fruit Fly lab
Science and Economics Both Work in Fruit Fly Program
Image caption: A close up of the Mediterranean fruit fly, Ceratitis capitata.
URL image link (Credit: Scott Bauer, USDA):