Learning more about no-see-ums and fruit flies

Most people in Iceland have probably noticed increasing numbers of biting in the country over the last few years. These tiny and hard-to-spot flies midges (called no-see-ums in English and lúsmý in Icelandic) settle on mammals to drink their blood, something which many of us have no doubt experienced first hand. "We believe that biting midges first arrived in Iceland around 10 years ago, but there is still a lot we don't know about their biology," says Arnar Pálsson, professor at the University of Iceland Faculty of Life and Environmental Sciences. Along with his colleagues, he has spent the summer researching the distribution and DNA of these aggressive newcomers, as well as the fruit flies you may have seen around the fruit bowl at home. The aim is to map the distribution of these species in the capital area and changes in their numbers over the summer.

Three biology students at the University of Iceland – Guðfinna Dís Sveinsdóttir, Nína Guðrún Baldursdóttir and Rafn Sigurðsson – are involved in the project, which is partially funded by a grant from the Student Innovation Fund. The Student Innovation Fund allows universities, research institutes and companies to hire undergraduate and graduate students for summer jobs on ambitious and demanding research projects. Andreas Gaehwiller Guðmundsson has also assisted on the project.

Little is known about biting midges

"The project is about investigating the distributions of two fly species in Iceland. Both are flies of the order Diptera: biting midges and fruit flies," explains Arnar. Little research has been conducted into midges abroad. For example, scientists do not know where they originated, where the larvae mature or which habitats they prefer. In the case of fruit flies, Arnar explains that they are harmless. They do not bite people or carry diseases; they eat decomposing fruit and frequently arrive in Iceland with food imports. 

Arnar has researched the evolution of organisms and published articles about the Icelandic biosphere, mainly Arctic char but also ants. He explains that this project was inspired by his fascination with insects and the wonders of the natural world. The team are using special midge traps in order to find out more about their distribution and habitat. "We're mainly looking for biting midges in the Kjós municipality, where they first became properly established. We place hatching traps and also use nets when it's not too windy. We've also gathered a few samples in the evenings with the help of barbeque guests," says Arnar with a grin. 

The fruit flies are captured in Reykjavík with egg traps placed in selected locations. "We check the traps weekly and then identify the species in the sample using a stereo microscope. The late summer we are also conducting DNA analyses," adds Arnar.

Results could be used to combat the spread of biting midges

Arnar hopes that the results of the project will reveal the hatching sites of biting midges, i.e. the kind of habitat where the larvae live and where the flies hatch out. The team also hopes to discover whether the flies complete one or two life cycles over the summer. "We want to better understand their distribution across the country and whether it's just one species, genetically homogeneous, or whether there are subspecies or even more than one species," adds Arnar. As far as the fruit flies are concerned, Arnar hopes to find out when they hatch and which species are most common in Iceland. 

This research will shed more light on how insects become established in Iceland, from the harmless fruit fly to pests like the biting midge. "In the case of the midges, this knowledge could help us prepare for future summers. If there are just a few specific hatching sites, we might be able to do something to prevent them multiplying," says Arnar.

Arnar's colleagues on the project are Matthías Svavar Alfreðsson, entomologist at the Icelandic Institute of Natural History, and Gísli Már Gíslason, professor emeritus of biology at UI.