The Swedish Malaise Trap Project (SMTP)
The Swedish Malaise Trap Project is a unique, large scale, national insect inventory conducted by the Swedish Museum of Natural History and funded by the Swedish Taxonomy Initiative. The purpose of the project is to provide the Swedish museums with extensive and representative high quality insect material. Within poorly known insect groups – notably hymenopterans and dipterans – lack of material is often a major obstacle to researchers. These two exceedingly species rich insect orders constitute the majority of terrestrial biodiversity, holding key positions in most ecosystems. The actual number of species within these orders is hard to estimate, and recent research indicates that their importance within the terrestrial ecosystems tends to increase with the distance from the equator. In Sweden, hymenopterans and dipterans together comprise more than two thirds of the known multicellular fauna.
75 so-called Malaise traps are used within this project. The Malaise trap, constructed in the 1930s by the Swedish entomologist René Malaise, is a highly efficient, tent-like trap made from mosquito net fabric, with a central, vertical wall and slanting sides. Flying insects colliding with the vertical wall will fly or crawl upwards, where they pass through a narrow opening at the top and fall into a tin filled with a liquid containing detergents and preservatives. Today the Malaise trap is part of the standard equipment used in most large scale insect inventories worldwide.
...scattered throughout the country
In order to optimise the diversity of the material, the Malaise trap have been placed in as many known Swedish hot spots of insect diversity as possible (i.e. areas known to possess an exceptionally high insect diversity, listed as such by the Swedish Environment Protection Agency). The 75 traps were placed at 50 sites, ranging from the southernmost coast to the northernmost mountain area. The traps were emptied mainly by volunteers, approximately every second week throughout the snow-free part of the year. Without the commitment of c. 100 Swedish amateur entomologists and field biologists, this project would have been impossible. The collected material comprises some 2,000 samples containing approximately 40 million insects! The material is sorted at the Linnaeus Research Station (Ölands Skogsby) and subsequently stored at the Swedish Museum of Natural History (Stockholm).
The extensive and time consuming work with sorting through the material and identifying the individual insects has only just begun. But already in August 2009 - when only a few percent of the specimens had been identified, and no more than some 35 % of the material had even been sorted by order - over 1,000 species new to Sweden had already been identified, some 50% of which were also new to science. The results from the Malaise trap project are so sensational that they even found their way to the placard of Aftonbladet (one of the major Swedish papers) on October 11th 2006.
So far, only material belonging to a few of the more than 400 Swedish insect families have been examined by taxonomists, and the majority of the new species hitherto found are small mosquitoes and parasitic wasps. For instance, over 800 species of scuttle flies (Phoridae) have been identified so far. This family was previously known to comprise about 300 Swedish species. More than 50 percent of the scuttle fly species new to Sweden were also new to science.
A unique scientific resource
The work with sorting through and identifying the material is currently at its most intensive stage. That work completed, the material will be of tremendous importance to systematics, taxonomical and ecological research, in Sweden and worldwide.
The Swedish Malaise Trap Project was initiated by Thomas Pape and Fredrik Ronquist, and lead by Kajsa Glemhorn at the Swedish Museum of natural History. If you would like to know more about, or partake in the project, please contact Kajsa Glemhorn at Kajsa.Glemhorn@stationlinne.se, phone +46 485 381 58
Text and photo: K. Glemhorn and D. Karlsson