Fifteen years & 20 million insects later: Sweden’s impressive effort to document its insect fauna in a changing world

The Swedish Malaise Trap Project (SMTP) was launched in 2003 with the aim of making a complete list of the insect diversity of Sweden. Over the past fifteen years, an estimated total of 20 million insects, collected during the project, have been processed for scientific study. Recently, the team behind this effort published the resulting inventory in the open-access journal Biodiversity Data Journal. In their paper, they also document the project all the way from its inception to its current status by reporting on its background, organisation, methodology and logistics.

The SMTP deployed a total of 73 Malaise traps – a Swedish invention designed to capture flying insects – and placed them across the country, where they remained from 2003 to 2006. Subsequently, the samples were sorted by a dedicated team of staff, students and volunteers into over 300 groups of insects ready for further study by expert entomologists. At the present time, this material can be considered as a unique timestamp of the Swedish insect fauna and an invaluable source of baseline data, which is especially relevant as reports of terrifying insect declines keep on making the headlines across the world.

The first author and Project Manager of the SMTP, Dave Karlsson started his academic paper on the project’s results years ago by compiling various tips, tricks, lessons and stories that he had accumulated over his years as SMTP’s Project Manager. Some fun examples include the time when one of the Malaise traps was destroyed by a moose bull rubbing his antlers against it, or when another trap was attacked and eaten by a group of 20 reindeer. The project even had a trap taken out by Sweden’s military! Karlsson’s intention was that, by sharing the details of the project, he would inspire and encourage similar efforts around the globe.

Animals were not as kind to our traps as humans,” recall the scientists behind the project. One of the Malaise traps, located in the Brännbergets Nature Reserve in Västerbotten, was destroyed by a bull moose rubbing his antlers against it.
Photo by Anna Wenngren

Karlsson has worked with and trained dozens of workers in the SMTP lab over the past decade and a half. Some were paid staff, some were enthusiastic volunteers and a good number were researchers and students using SMTP material for projects and theses. Thus, he witnessed first-hand how much excitement and enthusiasm the work on insect samples under a microscope can generate, even in those who had been hesitant about “bugs” at first.

Stressing the benefits of traditional morphological approaches to inventory work, he says: “Appreciation for nature is something you miss when you go ‘hi-tech’ with inventory work. We have created a unique resource for specialists in our sorted material while fostering a passion for natural history.”

Sorted SMTP material is now available to specialists. Hundreds of thousands of specimens have already been handed over to experts, resulting in over 1,300 species newly added to the Swedish fauna. A total of 87 species have been recognised as new to science from the project thus far, while hundreds more await description.

The SMTP is part of the Swedish Taxonomy Initiative, from where it also receives its funding. In its turn, the latter is a project by the Swedish Species Information Center, a ground-breaking initiative funded by the Swedish Parliament since 2002 with the aim of documenting all multicellular life in Sweden.

The SMTP is based at Station Linné, a field station named after the famous Swedish naturalist and father of taxonomy, Carl Linneaus. Situated on the Baltic island of Öland, the station is managed by Dave Karlsson. Co-authors Emily Hartop and Mathias Jaschhof are also based at the station, while Mattias Forshage and Fredrik Ronquist (SMTP Project Co-Founder) are based at the Swedish Museum of Natural History.


Original source:

Karlsson D, Hartop E, Forshage M, Jaschhof M, Ronquist F (2020) The Swedish Malaise Trap Project: A 15 Year Retrospective on a Countrywide Insect Inventory. Biodiversity Data Journal 8: e47255.

Efficiency of insect biodiversity monitoring via Malaise trap samples and DNA barcoding

The massive decline of over 75% insect biomass reported from Germany between 1989 and 2013 by expert citizen scientists proves the urgent need for new methods and standards for fast and wide-scale biodiversity assessments. If we cannot understand species composition, as well as their diversity patterns and reasons behind them, we will fail not only to predict changes, but also to take timely and adequate measures before species go extinct.

An international team of scientists belonging to the largest and connected DNA barcoding initiatives (iBOL, GBOL, BFB), evaluated the use of DNA barcode analysis applied to large samples collected with Malaise traps as a method to rapidly assess the arthropod fauna at two sites in Germany between May and September.

One Malaise trap (tent-like structure designed to catch flying insects by attracting them to its walls and then funneling them into a collecting bottle) was set in Germany’s largest terrestrial protected natural reserve Nationalpark Bayerischer Wald in Bavaria. Located in southeast Germany, from a habitat perspective, the park is basically a natural forest. The second trap was set up in western Germany adjacent to the Middle River Rhine Valley, located some 485 kilometers away from the first location. Here, the vegetation is eradicated annually due to St. Martin’s fires, which occur every November. Their findings are published in the open access Biodiversity Data Journal.

DNA barcoding enables the identification of a collected specimen by comparing its BIN (Barcode Index Number) against the BOLD database. In contrast to evaluation using traditional morphological approaches, this method takes significantly less experience, time and effort, so that science can easily save up on decades of professional work.

However, having analyzed DNA barcodes for 37,274 specimens equal to 5,301 different BINs (i.e., species hypotheses), the entomologists managed to assign unambiguous species names to 35% of the BINs, which pointed to the biggest problem with DNA barcoding for large-scale insect inventories today, namely insufficient coverage of DNA barcodes for Diptera (flies and gnats) and Hymenoptera (bees and wasps) and allied groups. As the coverage of the reference database for butterflies and beetles is good, the authors showcase how efficient the workflow for the semi-automated identification of large sample sizes to species and genus level could be.

In conclusion, the scientists note that DNA barcoding approaches applied to large-scale samplings collected with Malaise traps could help in providing crucial knowledge of the insect biodiversity and its dynamics. They also invite their fellow entomologists to take part and help filling the gaps in the reference library. The authors also welcome taxonomic experts to make use of the unidentified specimens they collected in the study, but also point out that taxonomic decisions based on BIN membership need to be made within a comparative context, “ideally including morphological data and also additional, independent genetic markers”. Otherwise, the grounds for the decision have to be clearly indicated.

The study is conducted as part of the collaborative Global Malaise Trap Program (GMTP), which involves more than 30 international partners. The aim is to provide an overview of arthropod diversity by coupling the large-scale deployment of Malaise traps with the use of specimen-based DNA barcoding to assess species diversity.

Sequence analyses were partially defrayed by funding from the government of Canada through Genome Canada and the Ontario Genomics Institute in support of the International Barcode of Life project. The German Barcode of Life project (GBOL) is generously supported by a grant from the German Federal Ministry of Education and Research (FKZ 01LI1101 and 01LI1501) and the Barcoding Fauna Bavarica project (BFB) was supported by a 10-year grant from the Bavarian Ministry of Education, Culture, Research and Art.



Original source:

Geiger M, Moriniere J, Hausmann A, Haszprunar G, Wägele W, Hebert P, Rulik B (2016) Testing the Global Malaise Trap Program – How well does the current barcode reference library identify flying insects in Germany? Biodiversity Data Journal 4: e10671.