The Swedish Malaise Trap Project (SMTP)

- addressing challenges in insect biodiversity research

The Swedish Malaise Trap Project (SMTP), funded by the Swedish Species Information Centre (ArtDatabanken), is a Station Linnés owned project. It aims to provide species determinations for all the 80 million insect specimens obtained from Malaise traps sampling at a wide range of landscapes and habitats. This would deliver an important and necessary contribution to a fundamental objective of the Swedish Taxonomy Initiative (STI): to present descriptions of all Swedish multicellular species that can be identified without advanced techniques in an encyclopedia on the Swedish flora and fauna (Nationalnycklen). Specimens from the SMTP traps, collected continuously over a three-year period (2003-2006) represent a gold-mine for biodiversity studies. Qualitative and quantitative analyses have benefited from SMTP trap samples, particularly during recent morphological and molecular systematics research involving Swedish insect species. To date, more than 500 species previously unknown to science has been discovered in these samples, and new localities in Sweden have been verified for a multitude of additional species. One essential challenge is to increase accessibility to this material while establishing new contacts for further scientific discovery. Progress in identification is spurred by taxonomic workshops, and specimen-level data capture is facilitated by sending standardized excel-sheets to the specialists. Incoming data will be integrated into the DINA collection management system and will be made available through the Swedish LifeWatch infrastructure. Selected specimens will be stored for future large-scale molecular bar-coding of the Swedish insect fauna, either dry-mounted or in 96% ethanol at low temperature. We estimate that the SMTP material contains at least half the species of Swedish insects, possibly considerably more, which means that this material provides a unique opportunity for cost-effective barcoding of a substantial fraction of the Swedish biota.

The success of the SMTP depends on volunteer efforts and external taxonomic expertise, which is provided by several hundred collaborators. As being an expert in insect taxonomy, you might want to help us to meet this challenge – We regularly sort trap samples and send undetermined specimens from almost 300 different higher-level groups (from order to subfamily and tribes) on Ioan to specialists all around the world. But you are certainly welcome to visit us at our home ground; Station Linné on Öland, which itself is worth the trip!



The Swedish Malaise Trap Project (SMTP)

Establishing and Collecting (2003-2006)

Large-scale entomological inventories have to rely on mass-sampling programmes (e.g. Hansson 1999), and the Malaise trap (Vårdal & Taeger 2011) remains the most cost-efficient device for collecting most of the neglected groups of Diptera and Hymenoptera. The Swedish Malaise Trap Project (SMTP) was launched in 2003 with the major goal of making high-quality material of Swedish insects available for the morphological and molecular research needed for a complete national inventory. Up to 75 Malaise traps at 54 localities across Sweden were run for three seasons (Karlsson et al. 2005). Some of the traps were deployed in remote places, while others were extremely exposed to the public, e.g. at the popular sand dunes at Sandhammaren in Skåne with up to 3,000 visitors on a typical sunny summer day. It is noteworthy that not a single Malaise trap was targeted for sabotage. The traps produced about 1,900 samples containing an estimated 80 million specimens. With a few exceptions, all of the collected material is in excellent shape, and the Diptera and Hymenoptera in particular represent a unique and increasingly utilized resource for taxonomic and systematics research nationally as well as internationally.


Sorting Progression and Networking (2006-2012)

The initial SMTP plan was to sort everything to the level of order, and with Diptera sorted further into large and small Nematocera plus large and small Brachycera, and with Hymenoptera sorted further into Symphyta, ‘Parasitica’ and Apocrita. It was estimated that a total of 36 man-years would be needed to sort the entire SMTP catch to these levels.

Unofficial in-group estimates from the project board and its taxonomic network estimated that we might be able to find as much as 1,000 species new to Sweden, of which possibly 200-300 would be new to science. However, the latter numbers were surpassed already after treating only fractions of the total catch of Phoridae (puckelflugor) and Platygastroidea (svartsteklar). After these sensational results became known, SMTP decided to sort Diptera and Hymenoptera to a much finer level. Three hymenopteran workshops have resulted in a strategy that provides an optimal trade off between sorting costs and attractiveness of the resulting fractions to taxonomic specialists around the world. By far the biggest challenge is the immense superfamily Ichneumonoidea, and in 2007-2010 SMTP received special STI-funding for a part-time assistant sorting Ichneumonidae to subfamily level (some subfamilies even to tribus).

The number of taxonomic specialists working on SMTP material has now surpassed the number of trap managers. In total, more than 200 persons have contributed with their services and knowledge to the SMTP – nearly all of them without financial comensation. The SMTP material continuously attracts the attention of graduate students, postdocs and senior scientists in Sweden and abroad, resulting in a steady stream of discoveries of species new to Sweden, many of them also new to science.

During 2010-2012 SMTP received STI-funding for a satellite project aimed at sorting Diptera and Hymenoptera to families or – for Ichneumonoidea – to subfamilies and, in some cases, tribes. All of this means that SMTP is now sorting the collected insects into 275 groups. Expanding the sorting efforts from seven to 275 groups has of course expanded the time scale for completing the sorting, and the initial estimate of 36 man-years is now up to 48. However, the increased sorting level has helped arouse the interest among experts world-wide. To date (August 2012), 79 taxonomic specialists have worked on the material. Of these, 31 are from Sweden and 48 from the rest of the world.

Among the almost 50 persons who are or have been working in the project at Station Linné, there are 6 volunteers, 5 work placement (arbetspraktik) cases, 6 MSc students and 10 PhD students.

Ever since the field part of the project was terminated in mid 2006, the focus has been on sorting and distribution of material for taxonomic research. In all, more than 50% of the collected samples are now (August 2012) processed, resulting in more than 40 million insects being available for study. More than 750,000 specimens from 184 groups of insects have been sent to taxonomists in 21 countries in Europe, North and South America and Asia, and more than 200,000 specimens are already determined to species. Most of these are still out on loan, but a steadily increasing stream of determined specimens is now flowing back to Station Linné. Vouchers and other important specimens will eventually be incorporated in the entomology collections at the Swedish Museum of Natural History in Stockholm, according to a written agreement between the museum and Station Linné.


The future

Our aim is to take advantage of the highly efficient SMTP team and the existing infrastructure in processing the SMTP material during the next years. Probably is 80 % of the material sorted to a level adequate for further specialist treatment by the end of 2015. We also aim to have material of some target groups dry-mounted, and a significant portion of the sorted material in various stages of the taxonomic research and identification process.


Organization and personnel

We now have a clear picture of the size and composition of the SMTP material, and the workflow needed to sort and distribute the material effectively. We also know how much effort is needed to deal with the logistic challenges of a project this size. Processing, distributing and archiving millions of specimens and handling the associated data pose major challenges. Add to that the handling of everything practical from administrative matters to organizing workshops and symposia.

After years of collaboration and networking we now have a fairly good idea of the taxonomic level to which different insect groups must be sorted to be interesting for specialists, and which personnel resources are required to process the material to those levels. The current SMTP crew is absolute top class when it comes to sorting insects. The handling time is from less than three seconds per specimens at the first tier (gross sorting), to about five seconds per specimen at the fourth tier (sorting to subfamilies and tribes of ichneumonids and braconids), with an average accuracy superior to 99%.

Despite the skills of the team, the extremely large number of specimens still makes the task challenging. In addition, we have noted that specimens stored in alcohol are not adequate for taxonomic work on some insect groups. These groups shall preferrably be dry mounted to make leading specialists willing to study them. Examples of such groups include many small hymenopterans, which are extremely difficult to study in wet conditions. Tests that we have performed also show that dry mounting the specimens can improve the long-term preservation of the DNA compared to storage in 96 % ethanol, which is the standard SMTP protocol.


Compile and make available species lists and specimen records

The SMTP routinely distributes a pre-formatted Excel file, in which all the trap ID’s have been entered as column headings, to facilitate the return of data from taxonomists. The only information that the SMTP collaborators need to fill out is the species names and specimen numbers. Previous experience has shown that this is by far the best way of ensuring broad participation. Data capture routines ensure that it is possible to compensate for lost samples in statistical analyses of the material. This means that scientists working with the material can get a comprehensive picture of the entire diversity in the SMTP material, comprising some 80 M specimens in total.


Continue to build the SMTP reference collection for future large-scale barcoding

Taxonomists working on SMTP material are required to return representative specimens of all identified species. Some of these specimens are dry- or slide-mounted as appropriate for the group, and serve as vouchers of the reported species. The voucher collection will eventually be deposited in the Swedish Museum of Natural History. The remaining returned reference material is stored for future large-scale DNA bar coding of the Swedish insect fauna, either dry-mounted or in 96 % ethanol in freezers.

The reference collection currently includes material of more than 1,000 species. The growth rate, which now is rapidly increasing, is currently at about 1,000 new species per year. When the entire SMTP material has been processed, we estimate that the reference collection will contain at least 50-60 % of the Swedish insect species, some 15,000 to 20,000 species, being particularly rich in previously poorly known insect groups such as Diptera and Hymenoptera.

An important concern is the period SMTP specimens remain in 80% ethanol before being sent out for identification. So far, all attempts to extract DNA from SMTP specimens reported to us have been successful but the material may of course degrade over the coming years. Currently, the bulk of the SMTP material is stored in the dark at room temperature in the Swedish Museum of Natural History and at Station Linné on Öland, but samples would obviously be better preserved if the material were stored at lower temperatures and the SMTP group is currently also working on a solution to this issue.

One of the primary aims for SMTP is to provide a rich source of reliably identified, high-quality specimens for the emerging efforts to build DNA reference libraries of the entire Swedish insect fauna. The availability of such libraries is the crucial bottleneck in developing new biotic inventory techniques based on Next Generation Sequencing (NGS), which are likely to revolutionize future biodiversity research and environmental monitoring.


Engage in outreach activities

Among our outreach activities, we will continue the popular and well-known formula developed by us under the name “Forskning för Folket” (Research for the People). Originally, the concept involved the project personnel moving their equipment and the materials from the lab to another site but in the last years we have simply opened up our regular lab certain hours every week during the summer, which is a better and more efficient way of achieving the same effect. We will also alert the media when we have particularly interesting results to report and we will continue hosting site visits. We also expect to give a number of lectures and participate in various courses, as we have done in the past.

The SMTP has appeared in more than 300 newspaper articles, hundreds of radio programs and a number of TV shows or news reels. Furthermore; Dave Karlsson is the “bug-expert” in the Swedish Radio’s popular morning program “Naturmorgon i P1” with about 400,000 listeners every Saturday. Dave participates in the program 6–10 times a year.


Analyze the size and composition of the Swedish insect fauna

The SMTP is probably the largest insect inventory program in the world, and it is unique in the actual number of sorted and determined insects. For the first time, we are close to completing the inventory of a large fraction of a biome of significant size. This allows us to effectively address questions about the composition and function of a biome (structural and functional biomics) based on complete knowledge of the parts, the species. This places Sweden at the forefront of a new type of biodiversity studies. During the coming project period, we are planning to finish a couple of studies of this kind based on the SMTP material. The availability of the SMTP data on the web through the Swedish LifeWatch infrastructure should stimulate similar studies by other research groups around the world.



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