A new species of dark-winged fungus gnat

Leibniz Association

In the context of the simultaneous exhibition “8 Objects, 8 Museums” by the Leibniz research museums, the Zoological Research Museum Alexander Koenig in Bonn presents its most fascinating capture: a new species of dark-winged fungus gnat.

A "world debut" in the museum garden
Scientists discovered a previously unknown new species of dark-winged fungus gnat in the park of the Museum Koenig right in the centre of Bonn. This is a particularly spectacular find since in Europe, new species are normally discovered in areas that are still relatively poorly explored. The gnat was accidentally trapped during the trial run of an automated trap in the course of activities for the “German Barcode of Life” project, which inventories the species diversity in Germany based on the genetic barcode. The barcodes of all plants, animals and fungi in Germany are currently being recorded and stored in a data archive. This is aimed at enabling a faster inventory of the species diversity for the increased protection of the overall biodiversity in the future. The new discovery was even more astonishing once it became apparent that the species is originally native to New Zealand and must have been introduced to Germany in the context of the so-called globalisation.

The gnat was discovered inside a Malaise trap – named after the Swedish entomologist René Malaise (1892–1978). Insects enter the lower, dark area of the trap, attempt to escape upward towards the light and become trapped in a collection container, where they are killed in high-proof alcohol and preserved for scientific processing.

The remarkably handsome species (top right) shows a contrasting colouration of orange, yellow, white and brown hues, which clearly set it apart from the three other species of dark-winged fungus gnats known from Europe to date. Its taxonomic description was published in April 2016 by Björn Rulik and citizen scientist Kai Heller.

However, the new dark-winged fungus gnat is not only peculiar with respect to its external characteristics – its uniqueness is also reflected in its DNA barcode. DNA barcoding has developed into a globally applied standard method for the fast and reliable identification of animal, plant and fungus species. Specific short sections of the genes – DNA barcodes – are unique for each species.

Taxonomy reflects the relationships between organisms by placing them in an organised system. In the past ten years, the Arthropoda division at the Museum Koenig described more than one-thousand new species. Nature and environmental conservation, agriculture, medicine and evolution research all depend on the results of taxonomy.

The captured specimen is archived and stored in the arthropod collection, and the gnat’s DNA barcode is archived in the museum’s tissue and DNA collection (“biobank”).

The new dark-winged fungus gnat Ctenosciara alexanderkoenigi was named in honour of the museum’s founder, Alexander Koenig (1858–1940). He studied zoology in Greifswald and Marburg, wrote his doctoral thesis on the bird lice and undertook extensive expeditions. In 1929, he donated the institute, which he built with his own private funds, to the State of Prussia.

Distribution and biology
Dark-winged fungus gnats occur worldwide and normally only reach a length of 3 to 5 mm. They owe their name to their dark body colour and the usually dusky-clouded wings. Well over 400 species can be found in Germany alone. Adult fungus gnats have a life expectancy of only a few weeks. They are harmless to humans, but may become a nuisance during mass occurrences in moist potting soil, since their larvae feed primarily on plant roots.

Micro CT scan of the dark-winged fungus gnat: Besides the long antennae, the bell-shaped split on the wing’s central veins is a characteristic trait of this family.

A female dark-winged fungus gnat can lay up to 200 eggs. The larvae feed on rotting plant material and fine roots and play an important role in the extraction of nutrients in the cycle of materials. The developmental cycle from the egg to the imago (adult animal) comprises three larval stages and pupation in the soil and is completed within less than one month.

The so-called army worm consists of thousands of larvae of the dark-winged fungus gnat species Sciara militaris (Nowicki, 1868). The larvae form a dense strand and move in one direction. New larvae join the strand continuously and create long migrating columns. With a speed of about half a metre per hour, the animals do not move particularly fast. Such “processions” are entirely harmless, yet this natural occurrence has given rise to numerous myths and legends.

From foreign lands to Europe
The new species of dark-winged fungus gnat is an invasive animal species that has conquered new habitats due to intentional or inadvertent human impact. Genetic studies show that it originates from Australasia and presumably reached Europe along with imported plants. In the meantime, four additional individuals have been found in northern New Zealand, which show the same DNA barcode as the animal from the museum park. The capture from Bonn is thus of double interest, since the gnat had not even been described yet from its own place of origin.

The Asian bush mosquito (Aedes japonicus, Theobald, 1901) is another invasive species in Germany – originally, it is a native of South China, Japan and Korea. Since 2000, this mosquito with patterned legs has also been documented in Europe. It appears to be displacing native species. A foreign species that threatens the native biological diversity, e.g., due to a lack of natural enemies, is called invasive (from Latin invadere: to penetrate, attack, break in).

The distribution area of an invasive species can increase in a very short time. How fast this can happen is shown in the following map. Between 2012 and 2014, a massive increase in the occurrence of the Asian bush mosquito can be observed.

Automated inventory of species diversity – a vision
The fight against the decline of species diversity suffers from our lack of knowledge just how fauna and flora change in space and time and how many species actually exist. For there are neither globally linked research programmes nor an automated inventory of all organisms. In order to automatically register species diversity (in analogy to automated weather stations) in the future, the AMMOD project (automated multisensor station for monitoring of species diversity) aims at combining innovative technologies.

Recording of animal voices (1) with audio recorders and analysis with specialised software: The museum is leading in establishing a reference archive for animal voices, photos and video recordings (2) with infrared cameras that are triggered via motion sensors or infrared sensors and capture images of small to medium-sized mammals and insects. A moth scanner is used to register nocturnal lepidopterans. Sniffers, smellscapes, scent measurement (3): “Artificial noses” on the basis of ion mobility spectrometry, which are sensitive to even the smallest concentrations of scents, are intended, e.g., to detect harmful pesticides.

Sky scanner (4): Automated camera analysis systems record flying organisms in the sky and offer information on preferred routes and landscapes used by migrating birds. Pollen collector (5) used to determine the entire diversity of plant pollen via DNA barcoding. Sample changer (6): The museum is working on an enhanced development of the malaise trap in order to collect and preserve flying insects at programmable time intervals.
Solar-powered control unit and data transmitter (7): In this self-sufficient central station, all recorded data are collected via Wi-Fi by the individual modules (1-6), compressed and sent to the main computer centre.

Zoological Research Museum Alexander Koenig
The Museum Koenig represents innovative biodiversity research for the protection of species diversity. This includes evolution research, taxonomy, modelling and monitoring. Biodiversity is an important basis of our life. It not only encompasses the diversity of animal and plant species, microorganisms, fungi and the genetic diversity within species, but also the complex ecological processes and interactions in a multitude of biotopes across the globe.

Together with the University of Las Palmas de Gran Canaria and the Zoological Society of London, the Museum Koenig is involved in a research project dedicated to the protection of angelsharks. The data regarding angelshark sightings are used to generate continually improved prognoses and simulations. For these, the Museum Koenig is developing increasingly more precise computer programmes.

Leibniz Gemeinschaft
Credits: Story

“8 Objects, 8 Museums” is a collaboration project between the Leibniz research museums and the Leibniz-Institut für Wissensmedien in Tübingen in the Leibniz Year 2016.

German Barcode of Life (GBOL) – Coordination project by the Zoological Research Museum Alexander Koenig – Leibniz Institute for Biodiversity of Animals regarding a » new species of dark-winged fungus gnat«

All documents and photos, unless noted otherwise:
German Barcode of Life (GBOL) or Zoological Research Museum Alexander Koenig, respectively
Photos: Jonas Astrin, Detlef Karbe, Ricosz Szczygiel, Carlos Suarez, Uwe Vaartjes
Graphics: Figure Australasia: public domain Central Intelligence Agency's World Factbook · Dispersal map of the Asian bush mosquito: modified after NordNordWest & Lencer with data from KABS 2015 CC BY-SA 3.0
Videos: Rühr PT & Rulik B (2016): Micro CT Scan Trauermücke Ctenosciara, https://youtu.be/j7xd3BUEzoA [CC BY-SA 4.0]
D3512K84 (2013): Sciara militaris Heerwurm Trauermückenlarven, https://youtu.be/qmXqe91-cIE [Standard YouTube License]

Text and object selection Björn Rulik & Sabine Heine
Public relations work: Sabine Heine & Björn Rulik
3D Visualisation: Peter T. Rühr
Translation: Hendrik Herlyn

Literature: Heller K & Rulik B (2016): Ctenosciara alexanderkoenigi sp. n. (Diptera: Sciaridae), an exotic invader in Germany? – Biodiversity Data Journal 4: e6460, http://dx.doi.org/10.3897/BDJ.4.e6460

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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