Researchers from Goethe University Frankfurt and the Senckenberg Biodiversity and Climate Research Center have modeled the spatial distributional patterns of black flies in Hesse, North Rhine-Westphalia, Rhineland-Palatinate and Saxony for the first time.
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In the study, published in Science of the Total Environment, the research team shows that black flies in Germany can be categorized into three groups with different distribution patterns and ecological requirements.
The researchers point out that medically-relevant species in particular could become more prevalent as a result of ongoing climate and land-use change.
Only 6 milimeters in length, black flies (Simuliidae) may look harmless like house flies, but their bites can be very unpleasant. Similar to mosquitoes, the females of these insects that are able to fly need a blood meal to produce eggs. Known as "pool feeders" they use their sharp 'teeth' to scratch the skin of the host and then ingest the resulting drop of blood.
"The anticoagulant and anesthetic substances introduced into the wound by mosquitoes can trigger serious allergic reactions or lead to secondary bacterial infections," states Prof. Dr. Sven Klimpel from the Senckenberg Biodiversity and Climate Research Center, Goethe University Frankfurt, the LOEWE Center for Translational Biodiversity Genomics (TBG), and the Fraunhofer IME Giessen.
Black flies can be found on all continents except Antarctica. Over 2,000 black flies species are known worldwide; in Germany, there are 57 of them.
According to Sarah Cunze, from the Goethe University Frankfurt and the first author of the study, almost all black fly species (98%) require a blood meal before laying their eggs.
These results are based on a valid data set comprising 1,526 records of black fly larvae in the four federal states of Hesse, North Rhine-Westphalia, Rhineland-Palatinate and Saxony and provide valuable insights of the distributional patters of these species.
In their study, the researchers deduce different trends in population development for the three groups under the ongoing climate and land use change: While the montane group is considered to be at risk due to increasing temperatures and growing chemical pollution of water bodies, the other species are characterized by a broad niche or higher tolerance to anthropogenic changes.
Consequently, the black fly species of veterinary and human medical relevance, which predominantly belong to the third group, could be promoted by the ongoing anthropogenic change and be subject to positive population trends. ■
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