DNA based methods for Diptera taxonomy and ecology
DNA based methods for Diptera taxonomy
The development of DNA based methods has offered completely new potential to study the taxonomy and evolutional history of insects in general. In this project we use DNA sequences for species identification of the species of the target dipteran groups. Insect species that are morphologically difficult to recognize can be identified at any stage using particular DNA sequences (DNA barcodes) as identifiers. This requires the use of a DNA sequence reference database that is generated based on the knowledge of the adult insects, and updated with all new information. We use both mitochondrial COI and nuclear ITS2 gene regions in our studies.
It has proven informative to use two unlinked genetic regions as they evolve with varying speed during evolution. By using the nuclear ITS2 region we can detect speciation that has occurred quite recently.
The application of DNA sequences will increase our knowledge of the biology of these fly groups by discovering cryptic species, by associating different life stages (male vs female, larvae vs adults), and thus facilitates an easy system for the identification of any life stage of any species also by non-specialists. DNA-based methods firmly anchored within a taxonomic framework have the potential to provide both a reliable, accurate identification of the species as well as taxonomy of target organisms. It is particularly important to generate DNA sequences of two independent markers.
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Trametes pubescens is the host fungus of Polyporivora boletina– flat-footed fly species. Photo: Gunilla Ståhls-Mäkelä
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The larva of a flat-footed fly (Polyporivora boletina) feeds on a polypore. Feeding marks are visible underneath the polypore. Photo: Gunilla Ståhls-Mäkelä
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Objectives
In this project we study the species of the genera Agathomyia (Platypezidae), their distribution and aiming at resolving the poorly known biology of their larval stages. Some of the known Agathomyia-species larval stages live solely in certain polypore fungi, and rearings of larvae will find out if other species also are specialised on particular polypores. Of the hoverflies we focus on the morphologically notoriously difficult Pipizini-group and study the species delineation, association of males and females and relationships of all Nordic species in this group. Of the big-headed flies (Pipunculidae) we aim to find out which of the species of the forest-dwelling Eurodylas elphas –group occur in Finland, and to associate female and male individuals of this group of big-headed flies. Combining a strong taxonomic expertise on these particular groups using traditional morphological methods, in congruence with the use of modern molecular methods will ensure the best possible results. Research group
Gunilla Ståhls-Mäkelä is the leader of the project from the Finnish Museum of Natural History and she is an expert on dipteran molecular taxonomy and evolutionary history. Research is carried out in close international cooperation with Ante Vujić (University of Novi Sad, Serbia), Christian Kehlmaier (Dresden Museum of Zoology, Germany), Hans Bartsch (Järfälla, Sweden) and Rune Bygebjerg (Zoologisk Museum, Lund, Sweden). The Finnish Expert group on Diptera participates in material for this project.
Further information
Gunilla Ståhls-Mäkelä, The Finnish Museum of Natural History, gunilla.stahls(at)helsinki.fi
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