On 2 August 2018, a new species was added to the list odonate species found in Estonia. A specimen of the new species, the Willow Emerald Damselfly (Chalcolestes viridis – Vander Linden, 1825) was caught by Mati Martin, chief specialist for systematic zoology of the UT Natural History Museum, in the vicinity of Karula (south-east Estonia) on the bank of a water body dammed up by beavers.
This is the first time that the species is found in Estonia. Previously, willow emerald damselflies have been found in North Latvia. ‘We have been looking for this odonate for several years already and so far this has been in vain,’ said Mati Martin, the entomologist who caught the damselfly. ‘In Latvia, specimens have been caught in various locations and its spread to the north was only a matter of time -- although, a part in that spread happening was certainly played by the uncommonly warm summer that we had in Estonia this year’, the entomologist remarked, confirming the arrival in Estonia of the damselfly species belonging to the family of spreadwinged damselflies (Lestidae).
The willow emerald damselfly has a peculiar way of laying its eggs which sets it apart from other damselfly species. Where other damselflies lay their eggs in water, in the tissue of water plants or in damp mosses, the female of the willow emerald damselfly leaves its eggs in the willow branches overhanging a water body. The larvae that hatch from the eggs will thus fall directly into water. Since this leaves a mark on the branches, the presence of the species can be ascertained on the basis of the damage to willow branches.
’Whether the arrival in Estonia of a species that is relatively widespread in South Europe is related to climate change or due to other reasons is hard to say. Sometimes it happens that south of here – in our immediate vicinity, in Latvia and Lithuania – a species that used to be rare becomes common and eventually makes its way north to us. I hope the willow emerald damselfly will find a home here like a number of other species that have recently reached us,’ Martin added.
The last species added to the list of Estonian fauna, the southern emerald damselfly (Lestes barbarus – Fabricius, 1798) was caught last autumn in Kabli (south-west of Estonia), but has not been found yet this year. Together with the willow emerald damselfly, there are now 61 species of odonates in Estonia.
For additional information and photos, kindly refer to the Novaator website of the Estonian Public Broadcasting Corporation.
Chief Specialist for Systematic Zoology
UT Natural History Museum