Chalcosyrphus eunotus

Chalcosyrphus eunotus
Male specie of Chalcosyrphus eunotus
Conservation status
Vulnerable  (IUCN 3.1) [1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Family:	Syrphidae
Subfamily:	Eristalinae
Tribe:	Milesiini
Subtribe:	Xylotina
Genus:	Chalcosyrphus
Subgenus:	Xylotodes
Species:	C. eunotus
Binomial name
Chalcosyrphus eunotus (Loew, 1873) [2]
Synonyms
Brachypalpus eunotus Loew, 1873 [2]

Chalcosyrphus eunotus, the logjammer hoverfly, is a species of hoverfly in the family Syrphidae. This hoverfly is found in deciduous and mixed forests close to running water in Europe and Western Asia.

Taxonomy

Chalcosyrphus eunotus was first formally described as Brachypalpus eunotus in 1873 by the German entomologist Hermann Loew. ^[2] In 1978 the Finnish dipterist Heiki Hippa moved this taxon from the genus Brachypalpus to the genus Chalcosyrphus. ^[3] The genus Chalcosyrphus is classified within the subtribe Xylotina in the tribe Milesiini of the subfamily Eristalinae of the family Syrphidae. ^[4]

Distribution

Chalcosyrphus eunotus is found in Europe and Western Asia and has a scattered distribution from Great Britain through western and central Europe south to northern Spain and east to Turkey and the Caucasus. ^[1]

Habitat

Chalcosyrphus eunotus is a saproxylic species which is able to tolerate a very restricted range of ecological conditions. It is only found in areas of streams which have not been artificially altered. The larvae are found in decaying would that has fallen into the water. The adukts have been foudn along stream edges in mixed forest of oak, elm and ash, often settling on semi-submerged logs. ^[5]

Biology

Chalcosyrphus eunotus is a rather secretive species with the adults being very infrequently observed furing their April to July flight period. They are closely associated with flowing water, typically small streams or brooks. In these habitats they are typically seen resting on fallen branches, or branches that are partially submerged or on stones partially in the water or on the leaves of large leafed emergent vegetation. The males patrol the stream, settling at resting places, repeatedly stopping at them. The male pursues passing females, after seeing them from a lookout position. They copulate on the wing. The female then ovipositions on or in the cracks and crannies in the bark of small alder and birch logs which are partially shaded as well as being partially submerged, on the edge of a small stream within riverine woodland. The eggs take between 2 and 4 weeks to hatch. After they emerge the larvae go into the wood of the log, instead of staying just below the bark. Here the larvae tunnel through the wood, with two or three larvae sharing the same tunnel. ^[6]

References

1. Pennards, G.W.A.; van Eck, A.; Popov, G. & Speight, M. (2021). "Chalcosyrphus eunotus (Europe assessment)". IUCN Red List of Threatened Species . 2021: e.T149170990A149170993. doi: 10.2305/IUCN.UK.2021-2.RLTS.T149170990A149170993.en . Retrieved 27 April 2025.
2. Loew, H. (1873). Systematische Beschreibung der bekannten europäische n zweiflugeligen Insecten. Von Johann Wilhelm Meigen. Zehnter Theil oder vierter Supplementband. Beschreibung europäischer Dipteren. Dritter Band. Halle: H.W. Schmidt. pp. viii + 320.
3. Andy Jukes (2009). "Chalcosyrphus eunotus A Red Data Book hoverfly Its status, distribution, ecology and conservation A report for Staffordshire Wildlife Trust" (PDF). Staffordshire Wildlife Trust.
4. "Classification of Syrphidae". Syrphidae Community Website. Retrieved 27 April 2025.
5. Soszynska, Agnieszka; Soszynski, Boguslaw; Klasa, Anna (2009). "Distribution and ecology of the saproxylic hoverfly Chalcosyrphus eunotus (Loew, 1873) (Diptera: Syrphidae) in Poland". Fragmenta Faunistica. 52: 191–195. doi:10.3161/00159301FF2009.52.2.191.
6. M. C. D. Speight (2017). Martin C.D.Speight; Emmanuel Castella; Jean-Pierre Sarthou & Cédric Vanappelghem (eds.). "SPECIES ACCOUNTS OF EUROPEAN SYRPHIDAE, 2017" (PDF). SYRPH THE NET: THE DATABASE OF EUROPEAN SYRPHIDAE (DIPTERA) Volume 97. Retrieved 27 April 2025.