Taxonomy
Microdon analis
Distribution
Species Biology
Preferred environment
Forest; overmature deciduous and coniferous forest with fallen timber left in situ, from upper altitudinal limit of Fagus, in Fagus/Picea forest and humid P. sylvestris forest, to acidophilous Quercus and Betula/Pinus forest. So far, this species has been found in Ireland only in association with inhabited nests of a black Lasius species, probably L. platythorax (only recently separated from L. niger) in open areas of low altitude Molinia heath, within or edging deciduous woodland. The ant nests concerned were in fallen, rotting trunks of Betula and Pinus, with the bark still more or less intact; in rotting fence posts of Pinus and Quercus, from which the bark had not been removed and, on one occasion, in a large moss hummock. The distribution of Lasius platythorax in Ireland is currently unknown, so it is not possible to gauge whether availability of appropriate ant hosts per se is limiting the range of M. analis here. It is more likely that absence of fallen, rotting timber in otherwise appropriate localities is preventing colonisation.
Adult habitat & habits
Flight period
Beginning May/beginning July. Larva: the larval hosts of this species have until recently been given as ants of the genera Formica and Lasius. However, Schmid (2004a) points out that two cryptic Microdon species have been confused under the name M. analis, one (M. major) apparently associated with ants of the genus Formica, the other (M. analis) with Lasius species. In the detailed description of the larva and puparium of "M. eggeri" provided by Hartley (1961) there is no reference to the ants with which the described Microdon developmental stages occurred. However, from the information supplied by Schmid (2004a) it can be concluded that Hartley's (1961) description is not based on M. major. Barr (1995) explicitly states that his observations of "M. eggeri" larvae were based on nests of Formica lemani. But re-examination of Barr's Microdon material shows that, whatever it is, it is not M. major. Available information suggests that when M.analis occurs in nests of ants of the genus Lasius, it may only occur with L. platythorax, a recently-recognised segregate of L. niger, an ant that normally nests in rotten wood (and hence occurs in forested locations). The mature larva, which occurs superficially in ants' nests just prior to pupariation in April, is more easily found than the adult insect. Similarly, the presence of this species can be detected by locating empty puparia in ants' nests. These empty puparia can persist for some months, at least. Larvae of M. analis can be distinguished from larvae of the other known European species except M. major by the keys in Doczkal & Schmid (1999). Developmental stages of M. analis and M. major can be distinguished using the features detailed by Schmid (2004a) and the key presented in the StN Keys volume may be used to separate the puparia of these two species.
Flowers visited
Adults are not known to visit flowers for feeding purposes.
Irish reference specimens
In the collections of NMI
Determination
See keys provided in the StN Keys volume. Doczkal & Schmid (1999), who figure the male terminalia, can be used to separate adults of this species from known European Microdon species other than M. major. At present, the adults of M. analis and M. major cannot reliably be distinguished, though Schmid points out that M. major is typically larger (body length 10-13mm) than M. analis (body length < 10mm). The adult of M. analis/M. major is illustrated in colour by Bartsch et al (2009b), Stubbs and Falk (1983) and Torp (1994). The concept of M. analis employed here is that of Schmid (2004a), who essentially confines use of the name analis to a taxon whose larvae are associated with ants of the genus Lasius. Since the Macquart type of analis is an adult, with no associated information on the ant species with which it developed, whether this application of the name analis is correct may be impossible to establish. There are also various synonyms of M. analis that possibly require re-investigation (see Doczkal and Schmid, 1999). All together, it would seem that the taxonomic status of M. analis is far from certain.
Distribution
World distribution(GBIF)
Requires confirmation,due to confusion with M. major, but probably from Scandinavia south to the Mediterranean and northern Africa; from Ireland eastwards through most of Europe into Russia and on to the Pacific coast; Mongolia. Based on larval host information the presence of M. analis can be confirmed from Ireland, Great Britain, France, Germany, Austria and Spain. Distribution of this species elsewhere (it is known, for instance from the Scottish highlands to the south coast of England, in Britain) suggests no good reason other than habitat loss for its present restricted range in Ireland. Taken in context with the rest of the Irish hoverfly fauna of deciduous forest, M. analis should be regarded as a relict forest insect, which was almost certainly widely distributed in Ireland (including in areas of pine forest) until forest clearance caused its disappearance from most of the island. Now it has to be regarded as threatened and would be a candidate for inclusion in any list of invertebrates requiring protection throughout the island.
Irish distribution
Added to Irish list under the name M. eggeri (Mik), by Breen (1977), on the basis of puparia from nests of "Lasius niger". Until publication of the key by Doczkal & Schmid (1999), there has been potential for confusion between M. analis and M. miki. Subsequent re-examination of all available Irish material has confirmed the presence in Ireland of M.analis, but M. miki has not been found here so far. More recently (Schmid, 2004) has shown that two cryptic species have been confused under the name M. analis. One of these, M. major (Andries), is associated with Formica species, the other (M. analis) with Lasius. There is at present no reason to suppose M. major occurs in Ireland since all bred material of Irish "M. analis" is derived from nests of Lasius. Today this species occupies a very restricted range in SW Ireland and is known from few records (see distribution map).
Temporal change
Records submitted to Data Centre in 2024
The following map is interactive. If you would prefer to view it full screen then click here.
References
Publications
Speight, M. C. D. (2008) Database of Irish Syrphidae
(Diptera). Irish Wildlife Manuals, No. 36. National Parks and Wildlife Service.
Department of Environment, Heritage and Local Government, Dublin, Ireland.
Speight, M.C.D. (2014) Species accounts of European
Syrphidae (Diptera), 2014. Syrph the Net, the database of European Syrphidae,
vol. 78, 321 pp., Syrph the Net publications, Dublin.