Isotomus speciosus (Schneider, 1787)
ssp. speciosus (Schneider, 1787)
[= Callidium semipunctatum Fabricius, 1798]
[= Clytus Stierlinii Tournier, 1872]

Subfamilia: CERAMBYCINAE  /  Tribus: CLYTINI
Isotomus speciosus
Isotomus speciosus speciosus[Photo © Daniel Rydzi]

Isotomus speciosus, a very nice and broadly distributed taxon (Europe, Caucasus, Transcaucasia), has been described from Vienna environs (Austria) as Callidium speciosum by David Hinrich Schneider in 1787 [❖]. However, in Central Europe I. speciosus is becoming rare due to the destruction of its natural habitats. It develops in the dead, dry wood of deciduous trees (Carpinus, Quercus, Castanea, Fagus, Ulmus, Acer). In our climate it prefers hornbeam (Carpinus betulus). I. speciosus attacks wood with a diameter of 3 to 35 cm, completely debarked, even with the bark or its remains. The larvae develop first in the surface layer and then enter very deep into the heartwood. Females often lay their eggs in the same material for many years, so that the wood is then completely consumed, similarly to Hylotrupes bajulus (on coniferous wood). Multiannual development, at least two years (the duration of development is affected by the moisture content of the wood). Adults, active from June to August, can be found on the wood in daytime but also during night. [✧].

Body length:10 - 22 mm
Life cycle:at least 2 years
Adults in:June - August
Host plant:polyphagous in deciduous trees
Distribution:Albania, Austria, Bosnia and Herzegovina, Bulgaria, Crete, Croatia, Czechia, France, Germany, Greece, Hungary, Italy, Latvia, Moldova, Montenegro, North Macedonia, Poland, Romania, Russia, Serbia, Slovakia, Slovenia, Ukraine, Armenia, Azerbaijan, Iran, Turkey

The depicted beetles were reared from larvae found in dead hornbeam (Carpinus betulus) in Kančí obora (Břeclav environs, South Moravia, Czechia) in June 2017.

Collected by Daniel Rydzi

Schneider D.H.:
Einige Berichtigungen und Ergänzungen der aus Schäffers Icones Insectorum Ratisbonensium in Fabricii Species Insectorum angeführten Allegaten verglichen mit Harrers Beschreibung der von Schäffer abgebildeten Insecten.
Neues Magazin für die Liebhaber der Entomologie 3 (2): 97–140, 1787. [download pdf icon]

Sláma M.E.F.:
Tesaříkovití – Cerambycidae České republiky a Slovenské republiky / Cerambycidae of the Czech Republic and Slovak Republic.
Milan Sláma private printing, Krhanice, 383pp [pages 174-175], 1998 [ISBN: 80-238-2627-1]. [download pdf icon]

Isotomus speciosus
Isotomus speciosus speciosus[Photo © Daniel Rydzi]
Isotomus speciosus
Isotomus speciosus
Isotomus speciosus
Isotomus speciosus speciosus[Photo © Daniel Rydzi]
Isotomus speciosus
Isotomus speciosus
Isotomus speciosus speciosus ♂+♀ [Photo © Daniel Rydzi]

SubfamiliaCerambycinae Latreille, 1802
TribusClytini Mulsant, 1839
GenusIsotomus Mulsant, 1863
SpeciesIsotomus speciosus (Schneider, 1787)
SubspeciesIsotomus speciosus speciosus (Schneider, 1787)