Pseudomalus violaceus (Scopoli, 1763)

Paukkunen, Juho, Berg, Alexander, Soon, Villu, Odegaard, Frode & Rosa, Paolo, 2015, An illustrated key to the cuckoo wasps (Hymenoptera, Chrysididae) of the Nordic and Baltic countries, with description of a new species, ZooKeys 548, pp. 1-116 : 17-18

Taxon classification Animalia Hymenoptera Chrysididae

Pseudomalus violaceus (Scopoli, 1763) Fig. 30

Sphex violacea Scopoli, 1763: 298.

Chrysis micans Olivier, 1791: 677.

Chrysis fuscipennis Dahlbom, 1829: 15.

Chrysis coerulea Dahlbom, 1831: 33.

Pseudomalus violaceus : Kimsey and Bohart 1991: 270.

Diagnosis.

Length 5-8 mm. The species differs from other species of the genus by its completely violet-blue (female) or black-green to black-blue (male) body, and a wide and shallow apical notch on T3. The scapal basin is also higher and dorsally deeply angled. Exceptionally small and worn specimens can be confused with Omalus puncticollis (or Omalus aeneus ), but the mesopleuron of Pseudomalus violaceus always strongly projects ventrally (as in Fig. 28) and the mesoscutum has large punctures, which are clumped postero-medially (as in Fig. 27).

Distribution.

Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden. Relatively rare. - Trans-Palearctic (?). Europe, Middle East, Siberia, Manchuria ( Linsenmaier 1997). Eastern records could be related to Pseudomalus bergi Semenov, 1932 ( Rosa et al. 2014) or other similar central Asiatic species, e.g. Pseudomalus bogojavlenskii Semenov, 1932 or Pseudomalus saturatus Semenov, 1932.

Biology.

Habitat: forest margins and clearings. Often found on leaves of sun-exposed deciduous trees and bushes. Flight period: June to August. Adults are attracted to honeydew of aphids ( Gauss 1987). Host: Pemphredon lugubris (Fabricius), more rarely also Passaloecus corniger Shuckard and Passaloecus eremita Kohl ( Crabronidae ) ( Nielsen 1900, Morgan 1984, Gathmann and Tscharntke 1999, our own obs.). Host records of other species (e.g. Trypoxylon Latreille) are doubtful, because of their deviant biology compared to other hosts. In Finland, the species has been reared from an old gall of Saperda populnea (Linnaeus) ( Cerambycidae ) on a Populus branch (M. Pentinsaari pers. obs.) and a rotten Alnus stump containing host nests.