bifasciatus ♀︎

Last update: 3 July 2020
SPECIES: Symmorphus bifasciatus




Symmorphus bifasciatus ♀︎


1. Distribution
2. Behaviour
3. Prey relations
4. Parasitic relations
5. Identification


S. bifasciatus [1] is a common species that can be found throughout the Netherlands, with exception of the provinces Zeeland and Groningen where the species is rare [2,3].



The species is active from May until half September [2,3].


S. bifasciatus nests usually in hollow stemms, but may be found in walls (also of buildings) and dead wood [3]. She uses bee hotels as well and can be found in galls of the grass fly genus Lipara (CHLOROPIDAE) [3].

The female normally fills a nest cel with one prey, but sometimes two or more prey specimen are used when there is an abundance [4].

The female applies an adaptive strategy when building nests, so that the length of the cell is changed based on the diameter of the bore hole [5]. The resulting cel has effect on the sex of the wasp that develops in that longer cells will produce more and heavier females [5]. There is no effect on males [5].
Also the larger the number of cells in a nesting cavity the less females will be produced. Older females will construct less cells and provide less provisions, and from those cell less females will develop [5].


The wasp uses artificial nest help and has a preference for [5]:
– nest blocks located at 1 to 2 meters in height
– nest blocks with an orientation north or west (hypotheses), she uses nest blocks with southern or eastern orientation as well
– bore holes 3-4 mm in diameter

SectionNest block
II2, 8


Adult S. bifasciatus wasps feed with necter and/or pollen. In literature the following plant species and groups are mentioned [5]:

ApicaceaePastinaca sativa [6]

Research has shown that prey is found in different tree species and that S. bifasciatus is flexible in finding appropriate prey sources. The following trees have been identified:

Populus tremula [4]
Salix sp. [4]
Alnus incana [4]

As far as I know these trees are not in the vicinity of the garden, which may explain that I only found the species once so far.


The species is narrow oligophagous on beetlelarvae from the family of leaf beetles (CHRYSOMELIDAE) [3]. Literatuur mentions the following species that occur in the Netherlands:

CHRYSOMELINAEPlagiosterna aenea (Linaeidea aenea) [4]
Phratora laticollis [4]
Phratora vitellinae [4]
Phratora vulgatissima [4]
Plagiodera versicolora [4]


The following nest parasites on  S. bifasciates are mentioned in literature:

Chrysis ignita [3,8]
Chrysis angustula [3]
Chrysis viridula (gezien bij nesten) [3]
Chalcid wasps
Melittobia acasta [3]

The following of these parasites have been observed in the garden:

Chrysis ignita


Length males: 7 – 11 mm
Length females: 7 – 11 mm

Symmorphus bifasciatus ♀︎


Symmorphus can be recognized by the longitudinal groove on tergite 1 [7]. It also has a medial keel on tergite 1, a characteristic it shares with the genus  Ancistrocerus.


Symmorphus bifasciatus ♀︎, longitudinal groove on tergite 1
Symmorphus bifasciatus ♀︎, medial keel on tergite 1


Symmorphus bifasciatus ♀︎
Symmorphus bifasciatus ♀︎

2. Thorax with short hairs, hairs on top (mesonotum) dark, hairs sides (mesopleura) light [7]

Symmorphus bifasciatus ♀︎, thorax dorsally with dark hairs (D), sides with light hairs (L)

3. Pronotum with continuous keel from reaching the tip [7]

Symmorphus bifasciatus ♀︎, pronotum with continuous keel

4. Antennal shaft black [7]

Symmorphus bifasciatus ♀︎, antennal shaft black

7. Tergites 1, 2 and 4 with yellow band, tergite 3 sometimes with yellow spot [7]

The variant S. bifasciatus eumenoides has two yellow kidney-shaped spots on tergite 2 [3].

Symmorphus bifasciatus ♀︎, Tergietes 1, 2 and 4 with yellow band, tergite 3 sometimes with yellow spot

8. Top part mesopleuron, above transverse groove, with large and deep pits, the space between the pits is smaller than pit diameter. [7]

Symmorphus bifasciatus ♀︎, mesopleuron, above the medial groove, with large deep pits

9. Vertical part tergite 1 shorter than the horizonal part

Symmorphus bifasciatus ♀︎, Vertical part tergite 1 (red) shorter than horizontal part (green)

1. Antenna with 12 segments [3]

Symmorphus bifasciatus ♀︎, antenna with 12 antennal segments

1. Antenna with 13 segments [7]
2. Antennal segment 13 as long as wide [7]


1 Nederlands Soortenregister


3 Peeters, T.M.J., C. van Achterberg, W.R.B. Heitmans, W.F. Klein, V. Lefeber, A.J. van Loon, A.A. Mabelis, H. Nieuwen-huijsen, M. Reemer, J. de Rond, J. Smit, H.H.W. Velthuis, 2004. De wespen en mieren van Nederland (Hymenoptera: Aculeata). – Nederlandse Fauna 6. Nationaal Natuurhistorisch Museum Naturalis, Leiden, knnv Uitgeverij, Utrecht & European Invertebrate Survey – Nederland, Leiden.

4 Budrienė, Anna. (2003). Prey of Symmorphus Wasps (Hymenoptera: Eumeninae) in Lithuania. Acta Zoologica Lituanica. 13. 306-310. 10.1080/13921657.2003.10512686.

5 BUDRIENE, Anna. Reproductive ecology and behaviour of predatory wasps (Hymenoptera: Eumeninae). Doctor al thesis. Vilnius, 2004.

6 AMOLIN, A. V.; OGOL, I. N. Ïèùåâûå ñâÿçè ñêëàä÷àòîêðûëûõ îñ (Hymenoptera: Vespidae) ñ öâåòêîâûìè ðàñòåíèÿìè (Magnoliophyta) â Äîíáàññå Trophic relations of wasps (Hymenoptera: Vespidae) with flowering plants (Magnoliophyta) in Donbass.

7 SCHMID-EGGER, C. H. Bestimmungsschlüssel für die deutschen Arten der solitären Faltenwespen (Hymenoptera: Eumeninae). Deutscher Jugendbund für Naturbeobachtung, 1994, 54: 90.

8 PEREIRA‐PEIXOTO, MARIA HELENA, et al. Diversity and specificity of host‐natural enemy interactions in an urban‐rural interface. Ecological Entomology, 2016, 41.3: 241-252.

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