CONTENTS

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

1. DISTRIBUTION

Symmorphus bifasciatus ^{[Soortenregister]} is a common species that can be found throughout the Netherlands, with exception of the provinces Zeeland and Groningen where the species is rare ^{[Waarneming.nl],[Peeters et al. 2004]}.

2. BEHAVIOUR

2.1. ACTIVITY

The species is active from May until half September ^{[Waarneming.nl],[Peeters et al. 2004]}.

2.2. DEVELOPMENT

Symmorphus bifasciatus nests usually in hollow stemms, but may be found in walls (also of buildings) and dead wood ^{[Peeters et al. 2004]}. She uses bee hotels as well and can be found in galls of the grass fly genus Lipara (CHLOROPIDAE) ^{[Peeters et al. 2004]}.

The female normally fills a nest cel with one prey, but sometimes two or more prey specimen are used when there is an abundance ^{[Budriene 2003]}.

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 ^{[Budriene 2004]}. The resulting cel has effect on the sex of the wasp that develops in that longer cells will produce more and heavier females ^{[Budriene 2004]}. There is no effect on males ^{[Budriene 2004]}.
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 ^{[Budriene 2004]}.

BEE HOTEL

The wasp uses artificial nest help and has a preference for ^{[Budriene 2004],[Woydak 2006]}:
– 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 ^{[Veenendaal 2013]}

3. PLANT RELATIONS

3.1. FOOD PLANTS

Adult S. bifasciatus wasps feed with nectar. In literature the following plant species and groups are mentioned ^{[Budriene 2004]}:

Apicaceae (Umbellifers)

– Foenicum vulgare (Fennel) [own observation] – Pastinaca sativa (Parsnip) [Amolin & Ogol 2019]

3.2. PREY PLANTS

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:

– Alnus incana (Alder) [Budriene 2003]

– Populus tremula (Poplar) [Budriene 2003]

– Salix sp. (Willow) [Budriene 2003],[Wood & Coulson 2016]

4. PREY RELATIONS

The species is narrow oligophagous on beetlelarvae from the family of leaf beetles (CHRYSOMELIDAE) ^{[Peeters et al. 2004]}.
The following species and groups occurring in the Netherlands ^{[Soortenregister]} are mentioned in literature:

CHRYSOMELIDAE (Leaf beetles)

Phratora (preference [Budriene 2003]) – Phratora laticollis [Budriene 2003] – Phratora vitellinae [Budriene 2003] – Phratora vulgatissima [Budriene 2003],[Wood & Goulson 2016] Phyllodecta – Phyllodecta vulgatissima [Woydak 2006] Plagiodera – Plagiodera versicolora [Budriene 2003] Plagiosterna – Plagiosterna aenea [Budriene 2003 (as Linaeidea aenea)]

Preyspecies outside the Netherlands:

–

–

5. PARASITIC RELATIONS

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

CHALCIDOIDAE (Chalcid wasps)	Melittobia – Melittobia acasta [Peeters et al. 2004]
CHRYSIDIDAE (Cuckoo wasps)	Chrysis – Chrysis angustula [Paern et al. 2015],[Veenendaal 2013],[Woydak 2006 (als Chrysis brevidens)],[Peeters et al. 2004] – Chrysis ignita [Pereira‐Peixoto et al. 2016],[Woydak 2006],[Peeters et al. 2004] – Chrysis fulgida [Paern et al. 2015] – Chrysis viridula (seen at nests) [Peeters et al. 2004]
ICHNEUMONIDAE (Ichneumon wasps)	Hoplocryptus – Hoplocryptus confector [Paern et al. 2015],[Schwarz 2007],[Woydak 2006 (also as H. dubius)]

Parasitic species outside the Netherlands:

–

–

6. IDENTIFICATION

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

Genus

The genus Symmorphus can be identified using the following characters:

1. Abdomen: a longitudinal groove on tergum 1 ^{[Schmid-Egger 2004]}.

2. Abdomen: a medial keel on tergum 1, a characteristic it shares with the genus  Ancistrocerus ^{[Schmid-Egger 2004]}.

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1. Thorax: with short hairs, hairs on top (mesonotum) dark, hairs sides (mesopleuron) light ^{[Schmid-Egger 2004]}

2. Pronotum: with continuous keel from reaching the tip ^{[Schmid-Egger 2004]}

3. Antenna: shaft black ^{[Schmid-Egger 2004]}

4. Terga: 1, 2 and 4 with yellow band, tergum 3 sometimes with yellow spot ^{[Schmid-Egger 2004]}

The variant S. bifasciatus eumenoides has two yellow kidney-shaped spots on tergum 2 ^{[Peeters et al. 2004]}. See also here.

5. Mesopleuron: top part above transverse groove, with large and deep pits, the space between the pits is smaller than pit diameter. ^{[Schmid-Egger 2004]}

6. Tergum 1: vertical part shorter than the horizonal part

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1. Antenna: with 12 segments ^{[Peeters et al. 2004]}

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1. Antenna: with 13 segments ^{[Schmid-Egger 2004]}
2. Antenna: segment 13 as long as wide ^{[Schmid-Egger 2004]}

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Literature

^{Amolin & Ogol 2019} Amolin, A. V., & Ogol, I. N., 2019. Trophic relations of wasps (Hymenoptera: Vespidae) with flowering plants (Magnoliophyta) in Donbass. Euroasian Èntomol. J, 18, 365-376.

^{Budriene 2003} Budrienė, A., 2003. Prey of Symmorphus Wasps (Hymenoptera: Eumeninae) in Lithuania. Acta Zoologica Lituanica. 13. 306-310. 10.1080/13921657.2003.10512686.

^{Budriene 2004} Budriene, A., 2004. Reproductive ecology and behaviour of predatory wasps (Hymenoptera: Eumeninae). Doctor al thesis. Vilnius.

^{Paern et al. 2015} Paern, M., Soon, V., Vallisoo, T., Hovi, K., & Luig, J., 2015. Host specificity of the tribe Chrysidini (Hymenoptera: Chrysididae) in Estonia ascertained with trap-nesting. European Journal of Entomology, 112(1), 91-99.

^{Peeters et al. 2004} 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.

^{Pereira‐Peixoto et al. 2016} Pereira‐Peixoto, M. H., Pufal, G., Staab, M., Feitosa Martins, C. E. L. S. O., & Klein, A. M., 2016. Diversity and specificity of host‐natural enemy interactions in an urban‐rural interface. Ecological Entomology, 41(3), 241-252.

^{Schmid-Egger 2004} Schmid-Egger, C., 2004. Bestimmungsschlüssel für die deutschen Arten der solitären Faltenwespen (Hymenoptera: Eumeninae). S. 54-102. ohne Gesamttitel]. Hamburg: Deutscher Jugendbund für Naturbeobachtung (DJN).

^{Schwarz 2007} Schwarz, M., 2007. Revision der westpaläarktischen Arten der Gattung Hoplocryptus Thomson (Hymenoptera, Ichneumonidae). na.

^{Soortenregister} Nederlands Soortenregister

^{Veenendaal 2013} Veenendaal R., 2013. Aantekeningen bij de biologie van Chrysis angustula (Hymenoptera: Chrysididae). HymenoVaria, 6(1), 18–20.

^{Waarneming.nl} Waarneming.nl

^{Wood & Goulson 2016} Wood, T., & Goulson, D., 2016. Aculeate bee and wasp survey report 2015/16 for the Knepp Wildland Project.

^{Woydak 2006} Woydak H., 2006: Hymenoptera Aculeata Westfalica Die Faltenwespen von Nordrhein-Westfalen (Hymenoptera, Vespoidea; Vespidae und Eumenidae) (Soziale Papier- und Lehmwespen) – Abhandlungen aus dem Westfälischen Provinzial-Museum für Naturkunde – 68_1: 3 - 133.

Citation

Krischan, O.R., 2025. Symmorphus bifasciatus. Kerfdier, www.kerfdier.nl. Accessed on 19 March 2025.