

1. DISTRIBUTION
Trichrysis cyanea [Soortenregister] is a common wasp in the whole of the Netherlands [Waarneming.nl].
2. BEHAVIOUR
2.1. ACTIVITY
The species is active between April and October [Waarneming.nl].
2.2. DEVELOPMENT
Like all cuckoo wasps this species is a parasite. In the garden it’s host is at least Trypoxylon digger wasps that nest in the bee hotel and there they can be found most often.
The larvae are parasitoids on the host larvae meaning they eat them.
3. IDENTIFICATION
It is a small wasp measuring 4 – 8 mm [Paukkunen et al. 2015].

The primary characteristics of the species are [Paukkunen et al. 2015]:
1. Antenna scapus lies deep in the frons
2. Keel (carina) on frons
3. Tergum III rear edge pointed like a trident, teeth can be small
4. Small black spots on sternum II
5. Vein of marginal cel is straight and continues up to the wing edge
6. Body metallic blue-green
7. Male sometimes have a black back or are seldom almost completely black (not shown in photo)
4. PARASITIC RELATIONS
T. cyanea is a parasitoid parasite on the following species in the Netherlands [Soortenregister]:
- Trypoxylon figulus [Paukkunen et al. 2015],[Tormos et al. 1996],[Paern et al. 2015],[Peeters et al. 2004]
- Trypoxylon attenuatum [Peeters et al. 2004],[Blösch 2000],[Asís et al. 1994],[Woydak 1996],[Lomholdt 1984],[Danks 1974],[Tormos et al. 2005]
Trichrysis cyanea is parasitised by the following species in the Netherlands [Soortenregister]:
- Hoplocryptus confector [Schwarz 2007]
Literature
Asís et al. 1994 Asís, J. D., Tormos, J., & Gayubo, S. F., 1994. Biological observations on Trypoxylon attenuatum and description of its mature larva and its natural enemy Trichrysis cyanea (Hymenoptera: Sphecidae, Chrysididae). Journal of the Kansas Entomological Society, 199-207.Blösch 2000 Blösch, M. (2000). Die Grabwespen Deutschlands – Lebens‐weise, Verhalten, Verbreitung. 71. Teil. In Dahl, F.: Die Tierwelt Deutschlands. Begr.: 1925. – Keltern (Goecke & Evers). – 480 S. 341 Farbfotos. ISBN 3‐931374‐26‐2 (hardcover). DM 98,–. Zool. Reihe, 78: 353-353. https://doi.org/10.1002/mmnz.20020780208
Danks 1971 Danks, H.V., 1971. Biology of some stem‐nesting aculeate Hymenoptera. Transactions of the Royal Entomological Society of London, 122.11: 323-395.
Lomholdt 1984 Lomholdt, O., 1984. The Sphecidae (Hymenoptera) of Fennoscandia and Denmark. Fauna Entomologica Scandinavica, 4.1: 2.
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.
Paukkunen et al. 2015 Paukkunen, J., Berg, A., Soon, V., Ødegaard, F., & Rosa, P., 2015. An illustrated key to the cuckoo wasps (Hymenoptera, Chrysididae) of the Nordic and Baltic countries, with description of a new species. ZooKeys, (548), 1.
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.
Schwarz 2007 Schwarz, M., 2007. Revision der westpaläarktischen Arten der Gattung Hoplocryptus Thomson (Hymenoptera, Ichneumonidae). na.
Soortenregister Nederlands Soortenregister
Tormos et al. 1996 Tormos, J., Asis, J. D., Gayubo, S. F., & Mingo, E., 1996. Description of the mature larvae of Chrysis gracillima and Omalus biaccinctus and new data on the biology of Trichrysis cyanea (Hymenoptera: Chrysididae). Florida Entomologist, 56-56.
Tormos et al. 2005 Tormos, J., Asís, J. D., Gayubo, S. F., Calvo, J., & Martín, M. A., 2005. Ecology of crabronid wasps found in trap nests from Spain (Hymenoptera: Spheciformes). Florida Entomologist, 88(3), 278-284.
Waarneming.nl Waarneming.nl
Woydak 1996 Woydak, H., 1996. Hymenoptera Aculeata Westfalica Familia: Sphecidae (Grabwespen), 3-135.
Citation
Krischan, O.R., 2025. Trichrysis cyanea. Kerfdier, www.kerfdier.nl. Accessed on [date month year].