1. DISTRIBUTION
Ephialtes manifestator [Soortenregister] is a less common wasp that can be found throughout the Netherlands [Waarneming.nl]. In the garden the species is a permanent resident that is present on the bee hotels every year.
2. BEHAVIOUR
2.1. ACTIVITY
The species is active from April until November [Waarneming.nl].
2.2. DEVELOPMENT
The wasp is a parasite on wasps, bees [Fitton et al. 1988],[Matsumoto 2005],[MacIvor 2019],[Peeters et al. 2004] and beetles [Baumann 1927].
The female deposits her eggs in the nests of her host using her long ovipositor. Using the ovipositor she penetrates the nestplug that the host used to close the nest entrance, or she uses cracks in the substrate that contains the host nest, see here.
The larvae of PIMPLINAE sub-family, and so E. manifestator as well, are ectoparasites [Gauld et al. 2002].
The larvae develop from late summer to spring and pupate in April, or earliest March [Baumann 1927]. After the pupa has shed it’s larval skin the ovipositor start to extend during a period of ±1 – 1,5 hours [Baumann 1927]. The boundaries of the cell are responsible for bending the ovipositor into its definitive shape bended parallel to the back and over the pupa head [Baumann 1927].
When the adult emerges from the pupa the ovipositor is pulled out of it by pulling and pushing the shafts of the ovipositor. The forward pointing hairs on the shafts play an important in pushing on the puppa skin [Baumann 1927].
The shafts consist of two halves that are folded over the ovipositor and hooked together.

3. HOST RELATIONS
The following species and groups occurring in the Netherlands [Soortenregister] are mentioned in literature:
Bees (APOIDAE) | –Red mason bee (Osmia bicornis) [Peeters et al. 2004] –European orchard bee (Osmi cornuta) [Peeters et al. 2004] –Ridge-saddled carpenter bee (Heriades truncorum) [Peeters et al. 2004] |
Wasps (HYMENOPTERA) | –Passaloecus gracilis [MacIvor 2019] –Trypoxylon figulus [Fitton et al. 1988],[Matsumoto 2005],[MacIvor 2019] |
4. IDENTIFICATION
There are a number of PIMPLINAE wasps that look very similar to this species and which are difficult to distinguish, especially:
- DOLICHOMITUS (does not fly on bee hotels [Breugel 2014] )
- SCAMBUS
- TOWNESIA
- PARAPERITHOUS (Tergite 2 with strongly indented corners [Fitton et al. 1988])
- LIOTRYPHON
Principle characteristic is the width of the face, that of E. manifestator is the widest.
It is a middle-large to large wasp [Fitton et al. 1988].
The characteristics of the species are [Fitton et al. 1988]:
1. Ovipositor: length > 3,6x length hind tibia
2. Clypeus: wide, wider than 1,7x height from antenna base to lower edge clypeus
3. Eye: inner line impression start well below antenna base
4. Mandibles: long, with two teeth. Lower tooth 2x longer than upper
Literature
Baumann 1927 Baumann, C., 1927. Beobachtungen über die Metamorphose der Schlupfwespen Coleocentrus exciitator Poda un Ephialtes manifestator L. Zeitschrift für Morphologie und Ökologie der Tiere, 9(1/2), 313-332.Breugel 2014 Breugel, P. van., 2014. Gasten van bijenhotels. – EIS Kenniscentrum Insecten en andere ongewervelden & Naturalis Biodiversity Center, Leiden.
Fitton et al. 1988 Fitton, M. G., Shaw, M. R., & Gauld, I. D., 1988. Pimpline ichneumon-flies. Hymenoptera, Ichneumonidae (Pimplinae).
Gauld et al. 2002 Gauld, I. D., Wahl, D. B., & Broad, G. R., 2002. The suprageneric groups of the Pimplinae (Hymenoptera: Ichneumonidae): a cladistic re-evaluation and evolutionary biological study. Zoological Journal of the Linnean Society, 136(3), 421-485.
MacIvor 2019 MacIvor, J. S., 2019. Adult emergence order in a community of cavity-nesting bees and wasps, and their parasites. bioRxiv, 556456.
Matsumoto 2005 Matsumoto, R., 2005. A new host record of Ephialtes hokkaidonis Uchida (Hymenoptera: Ichneumonidae: Pimplinae) with a description of oviposition behavior. BULLETIN-OSAKA MUSEUM OF NATURAL HISTORY, 59, 41.
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.
Soortenregister Nederlands Soortenregister
Waarneming.nl Waarneming.nl
Citation
Krischan, O.R., 2025. Ephialtes manifestator. Kerfdier, www.kerfdier.nl. Accessed on [date month year].