Official name:
Synonyms:
Trypoxylon attenuatum [Soortenregister]
see more on: www.gbif.org


CONTENTS
1. Distribution
2. Behaviour
3. Plant relations
4. Prey relations
5. Parasitic relations
6. Identification
1. DISTRIBUTION
Trypoxylon attenuatum is an uncommon wasp [Waarneming.nl] that occurs throughout the Netherlands with a peak in the southern province Zuid-Limburg [Peeters et al. 2004].
2. BEHAVIOUR
2.1. ACTIVITY
The species is active from beginning of April until half October [Peeters et al. 2004].
Two generations per year are possible [Blösch 2000],[Abraham 1982],[Danks 1971].
The daily activities start at 9 in the morning [Abraham 1982] with an activity peak in the afternoon [Abraham 1982]. The species is active in temperature of +20° or higher [Abraham 1982].
2.2. DEVELOPMENT
Nest
The females of this hypergeic species gnaw their nests in the pith of natural tube-like structures like plant stems and reed roofs, and Lipara (DIPTERA) galls in reed [Blösch 2000].
The nests consist of corridors with a length of 6 to 12 cm [Peeters et al. 2004] in which a sequential row of three [Woydak 1996] to seven brood cells [Peeters et al. 2004],[Blösch 2000] are constructed. The brood cells for males measure ±7,2mm in length. Their length and diameter are smaller than those for females which measure 8,5mm [Blösch 2000],[Danks 1971] in length. The nest tunnel diameter varies between 2-5 mm [6,[Tormos et al. 2005].
Cells are provisioned with 6-31 prey specimen [Peeters et al. 2004],[Asís et al. 1994],[Woydak 1996] with a maximum arond 30 [Peeters et al. 2004],[Asís et al. 1994].
Brood cells are separated with a 0,2mm thin wall of mud [Danks 1971]. The walls become thicker towards the nest entrance [Danks 1971].
The nest often includes a vestibular cel [Breugel 2014],[Abraham 1982],[Danks 1971],[Asís et al. 2007], with or without some prey specimen [Danks 1971], which can be short [Breugel 2014],[Asís et al. 2007] long [Asís et al. 2007] or missing altogether [Breugel 2014],[Danks 1971],[Asís et al. 2007]. Intercalary cells and double nest plugs are rarely present [Asís et al. 1994].
Egg
Trypoxylon eggs are saussage shaped [Danks 1971]. The egg is positioned on one of the last provisioned spiders before closing the cells [Danks 1971].
Larva
The yellowish larva spins a light brown cocoon that is suspended in threads closely behind the frontal cell wall, in the middle, or at the bottom of the cell [Blösch 2000],[Danks 1971]. A detailed description of the larva can be found in Asís [Asís et al. 1994].
Depending on the environment temperature the adult wasp will emerge over a week [Danks 1971]. The species knows potandry and often there will be more males than females [Blösch 2000],[Abraham 1982].
2.3. BEE HOTEL
The species will use bee hotels and artificial nesting structures [Breugel 2014],[Blösch 2000],[Danks 1971].
They nest in drill holes of 2,5 – 4 mm [Blösch 2000],Danks 1971].
3. PLANT RELATIONS
3.1. WOOD TYPES
The following wood types are mentioned in literature as medium for the wasp to built her nests
Adoxaceae (Moschatel family)) | |
Asteraceae (Composite family) | Cirsium (Plume thistles) [Danks 1971] |
Onagraceae (Willowherb family) | Chamaenerion [Danks 1971] |
Poaceae (Grasses) | Phragmites [Woydak 1996] – Phragmites australis (Common reed) [Peeters et al. 2004],[Blösch 2000],[Asís et al. 1994],[Asís et al. 2007],[Tormos et al. 2005] |
Rosaceae (Rozenfamilie) | Rosa (Roos) [Peeters et al. 2004] Rubus (Braam) [Peeters et al. 2004],[Blösch 2000],[Asís et al. 1994],[Woydak 1996],[Danks 1971] |
Scrophulariaceae (Helmkruidfamilie) | Toorts (Verbascum) [Peeters et al. 2004] |
Simaroubaceae | Ailanthus – Ailanthus altissima (Tree of Heaven) [Asís et al. 1994],[Tormos et al. 2005] |
3.2. FOOD PLANTS
The following plant species are mentioned in literature as food sources:
Apiaceae (Umbellifers) | Aegopodium [Blösch 2000],[Woydak 1996] Angelica [Blösch 2000],[Woydak 1996] Heracleum (Hogweed) [Woydak 1996] Pastinaca – Pastinaca sativa (Parsnip) [Blösch 2000] |
The wasps feed on honeydew as well [Blösch 2000].
4. PREY RELATIONS
The species uses adult [Asís et al. 1994],[Danks 1971] and immature [Asís et al. 1994],[Danks 1971] spiders (Araneae) [Peeters et al. 2004],[Blösch 2000] for her brood. The prey spectrum consists for a large part of web building spiders [Danks 1971].
The following species and group occurring in the Netherlands [Soortenregister] are mentioned in literature:
Araneidae (Orb-weaver spiders) preference group [Asís et al. 1994] | Araneus – Araneus sturmi [Asis et al 1994] Araniella – Araniella cucurbitina (Cucumber green orb spider) [Asi1s et al. 1994immature] Cercidia – Cercidia prominens [Danks 1971] Hypsosinga – Hypsosinga albovittata [Danks 1971als Singa albovittata] – Hypsosinga pygmaea [Danks 1971als Singa pygmaea] Gibbaranea – Gibbaranea bituberculata [Asís et al. 1994immature] |
Linyphiidae [Blösch 2000],[Asis et al. 1994],[Abraham 1982],[Lomholdt 1984] (Money spiders) preference group [Asís et al. 1994] | Bolyphantes [Peeters et al. 2004+Woydak 1996+Lomholdt 1984als Bolyphaltes] Cercidia Cercidia prominens [Danks 1971] Floronia – Floronia bucculenta [Asís et al. 1994] – Microlinyphia pusilla [Asís et al. 1994] – Microneta viaria [Asís et al. 1994] |
Oxyopidae | Oxyopes – Oxyopes heterophthalmus [Asís et al. 1994] |
Salticidae [Asís et al. 1994] (Jumping spiders) | Pseudeuophrys – Pseudeuophrys erratica [Danks 1971als Euophrys erratica] |
Tetragnathidae preference group [Asís et al. 1994] | Pachygnatha [Asís et al. 1994] |
Thomisidae [Asís et al. 1994],[Abraham 1982] (Crab spiders) | Synema – Synema globosum [Asís et al. 1994onvolw] Thomisus –Thomisus onustus [Asís et al. 1994onvolw] Xysticus [Asís et al. 1994onvolw] |
Prooisoorten buiten Nederland:
Araneidae (Orb-weaver spiders) | Larinioides – Larinioides sclopetarius [Asís et al. 1994] |
Theridiidae | Kochiura – Kochiura aulica [Asís et al. 1994als Anelosimus aulicus] |
5. PARASITIC RELATIONS
The following species and groups occurring in the Netherlands [Soortenregister] are mentioned in literature:
Chalcidoidae (Chalcid wasps) | Eulophidae Melittobia – Melittobia acasta [Marechal 1936] Eurytomidae Eurytoma [Danks 1971] – Eurytoma nodularis [Blösch 2000],[Peeters et al. 2004+Woydak 1996als Eurytoma rubicola] Torymus – Torymus armatus [Danks 1971als Diomorus armatus] |
Chrysididae (Cuckoo wasps) | Pseudomalus – Pseudomalus auratus [Peeters et al. 2004],[Asís et al. 1994],[Blösch 2000+Woydak 1996+Lomholdt 1984+Danks 1971als omalus auratus] – Pseudomalus pusillus [Peeters et al. 2004],[Blösch 2000+Woydak 1996+Lomholdt 1984als omalus pusillus] Trichrysis – Trichrysis cyanea [Peeters et al. 2004],[Blösch 2000],[Asís et al. 1994],[Woydak 1996],[Lomholdt 1984],[Danks 1971],[Tormos et al. 2005] |
Ichneumonidae (Ichneumon wasps) | Bathythrix – Bathythrix claviger [Danks 1971als Ischnurgops claviger] – Bathythrix fragiIis [Danks 1971als Ischnurgops fragilis] Enclisis – Enclisis macilenta [Blösch 2000als Caenocryptus inflatus = Enclisis inflatus],[Fitton 1982],[Danks 1971als Caenocryptus macilentus] Ephialtes – Ephialtes manifestator [Peeters et al. 2004] Mastrus [Danks 1971] |
Diptera (Flies) | Sarcophagidae Amobia – Amobia signata [Peeters et al. 2004+Woydak 1996+Lomholdt 1984als Pachyophthalmus signatus],[Povolny 1997] Tachinidae [Danks 1971] |
Parasitic species outside the Netherlands:
Chrysididae (Cuckoo wasps) | Chrysidea – Chrysidea pumila [Asís et al. 1994] Elampus – Elampus coeruleus [Marechal 1936, as Ellampus] |
Ichneumonidae (Ichneumon wasps) | Hoplocryptus – Hoplocryptus coxator [Blösch 2000als H. rubi ] |
6. IDENTIFICATION
Length males: 7,5 – 10 mm
Length females: 9 – 12 mm
Genus
The genus Trypoxylon can be identified using the following characters:
1. Forewing: with one submarginal cell [Klein 1999],[Jacobs 2007],[Dollfuss 1991]
2. Eye: inner edge with deep U-shaped emargination [Klein 1999],[Jacobs 2007],[Dollfuss 1991]
3. Abdomen: black [Jacobs 2007],[Dollfuss 1991]. Wasp entirely black [Klein 1999]
4. Abdomen: relatively very long [Klein 1999],[Jacobs 2007],[Dollfuss 1991]
The abdomen protrudes relatively far from beneath the wings.

specimen caught for photo identification on 08-vii-2021, length ±12mm



1. Antenna with 12 segments [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991]
2. Abdomen with 6 segments [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991]
HEAD
1. Distance between eyes vertex (l1) larger than distance between eyes at the clypeus (l2) [Klein 1999],[Jacobs 2007],[Dollfuss 1991], ratio 1,2-1,4 [Bitsch 2021]

2. Forehead (frons): without a shield-like area limited by carinae [Bitsch 2021],[Jacobs 2007],[Dollfuss 1991]
3. Forehead: medial keel above antennal inplant weakly elevated, en profil without clear bend towards forehead line [Bitsch 2021],[Jacobs 2007],[Dollfuss 1991]

4. Clypeus: apical edge middle lobe weakly protruding [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991], with obtuse, rounded [Klein 1999], side angles [Jacobs 2007],[Dollfuss 1991], lobe rather narrow [Bitsch 2021]
5. Occipital carina: lower part occipital carina not enlarged [Bitsch 2021],[Klein 1999],[Jacobs 2007]
6. Kop: upper part back head sparingly covered with prostrate hairs [Jacobs 2007]
THORAX
1. Upper side thorax (mesonotum): mat [Bitsch 2021],[Jacobs 2007],[Dollfuss 1991]
2. Pronotum: rear edge black [Bitsch 2021],[Klein 1999],[Dollfuss 1991]
3. Foreleg: shin (tibia) and tarsus black [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991]
4. Forewing: submarginal cel with acute or obtuse external angle [Bitsch 2021]
ABDOMEN
1. Length tergite 1 (l1) about as long as combined length tergites 2 and 3 (l2) [Klein 1999],[Jacobs 2007],[Dollfuss 1991], ratio between length segment I and abdomen = 3,0-5,0 [Bitsch 2021]





1. Antenna with 13 segments [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991]
2. Abdomen with 7 segments [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991]
HEAD
1. Distance between eyes vertex (l1) larger than distance between eyes at the clypeus (l2) [Klein 1999],[Jacobs 2007],[Dollfuss 1991], ratio 1,4-1,7 [Bitsch 2021]

2. Forehead (frons): without a shield-like area limited by carinae [Bitsch 2021],[Jacobs 2007],[Dollfuss 1991]
3. Forehead: medial keel above antennal inplant weakly elevated, en profil without clear bend towards forehead line [Bitsch 2021],[Jacobs 2007],[Dollfuss 1991]

4. Occipital carina: lower part not enlarged [Bitsch 2021],[Klein 1999],[Jacobs 2007]
5. Head: hypostomal bridge longitudinally striped [Bitsch 2021]
6. Antenna: apically weakly enlarged [Dollfuss 1991]
7. Antenna: last member as long as the four previous members together [Bitsch 2021],[Dollfuss 1991]
THORAX
1. Thorax: dorsally (mesonotum) mat [Bitsch 2021],[Jacobs 2007],[Dollfuss 1991]
2. Pronotum: rear edge black [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991]
3. Foreleg: shin (tibia) and tarsus black [Bitsch 2021],[Klein 1999],[Jacobs 2007],[Dollfuss 1991]
4. Forewing: submarginal cel with acute or obtuse external angle [Bitsch 2021]
ABDOMEN
1. Length tergite 1 (l1) about as long as combined length tergites 2 and 3 (l2) [Klein 1999],[Jacobs 2007],[Dollfuss 1991], ratio between length segmentI and abdomen = 3,0-5,0 [Bitsch 2021]

2. Genitals: apical part parameres split no deeper than hook aedoeagus [Bitsch 2021],[Jacobs 2007]; gonostyle split over only 1/3 its length [Klein 1999]

3. Genitals: base parameres with long straight bristles [Jacobs 2007]
Literature
Abraham 1982 Abraham, R., 1982. Zur Biologie von Trypoxylon attenuatum Smith, 1851 und T. figulus (Linnaeus, 1758)(Hymenoptera: Sphecidae). Entomologische Mitteilungen aus dem Zoologischen Museum Hamburg.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.
Asís et al. 2007 Asís, J. D., Benéitez, A., Tormos, J., Gayubo, S. F., & Tomé, M. A. M., 2007. The significance of the vestibular cell in trap nesting wasps (Hymenoptera: Crabronidae): Does its presence reduce mortality?. Journal of insect behavior, 20, 289-305.
Bitsch 2021 Bitsch, J., 2021. Hyménoptères sphéciformes d'Europe: Volume 2, Systématique (2e partie) : Crabroninae, Dinetinae, Eremiaspheciinae & Mellininae. France: Faune De France.
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
Breugel 2014 Breugel, P. van., 2014. Gasten van bijenhotels. – EIS Kenniscentrum Insecten en andere ongewervelden & Naturalis Biodiversity Center, Leiden.
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.
Dollfuss 1991 Dollfuss, H., 1991. Bestimmungsschlüssel der Grabwespen Nord-und Zentraleuropas. Stapfia, 24, 1-247.
Fitton 1982 Fitton, M. G., 1982. A catalogue and reclassification of the Ichneumonidae (Hymenoptera) described by CG Thomson.
Jacobs 2007 Jacobs, H.J., 2007. Die Grabwespen Deutschlands Ampulicidae. Sphecidae, Crabronidae–Bestimmungsschlüssel in Blank, SM & Taeger, A (Hrsg): Die Tierwelt Deutschlands und der angrenzenden Meeresteile nach ihren Merkmalen und nach ihrer Lebensweise, Hymenoptera III–Keltern, Goecke & Evers, 79: 1-207.
Klein 1999 Klein, W., 1999 De graafwespen van de Benelux: supplement. Jeugdbondsuitgeverij, 1-37. + Klein, W., 1996. De graafwespen van de Benelux. Jeugdbondsuitgeverij, 1-130.
Lomholdt 1984 Lomholdt, O., 1984. The Sphecidae (Hymenoptera) of Fennoscandia and Denmark. Fauna Entomologica Scandinavica, 4.1: 2.
Marechal 1936 Marechal, P., 1936. Ethologie des Trypoxylon (Hym. Sphég.) et observations sur T. attenuatum Sm. Bull. Ann. Soc. Entomol. Belgique, 76, 373-396.
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.
Povolny 1997 Povolny, D., 1997. The flesh-flies of Central Europe (Insecta, Diptera, Sarcophagidae). Spixiana Suppl., 24, 1-260.
Soortenregister Nederlands Soortenregister
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. Trypoxylon attenuatum. Kerfdier, www.kerfdier.nl. Accessed on 20 March 2025.