CONTENTS

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

 

1. DISTRIBUTION

Passaloecus corniger is an uncommon wasp ^{[Waarneming.nl]} that occurs throughout the Netherlands with an exception of the Wadden islands and is scarcer in the West ^{[Peeters et al. 2004]}.

2. BEHAVIOUR

2.1. ACTIVITY

The species is active from the end of May to the beginning of September ^{[Peeters et al. 2004]}.

Nests are constructed between June and August. Often two generations per year ^{[Blösch 2000],[Woydak 1996]}, the first generation emerges in August from from the June nests ^{[Blösch 2000],[Woydak 1996]}.

2.2. DEVELOPMENT

Nest

The females gnaw their nests in the marrow of natural tube-shaped plant stems ^{[Peeters et al. 2004],[Bohart & Menke 1976],[Ruchin & Antropov 2019],[Woydak 1996]}, but use abandoned insect burrows as well ^{[Peeters et al. 2004,[Bohart & Menke 1976],[Ruchin & Antropov 2019]}, for example the burrow of the weevil genus Xylosandrus ^{[Schulze et al. 2019]}.

She prefers nest holes with a a diameter of 1-3 mm ^{[Peeters et al. 2004],[Blösch 2000],[Corbet & Backhouse 1975],[Breugel 2014]} at a height of 50 – 250cm ^{[Corbet & Backhouse 1975]}. Existing cavities may be excavated further ^{[Corbet & Backhouse 1975]}. Usually passaloecus nests are unbranched ^{[Bohart & Menke 1976],[Vincent 1978]} with cell linearly positined behind each other. The nest plug of the rear cell forms the back of the next cell ^{[Vincent 1978]}. By exception an empty cell may be constructed between two filled cells, the intercalary cell ^{[Vincent 1978]}. One or more cells behind the nest plug, the vestibular cells, may be empty ^{[Vincent 1978]}. See also nest architecture.
The plugs between cells and the nest plug are made of light or dark resin ^{[Peeters et al. 2004],[Bohart & Menke 1976],[Blösch 2000],[Corbet & Backhouse 1975],[Breugel 2014],[Vincent 1978]} of pine trees ^{[Corbet & Backhouse 1975]}. The resin of the nest plug is decorated with plant matter or excrements ^{[Corbet & Backhouse 1975],[Breugel 2014]}, potentially as camouflage ^{[Corbet & Backhouse 1975]}.

Some females simultaneously built two or more nests ^{[Corbet & Backhouse 1975]}. Nests of previous seasons can be reused and are cleaned first ^{[Corbet & Backhouse 1975]}.

Generally Passaloecus nest cells are filled with 6-60 prey specimen ^{[Bohart & Menke 1976]}.

Egg

Passaloecus eggs are whitish and sausage-shaped ^{[Vincent 1978]}. The egg is usually attached ventrally or laterally on the prey ^{[Bohart & Menke 1976],[Vincent 1978]}. The position of the prey with the egg in the nest is variable ^{[Bohart & Menke 1976],[Vincent 1978]}.

2.3. BEE HOTEL

The species gladly use bee hotels to nest in ^{[Woydak 1996],[Breugel 2014]}.

As far as I know the species has not yet nested in the garden bee hotels, possibly because the smallest boring hole is 3mm in size.

2.4. MATING

The males show courting behaviour to get the female in the mood for mating ^{[Blösch 2000],[Breugel 2014]}. The entire act of mating, including the courting, will take about 30 minutes or longer ^{[Blösch 2000]}. This is extensively described in Blösch ^{[Blösch 2000]} and Breugel ^{[Breugel 2014]}.

2.5. HUNTING

Caught prey seems not to get stung ^{[Corbet & Backhouse 1975]} but is instead paralysed by a bite in the neck using the jaws ^{[Ruchin & Antropov 2019],[Piek 2013]}. Poison analyses shows Passaloecus poison does not induce paralysis ^{[Piek 2013]}.

P. corniger seems to steal from other species in the Passaloecus genus^{[Peeters et al. 2004],[Klein 1999],[Lomholdt 1984],[Ruchin & Antropov 2019]} and sometimes from the Crabronidae genus Psenulus ^{[Blösch 2000],[Breugel 2014]}, P. fuscipennis ^{[Breugel 2014]}, and Pemphredon, P. lugens ^{[Breugel 2014]}.

Extensive observation sets ^{[Corbet & Backhouse 1975]} show P. corniger stealing all her prey from other Passaloecus species, a.o. P. gracilis and P. insignis. These species had no trouble finding prey in an area of 15m in radius from their nests and reach a provision velocity of one to some minutes per prey specimen. This showed prey was readily available. Still no observations were made of P. corniger hunitng herself but instead robbing all prey specimen from surrounding Passaloecus species, among which P. corniger, in the direct surroundings of about 10-20cm from her own nest.
Other observers have not observed this behaviour ^{[Woydak 1996]}, potentially because the behaviour pays off in a dense population around the nesting location ^{[Lomholdt 1984]}.

Since the nests being robbed are close to the robbers’ nest she can reach a high provision velocity, sometimes even carrying two prey specimen at a time. The velocity may become to much for the owner who eventually abandons the nest ^{[Corbet & Backhouse 1975]}.

The larva present in the robbed nest cell may be removed by the robber ^{[Corbet & Backhouse 1975]}.

In this observation the nests being robbed were closed at most three days before by the owner ^{[Corbet & Backhouse 1975]}.

Typically the robber waits until the owner has left the nest but accidental encounters may occur in which the owner is still present or surprises the robber with it’s return. During the ensuing skirmish the robber will try to sting the adversary with its stinger ^{[Corbet & Backhouse 1975]}.

3. PLANT RELATIONS

3.1. WOOD TYPES

The following wood types are mentioned in literature as medium for the wasp to built her nests in:

Adoxaceae (Moschatel family)	Sambucus (Elder) [Bohart & Menke 1976]
Anacardiaceae (Cashew familye)	Rhus (Sumac) [Bohart & Menke 1976]
Betulaceae (Birch family)	Alnus – Alnus incana (Grey alder) [Kofler 2005] Corylus – Corylus avellana (Common hazel) [Kofler 2005]
Caprifoliaceae (Honeysuckle family)	Symphoricarpos (Snowberry) [Bohart & Menke 1976]
Celastraceae	Euonymus (Spindle) [Bohart & Menke 1976]
Cornaceae [4]	Cornus [Bohart & Menke 1976]
Fagaceae	Fagus – Fagus sylvatica (Beech) [Kofler 2005] ( in boreholes of Ptilinus pectinicornis ) Quercus (Oak) [Bohart & Menke 1976] – Quercus robur (English oak) [Kofler 2005]
Pinaceae (Pine family)	Cedrus (Cedar) [Bohart & Menke 1976] Picea – Picea abies (Norway spruce) [Kofler 2005]
Poaceae  (Grasses) [Bohart & Menke 1976]	Arundo [Bohart & Menke 1976] Bamboo [Bohart & Menke 1976]
Rosaceae (Rose family)	Rosa (Rose) [Corbet & Backhouse 1975] Rubus (Blackberry) [Woydak 1996]
Sapindaceae (Soapberry family)	Acer – Acer pseudoplatanus (Sycamore) [Schulze et al. 2019] (in drillholes of Xylosandrus (Coleoptera, Curculionidae))

Nests are made as well in pine bark, decayed wood and old lumber and beams ^{[Lomholdt 1984]}. Also galls are used ^{[Peeters et al. 2004],[Bohart & Menke 1976]}, of the Chloropidae (Frit flies) genus Lipara ^{[Blösch 2000],[Woydak 1996 (on Phragmites)]}.

The species collects resin from pine trees which is used for nest construction. The following tree species are mentioned in literature:

Pinaceae (Pine family)

Pinus – Pinus nigra (Black pine) [Corbet & Backhouse 1975] – Pinus sylvestris (Scots pine) [Corbet & Backhouse 1975]

3.2. FOOD PLANTS

The following plant species are mentioned in literature as food sources:

Apiaceae [Hüsing & Jäger 1964] (Umbellifers)	–
Asteraceae [Blösch 2000] (Composite family)	Cirsium (Thistle) Cirsium arvense (Creeping thistle) [Blösch 2000],[Woydak 1996] Solidago (Goldenrod) [Blösch 2000],[Dorow 1990],[Woydak 1996]
Crassulaceae (Stonecrop family)	Sedum (Stonecrop) [Blösch 2000],[Dorow 1990],[Woydak 1996]

Male wasps lick honeydew from leafs ^{[Corbet & Backhouse 1975]}. Possibly females feed with aphids ^{[Corbet & Backhouse 1975]}.

4. PREY RELATIONS

The species uses nymphs and adult ^{[Ruchin & Antropov 2019]} aphids (Aphidoidea) for her brood ^{[Peeters et al. 2004],Blösch 2000],[Klein 1999],[Lomholdt 1984]}.

The following species and groups occurring in the Netherlands ^{[Soortenregister]} are mentioned in literature:

Aphidoidea (Aphids) [Peeters et al. 2004],[Klein 1999],[Lomholdt 1984]

Eucallipterus – Eucallipterus tiliae [Timm et al. 2024]

Preyspecies outside the Netherlands:

–

–

5. PARASITIC RELATIONS

The following species and groups occurring in the Netherlands ^{[Soortenregister]} are mentioned in literature:

Chalcidoidae (Chalcid wasps)	Eurytomidae Eurytoma – Eurytoma nodularis [Peeters et al. 2004],[Woydak 1996]
Chrysididae (Cuckoo wasps)	Omalus * – Omalus auratus [Woydak 1996],[Paukkunen et al. 2015] – Omalus aeneus [Peeters et al. 2004],[Blösch 2000],[Woydak 1996],[Paukkunen et al. 2015] – Omalus puncticollis [Blösch 2000] Trichrysis – Trichrysis cyanea [Timm et al. 2024],[Peeters et al. 2004] Pseudomalus * – Pseudomalus auratus [Ruchin & Antropov 2019] ➡︎ brood idiobiont ectoparasitoid (eats food stock and larva) [Tsuneki 1952] – Pseudomalus violaceus [Ruchin & Antropov 2019],[Paukkunen et al. 2015]
Ichneumonidae (Ichneumon wasps)	Poemenia – Poemenia collaris [Peeters et al. 2004],[Woydak 1996] – Poemenia notata [Peeters et al. 2004],[Woydak 1996]

Parasitic species outside the Netherlands:

–

–

6. IDENTIFICATION

Length males: 7,5 – 10 mm
Length females: 10 – 11,5 mm

Genus

The genus Passaloecus can be identified using the following characters:

1.  1.  Forewing: with two submarginal cells ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

2. Forewing: with two cubital cells ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

3. Forewing: second submarginal cell not petiolate ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

4. Forewing: marginal cell pointed ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

5. Forewing: stigma considerably smaller than marginal cell ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

6. Head: inner edge eyes parallel ^{[Bitsch 2022],[Jacobs 2007],[Dollfuss 1991]}

7. Head: clypeus without side lobes ^{[Jacobs 2007],[Dollfuss 1991]}

8. Head: labrum without arcuate emargination ^{[Bitsch 2022]}

9. Side thorax (mesopleuron): smooth or very finely punctated ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}
10. Side thorax (mesopleuron): with one or two horizontal pit rows ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]} (here two)
Jacobs ^{[Jacobs 2007]} mentions hypersternaulus (H) and mesopleuraulus (M)
Dollfuss ^{[Dollfuss 1991]} and Bohart & Menke ^{[Bohart & Menke 1976]} mention the scrobal sulcus for mesopleuraulus

11. Thorax: pronotum not enlarged, hind edge does not reach tegula ^{[Jacobs 2007],[Dollfuss 1991]}

12. Thorax: notauli do not reach hind edge mesonotum ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

13. Thorax: hind tibia dorsally without thorns ^{[Jacobs 2007],[Dollfuss 1991]}

14. Abdomen: black ^{[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

15. Abdomen: not petiolate ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

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1. Antenna with 12 segments ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

2. Abdomen with 6 segments ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

3. Tergite 6 without pygidium ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

4. Sternite 7 without spine-like tip ^{[Jacobs 2007]}

HEAD

1. Frons with thorn between antennae ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}, as long as the width of the third antennal segment ^{[Bitsch 2022],[Klein 1999],[Dollfuss 1991]}

2. Clypeus: front edge with three teeth ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

3. Clypeus: densely silver haired ^{[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

4. Clypeus: as wide as labrum ^{[Bitsch 2022],[Dollfuss 1991]}

5. Labrum rounded ^{[Jacobs 2007],[Klein 1999]}, not heart-shaped ^{[Dollfuss 1991]}

THORAX

1. Side thorax (mesopleuron): with two clear pit rows ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

2. Side thorax (mesopleuron): clearly punctated ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

3. Side thorax (mesopleuron): vertical pit row consists of one row of pits ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

ABDOMEN

–

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specimen caught for photo identification on 15-vii-2021, length ±6mm

specimen 2 caught for photo identification on 9-vi-2022, length ±6mm

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1. Antenna with 13 segments ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

2. Abdomen with 7 segments ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

3. Clypeus densely silver haired ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

4. Tergite 6 without pygidium ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

5. Last sternite with spine-like tip ^{[Jacobs 2007],[Dollfuss 1991]}

HEAD

2. Antenna: segments 8-12 apically slanted ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

3. Antenna: segments 8-12 with tyloids ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

4. Antenne: underside apical segments black ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

5. Head: clear thorn between antennae ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]} its length almost equal to the width of antennal segment 3 ^{[Bitsch 2022],[Klein 1999],[Dollfuss 1991]}

THORAX

1. Side thorax (mesopleuron): with twee horizontal pit rows, hypersternaulus (H) and mesopleuraulus (M) ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}
   Dollfuss ^{[Dollfuss 1991]} mentions scrobal sulcus instead of mesopleuraulus.

2. Side thorax (mesopleuron): with single vertical pit row (episternal sulcus) ^{[Bitsch 2022],[Jacobs 2007],[Dollfuss 1991]}

3. Side thorax (mesopleuron): finely punctated, without or with weakly developed microsculpture ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999],[Dollfuss 1991]}

ABDOMEN

–

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Literature

^{Bitsch 2022} Bitsch, J., 2022. Hyménoptères sphéciformes d'Europe: Systématique (3e partie) : Pemphredoninae et Philanthinae. France: Fédération française des sociétés de sciences naturelles.

^{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

^{Bohart & Menke 1976} Bohart, R.M. & Menke A.S., 1976. Sphecid wasps of the world: a generic revision. - University of California Press, 695 p.

^{Breugel 2014} Breugel, P. van., 2014. Gasten van bijenhotels. – EIS Kenniscentrum Insecten en andere ongewervelden & Naturalis Biodiversity Center, Leiden.

^{Corbet & Backhouse 1975} Corbet, S. A., & Backhouse, M., 1975. Aphid‐hunting wasps: a field study of Passaloecus. Transactions of the Royal Entomological Society of London, 127(1), 11-30.

^{Dollfuss 1991} Dollfuss, H., 1991. Bestimmungsschlüssel der Grabwespen Nord-und Zentraleuropas. Stapfia, 24, 1-247.

^{Dorow 1990} Dorow, W., 1990. 3.7 Hymenoptera: Aculeata (Stechimmen). Schönbuche. Zoologische Unter suchungen, 1992, 127-264.

^{Hüsing & Jäger 1964} Hüsing, J. O., & Jäger, K., 1964. Zur Verbreitung, Biologie und Ökologie der Grabwespen (Hym. Sphec.) in der näheren Umgebung von Halle/S. mit speziellen Bemerkungen über Mellinus arvensis L. Hercynia-Ökologie und Umwelt in Mitteleuropa, 1(2), 186-206.

^{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.

^{Kofler 2005} Kofler, A., 2005. Weitere Funde von Grabwespen in Osttirol (Osterreich)(Hymenoptera: Sphecidae). Berichte-Naturwissenschaftlich Medizinischen Vereins in Inssbruck, 92: 161.

^{Lomholdt 1973} Lomholdt, O. (1973). Biological observations on the digger-wasp Passaloecus eremita Kohl. Videnskabelige meddelelser fra Dansk naturhistorisk forening i København, 136, 29-41.

^{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.

^{Piek 2013} Piek, T. (Ed.), 2013. Venoms of the Hymenoptera: biochemical, pharmacological and behavioural aspects. Elsevier.

^{Ruchin & Antropov 2019} Ruchin, A. & Antropov, A., 2019. Wasp fauna (Hymenoptera: Bethylidae, Chrysididae, Dryinidae, Tiphiidae, Mutillidae, Scoliidae, Pompilidae, Vespidae, Sphecidae, Crabronidae & Trigonalyidae) of Mordovia State Nature Reserve and its surroundings in Russia. Journal of Threatened Taxa. 11. 13195-13250. 10.11609/jott.4216.11.2.13195-13250.

^{Schulze et al. 2019} Schulze, E. D., Schweingruber, F., Gossner, M. M., Günther, A., Weber, U., Stumpf, B., & Komor, E.. 2019. Springtime bark-splitting of Acer pseudoplatanus in Germany. Forests, 10(12), 1106.

^{Soortenregister} Nederlands Soortenregister

^{Timm et al. 2024} Timm, L., Schaal, J., & Sann, M., 2024. A DNA-barcoding-based approach to quantitatively investigate larval food resources of cavity-nesting wasps from trap nests. Journal of Hymenoptera Research, 97, 45-56.

^{Tsuneki 1952} Tsuneki, K., 1952. Ethological studies on the Japanese species of Pemphredon (Hymenoptera, Sphecidae), with notes on their parasites, Ellampus spp.(Hym., Chrysididae)(With 5 Text-figures). 北海道大學理學部紀要, 11.1: 57-75.

^{Vincent 1978} Vincent, D. L., 1978. A revision of the genus Passaloecus (Hymenoptera: Sphecidae) in America North of Mexico. Wasmann Journal of Biology, 36.

^{Waarneming.nl} Waarneming.nl

^{Woydak 1996} Woydak, H., 1996. Hymenoptera Aculeata Westfalica Familia: Sphecidae (Grabwespen), 3-135.

Citation

Krischan, O.R., 2025. Passaloecus corniger. Kerfdier, www.kerfdier.nl. Accessed on 19 April 2025.

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