CONTENTS

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

1. DISTRIBUTION

Stigmus pendulus is an uncommon wasp ^{[Waarneming.nl]} that occurs in the interior of the Netherlands and is rarer at the coast ^{[Waarneming.nl],[Peeters et al. 2004],[Klein 1999]}.

2. BEHAVIOUR

2.1. ACTIVITY

The species is active from end April to beginning of October ^{[Peeters et al. 2004]}.

2.2. DEVELOPMENT

Nest

The species nests in abandoned corridors in wood made by other insects ^{[Peeters et al. 2004]}.

Ei

The egg is probably placed ventrally on the prey thorax or abdomen, as in P. americanus ^{[Bohart & Menke 1976]}.

2.3. BEE HOTEL

I’ve not yet observed the species on the bee hotels.

2.4. MATING

The species probably produces two generation per year ^{[Peeters et al. 2004]}.

2.5. HUNTING

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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	Sambucus (Elder) [Bohart & Menke 1976]
Betulaceae	Alnus Alnus glutinosa (Black alder) [Peeters et al. 2004] Carpinus Carpinus betulus (Common hornbeam) [Peeters et al. 2004]
Celastraceae	Euonymus [Bohart & Menke 1976]
Fabaceae	Erythrina [Bohart & Menke 1976]
Lauraceae	Sassafras [Bohart & Menke 1976]
Malvaceae	Tilia – Tilia (Lime) [Vikberg 1999]
Oleaceae	Chionanthus [Bohart & Menke 1976] Fraxinus Fraxinus excelsior (Ash) [Peeters et al. 2004] Syringa [Bohart & Menke 1976]
Paeoniaceae	Paeonia (Peony) [Bohart & Menke 1976]
Rosaceae	Rubus – Rubus (Bramble) [Peeters et al. 2004],[Bohart & Menke 1976]
Salicaceae	Salix – Salix (Willow) [Peeters et al. 2004]
Scrophulariaceae	Buddleja – Buddleja davidii (Butterfly bush) [own observation] (in drillholes of Anobium sp. (Coleoptera: Anobiidae))

Timber may be used as well ^{[Bohart & Menke 1976]}.

3.2. FOOD PLANTS

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

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4. PREY RELATIONS

The species uses Aphididae (Aphids) ^{[Peeters et al. 2004],[Bohart & Menke 1976]}, including nymphs ^{[Vikberg 1999]}.
The following species and group occurring in the Netherlands ^{[Soortenregister]} are mentioned in literature:

Aphididae (Aphids)

Myzus – Myzus lythri [Woydak 1996] Tuberculatus – Tuberculatus annulatus [Vikberg 1999]

Prey species outside the Netherlands:

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5. PARASITIC RELATIONS

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

Ichneumonidae (Ichneumon wasps)	Perithous – Perithous divinator [Peeters et al. 2004],[Woydak 1996] – Perithous scurra [Peeters et al. 2004, as P. mediator],[Woydak 1996]
Chalcidoidae (Chalcid wasps)	Torymidae Torymus – Torymus armatus [Peeters et al. 2004, as Diomorus armatus]

Parasitic species outside the Netherlands:

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6. IDENTIFICATION

Length males: 3,5 – 4,5 mm
Length females: 4 – 5,5 mm

Genus

The genus Stigmus can be identified using the following characters:

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

2. Forewing: with one discoidal cell ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999]}

4. Forewing: length pterostigma (P) about equally large as marginal cell (M) ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999]}

5. Abdomen: petiolate

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

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

3. Abdomen: tergum VI with pygidium ^{[Bitsch 2022],[Jacobs 2007],[Klein 1999]}

HEAD

1. Frons: in front of frontal ocellus with longitudinal furrow ^{[Bitsch 2022]}

BORSTSTUK

1. Pronotal lobe: black ^{[Bitch 2022],[Jacobs 2007],[Klein 1999]}

2. Top side (mesepimeron): smooth and glossy, with scattered punctation ^{[Bitch 2022],[Jacobs 2007],[Klein 1999]}

ABDOMEN

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1. Antenna: with 13 segments ^{[Bitsch 2022],[Jacobs 2007]}

2. Abdomen: with 7 segments ^{[Bitsch 2022],[Jacobs 2007]}

3. Abdomen: sternum VII with thorn ^{[Bitch 2022],[Jacobs 2007],[Klein 1999]}

HEAD

1. Clypeus: apical edge without notched sides ^{[Bitsch 2022]}

2. Frons: in front of frontal ocellus with longitudinal furrow ^{[Bitsch 2022]}

THORAX

1. Pronotal lobe: black, seldom apically somewhat lighter ^{[Bitch 2022],[Jacobs 2007],[Klein 1999]}

2. Top side (mesepimeron): smooth and glossy, with scattered punctation ^{[Bitch 2022],[Jacobs 2007],[Klein 1999]}

ACHTERLIJF

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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.

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

^{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.

^{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.

^{Vikberg 1999} Vikberg, V., 1999. Crossocerus assimilis and Bethylus boops, two aculeate wasps new to the fauna of Finland (Hymenoptera, Crabronidae and Bethylidae). Entomologica Fennica, 10(4), 245-246.

^{Waarneming.nl} Waarneming.nl

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

Citation

Krischan, O.R., 2025. Stigmus pendulus. Kerfdier, www.kerfdier.nl. Accessed on 12 May 2025.