Ectemnius cavifrons ♂︎

Last update: 22 May 2020


Collection
Ectemnius cavifrons

SPECIES: Ectemnius cavifrons
GENUS: ECTEMNIUS
FAMILY: Digger wasps (CRABRONIDAE)



OBSERVATION:
2020-V-212020-V-192019-VII-22

YEARS:
20192020

MONTHS:
JanFebMarAprMayJunJulAugSepOctNovDec


Ectemnius cavifrons ♂︎

1. DISTRIBUTION

Ectemnius cavifrons is a less common wasp that can be found throughout the Netherlands [3].

2. BEHAVIOUR

2.1. ACTIVITY

The species is active from half April to end September [4].

2.2. DEVELOPMENT

Nests are made in dead wood. Hoverflies (Syrphidae) are used as food for larvae [4]

3. IDENTIFICATION

It is a mid sized wasp. Length male 8-12,5 mm, female 11-16,5 mm [4].

There are a large number of Diggerwasps (CRABRONIDAE) that look similar and are difficult to differentiate [4].

The characteristics of the genus Ectemnius are [2,6,7]:

1. One submarginal cel in front wing [2,6]

Ectemnius cavifrons ♂︎, one submarginal cel in frontwing

2. Ocelli shaped in obtuse triangle [2]
This characteristic apparently does not apply to E. cavifrons because they are shaped in a acute triangle.

Ectemnius cavifrons ♂︎, ocelli make obtuse triangle in Ectemnius, this does not seem to be true for E. cavifrons

3. Mesopleuron wrinkled [2,6]

Ectemnius cavifrons ♂︎, mesopleuron wrinkeled

4. Mesopleuron with short keel in front of middle coxa (the connecting segment of the leg to the thorax) [2,7]

Ectemnius cavifrons ♂︎, mesopleuron in front middle coxa with short transverse keel

6. Abdominal tergites smooth, most species have fine punctuation to leathery matt, some exception with coarse puctation [2]

Ectemnius cavifrons ♂︎, Abdominal tergites smooth, mostly with fine punctation to leathery matt

7. Males with 12 antennal segments [2,6]

Ectemnius cavifrons ♂︎, antenna male with 12 segments

 

The main characteristics of the species are [2]:

Males

1. Antennal segment 3 with clear teeth [2,6]
2. Antennal segment 3 at least 2,5 [2] or 3 [6] times longer than wide
3. Teeth on antenna segements 4 and 5 equally large as teeth on segment 3 [2,6]

Ectemnius cavifrons ♂︎, teeth on antenna segments 4 and 5 smaller than on segment 3

4. No hairbrush with bend hairs on tooth 1 of antennal segment 3

Ectemnius cavifrons ♂︎, no hairdbrush with bend hairs on first tooth antenna segment 3

5. Antennal segment 6 normal shape [6]

Ectemnius cavifrons ♂︎, Antenne segment 6 shaped normally

6. Vertex completely dented around ocelli [2]

Ectemnius cavifrons ♂︎, vertex completely indentated around ocelli
Ectemnius cavifrons ♂︎, vertex completely indentated around ocelli

7. Ventral mesothorax without transverse keel [2]
(in species that do have this keel it supports a strongly pronounced edge, instead of the one on this species which is more rounded)

Ectemnius cavifrons ♂︎, Onderzijde borststuk (mesothorax) zonder dwarskiel

8. Dorsal area propodeum separated from sides by weakly developed keel [2,6]

Ectemnius cavifrons ♂︎, dorsal field propodeum separated from sides by weakly developed keel

9. Trochanter frontleg not enlarged [2,6]

Ectemnius cavifrons ♂︎, trochanter frontleg not enlarged

10. Tarsus 5 front leg strongly enlarged

Ectemnius cavifrons ♂︎, tarsus 5 strongly widened
Ectemnius cavifrons ♂︎, middle leg tarsus 5 strongly widened

11. Basitarsus middle leg from inside outwards widened with maximum width before the tip

Ectemnius cavifrons ♂︎, basal tarsus diverges widest before the tip

12. Front femora without tooth

13. Back edge tergite 7 rounded smoothly progressing into side [2]

Ectemnius cavifrons ♂︎, tergite 7 arches gradually to the sides

14. No teeth on mandible inner edge [2,6]

Ectemnius cavifrons ♂︎, no tooth on inner edge mandible

15. Clypeus hairs golden colored [2,6]

Ectemnius cavifrons ♂︎

16. Clypeus flat and stepped [2]

Ectemnius cavifrons ♂︎, clypeus shape

References

1 Nederlands Soortenregister

2 Hermann Dollfuss, "Bestimmungsschlüssel der Grabwespen Nord- und Zentraleuropas (Hymenoptera, Sphecidae) mit speziellen Angaben zur Grabwespenfauna Österreichs", Publikation der Botanischen Arbeitsgemeinschaft am O.Ö.Landesmuseum Linz, LINZ, 20. Dezember 1991

3 Waarneming.nl

4 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.

5 Albert de Wilde, Insecten fotosite ahw.me, Wespen

6 KLEIN, Wim. De graafwespen van de Benelux. Jeugdbondsuitgeverij, Utrecht, 1996, 1-130. KLEIN, Wim. De graafwespen van de Benelux: supplement. Jeugdbondsuitgeverij, 1999.

7 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.

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