‘Gasteruption assectator agg.’ background and definition

Last update: 8 June 2021

Gasterruption assectator aggregaat

In the 2016 published paper by Niklas Johansson and Kees van Achterberg [1] the authors describe three Gasteruption species that previously were defined as the species Gasteruption assectator.

When there is a suspicion that about a species that it may actually include a number of species this is referred to as a species complex, informally also called a species aggregate [2].

Based on newly found morphological characters it turns out that Gasteruption assectator actually includes the following three species:

  • G. assectator
  • G. boreale
  • G. nigritarse

Morphological characters

The species are identified based on the following morphological characters [1]:

1Width of hypostomal bridge♀, ♂
2Shape occipital carina♀, ♂
3Sculpture mesoscutum, coxae and head♀, ♂
4Colour facial hairs♀, ♂
5Hairs at tip ovipositor sheaths (dorsal view)
6Ratio length ovipositor sheath and tibia
7Shape head dorsally
Gasteruption assectator ♀︎, Hypostomal bridge (H) en Occipital carina (O)
Gasteruption assectator ♀︎, tip ovipositor shafts without distinct bristles
Gasteruption assectator ♀︎, length ovipositor sheath 1,0-1,3x length tibia

In the field these characters will be difficult to identify, especially characters 1 and 2 as they are accessible ventrally and character 5 is visible under appropriate enlargement. The other characters can be accessible in principle on good and sharp photographs.

On this site a species from this group with unclear characters is for the time being categorized as ‘Gasteruption assectator agg.‘ instead of ‘Gasteruption sp.‘ to make emphasize this background.

Potential garden species (Krimpen aan den IJssel)

G. nigritarse has been found in the East and South of the Netherlands [1] and therefore a less likely candidate as future garden visitor here in the West.

G. boreale has been found in the vicinity and can be a potential candidate visitor.

G. assectator is present in the garden.


1 Johansson N, Achterberg C van (2016) Revision of the Palaearctic Gasteruption assectator aggregate, with special reference to Sweden (Hymenoptera, Gasteruptiidae). ZooKeys 615: 73-94. https://doi.org/10.3897/zookeys.615.8857

2 Sigovini, Marco & Keppel, Erica & Tagliapietra, Davide. (2016). Open Nomenclature in the biodiversity era. Methods in Ecology and Evolution. 7. 1217-1225. 10.1111/2041-210X.12594.

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