‘Gasteruption assectator agg.’ background and definition

Last update: 24 June 2024

Gasterruption assectator aggregaat

In the 2016 published paper by Niklas Johansson and Kees van Achterberg [Johansson & Achterberg 2016] 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 [Sigovini & Keppel & Tagliapietra 2016].

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

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

Potential garden species (Krimpen aan den IJssel)

  • G. nigritarse is not present in the Netherlands [Nederlands Soortenregister].
  • G. boreale has been found in the vicinity and can be a potential candidate visitor.
  • G. assectator is present in the garden.

Morphological characters

The species are identified based on the following morphological characters [Johansson & Achterberg 2016]:

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
G. assectator complex characters per gender
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

The females G. boreale and G. assectator can be differentiated based on

  1. the surface structure of the head and the thorax dorsally
  2. the length ratio between ovipositor sheaths and the hind tibia
  3. the hairs on the tip of the ovipositor sheaths

The males G. boreale and G. assectator can be differentiated based on

  1. the surface structure of the thorax side
  2. the surface structure and gloss of the head, thorax and hind coxa
  3. the shape of the head behind the eyes

Apart from the hairs on the ovipostor sheaths that are only visible under high magnification, the other characters will be accessible on good enough photographs in the field.

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.


Johansson & Achterberg 2016 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

Sigovini & Keppel & Tagliapietra 2016 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.

Nederlands Soortenregister Nederlands Soortenregister

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