Euura respondens (Förster, 1854)

EUURA BERGMANNI GROUP

Euura respondens - Cryptic Willow Nematine

Nematus respondens Förster, 1854
Nematus desantisi D. R. Smith, 1983
Nematus nitens Thomson, 1888

This member of the Euura bergmanni group was added to the British list by Ian Andrews in 2021 and in 2022 from Newport docks. The latter record is less surprising, given that this species is proving to be of widespread invasive nature across many parts of the world. However, the former may suggest this species occurs much more widely across Britain without being recognised. The species was not featured by Benson (1958) and so it would not have been recognised until the publication of Prous et al. (2021). Males are distinctive, if the penis-valves are examined, but females have saws that are very similar to other related species. Larvae are apparently very similar to those of E. oligospila (Musgrove, 2024). 

Females closely resemble Euura bergmanni and Euura sylvestris. Euura respondens has a more rounded head in dorsal view than does E. bergmanni. The saw lancet has the second to fourth sutures angled obliquely and straight to weakly curved, apically. In E. oligospila and E. sylvestris those sutures are weakly to distinctly curved apically.  

In life, the males have a yellow to brown ground colour with a varying extent of black. The stigma is fairly uniformly pale, and the pronotum is extensively pale. The females are often green in life but the ground colour may be yellow. 

Euura respondens larvae feed on crack willow. The larvae are much like those of Euura oligospila.

Jump to other Euura bergmanni group species

Size: Female: 6.0 - 9.0mm, male: 4.5 - 8.0mm.

GB IUCN status: Data Deficient
GB rarity status: Unclear

Distribution: England, Wales

Flight period: Multivoltine, April to August

Plant associations: Salix fragilis and other Salix spp. Occasionally on Populus spp. (crack willow, other willows and occasionally on poplars)