Chrysopa perla

Chrysopa perla

A common species in Norfolk but it doesn't seem to visit garden moth traps as much as most other common green lacewings - I have caught it that way but I've found it more often during the day. The majority of records are between late May and mid July but it can be found from mid May and there are quite a few August records.

In common with most other members of the genus Chrysopa, the second segments of the antennae are black in this species. Unlike most of the others - but like the generally scarcer Chrysopa dorsalis - it is a blue-green insect with extensive black on the top of the head. On both species these black markings enclose a pale spot near the back of the head at the centre, but this spot is approximately circular in perla and oval or rectangular in dorsalis. The other fairly obvious difference between the two species is that dorsalis has a black subcostal vein (the long vein that runs along the length of the wing closest to the leading edge, running close to and parallel with the radial vein). This vein is predominantly green on perla (although it is, or at least may be, black surrounding the ends of the black costal cross-veins, the black extending narrowly along the costal side of the vein into the gap between the cross-veins). In the event of any ambiguity with these characters, there is also a difference in claw shape (refer to Plant (1997) for details).

The green subcostal vein is visible on all of the following photos, and the head pattern on those taken at a suitable angle, making this one of the easier species to identify.

Chrysopa perla, North Elmham (Norfolk, UK), 18th August 2018

Chrysopa perla, North Elmham Cathedral Meadows (Norfolk, UK), 20th June 2020

Note here the "green" vein Sc does actually have black spots on, around where the black costal cross-veins join, and these black spots are elongated along the costal edge of the vein. But the vein is clearly predominantly greem so I don't think this is likely to generate confusion. See also the tooth at the base of the tarsal claw which would not be present on dorsalis.

female Chrysopa perla showing costal vein and hind tarsus, Wendling Beck Environment Project (Norfolk, UK), 15th June 2023

This female laid eggs in the pot, spread out around the whole pot. I am not aware of any differences between the eggs of the various lacewing species but the way it is attached to the surface on a long stiff (but flexible) thread is common to at least other green lacewings.

Chrysopa perla egg, Wendling Beck Environment Project (Norfolk, UK), 15th June 2023

The key character for separating Apertochrysa ventralis (formerly Dichochrysa ventralis) from the other members of that genus is the black surface to the underside of the abdomen, but a while ago I wondered if it was a diagnostic character to separate it from all other green lacewings, or just the others in its genus. Well, if you look at a Chrysoperla perla from underneath (third photo below) you get my answer - definitely not diagnostic, in fact the black on the ventral surface of perla's abdomen is even more extensive than on ventralis.

Chrysopa perla, North Elmham (Norfolk, UK), 18th August 2021

I don't think this one was any bluer than the others on this page but the photo taken before capture has come out looking very blue. The second photo shows the black underside of the abdomen.

female Chrysopa perla showing underparts, claw and tip of abdomen from side, North Elmham Cathedral Meadows (Norfolk, UK), 3rd June 2022