Monostegia abdominalis

Alternative names
Tenthredo abdominalis

A small, orange bodied sawfly that is associated with Yellow Loosestrife (Lysimachia vulgaris) – the only sawfly to feed on this plant. It has been recorded on a few other plants including Creeping-Jenny (Lysimachia nummularia) and Scarlet Pimpernel (Lysimachia arvensis subsp. arvensis). The larva is similar to some other sawfly larvae, but has a diagnostic black mark on the head, in the centre above the eyes.

Identification difficulty

Adult Larva

Recording advice

Adult: Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Larva: Unless identified by a recognised expert, a photo is required. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed.


Where the larval foodplants are present.

When to see it

Late spring to autumn.

Life History

The species is entirely parthenogenetic (no males) and it has 2 or more broods a year.

UK Status

It seems to be widespread from southern England as far north as Yorkshire and Lancashire, but is not well recorded.

VC55 Status

Status in Leicestershire and Rutland not known.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map