Figwort Sawfly

• The group owes its name to the females' saw-shaped ovipositor, with which they cut a slit in the plant tissue to insert their eggs.
• They are the oldest group of hymenopterans: the sawflies have no wasp waist and keep the broad body of their ancestors, from before the appearance of bees, wasps and ants.
• Their larvae are told from butterfly and moth caterpillars by having more pairs of abdominal prolegs, a classic field identification trick.
• It is not a true wasp: the symphytans, or sawflies, are the oldest lineage of the Hymenoptera and have no wasp waist. The abdomen joins the thorax across its full width.
• Nor do they have a sting. What in wasps is a sting remains here a saw-shaped ovipositor, with which the female cuts into plant tissue to deposit her eggs inside. Hence the family's name.
• Its yellow-and-black coloration mimics wasps: it is a Batesian mimic, completely harmless.
• The larva looks like a butterfly caterpillar, but can be told apart by having more prolegs and a single ocellus on each side.
• The adult is a predator and hunts other insects on flowers, something unusual in the group, where most species keep to pollen and nectar.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Damp meadows, verges and streamsides with figworts

Size at birth

The larva is white with several rows of small black dots and reaches up to 30 mm, twice the length of the adult

Sexual maturity

Adults on the wing from June to August; they fly slowly, with their long yellow legs dangling, and allow a close approach

Gestation / incubation

The larva feeds actively in August and September and withdraws to hibernate in October; the cycle closes with a single generation a year

Litter / clutch size

The female cuts the plant tissue with her saw-shaped ovipositor and inserts the eggs there: the name of the group comes from that structure. Sawflies have no sting because the sting evolved from precisely that saw

Sources consulted: Buglife; Benson, revisiones de Symphyta; NatureSpot; Ficha de especie de Tenthredo scrophulariae; Ficha de especie de Tenthredo scrophulariae (Wildlife Natural); Wellcome Open Research, genoma de Tenthredo scrophulariae; Wildlife Natural; NatureSpot, ficha Figwort Sawfly

Best time: From June to August in meadows, woodland edges, paths and untidy gardens, always where figwort grows; it is easily seen on umbellifers