Food Plant: Persicaria amphibia (Amphibious Bistort)

Mine: August

Notes: Beavan & Heckford (2023) discovered the larva of this species for the first time in the British Isles and descibed its feeding signs. The larvae live within the upper portions of the stem of the host plant, usually between two nodes (5.5-8.0 cms apart). Whilst active a small amount of frass is extruded through a tiny hole in the stem; otherwise there are no further external signs of larval occupation. Care must be taken in determining this species, without seeing the larva, as a curculionid weevil Rhinoncus perpendicularis also bores within the stem but the frass produced is black, not granular and has no silk, unlike that of M.niphognatha. The exuviae are shown in lateral view. Pupation is within the stem in a white cocoon. A very rare species known from Kent, Hampshire, Devon and East Sussex.

Data: 27.viii.2022, Stodmarsh, Kent, VC15

Image:© S. D. Beavan & R. J. Heckford