Heterarthrus fiora

    Alternative names
    Heterarthrus aceris
    Description

    The larvae of the sawfly Heterarthrus aceris mine the leaves of Sycamore (Acer pseudoplatanus) producing a large upper-surface (often almost full depth) blotch, without a trace of an initial corridor, beginning in the very tip of a leaf segment. The full grown larva spins itself a disc shaped cocoon within the mine having previously has made a circle of perforations in the upper epidermis with its mandibles. The cocoon is formed, attached to the upper epidermis, and the larva becomes immobile. The perforated circle of epidermis starts to dry, warps, and finally becomes detached from the surrounding tissue and drops to the ground. The resulting excision has a diameter of about 7 mm, and is best seen when the leaf is held against the light (Bladmineerders van Europa).

    Identification difficulty

    Adult, Larva and leafmine (when the host plant is identified)

    Habitat

    Wherever Sycamore occurs.

    When to see it

    Mine: univoltine in early summer.

    UK Status

    Not well recorded, but seems to be widespread in England and Wales.

    VC55 Status

    Rare or under recorded in Leicestershire and Rutland.

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    Leicestershire & Rutland Map

    MAP KEY:

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

    UK Map