Simacauda dicommatias

Simacauda dicommatias is native to temperate Andean forests in Argentina and Chile. In 2020, larval feeding signs were found in Cornwall, Great Britain; the first known record of this species for the UK and mainland Europe.

Ovum Eggs have not been observed but are likely to be inserted into the underside of a leaf of Chilean myrtle, preferring new growth towards the end of a stem.

Larvae The larvae mine the leaves, initially in a long gallery filled with black frass and often cross the midrib. The mine terminates in a small, irregular blotch often at, or near the edge or tip. Larvae then leave the mine making a larval case from the blotch; it then makes a further two cases from leaves. In Cornwall the species is univoltine with tenanted mines found in late March, late June and in the autumn. Larvae have not been found in Argentina or Chile.

Pupa The larva pupates in the third case which, is away from the feeding area and attached to the underside of a leaf.

Imago Simacauda dicommatias is similar to Psychoides filicivora and care should be taken when recording either species in Cornwall where both larval foodplants occur.

Food plants. In Cornwall, larvae have been found at twenty-six sites on Chilean myrtle. At one site cases were also found on white Chilean myrtle (Luma chequen), and another on an unidentified Myrtaceae, but could be Myrceugenia ovata.