Host plants:
The larvae usually feed on as well decaying and green leaves of swamp grasses like reed, sedges or Phalaris arundinacea. However, in rearing after hibernation, green leaves of Dactylus have been prefered to dead one. Occasionally the larvae will also feed on decaying material of other plants.
Habitat:
Macrochilo cribrumalis inhabits wet, rarely mown meadows, reed-beds with Phragmites and Carex, shores, open swamp woodlands and similar places.
I recorded the larva in an accumulation of mown sedges already in hibernation in mid-November 2020. The site was the shore of the river Iller near Memmingen (S-Germany). It consisted of a broad reed belt on the waterside and then - more inland - a water-logged sedge belt. The sedge belt is unfortunately partially mown and nowadays used as a disposal of liquid manure by agriculture. This time it was mown even into the otherwise fallow part. The larva was found at the transition zone mown-unmown in a heap of Carex leaves that had been cut but not removed. Groves occurred some ten meters away, but not at the spot of the record.
In early April 2021 I recorded many larvae in penultimate instar in a small open Scirpus sylvatica / Carex swamp in wet woodland with Lopinga achine also near Memmingen.
Life cycle:
The larva hibernates in the penultimate instar. It may be found between late August and May. In winter it withdraws to accumulations of dead reed and sedge leaves near the ground. The moths occur in one generation between June and early August.
Endangerment factors:
Many sites have already been destroyed by intensification of agriculture. Other threats are too heavy bush encroachment, afforestation or overbuilding.
Remarks:
The usually local and regionally missing species occurs in Europe from southwest France across the southern foothills of the Alps and parts of the Adriatic region to the Carpathians and in the north from east England to southern Finland.