Mythimna favicolor (Barrett, 1896)

Host plants:
The larvae feed on grasses of the salt marshes (salt meadows) of the North Sea, especially on Festuca rubra ssp. litoralis, Agrostis stolonifera and Puccinellia maritima. Occasionally also other grasses like Elymus species are also used, but they have low importance.

Habitat:
Mythimna favicolor inhabits especially coastal marshes of the North Sea with salt meadows and there areas that are not too heavily flooded in winter.

Life cycle:
The larva hibernates half-grown (in case of a second generation smaller than in the case of only one generation). In Spiekeroog island a larva was found in mid-March 2024. This larva was obviously still in the same instar in which hibernation occurred. This larva needed two more moults to become mature. The older larvae are active during night and stay near the ground in the grassy felt during daytime. They are usually mature in May. The moths occur between June and early August and often again in a partial second generation between late August and early October. They feed on grass flowers and flowers of plants of the salt meadows like Limonium. In autumn the young larvae often rest higher on the dying grasses as it is the case with most congeners and thus can be beaten.

Endangerment factors:
Mythimna favicolor has already been pushed back severely especially aside of the isles by habitat destroyment (dewatering, intensification, dyking) and too intense grazing. Besides that storms and long enduring inundations become more and more frequent due to global warming.which negatively affects hibernating larvae.

Remarks:
Mythimna favicolor is endemic to the North Sea area and occurs from SE-England across coastal parts of Belgium, the Netherlands, NW-Germany to SW-Denmark. The taxon is closely related to Mythimna pallens and is sometimes considered a form of the latter. Distinct genetic differences are obviously missing. I personally tend to consider it as a distinct species because of the strict habitat binding of favicolor. According to literature typical pallens often occur in adjacent habitats like grey dunes or grasslands. A mixture seem not to happen. But there is still more research needed to fully understand the true nature and relationship of the two taxa.

Literature:
Wegner, H. (2015): Die Salzwiesen-Graseule Mythimna favicolor Barrett, 1896) an der Westküste Schleswig-Holsteins – Beobachtungen zur Bionomie (Lep., Noctuidae). Melanargia 27: 45–52.