- Subfamily: Rivulinae
- Wingspan: 18-22 mm
- Flight period: May - Oct
- Spread: Common
- Host plants: Cyperaceae, Poaceae
The Rivula sericealis also called Straw Dot is a moth of the Erebidae family, subfamily Rivulinae, with a wingspan of 18-22 mm.
Visible throughout Europe, it is absent only from Iceland, in Italy it is also present in the islands. *
It is also found throughout the Palearctic region as well as in Japan.
It is a small triangular-shaped moth, which takes its name from the sometimes silky appearance of the wings.
The background color of the anterior wing of Rivula sericealis , varies from yellow / ocher to more or less light brown and also has a large purplish brown spot in the central area of the wing near the costa. This spot is formed by two black points, sometimes just hinted at and outlined in clear, united by a shade of purplish brown flakes. The outer edge shows a semi-smudged orange-brown transverse band with small white dots forming an outer line.
The hind wings are pale ocher with more or less intense brown shades which sometimes cover the entire wing. **
The Rivula sericealis flies from May to October in two generations depending on the location. The habitats where it can be encountered are wet meadows, riparian forests, banks of rivers and streams, river valleys, in general areas with a strong presence of water. Predominantly nocturnal, it soars towards the crisp, and is often attracted to artificial lights.
The eggs are white, spherical, slightly flattened, not smooth. The larva is green with a darker topline and white subdorsal lines, has long sparse black hairs and a greenish head. The pupa is elongated, initially green with two white lines, then changes color to yellow / brown. **
The larvae feed on Cyperaceae, such as Carex sp. And on many belonging to the Poaceae such as Brachypodium sylvaticum and Molinia caerulea.
* Lepidoptera mundi https://lepidoptera.eu/ - Fauna Europea https://fauna-eu.org/
** Bestimmungshilfe für die in Europa nachgewiesenen Schmetterlingsarten - http://lepiforum.de/