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Noctuidae : Acronictinae

Knot Grass

ACRONICTA (Viminia) rumicis (Linnaeus, 1758)
Picture
Life Cycle Guide
Picture
Description
Wingspan: 30-35mm
Worldwide Distribution: Europe : North Africa : Asia-to Korea and Japan
UK Distribution: Resident : England,Ireland,Wales,Isle of Man and Channel Islands-Well distributed and frequent. Scotland-Mainly lowland
UK Conservation Status -
  • Common = >300 10Km Squares
  • BAP : 2007 - Priority Species
  • Vulnerable 
  • NERC S.41 : 2008 (England) & NERC S.42 : 2009 (Wales) - Species "of principle importance for the purpose of conserving biodiversity"
  • Northern Ireland : 2010 - Priority Species
European Conservation Status -
  • Least Concern
Original Species Name -
  • Phalaena rumicis (Linnaeus, 1758)
Type Species - Acronicta
  • Phalaena leporina (Linnaeus, 1758)
Type Locality -
  • Not Specified
Flight Period: Southern Britain-end March-end June & July to early October-Bivoltine-two generations : Midlands,northwards-May-July-single generation
Habitat: Woodland : Gardens : Heathland : Downland
Similar Species -
  • Scarce Dagger Acronicta auricoma ([Denis & Schiffermüller], 1775)
Larva: The final instar larva has a base colour of black and is covered with tufts of stiff orange hairs. Viewed from side-a central lateral line of white intermittent marks separated at the abdominal segments with red abdominal segment central marks which carry the stiff hair tufts.Viewed from top-a red central line of marks which temporarily widen at each abdominal segment and two rows of white marks at each abdominal segment which are highlighted in black with each containing the orange hair tufts.End May-early October in the south in two broods.
Pupa: Pupates in a cocoon amongst leaf litter
Overwinters as: Pupa
Observations: The Knot Grass A.rumicis is a common and widespread moth that has rapidly declined by 80% over the past 35 years and as such is identified in the UK BAP priority action plan and carries conservation priority in order to reverse the situation.

The moth has two chalky white spots located along the inner margin or trailing edge of the forewing, located approximately 2/3 distance from the base whereas the Scarce dagger A.auricoma has a white broken postmedial cross-line, being the diagnostic feature.
The Knot Grass has a pair of orbicular spots or rings in black with a black dot situated at the centre of this spot.

The larva of this moth is polyphagous feeding on a wide variety of plants covering many plant families.

The moth is attracted to light and in this case it was found on the house wall about four metres from the light trap.Thay are also attracted to sugar and are known to feed on flowers.

The moth has two generations in the south and a single generation in the north.
Photo Gallery
Larva
Larval Food Plants Worldwide
Note - Plants hyperlinked in red below take the visitor to the relevant plant page on"Plants for a Future" website where further information like photos,physical characteristics,habitats,edible uses,medicinal uses,cultivation,propagation,range,height etc. are clearly listed.
  • Plant Families - in bold red below takes the visitor to the relevant "Lepi-plants" page where other butterflies & moths using the plants below are listed.
Larval Food Plants
Taxonomy
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Type Species - ACRONICTA:

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Type Locality:
Animalia
Eumetozoa
Arthropoda
Hexapoda
Insecta
Lepidoptera
Noctuoidea
Noctuidae
Acronictinae
ACRONICTA Ochsenheimer, 1816
Viminia Chapman,1890
Acronicta (Viminia) rumicis (Linnaeus, 1758)
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Phalaena leporina (Linnaeus, 1758)
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PHALAENA Noctua Rumicis (Linnaeus, 1758)
= Acronycta salicis Curtis, 1826
= Acronycta diffusa Walker, 1857
= Acronycta rumicis pallida Rothschild, 1920
= Acronycta rumicis rumicina Bryk, 1949
= Apatele rumicis oriens Inoue & Sugi, 1958.
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Phalaena rumicis rumicis (Linnaeus, 1758)
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Syst. Nat. (Edn 10) 1 : Title Page : p.516 - n.112
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Not Specified