T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Janita's Tussock butterfly (Argyrophenga janitae)

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Nymphalidae
Subfamily: Satyrinae
Tribe: Satyrini
Subtribe: Hypocystina
Genus: Argyrophenga
Species: A. janitae
Binominal name: Argyrophenga janitae
Common name:  Janita's Tussock, Tussock butterfly, Tussock Ringlet. Eastern Tussock, Common Tussock

Argyrophenga janitae (Tussock butterfly) is a medium sized butterfly, dark ochre colour with large orange spot covering a large part of each of the four wings. In each of the orange spots on the forewings is a black spot with two white spots. The rear wings have a line of four black eyespots each centred with a white dot. The outside black spots are smaller. The underwing is identical with the earlier double eyespot in the orange spot, posterior are light brown striped dull in the sense of the veins of silver white lines.
Argyrophenga janitae is present only in the Southern Alps of the South Island of New Zealand in grassy habitats at elevations between 500-2000m.
The eggs are laid singly on grasses that include Poa, Festuca, Chionochloa and Agropyron, or they may be dropped randomly among them in flight.
The fully grown larva is a green caterpillar with a pair of pale greenish-yellow dorsal stripes which continue onto the head horns. There is also a thin greenish-white stripe below the spiracles.
The pupa can be either pale green or straw coloured, and is suspended by the cremaster from a grass stem. There is one generation per year in lowland areas but it is suspected that larvae may pass 2 winters at high elevations.
The butterfly flies from mid-November to mid-April; it has a weak bobbing flight. When settling they often land awkwardly among grasses and have trouble finding a footing. They will bask with wings fully outspread in calm sunny weather but keep them closed if it is overcast or breezy. If alarmed they flash open their wings momentarily to expose the diematic ocelli (defensive markings on the wings), and then instantly drop deep into the grass tussocks where the striped undersides of their hindwings afford them excellent camouflage among the stems and grass blades.