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Contents > Butterflies > Resident > Ringlets > Harris's Tussock

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Harris's Tussock

 

Argyrophenga harrisi

	Ovum Larvae Pupa Imago Classification Habitat Food Plants Lifecycle Unknown Facts

Distribution & Status Rare Found in North West Nelson, Mt Owen and Lewis Pass. It has declined due to improved pastures for farm animals and burning of Tussock areas to improve the palatability of Tussocks for Sheep. Observations map

Scientific Classification More info Family Nymphalidae SubFamily Satyrinae Tribe Satyrini SubTribe Coenonymphina Genus Argyrophenga Taxon harrisi

Also Known As;

Tussock Ringlet, Nelson Tussock

Description

A native species of Butterfly that still needs farther study and whose life history is not well known. (See bottom of page for unanswered questions). Suspected lifecycle is one year in most of its range and maybe longer in the sub-alpine areas of range, since third, forth and fifth instar larvae have being found in early spring in Tussocks adjacent to snow patches after overwintering. It is very well camouflaged with closed wings, as they have silver streaks on the underside of the back wings that blend in with grass blades. Harris's Tussock prefers wetter areas then the Common Tussock. Harris's Tussock has the smallest range of the 3 Tussock Butterflies and only overlaps Janita's Tussock in the Tasman Mountains where both species fly together. The ovum and pupa are nearly the same on all three Tussock Butterfly species. It is named after Mr AC Harris in recognition of his life-long work on NZ insects.

Ovum  In English

Ovum are either laid singularly on the foodplant or dropped when flying above the foodplant. Uniform white to pale-green for first 2 days, then become mottled brown in colour. Just before hatching the general colouration becomes silvery due to a layer of air between the shell and the larva inside. Barrel-shaped with 15-18 vertical ribs. They hatch after approx 6 days. Upon hatching, the larva chews around the crown and pushes it up to leave, then most of the shell is eaten by the newly hatched larva for it's first meal.

Larvae  In English

It is sleek leaf-green with predominant white sub-dorsal stripe that is as wide as the lateral stripe down the side, tapers towards the tail and has distinguishing short brown setae. It has a bifid head and tail. They have 5 instars. They usually spend their resting time head-down below the notch they are presently eating. This can take several days as they are slow eaters. They eat through the leaves of Tussock or grass leaving small elongated notches along the margin. As they are elongated larvae and almost the same colour as the leaves, they are very well camouflaged. They are very similar to the Forest Ringlet larva, but unlike the Forest Ringlet, the first instar larvae have a pale-brown head instead of a black head. Tussock larvae also have setae which are absent on the Forest Ringlet. Before pupating, they spend about 2 days head-down on a leaf with their anal prolegs attached to a silken pad, however they use all their prolegs to hold onto the leaf unlike the Forest Ringlet, which hangs free. Grows up to 28mm when fully grown.

Pupa  In English

Greenish with varying markings and a forked head. It is elongated and attached to Tussock leaves by cremaster and usually lies flat along a blade for disguise in the heart of the plant. Pupation lasts between 12 to 18 days.

Imago  In English

The imago has a 33-44mm wingspan, male average and female average is 40mm. Flight is weak and takes on a hopping appearance. They quite often land roughly and then have to find their footing. In full sun they keep their wings wide open, but quickly close them if there is any disturbance, including wind. I have observed that if faced with danger while resting or just landed near the top of a Tussock, it will flash its wings quickly (like an Admiral or Monarch), then immediately as drop low as possible into the Tussock with its wings closed. Historical literature notes similar behaviour while flying. Both genders have black spots with 2 white ocelli on the forewings and several black spots with 1 white ocelli each on the hindwings. Even so the ocelli are on the upper wing surface, they show through to the underside. Has reduced orange wing patches, but has brown scaling to outline the veins on all wings compared to the Common Tussock and Janita's Tussock. Sometimes the eye-spot occupies almost the entire orange wing patches. Sexual dimorphism is reduced compared to the Common Tussock, the females are only slightly lighter on the golden-yellow wing patches then the males. The definitive feature of Harris's Tussock is that the silver border on the underside of the hindwing does not go forward of the silver stripe which meet at the front outer edge. This silver border goes farther forward on the Common Tussock. Males appear more common, but is probably due to them spending more time on the wing.

Habitat

Montane to subalpine tussock, between altitudes of 800-2000m.

Food Plants

Broad-leaved Snow Tussock (Chionochloa flavescens) in the sub-alpine zone, Snow Tussock (Chionochloa spp) and Other Tussock's (Poa spp).

Lifecycle

Note: there is possible inaccuracies for the egg, larvae and pupation stages.

Unknown Facts

Harris's Tussock is a species of Butterfly that still needs farther study.

Unanswered questions are;

• How long is the period the ovum take to mature?
• What are the 'other' Tussocks and grasses they use for foodplants?
• Their distribution?
• Their lifecycle - is it different from other the other Tussock Butterflies?
• Is there a short summer generation?
• Altitudinal variation?
• Courtship behaviours?
• Do they hybridise with other Tussock Butterflies?

Please contact nzButterfly.info if you can answer any of the above questions.

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Contents > Butterflies > Resident > Ringlets > Harris's Tussock