Newsletters


Issue Number #36
Issue Date Spring 2006
Number of Articles Online 1 Articles
Download Print Version Newsletter36.pdf
Download Size 478 kB
Estimated Download Time (broadband) 1 minute
Estimated Download Time (dialup) 2 minutes

Return to Newsletter Index   Return to Article Index

Title Threatened Butterflies of Tasmania
Author Mary Jolly

Synopsis of a Presentation by Dr Phil Bell, (Zoologist, Threatened Species Section, DPIW) at the AGM of the Understorey Network 2006.

Phil's talk was accompanied by a very interesting variety of images showing examples of typical habitat, caterpillars feeding and pupae sheltering on the understorey plants vital for their survival and also the monitoring activities of his department.

Introduction

There are less than 40 species of butterflies native to Tasmania and these belong to four major groups.

Skippers (Family: HESPERIIDAE) 10 species, 2 of which are listed as Endangered.
Browns (Family: NYMPHALIDAE) 14 species, 1 of which is listed as Vulnerable.
Blues (Family: LYCANAENIDAE) 9 species, 2 of which are listed (1 Rare).
Swallowtails (Family: PAPILIONIDAE) 1 species - not listed as threatened.
Whites (Family: PIERIDAE) introduced species.

This synopsis presents brief notes on distribution, habitat, life history and threats in relation to four of the five listed species.

The Skippers

All skippers have an erratic flight pattern.

Chaostola Skipper (Antipodia chaostola leucophaea - Endangered)

Distribution
Restricted to a few localities on the east coast including Freycinet, Little Swanport, Hope Hole Bottom, Hobart, Kingston and Coningham. On the wing in open eucalypt forests from mid-October to mid-December.
Habitat
Food plant Gahnia radula, G.microstachya, G.grandis. Dry sedgey or heathy forest/woodland on east coast with the above food plants in the understorey. Forest communities include E.amygdalina on sandstone, E.tenuiramis on granite, the latter especially inland.
Life history
Chaostola skipper has a two year lifecycle. Larva forms shelter by joining leaves of its food plant with silk and it pupates in the shelter.

A distinguishing feature is that the Chaostola skipper forms the opening of its shelter tube at the bottom - all others have the entry at the top of the tube.
Threats
The main threats to this butterfly are habitat clearance for agriculture, residential development and plantations, grazing, destruction of its food plant Gahnia radula during forest harvesting operations and roading, and habitat fragmentation.

Marrawah skipper (Oreisplanus munionga larana - Endangered)

Distribution
Coastal between Temma and Woolnorth, Welcome Swamp and Welcome River and sighted at Penguin in 2005, indicating that there may be additional potential habitat on the NW Coast and islands. On the wing in a very small area around Marrawah in the far northwest of Tasmania mid-January to mid-February.
Habitat
Food plant Carex appressa. Lives in Carex appressa dominated sedgeland and grassy sedgeland; Melaleuca ericifoliascrub; M.ericifolia forest but also wet Eucalypt forest (tall E.obliqua / wet E.brookeriana) with groundcover dominated by C.appressa.
Life history
Larvae form tube shelters with Carex leaves and pupation takes 14-18 days.
Threats
Grazing by cattle which eat the food plant and trample habitat, land clearance, and, as well as direct destruction of habitat, indirect effects such as changes in drainage patterns, insecticides etc. Fire can kill an entire population and in the absence of disturbance Carex habitat is often lost.

The Blues

The Blues can be blue, brown or orange in colour and are usually small in size. There are several subspecies, some showing strong regional differences.

Tasmanian hairstreak (South Coast variety) (Pseudalmenus chlorinda myrsilus - Rare)

Distribution
In southeast Tasmania on the Forestier and Tasman Peninsulas, opposite Maria Island. Cape Frederick Hendrick, Coal Mine Hill, Lime Bay, Mount Stewart, Saltwater River and Rheban Spit.
Habitat
At Cape Frederick Hendrick, in coastal E.amygdalina forest and at Lime Bay, Saltwater River and Rheban Spit, in E.Viminalis coastal shrubby forest. There is potential habitat at Seven Mile Beach, Marion Bay and Maria Island.
Life history
Food plants are Acacia dealbata, A.mearnsii and A.melanoxylon while its pupation/larval site is under the bark of nearby mature E.viminalis. A Special feature is it's complex life cycle involving the wattles, E.viminalis and a small ant. There is an obligatory relationship between the caterpillar of this butterfly and a small black ant called Anonychomyrma biconvexa.

The eggs are laid on twigs of silver wattle. Caterpillars feed by day on leaves and can be in aggregations. They will pupate on blackwood in cracks or crevices of rough bark, but generally on silver wattle, under loose bark on nearby white gum, under stones, hollow branches or curled leaves on the ground. Their choice of pupation site is influenced by the presence of attendant ants. Larvae develop over late spring to early summer (about 1 month). The pupae are dormant over winter with adults emerging in the following spring.
Threats
Clearing of known and potential habitat; repeated firing at high frequency; fragmentation of populations; disturbance of one or more links in the complex life cycle. There were 42 sites recorded in 1977 (Couchman) and by 1987 65% of those were locally extinct and 24% at risk (Prince).

The Chequered Blue is also on the Threatened species list and can be found in saltmarsh at Cambridge Airport, Hobart and has also been recorded on Flinders Island.

The Browns

Ptunarra brown (Oreixenica ptunarra - Vulnerable)

There are several other species of brown very easily confused with this vulnerable species.

Distribution
Eastern and Southern Midlands, Central Highlands and Northwest Plains from 400-1000m but mainly above 600m.
Habitat
Food plant is Poa spp. Lives in Poa grasslands and grassy sedgelands (Gymnoshoenus/Lepidosperma); grassy Poa shrubland with Hakea microcarpa / Richea acerosa and grassy Poa woodland and forest with E.rodwayi, E.pauciflora, E.ovata and E.delegatensis, E.viminalis and E.globulus.
Life history
Eggs are laid in Poa tussocks. They hatch after 6 weeks but the caterpillars are inactive over winter. They feed during spring then moult and pupate in the tussocks. Pupation takes 5 weeks and the adults emerge in autumn. Their flying season is for 2-3 weeks in March/April when they fly from 10 am to 4 pm on calm, warm, sunny days.
Threats
Conversion of Poa grassland to exotic pasture/cropland or plantation; fragmentation of habitat; degradation of habitat due to grazing, burning and insecticide drift. Further threats are posed by the European wasp and a danger of being ingested by stock.

There will be many members peering ever more closely at Carex appressa, Gahnia radula etc. on bush excursions and seed collecting days after this engrossing presentation.


Copyright 2000-2009, Understorey Network Incorporated. Updated 2014-10-24
Database development and website design by Andrew Smith