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Inland Hairstreak (Jalmenus aridus)

The Inland Hairstreak is a small butterfly recorded from the Eastern Goldfields around Kalgoorlie, where it is associated with open woodland and hostplants growing beside open, well-drained ground. Its breeding sites are localised and adults are present for only a few weeks in most years, so check suitable habitat carefully before clearing. In Western Australia it is DBCA Priority 2, a priority category rather than a listing under the Biodiversity Conservation Act 2016.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Priority 2.

Seasonal activity

Adult records are concentrated in October, with a few in November and one in April. Adults are reported to be present for only a few weeks each year, so these records are a guide rather than a guarantee of activity at a particular site.

Adult records: Most records are from October; a few are from November and one is from April.

Survey planning: Prioritise adult searches around the reported flight period and treat non-detection outside it cautiously.

A complete month-by-month activity calendar has not been established, and adults are not confirmed to be present in every reported month each year.

  • Adult flight and survey window: Species records are concentrated in October, with a few in November and one in April. The month scale is not specified here; use these stated records when planning surveys.
  • Planning window: Year-round works planning precaution only. Survey timing and non-detection should be interpreted in light of the short, variable adult flight period.

Identification: Appearance and size

Use the butterfly’s small size and the presence of larvae, pupae or oviposition activity to support identification. Diagnostic detail is limited.

The Inland Hairstreak is a lycaenid butterfly. Its wingspan is about 25 mm. Its colour pattern and other reliable visual identification marks have not been documented.

Identification: Similar species

Similar species and distinguishing characters have not been documented. Do not rely on a brief adult sighting alone where identification is uncertain.

Identification: Field signs

Useful breeding evidence includes larvae, pupae, pupal exuviae, freshly emerged adults, or a female showing oviposition behaviour on a hostplant trunk or lower stem. Larvae may be attended by Froggattella kirbii ants.

Distribution: Known range

Known records are concentrated in the Eastern Goldfields of Western Australia. The species is poorly known, and the full extent of its range has not been established.

The species was originally known from its type locality near Lake Douglas, about 12 km south-west of Kalgoorlie. Later surveys reported additional locations, with the 2023 study documenting 10 locations across an area of about 5,000 km².

Distribution: Western Australian records

The DBCA priority list flags the Goldfields region. Atlas of Living Australia records show 29 Western Australian records at 11 distinct 0.1-degree locations, between latitude -31.2 and -30.6 and longitude 121.3 and 121.7. Records outside Western Australia were excluded as likely errors.

Distribution: Survey implications

A lack of records at a site does not confirm absence. The species is difficult to detect because adults are present for only a few weeks each year, and breeding sites can be spatially patchy.

Habitat: Preferred setting

The documented preferred habitat combines suitable hostplants, open woodland structure and adjoining patches of exposed ground. Hostplants or ants alone do not establish that the butterfly is present.

Preferred habitat is open woodland with mature Senna artemisioides subsp. filifolia, mixed flowering shrubs, and open areas of well-drained exposed ground adjoining hostplants.

Habitat: Associated species

The ant Froggattella kirbii must be present at breeding sites. Acacia tetragonophylla and Senna artemisioides subsp. filifolia are reported hostplants, but both the ant and the plants have broad distributions and their presence alone is not a reliable indicator of a breeding site.

Foraging habitat: Larval food plants

Larvae feed on hostplants. Adult nectar use and specific adult foraging behaviour have not been documented.

Larvae feed on hostplant flowers and phyllodes. Reported hostplants are Senna artemisioides subsp. filifolia and Acacia tetragonophylla.

Foraging habitat: Adult feeding

Adult food plants and foraging locations have not been documented. Do not assume that every flowering shrub in suitable woodland is used by the butterfly.

Breeding habitat: Breeding evidence

Breeding is associated with hostplants and the attendant ant Froggattella kirbii. Confirmed evidence of reproduction is more informative than the presence of potential habitat alone.

A breeding site is defined by resident and reproducing butterflies, supported by freshly emerged adults, female oviposition on a hostplant trunk or lower stem, or larvae, pupae or pupal exuviae.

Breeding habitat: Larvae and ants

Larvae feed on hostplant flowers and phyllodes while Froggattella kirbii ants attend them. The association is mutualistic: larvae provide secretions that ants feed on, and ants protect larvae from predators and parasitoids.

Breeding habitat: Breeding-site pattern

Breeding sites are considered spatially patchy and separated sites may be several kilometres apart. The study used a separation of at least 5 km when defining distinct breeding sites.

Sheltering habitat: Known information

Specific shelter or resting sites have not been identified for this butterfly.

Specific sheltering, roosting or overnight resting locations have not been documented. The reported open woodland habitat and hostplants do not confirm a particular sheltering feature.

Sheltering habitat: Precaution

When suitable habitat is present, retain hostplants and adjoining vegetation where practicable rather than attempting to identify or clear presumed resting sites.

Threats: Conservation status

Species-specific threats have not been formally assessed. Habitat disturbance is a practical works-site risk where suitable habitat or a breeding site may be present.

No national listing is recorded.

Threats: Works-site risks

Clearing or disturbance could remove hostplants, adjoining open-ground habitat or breeding-site features. This is a precautionary assessment of potential project impacts; these are not formally assessed species-specific threats.

Threats: Knowledge gaps

The species is poorly known, and its short adult flight period and patchy breeding distribution make absence difficult to establish from limited surveys.

Survey methodology: 1. Desktop assessment

The 2023 study reports that searching for adults is the practical way to survey for breeding sites. Survey timing and effort should account for the short flight period and the difficulty of searching for highly localised immature stages.

Review available species records, DBCA information and proposed clearing boundaries. Map mature Senna artemisioides subsp. filifolia, Acacia tetragonophylla, open woodland, mixed flowering shrubs and adjoining exposed ground as habitat features to inspect, not as proof of occupancy.

Survey methodology: 2. Time field searches

Plan adult searches around the reported flight period. Most specimen records are from October, with a few from November and one from April; adults may be present for only a few weeks each year. These records do not guarantee the flight period at a particular site or in a particular year.

Survey methodology: 3. Search suitable patches

Search potentially suitable habitat for adult butterflies, giving attention to hostplants and the adjoining open areas described for the species. Record survey date, conditions, search effort, habitat and any observations.

Survey methodology: 4. Check breeding evidence

Where adults or suitable habitat are found, check hostplants for larvae, pupae, pupal exuviae and oviposition behaviour where this can be done without damaging vegetation. Broad searches for immature stages are not practical because they are extremely localised and hostplants are numerous.

Vegetation associations: Woodland

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

Preferred habitat is open woodland with mature Senna artemisioides subsp. filifolia, mixed flowering shrubs, and open areas of well-drained exposed ground adjoining hostplants.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: WA.

Habitat use: general

Attribution gap: No sentence-level reference is attached to the original profile block. Review the profile bibliography; this candidate is not source-verified.

Ecosystem associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific ecosystem association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Soil and substrate associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific soil association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Water and wetland associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific water association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Fauna records and mapped habitat: Not yet analysed

Record locations can be overlaid with mapping, but record frequency alone does not measure habitat preference. No species is excluded from desktop assessments by this analysis.

No quality-controlled record-to-map analysis has been completed for this species. The existing generalised distribution dots and indicative range polygons have not been treated as precise occurrence coordinates.

A defensible run needs dated, independently attributable records, coordinate uncertainty, duplicate and captive-record checks, layer versions and regional scope. Preference and absence require additional survey-effort and detection evidence.

Habitat limitations and contrary evidence: No supported exclusion recorded

Not recorded is not the same as cannot occur. Low suitability, resident habitat, breeding habitat and occasional movement are different conclusions.

This library has not established a vegetation, ecosystem or soil-type exclusion for this species. This does not mean all habitat is suitable; the evidence needed to justify an exclusion has not been assembled.

Habitat limitations and contrary evidence: Before using a negative association

  • Confirm the taxon, geographic region, life stage and habitat function covered by the evidence.
  • Check survey methods, season, repeated effort and detectability before interpreting non-detection.
  • Investigate credible contradictory records and microhabitats absent from broad mapping.
  • Do not convert a missing map class, low record count or failed data request into species absence.

Before habitat disturbance: 1. Review records and plans

Plan clearing around the possibility of a localised breeding site where the documented habitat occurs. A vegetation or ant record alone cannot confirm presence or absence.

Check the latest available fauna records and determine whether proposed works overlap known locations or potential habitat. Confirm the project’s applicable environmental approvals and referral requirements.

Before habitat disturbance: 2. Map habitat features

Before clearing, map mature Senna artemisioides subsp. filifolia, Acacia tetragonophylla, mixed flowering shrubs, open woodland and adjoining exposed, well-drained ground. Avoid treating hostplants or Froggattella kirbii alone as evidence of a breeding site.

Before habitat disturbance: 3. Survey and brief crews

Arrange appropriately timed adult searches where suitable habitat may be affected. Brief spotter catchers and clearing crews on the reported signs of breeding and on the need to stop and report any suspected Inland Hairstreak or breeding evidence.

During habitat disturbance: 1. Check the work area

Use a cautious, staged approach where clearing overlaps suitable habitat, particularly if butterflies or breeding evidence are found.

Before each clearing stage, check the marked habitat and any approved exclusion areas. Watch for adult butterflies around hostplants and for larvae, pupae, pupal cases or oviposition behaviour.

During habitat disturbance: 2. Stop and report

Pause work in the immediate area if the butterfly or credible breeding evidence is detected. Notify the environmental lead, record the location and observation, and obtain advice before resuming.

During habitat disturbance: 3. Keep disturbance controlled

Keep vehicles, personnel and materials within approved work areas. Avoid unnecessary damage to hostplants and adjoining habitat while the observation is assessed.

After habitat disturbance: 1. Record outcomes

After work, document outcomes and check that retained habitat and any agreed controls remain in place.

Document clearing locations, survey effort, detections, breeding evidence, stop-work actions and any habitat retained. Provide records to the project environmental lead for follow-up and reporting.

After habitat disturbance: 2. Inspect retained habitat

Check that marked hostplants, adjoining open-ground habitat and exclusion areas have not been unintentionally disturbed. Report damage or new observations promptly.

After habitat disturbance: 3. Review future work

Use survey results and any confirmed breeding evidence to inform later work stages. Do not interpret a survey outside the reported adult flight period as definitive evidence of absence.

Rehabilitation actions: 1. Retain habitat where possible

Habitat features and larval hostplants are known, but a species-specific rehabilitation method has not been established. Plan any rehabilitation as a precaution and assess it over time.

Prioritise avoiding impacts to existing hostplants and associated habitat. Retaining established vegetation is preferable to assuming replacement planting will recreate a breeding site.

Rehabilitation actions: 2. Restore relevant features

Where rehabilitation is required, consider the documented habitat components: open woodland, mature Senna artemisioides subsp. filifolia, mixed flowering shrubs and adjoining open, well-drained ground. A planting prescription or restoration timeframe has not been established.

Rehabilitation actions: 3. Monitor and adapt

Record plant establishment and habitat condition, and arrange appropriately timed checks for adults and breeding evidence. Do not claim that rehabilitation has recreated occupied habitat unless supported by survey evidence.

Sources