Clepsicosma sp. ‘Titirangi’ (of Stringer et al. 2012)

Clepsicosma sp. ‘Titirangi’

Current DoC threat status

Nationally Vulnerable

Recognition / similar species

This species somewhat resembles the common Clepsicosma iridia, but is smaller and browner, and lacks the distinct black band with metallic reflections on the hindwing that characterises C. iridia.

Known distribution and abundance

Known from two gumlands and one coastal site in Northland (Whakaruangangana, Ngawha Springs and Uretiti Beach), and from a single coastal site in the Waitakere Ranges, Auckland (Kakamatua Inlet). The single specimen collected in suburban Titirangi in the 1950’s was probably a wanderer from Kakamatua or another unknown site.

Habitat

The exact habitat requirements are uncertain. The chief habitat appears to be gumland. Kakamatua Inlet is close to an area (Spragg Monument) with gumland-like vegetation and the moths collected there may be wanderers from this vegetation. Whether this also applies to Uretiti Beach is unknown. Kakamatua Inlet itself is an estuary with tall wetland vegetation grading into a sandy beach with limited associated dune flora; there are numerous exotic weeds including gorse and pampas grass. It is possible that a plant (probably a native monocot) shared between the coastal and gumland sites is the host and that this is the true determinant of the moth’s presence.

Host-plant and biology of early stages

Unknown. The closely related C. iridia is associated with large Gahnia sedges, e.g. G. xanthocarpa and G. setifolia, in forest; adults always keep close to the shelter of these sedges but the moth has never been reared. This unnamed species has always been collected at light so no plant association has been noted.

Flight period (months of year) and behaviour of adult

Most specimens have been found in February, with a single record from January, and one from late December. Both males and females come to mercury vapour light in small numbers.

Potential monitoring technique(s)

Light trapping with mercury vapour light at known or potential sites is the only possible method of monitoring given our current knowledge.

Threats

The area of gumland habitat is greatly reduced, and some remaining gumlands are on private land and still threatened with destruction; security of the Northland sites for this moth needs assessing. The Kakamatua/Spragg Monument site is protected as part of the Waitakere Ranges Regional Park, but management of the habitat may be an issue given our poor understanding of the moth’s ecology. The gumland-like vegetation at Spragg Monument is gradually reverting to forest; this process was set back by a fire about 15 years ago, which promoted dense new growth of native Cyperaceae and other ground flora. If the moth depends on more open early-successional vegetation (as seems likely given that it has not been recorded in forest), some active management may be needed. If the species is breeding at Kakamatua rather than wandering there, weed encroachment is probably the major threat at this site; however, weeds have been very actively managed there in recent years.

R.J.B. Hoare

Reference

Stringer, I.A.N., Hitchmough, R.A., Dugdale, J.S., Edwards, E.D., Hoare, R.J.B. and Patrick, B.H. 2012. The conservation status of the New Zealand Lepidoptera. New Zealand Entomologist 35(2): 120-127.