wgnco-52656 COASTAL BUTTERFLIES AND MOTHS OF WELLINGTON AND SOUTH WAIRARAPA Brian H Patrick Otago Museum Box 6202 Dunedin 1. INTRODUCTION 1.1 The Setting It has long been recognised that the wild coastline of the southern North Island is home to a rich array of native insects and plants. Rich not just because of an abundance of species but also because an upland element – species more typical of alpine and montane areas of the South Island is present. This is an exciting coastline for the naturalist with high cliffs and steep slopes clothed in low shrubs, herbs and grasses, scree-like gravel slopes and beaches, rocky headlands and shrubby hillsides. Contrasting bone-dry divaricating shrublands on one hand and lush sedgelands and herbfields sheltering in low forest on the other. The landscape is high in natural values. In many ways this coast looks and feels like part of the upland South Island, and in fact many of its species are either the same or closely related to such species in upland habitats on the other side of Cook Strait. Several high profile insects are present on this coastline, although neither is widespread there. These include the following; Huttons speargrass weevil Lyperobius huttoni a large-bodied species typical of the eastern South Island high country Myers black cicada Maoricicada myersi a southern Wellington endemic species The former is an upland species here at its northern limit – possibly a relict distribution (Fleming 1971). It is more widely known from the eastern South Island south to the Waitaki River, while the latter has most of its close relatives singing from rocky vantage points on the many peaks of the South Island. Fleming (1971) elegantly described this black cicada species and circumscribed its distribution, song and ecological association. Patrick (1994) reported on the butterflies and moths of the coastline of the southern South Island and also found an upland fauna component on that similarly rugged coastline. Sawyer et al (1998) documented the many threatened and rare New Zealand native plants that survive in refugia on this coastline. Rogers & Walker (2005) noted that the South Wellington coast was rich for native plant families, genera and species. They also noted that eleven species growing on this coastline have a limited distribution, being confined to up to two additional areas. 1.2 Previous Sampling Effort R.M. Sunley reared moth larvae associated with coastal plants at Makara particularly Pimelea prostrata (Sunley 1911). He recorded three significant moth species from this then common hostplant – Meterana pictula, Ericodesma aerodana (as Tortrix indigestana) and Notoreas new species (as Lythria perornata) 1 wgnco-52656 (Hudson 1928). George Hudson himself collected on the coast including the type of the obscure Scoparia humilialis at Sinclair Head (Hudson 1951). David Gaskin comprehensively sampled the moths by way of a light trap from 1962-1964 at his Karori home in Wellington (Gaskin 1964a, b, c & d). Using a 150 watt clear bulb over three hours per night he recorded 170 species of moths over these two years. Interestingly none of the rare or threatened moths which are the focus of this study were found in his trapping programme. John Grehan performed an insect survey of Somes Island (Matiu) in Wellington Harbour in which he sampled the Lepidoptera (Grehan 1990). No rare moth species were found but he interestingly commented on the biogeography of the insect species he did find and recognised strong links to the South Island high country. 1.3 Possible Sampling Regime It is clear, based on the above summary of entomological research, that the night-flying moths of this coastline have been somewhat neglected. Modern technology in light trapping can quickly and efficiently reveal the presence of nocturnal species that are otherwise difficult to detect. The presence of nocturnal moth species that have been fortuitously discovered and known from single or very few collections can be relatively easily confirmed or not. This survey, in contrast to my previous ten entomological visits to this coastline, concentrated on sampling nocturnal moth species while not ignoring diurnal butterfly and moth species. 1.4 Aim Of This Survey A survey of moth species of this coastline was undertaken for the Department of Conservation to ascertain the conservation status of a suite of data deficient and possibly threatened moth species (MacGuinness, 2001, Patrick & Dugdale, 2000). The aim of this survey was to not only to attempt to find these species (listed below), but to try to tie each species, if found, to a certain community and if possible hostplant. This additional information would be invaluable in any future management of either the moth species or their communities or both. 1.5 The Species • MacGuinness (2001) lists these eleven data deficient moth species as follows: (author and Type Locality if in Wellington region is added) Geometridae Notoreas new species “Wellington” Helastia siris (Hawthorne 1897) Cape Terawhiti, Wellington Austrocidaria lithurga (Meyrick 1911b) Makara Noctuidae Bityla sericea Butler 1877 Graphania omicron (Hudson 1898) Karori, Wellington Meterana pictula (White in Taylor 1855) Tortricidae Ericodesma aerodana (Meyrick 1881a) Tineidae Erechthias lychnopa Meyrick 1927a Sinclair Head, Wellington 2 wgnco-52656 Oecophoridae Chersadaula ochrogastra Meyrick 1923 Breaker Bay, Wellington Izatha rigescens Meyrick 1929 Howard Point, Wellington Harbour Elachistidae Elachista eurychora (Meyrick 1919) Paekakariki • Patrick & Dugdale (2000) catagorised the eleven species as follows: Category C (known only from Type Locality) Chersadaula ochrogastra, Erechthias lychnopa, Izatha rigescens & Graphania omicron Category D (Uncommon or rare, biology unknown) Austrocidaria lithurga, Bityla sericea & Helastia siris Category E (Type Locality grossly altered) Elachista eurychora Category G (Hostplant, niche at risk) Meterana pictula, Ericodesma aerodana & Notoreas new species 2. METHODS 2.1 Timing A two week-long survey in mid summer was planned to coincide with the flight season of the maximum number of the listed potentially threatened taxa. Key sites were chosen for this survey from my previous experience of this coastline in the field and from a study of topographic maps looking for other strategic sites. Table One presents a list of the present survey together with the previous ten expeditions that sampled this coastline in different seasons, noting other entomologists who accompanied me. 2.2 Sampling sites 2.2.1 Light trapping was carried out at the following sites during the 2003-2004 Expedition: • Orongorongo River mouth area shrublands • Turakirae Point Scientific Reserve • Windy Point • Waitetuna Stream, Cape Palliser • Kirikiri Stream, Cape Palliser • Sinclair Head 2.2.2 Whereas day collecting was performed at: • Orongorongo River mouth area – coast and shrublands • Baring Head to Turakirae Point • Windy Point • Palliser Bay • Lake Ferry to Cape Palliser • Te Humenga Point 3 wgnco-52656 • Red Rocks to Sinclair Head • Waitetuna Stream to Te Kaukau – White Rock 2.3 Sampling Methods Sampling was done by both day and night although it was expected that night time light trapping would be the most productive based on the habits of the particular species involved. The light trapping utilised a 240 volt powered 250 watt mercury vapour, ultra violet light bulb. Otherwise hand sampling of plants for larvae and adult moths or catching day flying moths with a net was employed with success. Several species were successfully reared back in Dunedin that were not found as adults during the survey timeframe. John Dugdale’s Lepidoptera catalogue (Dugdale 1988) proved to be a reliable and interesting guide to the early records from this coastline, leading to many forays into the older literature in pursuit of “old moth records” and “old moth identities”. All specimens collected are pinned and stored dry in the Natural History collections of the Otago Museum, Dunedin. Table One List of Expeditions to Coastal Wellington & South Wairarapa Coast by the author July 1978 Coastal Wellington City 9-12 May 1988 Turakirae; with John Grehan 13-14 November 1992 Pencarrow; with George Gibbs and John Grehan 2-3 May 1994 Mana Island; with DoC Conservancy Scientists 24-26 November 1994 Titahi Bay; with Greg Sherley 13-14 November 1996 Lake Ferry - Cape Palliser – White Rock; with Holly Patrick 6 February 2000 Makara 8 April 2001 Onoke Spit; with Aalbert & Susan Rebergen 28-30 October 2001 Te Humenga Point – Cape Palliser; with George Gibbs 12-13 April 2003 Lake Ferry - Cape Palliser; with Hamish Patrick 29 December 2003 – 12 January 2004 Red Rocks - Sinclair Head, Baring Head - Turakirae, Windy Point, Lake Ferry – Te Kaukau; with Christine, Holly & Hamish Patrick 3. RESULTS 3.1 Weather The 2003-2004 Expedition was fortunate in having superb weather for almost all of the sampling. The hot daytime temperatures and warm, calm night-time weather greatly increased the success of the survey. This is epitomised in the capture of 78 and 100 species of moth attracted to light on two consecutive nights (1st and 2nd January 2004) at Waitetuna Stream and Kirikiri Stream, Cape Palliser respectively. 3.2 Survey Results Table Two lists the total Lepidoptera from all eleven expeditions to this coastline by the author, with notes on the significance, hostplant, ecology and distribution of the species. 4 wgnco-52656 5 wgnco-52656 Table Two: Lepidoptera of Coastal Wellington & South Wairarapa Coast T = Type Locality X = recorded