Orocrambus fugitivellus (Hudson, 1951)
Orocrambus fugitivellus (Hudson, 1951)
Current DoC threat status
Nationally Critical.Recognition / similar species
Similar to Orocrambus jansoni in size, patterning and diurnal activity. However, O. jansoni lacks a conspicuous pale costal streak on the forewing, and the hindwings are dark; O. fugitivellus has a distinct creamy costal streak and the hindwings are pale basally. Orocrambus jansoni is endemic to the central North Island, so in practice confusion is unlikely.
Known distribution and abundance
Known only from one locality in the eastern Mackenzie Basin; broadly in the Grays River headwaters on both sides of Haldon Road between 560-650 m a.s.l. north to Dog Kennel Corner.Adults are locally abundant between late January and late March, and under the best weather conditions can be very abundant flying in calm conditions with hot sunshine.
Habitat
A small corner of the plains of theMackenzie Basin which is presently predominantly short-tussock grassland, much of which is seasonally damp with shallow standing water for periods of the winter and early spring.At present these sites are grazed by cattle and sheep so are a mix of indigenous and exotic grasses; sedges and herbs are present. The moth is most common in summer-dry channels of this habitat.
The most common plants in this habitat are the exotic browntop and natives silver tussock Poa cita, Carex species and Baumea.
Host-plant and biology of early stages
Nothing known, but presumed to feed on a mix of indigenous and exotic grasses, maybe sedges also, from within a larval “sock” at the base of the larval hostplant.
Flight period (months of year) and behaviour of adult
Adults emerge and between late January and late March. The males fly by day (diurnal), low to the ground and are readily seen with their flight pattern, bright coloration and hovering habit. Adults are most common flying in the heat of the day after midday. The female has very small wings and is completely flightless. The flightless females are active from midday when they crawl up grass seed-heads in calm weather.
Potential monitoring technique(s)
A daytime walk-through survey would be effective in monitoring adult numbers. Standardised method including time of year, time of day and maximum of 30 minutes of counting per person would suffice.
Threats
All the known habitat of the moth species is currently under Pastoral Lease, although negotiations to protect some of the moth’s habitat are underway. The moth is doing reasonably well under the current farming regime, though there may be some ongoing degradation of its habitat by normal pastoralism i.e. sheep and cattle grazing. A change to iriigation and intensive dairying would likely make the moth species extinct as this would involve wholesale earth movement and changes that the species could not survive. Given the poor economics of extensive sheep farming, some change is inevitable and is currently being mooted and investigated in the Mackenzie Basin.