New locality records for two species of protected weevils, Anagotus fairburni (Brookes, 1932) and Hadramphus stilbocarpae Kuschel, 1971 (Coleoptera: Curculionidae), from southern Fiordland, New Zealand

Tuhinga 29: 20-34

ABSTRACT: The flax weevil Anagotus fairburni (Brookes, 1932) and knobbled weevil Hadramphus stilbocarpae Kuschel, 1971 were among the first New Zealand insects to be granted legal protection. Both are large flightless species with narrow host–plant requirements. Their disjunct distributions are probably the result of predation by introduced rodents, with populations of both having apparently been extirpated by ship rats (Rattus rattus) at one documented site (Taukihepa/Big South Cape Island). Within Fiordland, flax weevils were previously known from a single small island in Breaksea Sound, and knobbled weevils had been reported from five outer islands, from Secretary Island south to Resolution Island. We report the presence of both species in Dusky Sound, and flax weevils in Chalky and Preservation Inlets, based on surveys of 134 islands in 2016 and 2017. Signs of flax weevil feeding were recorded on 56 widely scattered islands, with live or dead animals found on seven of these during the limited search time available. A single knobbled weevil was found at night on a small island in the Seal Islands, southwest of Anchor Island. The status of both weevil species is discussed in relation to the past and present distribution and control of rodents and stoats.

KEYWORDS: Anagotus fairburni, conservation, distribution, Fiordland, flax weevil, Hadramphus stilbocarpae, knobbled weevil, rats, Rattus norvegicus, Rattus rattus, threatened invertebrates.