Endemics and adventives: Thysanoptera (Insecta) biodiversity of Norfolk, a tiny Pacific Island

Abstract

The thrips fauna of Norfolk Island is a curious mix of endemics and adventives, with notable absences that include one major trophic group. A brief introduction is provided to the history of human settlement and its ecological impact on this tiny land mass in the western Pacific Ocean. The Thysanoptera fauna comprises about 20% endemic and almost 50% widespread invasive species, and shows limited faunal relationships to the nearest territories, Australia, New Caledonia and New Zealand. This fauna, comprising 66 species, includes among named species 29 Terebrantia and 33 Tubulifera, with four Tubulifera remaining undescribed. At least 12 species are endemics, of which 10 are mycophagous, and up to 10 further species are possibly native to the island. As with the thrips fauna of most Pacific islands, many species are widespread invasives. However, most of the common thrips of eastern Australia have not been found on Norfolk Island, and the complete absence of leaf-feeding Phlaeothripinae is notable. The following new taxa are described: in the Phlaeothripidae, Buffettithrips rauti gen. et sp. n. and Priesneria akestra sp. n.; and in the Thripidae, Scirtothrips araucariae sp. n. and Thrips merae sp. n.

Australian mycophagous species of the genus Deplorothrips (Thysanoptera, Phlaeothripinae)

“…Extreme examples of more than one species being found in the same general area are the records given here from two small islands in the Pacific Ocean, with three Deplorothrips species from Lord Howe Island, and four from Norfolk Island. These records from small islands are particularly interesting because the thrips fauna of such places largely comprises introduced species (Mound & Wells 2015). The genus Deplorothrips thus poses complex ecological as well as taxonomic problems, to which this contribution is a basic introduction.…”

Pseudolycoriella skusei sp. nov. (Diptera: Sciaridae), a new dark-winged fungus gnat from Norfolk Island and Australia

“…The first European visitor was Captain James Cook, in 1774, when he briefly landed with a few of his crew while en route to New Zealand (Mound & Wells 2015). In 1788, a penal colony was established, to accommodate convicts from New South Wales and subsequently from Van Diemen's Land (Tasmania).…”

“…The island has been extensively deforested since settlement and subsequent deliberate and accidental introductions of various plant species has further modified the landscape (Mound & Wells 2015). Insects on the island comprise a mix of endemic, native and adventive species (as defined by Mound & Wells 2015).…”

“…Insects on the island comprise a mix of endemic, native and adventive species (as defined by Mound & Wells 2015). Mechanisms of introduction to the island presumably include natural colonization i.e.…”

“…active migration and passive wind dispersal, transoceanic (via logs and other floating detritus) and human assisted movement (accidental or intentional introductions); however the precise mechanism of introduction isn't clear in most cases. See Bickel (2009) for a discussion on the biogeography of Diptera in the Southwest Pacific region, Holloway (1977) for a detailed account of the biogeography of Norfolk Island insects, with a focus on the Lepidoptera, and Mound & Wells (2015) in relation to thrips (Thysanoptera).…”