Biology of the invasive delicate skink (Lampropholis delicata) on Lord Howe Island

Abstract

Lord Howe Island (LHI) is a remote oceanic island in the south-west Pacific that is World Heritage listed due to its diverse, and largely endemic, biota. A suite of introduced species have colonised the island, resulting in the widespread population declines of many native species. The delicate skink (Lampropholis delicata DeVis) was accidentally introduced to LHI from mainland eastern Australia, but there has been no detailed investigation of its biology on the island, or its potential impact on the native biota. We conducted a detailed study of the distribution and biology of the delicate skink on LHI over a six-year period (2007–12). The delicate skink was introduced to LHI in the 1980s, and rapidly spread across the island. It presently occurs in all 21 low-elevation vegetation communities on LHI. The delicate skink is diurnal on LHI, and displays seasonal variation in activity with a peak in November–December. The delicate skink exhibits sexual dimorphism with females having larger body and abdomen sizes and males having longer and broader heads, although the degree of genetic admixture may influence morphology on LHI. Females reproduce in spring and summer (September–February), with a positive relationship between body size and clutch size. Clutch size ranges from 1 to 7 (mean 3.4) and communal egg nests (11–200+ eggs) are common. Tail loss is common on LHI (55%), but is more frequent in adults and females. We conclude that, based on its distribution and abundance, the delicate skink has the potential to impact the diverse and endemic invertebrate fauna on LHI.

Patterns of niche filling and expansion across the invaded ranges of an Australian lizard

“…Europe, north‐eastern USA), including noted biodiversity and reptile hotspots such as south‐east Asia, South America, central Africa, and Madagascar. The potential for L. delicata to outcompete native lizard species in Hawaii (Baker ), Lord Howe Island (Chapple et al ), and New Zealand (Peace ) has led to biosecurity protocols being developed for the species to limit its spread within these introduced regions (Chapple et al , ). Similar protocols should be adopted in the regions identified in the current study as being highly suitable for L. delicata , to prevent its continued spread across the globe.…”

Sex‐specific shifts in morphology and colour pattern polymorphism during range expansion of an invasive lizard

“…Despite the presence of intraspecific hybridization in the central and southern regions of Lord Howe Island among individuals from different native‐range source regions (Chaplin, ; Chapple, Miller, et al., ; Chapple et al., ; Moule et al., ), no morphological shifts in shape were observed on the island. This result is in contrast to the invasive range of the brown anole ( Anolis sagrei ), where there was a positive relationship between the extent of morphological change and the degree of genetic admixture present within the invasive population (Kolbe, Larson, & Losos, ).…”

“…The Lord Howe Island population was treated as three separate invasive populations because each region of the island has different source clades. The northern portion of the island was colonized by the source Clade 5; the central region by Clades 3, 4, 5 and 9a; and the southern region by source Clades 4 and 9a (Chapple, Miller, et al., ; Chapple et al., ; Moule et al., ; Table ). Additionally, the density of historic sampling in Hawaii also allowed an examination of phenotypic changes over time.…”

“…Intraspecific hybridization (i.e. genetic admixture) has been shown to occur among the four source clades on Lord Howe Island (Chaplin, 2013). Abbreviations for Australian States: NSW = New South Wales, QLD = Queensland.…”

The effect of skin reflectance on thermal traits in a small heliothermic ectotherm

“…This species was selected as it exhibits a high degree of inter-as well as intra-population variability in terms of its: 1) dorsal colouration and patterning, 2) thermal traits and 3) its microhabitat use (Chapple et al, 2014;Wilson and Swan, 2013;Goulet et al unpublished).…”