Origin, spread and biology of the invasive plague skink (Lampropholis delicata) in New Zealand

The plague skink (Lampropholis delicata) is the only reptile species that has established, and subsequently become invasive, in New Zealand. Native to eastern Australia, the plague skink was first detected in south Auckland in the mid-1960s. A molecular study has identified the source population for the introduction as inland northern New South Wales, near Tenterfield. The plague skink has now spread across the majority of the North Island via human-assisted jump dispersal. It has the potential to extend its distribution to the entire North Island, apart from the Central Plateau region, and also to the Nelson-Marlborough and Canterbury regions of the South Island. Sexual dimorphism exists in plague skink populations in New Zealand, with females having larger body size and interlimb lengths and males having longer and broader heads. Population density appears to influence body size in males. Plague skinks in New Zealand lay eggs, often communally, in sheltered microhabitats, with the eggs hatching in February and March. The mean clutch size varies among populations, and clutch size is positively related to female body size. Plague skinks utilise a wide variety of habitats, both natural and modified, are diurnal and are opportunistic insectivores. The evidence for the impact of the plague skink on the native New Zealand biota is currently equivocal. The plague skink has recently spread to conservation-sensitive offshore islands in the Hauraki Gulf, including Great Barrier Island, promoting additional research into eradicating or mitigating the spread of the species within New Zealand.