A survey of beetle diversity (order Coleoptera) on Lizard Island

The beetles (order Coleoptera) of Lizard Island, a small granitic island on the mid shelf of the Great Barrier Reef, have never been assessed in the scientific literature. Prior to our work, only a single beetle genus had been documented on the island (Caryotrypes Decelle, 1968), based on a single specimen collected in 1993 (Reid & Beatson 2013). We conducted a survey of Lizard Island in April 2019 to determine which beetle families are present on the island and which families are the most diverse. The survey also assessed the beetle diversity in different habitats on the island and two smaller islands nearby. Our sampling yielded 111 beetle morphospecies representing at least 23 families, and showed evidence of differential taxonomic composition across the island. The most diverse families were Curculionidae, Carabidae, Scarabaeidae, Tenebrionidae, and Cerambycidae, in general accordance with global patterns in Coleoptera diversity. Greater habitat complexity and vegetation diversity appeared to correspond with greater beetle diversity at certain collection sites. The most densely forested area of Lizard Island yielded the greatest number of morphospecies, while a patch of mangrove forest yielded the least. Several morphospecies were found to be restricted in distribution, including two found only among beachfront Spartina grasses (families Anthicidae and Phycosecidae)