Distinguishing Male and Female Chinese Rose Beetles, Adoretus sinicus, with an Overview of Adoretus Species of Biosecurity Concern

The Chinese rose beetle, Adoretus sinicus Burmeister (Coleoptera: Scarabaeidae: Rutelinae: Adoretini), is a broadly polyphagous scarab beetle that is economically important and causes damage to a wide variety of host plants including agricultural crops and ornamentals in Southeast Asia, China, the Hawaiian Islands and several other Pacific Islands. The species has become established in numerous regions and is of biosecurity concern because importation of this species to other regions poses a threat to agriculture due to its generalist herbivore feeding habits. Field and laboratory research directed towards control of the species is hampered by the lack of characteristics that allow accurate determination of the sexes on live beetles in the field. Here, three recognizable and reliable non-destructive morphological differences between the sexes of A. sinicus are documented: (1) the form of the terminal sternite; (2) the length to width ratio of protarsomere 1, and; 3) the ratio of the combined length of protarsomeres 2–4 to the length of protarsomere 1. Because many Adoretus species are of biosecurity concern, and because tools to identify Adoretus species are lacking, we review the natural history and research on control associated with A. sinicus as well as the genus as a whole.