Allochronic populations of the black chafer Holotrichia loochooana loochooana (Coleoptera: Scarabaeidae) that occur on Miyako Island, Okinawa, Japan

Abstract

Two behaviorally different populations of the black chafer Holotrichia loochooana loochooana (Sawada) (Coleoptera: Scarabaeidae) were discovered on Miyako Island, Okinawa, Japan. In a population occurring at the tip of the northern peninsula, adult females and males emerge from soil and mate during a long period of time before sunset. In the other populations found in the secondary forest and the sugarcane fields at the central area of the island, adults were observed to emerge and mate during a short period of time at dusk. The males of the former population were attracted to female pheromone during an extended period from mid-afternoon to just before sunset, whereas those in the latter were similarly attracted but only during a short time at dusk. The mean elytron length of males was significantly shorter in the former populations than in the latter populations. These findings might suggest the presence of two allochronic H. loochooana loochooana populations on Miyako Island that are separated by only 12 km. Diversity and differentiation between these two populations are discussed.