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Summary. Under field conditions significantly more black chafer, Holotrichia loochooana loochooana (Sawada) (Coleoptera: Scarabaeidae) males landed on black and gray sources than white ones containing 10 mg of female pheromone, anthranilic acid. When a broader spectrum of colours was tested the frequency of male landing was intensively proportional to as the lightness of the colour of the lures. These findings demonstrated that mate location by H. l. loochooana males is dependent on both olfactory and visual stimuli of the source. In contrast, female aggregation was not affected by colour.

Summary. Both male and female Holotrichia loochooana loochooana (Sawada) (Coleoptera: Scarabaeidae) were attracted with female-produced pheromone, anthranilic acid (2-aminobenzoic acid), in the field. Male chafers were observed to apparently directly locate cotton balls impregnated with 1 to 10 mg of pheromone. In contrast, females never directly oriented to the treated balls but landed 0.2-1.5 m away and exposed their abdominal glands in a calling posture, which occasionally resulted in aggregation of both females and males. This suggested the mating aggregation of this species could be primarily induced by pheromone released by females. A hypothesis for adaptability of female aggregation is proposed and discussed.