RESUMO
Abstract Description of immatures and mating behavior of Liogenys bidenticeps Moser, 1919 (Coleoptera: Melolonthidae: Melolonthinae). Some species of Melolonthinae are associated with several species of cropped plants, with larvae consuming roots and, in some cases, are considered as crop pests. In some agricultural regions of Brazil, larvae of L. bidenticeps are found associated with cultivated plants, and little information is available about this taxon. This study, aiming at expanding the knowledge about the morphology and behavior of this species, provides the description of immatures and mating behavior of adults. The studies were conducted at the experimental farm of the Universidade Estadual de Mato Grosso do Sul in Aquidauana, Mato Grosso do Sul state, Brazil, and the adults were collected with light trap and raised in the laboratory. Mating behavior was documented on video both in the field and under laboratory conditions. Descriptions and illustrations of the third instar larva and pupa are presented. Adults have crepuscular flight activity and their copulation lasts an average of 20.25 min, occurring from 19:00 to 22:00 h. On some occasions, females did not accept males for copulation, indicating an active selection of males by females. Field observations demonstrated that adults feed on Brazilian pepper leaves (Schinus terebinthifolius, Anacardiaceae) and cashew flowers (Anacardium occidentale, Anacardiaceae), where male and female meet each other and copulation occurs.