Is Megaplatypus mutatus (Chapuis) (Curculionidae: Platypodinae) a threat to Khaya grandifoliola (Meliaceae)? Observations from Brazil

ABSTRACT The ambrosia beetle Megaplatypus mutatus (Chapuis) (Coleoptera: Curculionidae: Platypodinae) is native to South America and is an important forest pest in poplar plantations in Argentina as well as in Italy where it has been introduced. Unlike most platypodine ambrosia beetles, it targets specifically live and vigorous trees. We report for the first time an attack on African mahogany trees, Khaya grandifoliola C. DC., by M. mutatus in Brazil, indicating its preference for trees with larger diameters. Most attacked trees exhibited only one or two gallery entrance holes, primarily along the lower 2 m of the trunk. However, colonization was impeded by gummosis, a plant defense mechanism. Overall, the attack rate was low, with nearly all of them failing to produce progeny. Megaplatypus mutatus exhibited a multivoltine life cycle in the study region, and most specimens captured in traps baited with the beetle’s sex pheromone were females. Adults of neither sex responded to traps baited with ethanol. Although successful reproduction was not evidenced in K. grandifoliola, gallery initiation could still affect timber quality. Therefore, regular monitoring of Khaya plantations for potential M. mutatus infestations is recommended to mitigate potential impacts on tree health and timber value. Additionally, we proposed here a novel classification of Platypodinae species into ‘A’ and ‘B’ categories, based on their behavioral patterns and ecological interactions.