Emergence and pre-emergence behavior of two species of solitary bees of the tribe Anthidiini in trap nests

The tribe Anthidiini, from the family Megachilidae, includes cleptoparasitic and solitary species that nest in pre-existing cavities. In solitary species, females perform all nesting and oviposition activities without contact with their offspring. Although the life cycle of some solitary bees is known, the processes preceding the emergence of these individuals are still poorly understood. This study focused on the pre-emergent behavior of Ephanthidium tigrinum and Dicranthidium arenarium, using transparent trap nests for daily observation. Both active (movement; cell wall excavation; agonistic interaction; excavation of the closing plug and cleaning) and inactive (rest and sleep) behaviors were recorded. In both species, the emergence process began in the morning, days before the first bee emerged, suggesting a collective preparation. The study provides valuable insights into this behavior.