Using Micro-Computed Tomography to Study Larval Development in a Ground-Nesting Solitary Bee

Solitary bees represent over 80% of bee biodiversity and a substantial portion of pollinator diversity, though many are understudied compared with their social relatives. Most solitary bees nest in the ground and are difficult to rear in captivity, making research especially challenging. Here, we evaluate the use of micro-computed tomography (micro-CT) to track the growth and survival of solitary bee larvae encased in substrate, with the broader goal of understanding overwintering strategies in the ground-nesting bee Melissodes tepidus timberlaki. Because these bees develop within enclosed brood cells, traditional observational approaches often require destruction of the cell, limiting repeated observations. Micro-CT offers a non-destructive technique that preserves brood cells and enables longitudinal observation of larval development in captivity. Using this method, we assess the feasibility of measuring larval position, body size, survival, development, and brood cell architecture.