Orientation Inside Linear Nests by Male and Female Osmia bicornis (Megachilidae)

Numerous species of solitary bees and wasps build linear nests with only one entrance. Developing insects must orient themselves inside their nest to choose the correct direction in which to emerge. Misorientation and chewing towards the dead end of the nest can result in significant mortality. Most insects position themselves towards the nest entrance during cocoon construction; however, some individuals are misoriented. We tested whether imagines can examine and possibly correct their orientation after emerging from their cocoons. Males were usually able to correct their misoriented position based on the shape of the cell wall and emerged through the correct entrance, whereas most females pursued the direction that they faced in their cocoons. We suggest that there can be more than one time point during development when bees can control their position in relation to the nest entrance and that the importance of these time points varies between sexes.