Distinct water balance profiles for shallow diapausing, deep diapausing, and nondiapausing apple maggot pupae (Rhagoletis pomonella)

The apple maggot, Rhagoletis pomonella, has three different pupal developmental programs: nondiapause, shallow diapause, and deep diapause. In this study, we examined the water balance requirements of nondiapausing, shallow diapausing, and deep diapausing pupae. Differences in size (dry and water mass) and percent water content were minimal between the different groups. The three developmental profiles produced distinct ranges of water loss rates; the nondiapause pupae were the most porous (0.8-1.2%/d), deep diapause pupae retaining water most effectively (0.1-0.3%/h), and shallow diapause pupae lost water at an intermediate rate (0.4-0.65%/h). The critical transition temperature was higher in diapausing than nondiapausing pupae, a consequence of additional hydrocarbons deposited on the puparium of diapausing pupae, but we have not yet determined whether there is a difference between the puparia of shallow and deep diapausing individuals. Our results identified distinct pupal water balance profiles for nondiapausing and diapausing apple maggots.