Water balance in the sugarbeet root maggot Tetanops myopaeformis, during long-term low-temperature storage and after freezing

The sugarbeet root maggot Tetanops myopaeformis Roder (Diptera: Ulidiidae) can be stored in moist sand at 46 degrees C for up to 5 years and is freeze-tolerant. The majority of stored larvae survive in a state of post-diapause quiescence and the remainder are in a multi-year diapause. The present study aims to determine larval water content and water loss rates in diapausing and low-temperature stored larvae. Body water content ranges from 57% to 70.1%. Two distinct groupings of larvae are revealed based on dry weights. The first group consists of the diapausing larvae and larvae stored for 1 year. This group has significantly higher dry weights than the second grouping, which consists of the larvae stored for 2 and 3 years. There are no significant differences within each group. Larval water losses follow a first-order kinetic relationship with time. Larvae stored for 2 years lose water at a significantly higher rate than diapausing larvae. Larvae exhibit no active water uptake at storage temperatures. A freezing event does not induce a significant decrease in wet weights, nor does it increase larval water loss rates. These results indicate that metabolic water and the microclimate during storage are key factors enabling the long-term survival of T. myopaeformis larvae during low-temperature storage, and may provide insights for maintaining other insect species under similar conditions.