Meeting Abstract

P1.64  Monday, Jan. 4  Pinpointing termination of diapause in apple maggot flies by reconciling metabolic increase with resumption of cell division and development OCHS, G*; RAGLAND, GJ; HAHN, DA; University of Florida; University of Florida; University of Florida gsochs@gmail.com

Diapause, or dormancy, is a state of developmental arrest that buffers an insect against harsh conditions and synchronizes active stages with favorable conditions. The timing of diapause termination is critical to this synchronization, and variation in timing is often adaptive. We are interested in identifying the mechanisms underlying rapid evolution of timing between putatively speciating populations of apple maggot flies (Rhagoletis pomonella) that terminate diapause at different times of the year to exploit different host fruit resources. Two key markers of diapause termination are a marked increase in metabolism and resumption of active cell cycling and development. We have previously characterized the metabolic trajectory of diapause termination, and in this study we are testing whether markers of cell cycling coincide precisely with metabolic increase. Characterizing the timing of this developmental marker in relation to metabolic markers will allow us to identify the most important sampling points for future genetic and functional genomic dissection of the diapause termination process. We measured pupae at intervals prior to and following metabolic increase for two prominent molecular indicators of active cell division: 1) protein expression of Proliferating Cell Nuclear Antigen (PCNA), and 2) chromatin content of brain nuclei via flow cytometry. We show that diapausing pupae arrest in the G0/G1 phase of the cell cycle, present a time series for diapause termination and resumption of development, and discuss implications for future work in this system.