Survival of the fattest: correlating Rhagoletis zephyria pupal weight and likelihood of emergence

Rhagoletis zephyria, more commonly known as the snowberry fly, is a native species that is widely distributed across the United States, including the state of Washington. R. zephyria survives on snowberries located both east and west of the Cascade mountain range, unlike its closely related sister species R. pomonella, the apple fly, which is invasive to the region and primarily exists in the western half of Washington state. The life cycle of R. zephyria depends on females depositing fertilized eggs into the snowberry fruit, within which they develop into larvae. Larvae then drop from the fruit to the ground, where they form a puparium to prepare for diapause until emergence as flies the following fruit season. The hybridization between these two closely related species presents a potential economic hazard to Washington's apple growing industry. As a part of our umbrella research program, we explore the correlation between the initial weight of R. zephyria pupae and their likelihood of survival to emergence. These results will help us better understand the emergence patterns of these flies and will aid future researchers to estimate viable sample sizes for a variety of experiments.