The study looked at how female beachfleas control the environment for their developing eggs. They compared the survival of eggs kept in the female's pouch to those cultured in different levels of seawater. They found that eggs in the pouch had higher survival rates, especially in diluted seawater. The fluid in the pouch was more concentrated than the surrounding seawater in lower dilutions, but less concentrated in full seawater. This suggests that females regulate the fluid to help embryos survive, possibly by directing urine into the pouch. This is the first time maternal control of the environment for developing embryos has been shown in these types of crustaceans. The findings shed light on how beachfleas adapt to different environments during their development.