The University of San Diego’s Divya Sitaraman, assistant professor of psychological sciences, recently studied two fundamental behaviors in fruit flies: sex and sleep, reports NBC7.

It turns out, male fruit flies would rather sleep than have sex.

“They would always choose sleep over courtship,” Sitaraman explained. “The females do not show the same preference for sleep over sex.”

According to the study, male fruit flies prioritized behaviors differently than females in this scenario: when they were sleep deprived, they reduced their courtship behaviors.