I had a fun feeding/inflation/pregnancy concept that I chose to apply to predasites because they seemed appropriate for it (and cute as heck). When one wants to reproduce, it absolutely gorges on food for days on end, converting all of it into a nutrient-rich liquid, and ending up with,

functionally, a sloshing balloon of a belly. Then it does... whatever it needs to do to conceive. If successful, the resulting litter is fed by the stored nutrients, putting minimal strain on the parent. If not... hey, massive personal food store for the non-parent!