Jacksons can retain sperm to fertilize multiple clutches of babies, so they don't have to mate every time (although they do have to mate at some point in order to get the sperm to retain it - they are not parthenogenic). I have read that studies have shown that they have up to 3 clutches of babies growing inside them at one time.
Wouldn't that seem to imply that sperm is not being stored, but, rather that individual clutches are developed separately after being fertilized at the same time?