Mehk: Hey, I killed you this pretty thing! O:

Irika: ...Thank you, Mehk. ^^;; *throws it in her growing bug box for lack of any better ideas* >>;;


--

Lellians are instinctive predators, much more than humans, so a large part of their social interaction involves killing stuff. This can cause issues with interspecies relationships if both parties don't know where the other stands.
It's really important for the mental health of a lellian to offer dead things to its packmates, so rather than trying to completely discourage the behavior you should make clear what you can accept without freaking out.

Common lines to draw are:
No pets
Nothing with a spine
Bugs only
Fish only
No intelligent beings
etc.


Some lellians do manage to transfer their prey drive to inanimate objects, although they still have to 'kill' them. For this reason, you shouldn't complain if the box of chocolates a lellian brought you is kind of squished.
They killed that chocolate just for you, after all.