Desert bugs

1) I already talked about the oasis in my message:

2) Antlion does not appear during the summer
3) The Antlion attack was not on the surface or in the caves.

It seems to me that something has happened to the very mechanics of the desert.

P.S.: If you go out of the caves in the summer to the surface and go into the desert to the oasis, then you will find that everything works and Antlion appear too.