Why grant select is needed on a table when you are only inserting records

Question

Please can you tell me why a grant select is needed when inserting records which are being inserted across a link?
We have a table in database1 which we are trying to insert records from database2. database2 has a db_link to database1.
The table residing in database1 has grant insert to the named user in the db_link. But unless there is also a grant select to that user we cannot insert records. We do not actually need to be able to select the records across the db_link, but nevertheless we get the following error on trying to insert records without the grant select being in place:
ORA-01031: insufficient privileges
Cause: An attempt was made to change the current username or password without the appropriate privilege. This error also occurs if attempting to install a database without the necessary operating system privileges. When Trusted Oracle is configure in DBMS MAC, this error may occur if the user was granted the necessary privilege at a higher label than the current login.
Action: Ask the database administrator to perform the operation or grant the required privileges. For Trusted Oracle users getting this error although granted the the appropriate privilege at a higher label, ask the database administrator to regrant the privilege at the appropriate label.
Your thoughts would be appreciated.

Answer 1

Since there is no remote describe function, a select must be done to get the table structure. This is talked about in Note: 1004923.6.