For wild apes, there's nothing better to eat (3,4)
I believe the answer is:
pea soup
'for wild' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'apes there's nothing better to eat' is the wordplay.
'there's nothing' becomes 'o' (I've seen this in other clues).
'better' is an anagram indicator (with an improved letter-order).
'to eat' becomes 'up' (I can't justify this - if you can you should give a lot more credence to this answer).
'apes'+'o'='apeso'
'apeso' with letters rearranged gives 'peaso'.
'peaso'+'up'='PEA-SOUP'
Can you help me to learn more?
(Other definitions for pea soup that I've seen before include "starter course?" , "Food - thick yellow fog" , "Dish like old London fog" , "Thick vegetable broth" , "Green potage" .)