GO term annotation for Callosobruchus

I have list of differentially expressed gene for Callosobruchus maculatus (seed beetle). I want to do gene ontology enrichment analysis. This is a non model organism and we do not have GO term annotation for this species.

How to dot it?

Find the (model) organism for which GOs exist and that is evolutionarily most closely related, then try to identify the homolog genes in that species and use these genes for the enrichment analysis.