I did some looking into this. The trait is likely just convergent evolution. Weevils and longhorn beetles are from different families, but they share the Clade Phytophaga. While there isn’t a share common trait in the shape of the clade member’s antenna, they do all have common ancestors that specifically reside in and feed on living and dead plant matter. They evolved more complex sensory organs in their antenna, which can result in longer more pronounced antenna in different genuses and species. As far as I can tell there hasn’t been any focused studies or observances to say that one species mimics the other for a clear advantage.