'larval-enhancing' is a modern English compound combining 'larval' (relating to larvae) and the present-participial adjective 'enhancing' (from 'enhance').

'larval' derives from Latin 'larva' (originally 'mask' or 'ghost'), later used in biology to mean an immature form of an animal; 'enhance' comes into English via Old French (enhauncer/enhaancer) and Middle English 'enhauncen', becoming modern English 'enhance'. The compound 'larval-enhancing' is a recent formation used in scientific and technical contexts.

The element 'larva' originally meant 'ghost/mask' in Latin but shifted to the biological sense 'immature stage of an animal'; 'enhance' originally meant 'to raise/make higher' and evolved to include 'increase or improve' — combined, they now mean 'increasing or promoting larvae'.