Which insect is primarily used as fish bait in its larval stage?

The yellow mealworm is widely recognized for its use as fish bait, particularly in its larval stage. This life stage of the darkling beetle (Tenebrio molitor) is high in protein and easily digestible, making it an attractive option for various fish species. The larval form mimics the natural prey of fish, enhancing its effectiveness when used as bait during fishing.

In contrast, the other options listed do not have the same reputation or suitability for use as fish bait. The drugstore beetle and cigarette beetle are more commonly associated with the contamination of stored food products rather than serving as bait. Meanwhile, the rice weevil is primarily known for infesting grains and does not have a role in fishing activities. Thus, the yellow mealworm stands out as the primary choice for fish bait in its larval stage.