If the task is to make an ant robot that will be indistinguishable by its behavior, then it will be difficult, because you need to create artificial intelligence, which has not really been created yet. The ant in this regard is not so simple. And if it is just an imitation of an ant, something like a robot vacuum cleaner that drives around the house, then it is much easier. We can estimate: System of movements (control of the body and organs), decision-making system + memory system + learning system, basic skills, orientation in space and building routes. To all this, it is worth adding a system of image recognition from the eyes in order to build a map of the world based on life experience.
Each of the directions can have a different level of elaboration and depends on fanaticism and resources)
The system of image recognition alone and turning it into a 3D map can take up hundreds of thousands of functions.
This will probably be a very difficult program. Well, or even more difficult.
Perhaps it is worth clarifying. If the question means "repeat all the recorded actions of an insect from 8-00 to 15-00 05/21/2018", then it will be voluminous , but in general a simple program. But if it is meant that the program should simulate the actions of an insect, then you need to somehow simulate the work of the TS. the insect's "decision-making center", which is very difficult. I admit that this problem can be solved hypothetically, but ... For example, the project on modeling the OpenWorm worm has not been completed, it seems. Although there was a slightly different, broader task. But the worm is also a simpler object in relation to the insect. In general, it is not clear. But it is clear that there will be many difficulties.