This is a rather difficult question to answer, and one that scientists have been working on for a very long time. For one thing what do we mean by "intelligent?" Secondly, insects are so very different from us humans that it makes it very hard to actually study how advanced traits such as problem solving, advanced communication, memory, and social skills are in them. The closest scientists have come so far in being able to evaluate an insect's intelligence is to look at the size of their mushroom bodies, the parts of an insect's brain that are responsible for memory, learning, and, in a manner, intelligence. The idea is that the larger the mushroom bodies are, the more intelligent the insect is. One thing that scientists have discovered is that what they call "generalist" insect tend to be more intelligent that other insects. "Generalist" are ones that have to learn to do a multitude of things such as adapt to eat a number of different foods or survive in many habitats, unlike insects such as fleas that only have one purpose in life that is finding one kind of host and feeding from it. A few different generalist insects are bees, ants, and other social insects. Which insects seem to be the most intelligent to you and why?