Do tropical regions have bigger insects than colder regions?

Overall, yes. There are many factors that affect insect size. The tropics have higher temperatures, more food, longer/constant growing seasons, etc., all of which affect insect growth. read more

You will find a greater diversity of insects in the tropics, including some giant insects, but also some extremely tiny ones. Within a species, however, the pattern is not so obvious. Some insect species are larger in colder climates, for example. read more

We also do not know whether glaciations were accompanied by great extinctions in tropical areas. Additionally, most of the evidence we have has come from Amazonia, and what is the case there may not be true of other tropical regions. read more

A study of 2300 species of mammals and 6700 species of birds helps explain why there are more species in the tropics than at higher latitudes. Researchers found that while the tropics harbor more species, the number of subspecies increases in the harsher environments typical of higher latitudes. read more