Why are there so many species of insects and so few species of mammals?

Answer 1

It's because of the birth rate. Simple mutations create new species over time. The more offspring at a time, the quicker the chance that mutations create new species.

Answer 2

come to imagine if it is the other way around, we will not have enough space for the mammals. Biologically though, insects are smaller in size, requires less food to mature, while mammals needs a lot of food. we are therefore limited by the food available to us. Insects diet are simple and abundant, lifetimes are likewise short and genetically simpler vs mammals so mutation could easily transform them to a new species unlike mammals.

Answer 3

Insects have been around a lot longer than mammals and so have had a lot longer to adapt to many different environments. Therefore more species.

Answer 4

Insects breed ever so much faster than mammals. You might also speculate that there may be physical barriers to gene flow, such as mountain ranges, that would tend to isolate insect populations more effectively than they'd isolate mammal populations. Et voila, genetic drift!