Read the following excerpt and answer the question asked at the end. The answers to the questions should be based on the excerpt. Of the different groups of tropical insects, 
butterflies and ants are probably the most taxonomically well known. While butterflies can be very good indicators of environmental changes, the adults fill only a few ecological niches, most species being pollinators or scavengers. Ants, on the contrary, play a much more variable role in any ecosystem. Ants are considered to run much of the terrestrial world as the premier soil turners and channelers of energy. They also pay the role of predators, pollinators, harvesters and decomposers in any terrestrial ecosystem.