Does the weight of all the ants in the world equal all the humans?

Readers answer other readers' questions on subjects ranging from trivial flights of fancy to profound scientific concepts

When I started in school in 1968 we were told that the weight of all the people on earth (then about 3.5 billion) was equal to the weight of all the ants on earth. Was this true? I heard this repeated as a fact on the radio just the other day, with the world population now at 7.3 billion. Has the population of ants likewise increased? Have ants got heavier? Or both?

Gareth Pritchard, Daventry, Northants