So. The littlest ants were about 0.5 mm and the bigger about 1.5mm I think - and the little ones really seemed interested in the big ones. One of the photos is taken seperately to the others but I think is the same species? Taken with 21X microscopic lens on iPhone.
Hi JJ, yes, these all seem to be the same species. Pheidole is a genus that always has spectacularly large 'major' workers compared with the 'minor' workers. Cheers, Jon