Ants (IMAGE) Rockefeller University Caption In many ant species, workers are much smaller than queens and cannot reproduce. Researchers wanted to know: how did these physical and behavioral differences evolve? Credit Daniel Kronauer Usage Restrictions Image may be used only to illustrate the research described in the accompanying release. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.