Threespined Stickleback (image) University of Illinois at Urbana-Champaign Share Print E-Mail Caption The male, threespined stickleback defends its nest against invaders. Researchers tracked changes in gene activity in its brain after it encountered another male near its nest. Credit Katie McGhee Usage Restrictions Photo may be used only to accompany stories about the research described in this release. Please credit: Katie McGhee. Share Print E-Mail 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.