There are three different females and a male in these photos. EGKs around Canberra with this type of collar include both Gonacon-treated females and females which received the same injection without vaccine (controls). However at ANBG I think there were no control females. Check with Claire Wimpenny, but I suspect that a male persisting in following a collared female EGK at ANBG, would indicate a Gonacon treatment has most likely come to the end of its effect, and a bulging pouch a few months later would confirm that.