Bugs resort to several colours to protect themselves

Image: Dr Damien Esquerré, ANU - New research has revealed for the first time that shield bugs use a variety of colours throughout their lives to avoid predators. Shield bugs are often bright, colourful insects that use colours to warn of their distastefulness to predators. The paper,  published in The Royal Society , found that it is impossible to predict how an adult bug will look based on their colour when young. Co-author Dr Megan Head from The Australian National University (ANU) says while many adult animals look like larger versions of their younger selves, with insects that's often not the case.  "With insects in particular it's common for the young to look completely different from the adults," she said.  "Just think of caterpillars - some of the most beautiful caterpillars turn into the dullest moths or butterflies, and vice versa. We were interested in understanding what influences whether young and adults within a species share the same colour patterns."  The researchers found that in most species, the same individual bug will use different colour combinations as nymphs - young bugs - and adults, for example going from red and green to yellow and green.  "This is significant because many of these species use colour to warn predators that they are distasteful, and for years it has been thought that animals living in the same environment - like nymphs and adults of the same species - should use similar warning colours, not different ones," said lead author Dr Iliana Medina, from the University of Melbourne.