One popular strategy against predators is to warn them using lurid colors or patterns. In this gallery they tell you: I am poisonous or dangerous, or maybe I just pretend to.
Zygaena carniolica imago 3 3 3 Digelfeld, Hayingen / Schwäbische Alb, Germany, 30/07/2006 Zygaena carniolica imago 3 3 3 Digelfeld, Hayingen / Schwäbische Alb, Germany, 30/07/2006 Zygaena carniolica imago 3 3 3 Digelfeld, Hayingen / Schwäbische Alb, Germany, 30/07/2006 Orgyia antiqua larva Grafing Bf., Germany, 27/07/2008 Tenthredopsis sp. imago Kirchseeon, Germany, 18/06/2006 Nomada sp., Cuckoo bee imago ♀ Kirchseeon, Germany, 25/03/2007 Nomada sp., Cuckoo bee imago ♀ Kirchseeon, Germany, 25/03/2007 Nomada sp., Cuckoo bee imago ♀ Kirchseeon, Germany, 25/03/2007 Nomada sp., Cuckoo bee imago ♀ Kirchseeon, Germany, 25/03/2007 Nomada sp., Cuckoo bee imago ♀ Kirchseeon, Germany, 25/03/2007 Nomada sp., Cuckoo bee imago Weil der Stadt, Germany, 19/04/2006 Nomada sp., Cuckoo bee imago Weil der Stadt, Germany, 28/04/2008 Nomada sp., Cuckoo bee imago Zorneding, Germany, 22/05/2005 Eriozona syrphoides imago ♀ G Kirchseeon, Germany, 04/09/2005 Vespa crabro, Hornet imago Kirchseeon / Eglharting, Germany, 13/05/2007 Vespa crabro, Hornet imago Frauenöder Filz bei Rott am Inn, Germany, 26/08/2006 Vespa crabro, Hornet imago Venusberg b. Aidlingen, Germany, 07/08/2006