The great biologist J.B.S. Haldane gave the world some memorable quotes on diversity and evolution but rabbits aside, it is his quote about beetles that must have lived longest. For those who don’t know, he was fielding a question about what biology could tell us about a Creator and replied that he must have an inordinate fondness for beetles.
In a space not much bigger than a piece of A4 paper this posits a famous quote by a famous biologist (a nice bit of history there), explains the reasoning behind it (namely the colossal diversity of beetles and their incredibly varied ecology and lifestyles) and provides a huge mess of specimens to demonstrate that diversity in colour, shape, size etc. This gives a huge opportunity for people to really compare and contrast much about related forms (even with this level of diversity) and to get across a much under appreciated point. Simple but brilliant.