Nature’s Nether Regions by Menno Schilthuizen was absolutely fantastic. Yes it is about genitalia and the myriad of jokes that come with them, but it is also about evolution, specifically the competition between males and females and even between hermaphrodites that are both male and female. Genitals evolved across animals in such a diverse manner that they are literally the cornerstone for much of insect species identification. From monkeys with spikes on their genitals to male bedbugs who inseminate females via other males to land snails who shoot love darts at each other, the variation seems endless. I suspect the author had to hold himself back from writing the book twice as long as the published form, there was so much to say.
My favorite quote: “The penises of beetles, flies, butterflies, moths, and many other insects often carry such accessories (although they are called by different names in different types of insects), and they are used to drum, tap, slap, or stroke the outside of a female’s genital region during sex while the rest of the aedaegus is working on her inside.”