A Most Bizarre Sex Act
Spiders weave a tangled sexual web that leads to stiffer competition for passing on their genes. Scientific American reports on a recent study published in the May 2009 issue Evolution that shows how the genitalia of Nephilid and Golden Orb Weaver spiders evolved from simpler to more complex structures.
Male spiders that had more hooks, ridges and twists on their palps stood a greater chance of passing on their genes then their less complex competitors. When the male copulates with the female, the palp breaks off inside the female so there is a greater chance of his sperm fertilizing the female’s eggs. He is not only content from giving her his all, but will stick around her web and chase off any competitors. Female ducts evolved from those that gave straight easy access to more convoluted ducts with twists and turns making it harder for penetration by males lacking the right equipment.