Tuesday, December 06, 2011

Difference Between Humans and Animals, Part XXVII

Christmas present edition:
Male nursery web spiders often woo potential lady-friends with gifts wrapped in silk. Mating may ensue, during which a female unspools the present, expecting to find a tasty treat. But the males can be unscrupulous. Some offerings contain inedible plant seeds or empty insect exoskeletons.
But he won't stop skimping until she starts noticing:
Females clearly prefer males bearing edible presents. But some males know they can get limited action without expending the energy on a real gift. And the females laid almost the same amount of eggs fertilized by males bearing real or phony gifts. With both strategies successful, the behavior gets maintained. And the species stays stocked with deadbeat dads.
The difference for humans is we have posters:

But don't worry gentlemen, the ladies of the animal kingdom can be cheaters too:
The Scientific American blog post (based on this paper) makes it sound as if the males are the only ones using deception and dirty tricks. But why do the males silk wrap their gifts? Why not just present the females with food? 
Females presented with food will often grab the food and run, leaving the males doubly hungry. A wrapped package is harder to steal (the males have a better grip on the silk) and as the females slowly unwrap their potentially delicious presents the males copulate.
Sounds kind of like engagement rings.


You are the reason why I do not write privately. I would love to hear your thoughts, whether you agree or not.