the-great-fairy-wren-caper

You probably already know how this one goes. I’m a bit late on getting it out the door. If not, kudos. This is for you.

Evolution is often simplified to be about predator vs prey. In order to survive, you must eat and avoid being eaten. But the reality is more complex than that. In the game of  survival, one must manage many pieces across an ecological board, and being able to effectively manage resources is arguably paramount. Insert joke here about needing more vespene gas or controlling the Spice.

Parasitism is one such tactic organisms have adapted in order to win the game of survival. After all, why kill your prey when you can just milk it for its entire life? One doesn’t even have to draw blood to be an effective, either. In the game of survival, passing the buck can be just as effective. This is where brood parasitism comes into play. Take the modus operandi of the Horsfield’s Bronze Cuckoo in today’s comic: While a pretty unethical, asshat move, these deadbeat parents of the animal kingdom are doing survival right. Why spend time and food raising your young when some poor sap will do it for you? Why expose yourself to predation by sitting on an egg all day? You just need to find an unwitting mark.

Enter the Superb Fairywren, which was apparently named after a My Little Pony character. The little songbirds are unique in that while they form monogamous pairings, the individuals are sexually promiscuous and will mate with other individuals outside of the pairs. These birds are no deadbeats however, and will actually take care of each other’s young. This sort of altruism makes us feel fuzzy inside, but to the opportunistic parasite, the Fairywren looks like the perfect target for the longest of cons.

You may remember a while back we looked at altruism and cheating in microorganisms. If there is a system to be gamed, somebody will game it. But as we also learned, evolution is an arms race, and the cheated will always find a way to detect the cheaters. We’ll look more at that in the next installment, and for now I’ll leave you with this ridiculous case of brood parasitism between a Reed Warbler and a Common Cuckoo.

Image courtesy of Per Harald Olsen

For more Crowlmes and Flockson, check out their inaugural comic on causal reasoning in New Caledonian Crows