Mafia Hypothesis for Brood Parasitism

Brood Parasitism happens when a bird, like a cuckoo, lays its egg in the nest of a host bird, for the host to hatch and rear.

Why doesn't the host simply kill the parasitic egg or the cuckoo once it has hatched? It grows to look nothing like the hosts chick.

The Mafia Hypothesis basically says that selective pressures favoured ignorant birds over smart ones. The smart ones could identify the cuckoo egg and would reject it. The cuckoo, which checks up on the progress of its offspring, destroys the entire brood if its egg is missing or "cold". So, says the Mafia Hypothesis, ignorance was the favoured strategy and birds that couldn't distinguish their own eggs from the cuckoo's, or their own tiny chicks from the overgrown chick of the cuckoo survived better and passed on their ignorant genes!

The Mafia Hypothesis does not appear to go into the fact that ignorance does not save the brood anyway. The cuckoo egg hatches first and the hatchling proceeds to evict all the other eggs by pushing them over the side of the nest. All they discuss is predation after rejection of the egg, not the behaviour of the cuckoo hatchling.


The hypothesis doesn't discuss the fact that destroying one cuckoo egg prevents it from reaching adulthood and potentially saves many future broods. There is no mention of the fact that the cuckoo population is likely to get wiped out much more quickly the host population.

Ignorance? Reed Warbler feeding a chick way huger than a warbler chick.



Ignorance? Mafia Hypothesis..

http://en.wikipedia.org/wiki/Brood_parasite

It has often been a question why the majority of the hosts of brood parasites care for the nestlings of their parasites. Not only do these brood parasites usually differ significantly in size and appearance, but it is highly probable that they reduce the reproductive success of their hosts. So [size=14pt]what possible benefits are gained from providing this parental care?[/size] Through studies in an attempt to answer this question evolved the "Mafia hypothesis". This hypothesis revolves around host manipulations induced by behaviors of the brood parasite. Upon the detection and rejection of a brood parasite's egg, the host's nest is depredated upon, its nest destroyed and nestlings injured or killed. This threatening response is indirectly enhancing selective pressures favoring [size=14pt]aggressive[/size] parasite behavior that may result in positive feedback between Mafia-like parasite and compliant host behaviors.[13]

(LOL! Aggressive predation vs what? Benevolent predation?)