In the tropical jungles of Central America, where there are many predators, a species of kuku has found a security number by building two commonly-supported nests of two or three breeding pairs.
Why, then, these delightful birds sometimes make a ditching of cooperation and, instead, the eggs become nests outside the community community, like social parasites, so that other women expect their chicks to rise?
In a paper published in the journal NatureResearchers at Princeton, who are commonly known as "Crocus Cucumbers", are commonly used most, but have become social parasites after destroying common nests. The breeding season begins with eggs in a basket, but if there is a predator, the birds become a strategy for opening eggs around the nests.
"When different population reproductive reproductive females are different, such as co-operative and parasitic nests, that is, an evolutionary puzzle. Why do women ask that their eggs collect eggs, other males never did," said Christina Riehl, ecologist and Assistant Professor of Evolutionary Biology. Meghan Strong, a specialist in the Department of Ecology and Evolutionary Biology, has completed his studies with graduate, postgraduate and fellowships at the Princeton Environmental Institute (PEI) several times.
"Parasitic strategy is a second-line option," said Riehle. "As if birds say," If our co-operative attempt fails, go to Option B. "
The group concluded that two reproductive strategies could make a population, cooperative to achieve the same number of children as co-operativism, and then a mixed parasite strategy. If one reason is better, all birds would probably be the most successful strategy.
One of the largest ones is one of the few species of birds, where young women are not born together. On the contrary, social parasitism is quite common, since more than 250 species of birds are found.
In order to find out why parasitism is commonly cooperative, scientists watched birds and their nests in an 11-year period at the Monumental Monument of Barro Colorado. The birds build nests in the branches of the Panama Canal, and the researchers ask to reach them by boat.
Under a constant threat against predators and monkeys, almost all anis begin the breeding season in common groups, researchers have found.
However, social parasitism is also widespread, researchers have found that 25% of the deceased had been paralyzed by a non-member group.
The caves were destroyed by the cave by the cave, which was often found in the cave at the beginning of the cycle, mostly to cover the parasites, usually nesting near the nest in the nest.
The researchers asked whether the collective nests that are changing in the middle would really bring children from social parasitism.
Although eggs for many reasons are a good strategy, social parasitism has disadvantages. Eggs are a little bit smaller and therefore they are less. And because of the risk of finding out, these eggs are less likely to survive until the chickens are nest.
On the other hand, female co-operatives had less egg but made more efforts to keep chicks more alive.
Getaway: Two reproductive strategies, the viable multiplication strategies are only a mixed approach to starting community breeding and parasitism.
Mark Hauber is an ornithologist and environmental conductor at the University of Illinois, which was not analyzed by Urbana-Champaign. "The study explains why evolutionary growth evolves in this species: solitary growth or parasitism alone are not enough production," Hauber said. "But co-operative breeding with clutterings or failure to cooperative growth, parasitism are the following: they are apt-wise, so parasitism remains in the population and therefore is a cooperative breeding."
The group also found that women had gone to parasitism after failing their nest for a year.
"When I started working on captive captives in my zebra, some individuals may be more parasitic than others," said Hauber. "This has now been proven and well confirmed by the wildlife of tropical living birds."
Continuous examination controls 40 to 60 nests annually. In general, current discoveries have analyzed genetic data for 1,776 eggs, from 240 birds from 210 to 2007-17.
Every year, the group begins the breeding season in June, looking for the nest of the plant along the coast. Researchers control nest of the day to collect new eggs and collect eggs in the blood, to obtain identification of each egg mother through genetics. Each egg is measured and measured and blood is collected from blood to confirm their origin.
"It is often included in cold stores, the most demanding portion of measurements," said Luke Carabia, a class of 2019, as a PEI fellowship. "Some poultry groups cooperate very well and grow nesting on the chest, others have built their nests on all their tops or in deep grasses, and birds often use a towering wing of an angry beast, or collecting the right places."