The “thief” among animals

  In real life, thieves always make people spurn and hate, because they do not work on their own, but use illegal means of stealing and enjoy the fruits of other people’s labor. It’s incredible that there are such “thief” in the animal kingdom!
  In many parts of our country, every spring and summer, you can hear a bird’s call, that is, cuckoo. The cuckoo is not unfamiliar to all of us. It is actually called Rhododendron. It is a species in the Rhododendron family. It is a summer migratory bird. “Giving birth to children.” Therefore, its call is mostly “cuckoo” sound, so people call it “cuckoo”.
  In my country, there are many rhododendrons, such as middle rhododendrons, little rhododendrons, four-tone rhododendrons (calling “Quickly cut wheat” or “Bachelor so bitter”), eagle cuckoos (calling “back to Guiyang” or “top water” “Pen”), noisy cuckoo (called “doghouse”, so people also call “doghouse”), etc. No matter what kind of cuckoo bird, in spring and summer every year, they always scream from morning to night, and the sound is very loud, sounding very sad, so since ancient times, there is a saying that “cuckoo cuckoo blood”. To say that they “cry blood” is probably just a rhetoric, but why do they keep screaming all day long?
  It turns out that cuckoos do not make their own nests, nor do they incubate their eggs or have children. Instead, they secretly place their eggs in other nests and let these “righteous” birds help them incubate their eggs and feed their young . In this way, the cuckoo “has nothing” to do, so he calls out all the time nearby. But this call may be an act of calling their children. Therefore, when the cuckoo was raised enough to fly, he left his adoptive parents and moved with these real parents. What’s interesting is that some “righteous parents” hatched unconsciously, even if they were not their own chicks, they did their best to feed them.
  Therefore, the cuckoo bird can be regarded as a “thief” in the animal kingdom, and similar “thief”, in the animal kingdom, there are such kinds of birds, fish and insects, they do not build their own They are infertile, and they secretly lay their eggs in other kinds of nests. Zoologists call this kind of “thief” behavior as nest parasitism, “thief” like cuckoo is called host, and the species that is “stolen”, that is, “letting” the host to lay eggs is called host. Birds have studied more nest parasitic behavior.
  Among birds, there are about 80 kinds of nesting behaviors, accounting for 1% of the total number of birds. Most of them are distributed in a few families, such as the Rhododendron family (big cuckoo bird, etc.), the cuckoo family (weaver bird, etc.), the pseudo-oripe family (cowbird, etc.), the saccharidae (snake honey crack, etc.) and Anatidae (only one species, black-headed duck).
  The host’s choice of host is sometimes a species with roughly similar living habits, sometimes a species with a close relationship, but sometimes the two are far apart in their relationship. The big cuckoo is a well-known “thief”. It can steal its eggs in the nests of more than 100 other birds. It can be said to be “steal if you can.”
  Because it is a “sneak up” behavior, the host often has the following characteristics during the long-term adaptation process: First, the speed of spawning is fast, and it is often used by the host to go out for food; Hosts often eat or throw these eggs out of the nest. Secondly, in most cases, only one egg is laid in one host nest, and two or more eggs are few. Thirdly, the host’s eggs will hatch earlier, and its chicks have the habit of throwing away other birds’ eggs and chicks, and are exclusively raised by their parents. Finally, the morphological characteristics of the host eggs are generally close to those of the host, but there are many very different ones. For example, in the parasitic nests of rhododendrons found in the Kuankuoshui Nature Reserve in Guizhou in 1999, some are very similar, while others are in the eggs. There are big differences in size and color.
  Obviously, parasitism is very detrimental to the host, and their interests conflict with each other. As a result, many parasitic hosts also have many anti-parasitic behaviors, that is, “anti-thief” and “thief catching”. Some saw the “thief” enter their territory and attacked or expelled them. Interestingly, some cuckoos seem to be driven away by some weaker birds because they are “guilty of being a thief”; some try to build their nests more hidden, or cover their eggs when they go out; Those who can recognize the parasitic eggs, either throw them out of the nest, or simply make another nest, so that the original eggs and the parasitic eggs “will die together.”
  In this way, between the host and the host, like a “police and a thief”, there is always a struggle between parasitism and anti-parasitism. The host always makes its “steal” ability more superb, and the host always makes its “theft prevention” and “stealing” ability more perfect, so in natural selection, both behaviors have been evolved, this is What we know as “coevolution” or “coevolution”. However, people still know very little about the evolution of nest parasites and hosts, and more in-depth research is needed.

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