This is a 90-year-old hypothesis that has just been confirmed by the team led by Professor Claire Spottiswood from the Department of Zoology in Cambridge (UK), Michael Sorenson from Boston University (US) and the Institute of Ornithology in Cape Town (South Africa). In 1933, the British geneticist, Reginald Bonet, known for developing a tool for finding offspring’s ancestors, put forward the hypothesis that parasitism developed by certain bird species is transmitted through the mother. By analyzing the genomes of 196 parasite anomalies (Anomalospiza imberbis) captured in 141 nests of grasshopper birds, which are small beavers that were strongly affected by the intruder, the researchers were able to confirm this hypothesis in this species from South Africa. Their results have just been published in PNAS.
The relationships between the different species of parasitic birds and the hosts forced to raise their offspring date back at least two million years. It is a well-known and well-studied example of the co-borrowing of co-evolution from the Red Queen Theory, a term borrowed from Alice in Wonderland by Lewis Carroll. When a species develops a mutation that allows it to gain an advantage, the species with which it evolves will develop a defense that restores balance. This is what happens to Alice when she runs while the scene moves at her same speed: she has the impression that she is standing still. For parasitic birds, it is essential to maintain this ability to mimic the eggshell of parasitic species, otherwise they will be spotted by their victims and chased from the nest. So there is no doubt that the genes responsible for this ability would be lost if one of the parents was bred by a different host than the mother’s host, which is a huge risk because these parasitic species do not form faithful pairs. Researchers have demonstrated that aberrant aberrations transmit this ability through the female’s W chromosome similar to the male’s Y chromosome in humans. Thanks to this transmission, like Alice, parasites run at the same speed as the landscape.
An arms race that turns in favor of the victims
But this could change. “While this maternal heritage has enabled anomalies to exploit a large number of species, the ability to develop a counter-adaptation is likely to be lost if their host opposes new defences.”explains Claire Spottiswood at the University of Cambridge website. Thus the parasites seem to have a daunting problem because some of the infected species have developed an astonishing array of egg colors that help them distinguish the parasite’s eggs from their own.”
This is a 90-year-old hypothesis that has just been confirmed by the team led by Professor Claire Spottiswood from the Department of Zoology in Cambridge (UK), Michael Sorenson from Boston University (US) and the Institute of Ornithology in Cape Town (South Africa). In 1933, the British geneticist, Reginald Bonet, known for developing a tool for finding offspring’s ancestors, put forward the hypothesis that parasitism developed by certain bird species is transmitted through the mother. By analyzing the genomes of 196 parasite anomalies (Anomalospiza imberbis) captured in 141 nests of grasshopper birds, which are small beavers that were strongly affected by the intruder, the researchers were able to confirm this hypothesis in this species from South Africa. Their results have just been published in PNAS.
The relationships between the different species of parasitic birds and the hosts forced to raise their offspring date back at least two million years. It is a well-known and well-studied example of the co-borrowing of co-evolution from the Red Queen Theory, a term borrowed from Alice in Wonderland by Lewis Carroll. When a species develops a mutation that allows it to gain an advantage, the species with which it evolves will develop a defense that restores balance. This is what happens to Alice when she runs while the scene moves at her same speed: she has the impression that she is standing still. For parasitic birds, it is essential to maintain this ability to mimic the eggshell of parasitic species, otherwise they will be spotted by their victims and chased from the nest. So there is no doubt that the genes responsible for this ability would be lost if one of the parents was bred by a different host than the mother’s host, which is a huge risk because these parasitic species do not form faithful pairs. Researchers have demonstrated that aberrant aberrations transmit this ability through the female’s W chromosome similar to the male’s Y chromosome in humans. Thanks to this transmission, like Alice, parasites run at the same speed as the landscape.
An arms race that turns in favor of the victims
But this could change. “While this maternal heritage has enabled anomalies to exploit a large number of species, the ability to develop a counter-adaptation is likely to be lost if their host opposes new defences.”explains Claire Spottiswood at the University of Cambridge website. Thus the parasites seem to have a daunting problem because some of the infected species have developed an astonishing array of egg colors that help them distinguish the parasite’s eggs from their own.” Anomalies are considered more difficult because females specialize in the parasitism of one species. “This is also what happens to our gray cuckoo clocksnotes Jeremy Dupuy, project manager at the Bird Conservation League (LPO). Females are likely to be pollinated by the scents and songs of the species on which they are raised, and thus preferentially return to parasitize them.. “
The eggs laid by different females parasitize different species. Each female mimics the color of the affected species. © Claire Spottiswood
African researchers have discovered that the bird bird has become very effective in rejecting intruder eggs. Females actually lay eggs that have a red or blue background, and some have developed into olive green, which cannot be confused with producing abnormal shapes. For Parasite, the scene stops, while Alice (the critics’ birds) continues to run. “Maybe the same thing happens to our gray cuckoo clocks,” Refers to Jeremy Dupuy. Kokolos Kanuros which currently sing in our forests and wetlands parasitize many species but like anomalospizes, each female is specialized in a particular species. Reed bird, songwriters, blackbird, grouse, the list is long. But the case of two species of warbler, avarvat and verdirol, is interesting. “We note that the Eiffel bird is highly parasitic, while the Verdirol bird detects cuckoo eggs well and is able to get rid of them.” Therefore, females specializing in this species will either have to choose another species, or take advantage of the naivety of a small pair of verdular reed birds that have never been conquered to deceive them.
mysterious migration
Rest assured, the cuckoo clock in Rivne is not in danger of disappearing. The numbers are healthy even for the Mediterranean cuckoo Gland Clamator which parasitizes only on magpies. Each spring, females lay about twenty eggs, scattered in as many or nearly as many nests and the success rate is satisfactory. However, these migratory species are especially surprising. Once the eggs are laid, the parents return to Africa at the end of June, leaving their offspring to the surrogate parents, Jeremy Dupuy says: However, the young ones find their way back to the forests of the Congo Basin for their parents on their own without doing anything wrong.” There are only hypotheses here to explain such a feat: innate behaviour, navigation using day length and latitude, or a bit of both…
In an effort to break them, the British Ornithological Trust has been equipping British cuckoos for several years to track their ways. An approach that France will begin to take in a very particular context. To determine the impact of the establishment of floating wind farms in the Gulf of Lion in the Mediterranean on migratory birds, the MigraLion program led by the Scientific Center Latour de Vallat in Camargue will equip several species of migratory birds with GPS. Among them are the gray cuckoo and the jay cuckoo. “We hope to learn more about their behavior,” Jeremy Dupuy thought.