From ScienceDaily:
Now researchers at the University of Tennessee and the University of Oxford suggest that in some cases, filial cannibalism and offspring abandonment might even be considered forms of parental care. Published in Frontiers in Ecology and Evolution, their mathematical model shows that when overcrowding threatens offspring survival — which often occurs due to spread of infection or competition for resources — sacrificing a few so the most can live becomes the ultimate form of tough love.
They created a mathematical model that, they say, demonstrates: Live fast, die young, be prepared to abort
“The fitness benefit of offspring abandonment and filial cannibalism also increases as adult death rate increases, particularly for the case of filial cannibalism,” adds co-author Prof. Michael Bonsall of the University of Oxford.
In other words: if you’ve got fewer shots at reproducing, you’ll need to be ruthless in protecting your brood. But if offspring mortality is density dependent, why produce so many eggs in the first place?
“It is not always possible for parents to predict the environment that their offspring will end up in,” explains Bonsall. “Factors like food availability, oxygen availability, diseases presence and predation, might change in an unpredictable manner. Likewise, in many fish and other animals females deposit their eggs in the nests or territories of males and leave, so cannot predict an optimal laying density given that additional females might subsequently add eggs to the nest.”
“It’s up to empiricists now to test these models in a variety of species,” the authors conclude. Paper. (open access) – Mackenzie E. Davenport, Michael B. Bonsall, Hope Klug. Unconventional Care: Offspring Abandonment and Filial Cannibalism Can Function as Forms of Parental Care. Frontiers in Ecology and Evolution, 2019; 7 DOI: 10.3389/fevo.2019.00113 More.
Here’s how you can tell that Darwinian evolution (natural selection on random mutations produces information) functions as a superstition today: Everything and its opposite is considered a demonstration. In a world where, over hundreds of thousands of years, many life forms go extinct—and an adopted behavior may, over a long period of time, be a factor in an extinction—the theorist assumes that whatever is happening is, on the contrary, a demonstration of Darwinian fitness — and constructs a mathematical model that supports that view.
There are all kinds of these stories out there — about why birds lay eggs in others’ nests, why stressed mares miscarry to avoid infidelity being detected, and how birds plan for their offspring’s future (Huh? Birds that can’t avoid wind turbines can plan for their offspring’s future?)
The rule in the discipline seems to be: Never call anyone to account for fronting nonsense as long as it is Darwinian nonsense.
Note: Stressed mammals do sometimes eat their offspring in the same way that a wounded dog who is being led to safety might turn and sink his teeth into the human who is helping him. But if a mammal is intellectually complex enough to have an individual psychology, please, see the behaviour as a response to the stress rather than as the unfolding of some grand Darwinian plan. We owe it to our furry and feathery domestic friends to try to understand them at least that far.
See also: Darwinian cheating story about birds not confirmed The strategy is not outstandingly successful and the researchers are now looking for an explanation other than a selective advantage. That’s wise on their part. This sounds like another strategy where the bird merely adapts; sometimes it works and sometimes it doesn’t. No big Darwin theory is needed.
Why stressed mares miscarry (going full Darwin here)
and
Birds are found to plan like humans for their offsprings’ future. Yes, the Darwinbird of pop science can do that!
Also: Sexual trappings (dimorphism) may increase the likelihood of extinction, not survival
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