In fact, eating or abandoning offspring has been documented in a variety of mammal and bird species -- as well as fish, insects and spiders. Hunger and quality control are among the many reasons proposed for this counterintuitive survivor of natural selection.
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.
Role - Density - Benefit - Cannibals - Researchers
To understand the role of overcrowding or 'offspring density' in the survival benefit of filial cannibals, the researchers focused on species that lay eggs.
"Communal egg laying is common in a range of fish, insects, reptiles, and amphibians," says senior author Dr. Hope Klug, Associate Professor at the University of Tennessee, Chattanooga. "This makes it easier to protect, clean, incubate and feed the eggs -- but can also increase disease transmission, and competition for food and oxygen."
Density - Egg - Survival - Cases - Cannibalism
Offspring density has been found to affect egg survival, and in some cases abandonment or cannibalism, in many of these species.
"For example, in the beaugregory damselfish, fathers were more likely to eat eggs under low oxygen conditions," notes Klug. "Such cases have led the to the hypothesis that eating or abandoning offspring may be an adaptation to improve overall survival of offspring by reducing their density."
Klug - Colleagues - Model - Hypothesis
Klug and colleagues created a mathematical model to test this hypothesis.
"The model introduced an imaginary individual with a mutation for filial cannibalism or offspring abandonment, into...
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