Old but gold: males preferentially cannibalize young eggs
Although counterintuitive at first sight, filial cannibalism is common in the animal kingdom and has been recognized as a mechanism to increase the cannibalizing parent’s lifetime reproductive success. However, previous evidence is often inconclusive and the adaptiveness of filial cannibalism is still not fully understood. We here address the notion that parents do not cannibalize at random but preferably consume offspring with a particular phenotype. To assess if differences in developmental stage and thus reproductive value of eggs trigger such selectivity, we experimentally presented male common gobies (Pomatoschistus microps) with two differently aged egg clutches within mixed broods. We found that males consumed significantly more young than old eggs. This result indicates that parents are not only able to discriminate between eggs based on developmental stage, but might use this to reduce the cost of partial filial cannibalism by selectively removing eggs of lower reproductive value.
KeywordsFoster care Life history evolution Offspring age Paternal care Reproductive value Selective filial cannibalism Kin discrimination
We thank the staff of Tvärminne Zoological Station for logistical support, Silke Probst for counting fish eggs, Nils Anthes for statistical advice and discussions, and Nils Anthes, Ines Häderer, and Tobias Gerlach for valuable comments on the manuscript. This project was financially supported by a grant from the Volkswagen foundation to KUH (grant number I/84 846).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
The study complies with all the relevant laws of Finland and was approved by Finnish authorities. All procedures were declared as class 0 experiments and inspected and approved by ELLA, Animal Experimental Board in Finland on site at Tvärminne zoological station in Hanko, Finland.
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