Keresztágyazódás

Keresztágyazódás, meaning "cross-nesting" in English, is a term used in evolutionary biology and ornithology to describe a reproductive phenomenon where female birds lay their eggs in the nests of other individuals of the same species. This behavior is distinct from brood parasitism, where eggs are laid in the nests of different species.

In cross-nesting, the female bird that laid the egg in another's nest typically does not participate in the incubation or rearing of the offspring. The host female, unaware of the foreign egg, incubates all the eggs in her nest and cares for all the hatched chicks. This can lead to a reduced reproductive success for the host female, as she expends resources on offspring that are not genetically her own.

The reasons for cross-nesting can vary. It may be an adaptation to avoid the costs of parental care, such as high predation risk or intense competition for resources. It can also be a strategy to increase the chances of passing on genes, especially in environments with low nesting success rates. For the parasitic female, it can be a way to maximize her own reproductive output with minimal investment.

Cross-nesting has been observed in a variety of bird species, including some ducks, coots, and shorebirds. While it can be a disadvantage for the host individual, it can be an effective reproductive strategy for the parasite, contributing to the genetic diversity and survival of the species under certain ecological conditions.