Who cares? Elucidating parental care evolution in extant birds

Area of Science:

• Evolutionary biology
• Ornithology
• Behavioral ecology

Background:

• Birds exhibit diverse parental care strategies, from no care to biparental and cooperative systems.
• The ancestral state of parental care in birds and the evolutionary pathways between different care types remain debated.

Purpose of the Study:

• To determine the most probable ancestral parental care type in extant birds.
• To investigate the rates and directions of transitions between different parental care types throughout avian evolution.

Main Methods:

• Utilized a comprehensive database of 5,438 bird species, representing approximately 50% of extant avian diversity.
• Employed advanced phylogenetic comparative methods to account for model and phylogenetic uncertainty.
• Controlled for state-dependent diversification effects to ensure robust evolutionary inferences.

Main Results:

• The most likely ancestral state for extant birds is male-only parental care, with a posterior probability of 0.8.
• Transition rates among parental care types are generally low and exhibit heterogeneity.
• Loss of parental care is exceedingly rare; transitions from female-only or cooperative care predominantly lead to biparental care.

Conclusions:

• Male-only care is inferred as the ancestral state for parental care in birds.
• Parental care systems in birds are evolutionarily stable, characterized by low transition rates and rare loss of care.
• Future research should focus on identifying factors that promote the persistence of specific parental care strategies.