Immune challenge reduces begging effort and modifies begging call structure in spotless starling nestlings

• Published in: Behavioral ecology and sociobiology 2024-07, Vol.78 (7), p.81, Article 81
• Main Authors: Parejo-Pulido, Daniel, Redondo, Tomás, Pérez-Rodríguez, Lorenzo
• Format: Article
• Language: English
• Subjects: Acoustics; Animal Ecology; Animal reproduction; Begging behavior; Behavior; Behavioral Sciences; Biomedical and Life Sciences; Birds; Costs; Dietary restrictions; Families & family life; Food; Food quality; Hunger; Hypotheses; Illnesses; Immune response; Immune system; Juveniles; Life Sciences; Lipopolysaccharides; Offspring; Original Article; Parental behavior; Physiology; Sensitivity analysis; Sickness behavior; Signal quality; Social behavior; Zoology
• ISSN: 0340-5443; 1432-0762
• DOI: 10.1007/s00265-024-03497-w

Symptoms of illness offer insights into an organism’s condition, altering social signals that affect others’ behavior. Nestling birds employ begging signals to solicit parental care, but the extent to which begging reflects nestling health beyond hunger remains controversial. We investigated how experimentally induced changes in health affect begging signals in spotless starling ( Sturnus unicolor ) nestlings. To alter health status, we challenged nestlings by injecting lipopolysaccharide (LPS) -an antigen that elicits an immune response- or a control substance (PBS) and observed begging behavior under controlled food deprivation conditions. LPS-treated nestlings exhibited delayed gaping, reduced stretching, and less begging time compared to control nestlings. Moreover, LPS-treated nestlings produced calls with higher spectral entropy, particularly when deprived of food for longer. Our findings indicate that begging signals are sensitive to induced sickness. However, addressing mechanistic issues is crucial for effectively testing whether begging reflects nestling condition as a signal of quality in future experimental setups. Significance statement This study demonstrates that begging signals of nestling birds reflect their health status beyond mere hunger, addressing a longstanding debate in behavioral ecology. By experimentally inducing sickness in spotless starling nestlings, we reveal that changes in health affect postural and acoustic begging behavior. However, ascertaining the implications of this finding for current begging theory proves challenging without information about the causal mechanisms underlying sickness behavior. Understanding how nestlings communicate their condition to parents through begging signals holds implications for comprehending parental care dynamics and lays the groundwork for future research in parent-offspring communication.