Benefits of Extra Begging Fail to Compensate for Immunological Costs in Southern Shrike (Lanius meridionalis) Nestlings Moreno Rueda, Gregorio Redondo, Tomás Animal signaling and communication Bird physiology Diet Evolutionary immunology Evolutionary theory Food Immune physiology Immune response Theoretical models aimed at explaining the evolution of honest, informative begging signals employed by nestling birds to solicit food from their parents, require that dishonest signalers incur a net viability cost in order to prevent runaway escalation of signal intensity over evolutionary time. Previous attempts to determine such a cost empirically have identified two candidate physiological costs associated with exaggerated begging: a growth and an immunological cost. However, they failed to take into account the fact that those costs are potentially offset by the fact that nestlings that invest more in begging are also likely to obtain more food. In this study, we test experimentally whether a 25% increase in ingested food compensates for growth and immunological costs of extra begging in southern shrike (Lanius meridionalis) nestlings. Three nestmates matched by size were given three treatments: low begging, high begging-same food intake, and high begging-extra food intake. We found that, while a higher food intake did effectively compensate for the growth cost, it failed to compensate for the immunological cost, measured as T-cell mediated immune response against an innocuous mitogen. Thus, we show for the first time that escalated begging has an associated physiological net cost likely to affect nestling survival negatively. 2014-03-25T09:56:07Z 2014-03-25T09:56:07Z 2012 info:eu-repo/semantics/article Moreno-Rueda, G.; Redondo, T. Benefits of Extra Begging Fail to Compensate for Immunological Costs in Southern Shrike (Lanius meridionalis) Nestlings. Plos One, 7(9): e44647 (2012). [http://hdl.handle.net/10481/31082] 1932-6203 doi: 10.1371/journal.pone.0044647 http://hdl.handle.net/10481/31082 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Public Library of Science (PLOS)