MHC-II distance between parents predicts sex allocation decisions in a genetically monogamous bird

• Published in: Behavioral Ecology
• Main Authors: Pineaux, Maxime, Merkling, Thomas, Danchin, Etienne, Hatch, Scott, Leclaire, Sarah, Blanchard, Pierrick
• Other Authors: Evolution et Diversité Biologique (EDB), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Institute for Searbird Research and Conservation, ANR-11-IDEX-0002,UNITI,Université Fédérale de Toulouse(2011)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BDLR.RS]Life Sciences [q-bio]/Reproductive Biology/Sexual reproduction; Black-legged Kittiwake; rissa tridactyla
• Online Access: https://cnrs.hal.science/hal-03770671; https://cnrs.hal.science/hal-03770671/document; https://cnrs.hal.science/hal-03770671/file/MHC%20based%20sex%20allocation%20August%202021.pdf; https://doi.org/10.1093/beheco/arab130

International audience Theory predicts that parental heritable characteristics should shape sex allocation decisions when their effects on reproduction or survival are offspring sex-dependent. Numerous studies have questioned to what extent characteristics displayed by one of the parents matched theoretical expectations. This contrasts with the handful of studies that investigated whether compatibility between parents could also trigger selective pressures for sex allocation adjustments. We studied the genetically monogamous black-legged kittiwake (Rissa tridactyla), where previous data revealed that female chicks suffered higher fitness costs from low diversity at genes of the major histocompatibility complex (MHC) than male chicks. We predicted, and found in our dataset, that MHC-similar parents, producing low MHC-diverse offspring, should avoid the production of females. The relation between MHC-distance between parents (i.e. the functional distinctness of their MHC alleles) and offspring sex was not linear, such that MHC-dissimilar parents also overproduced sons. Overall, our results suggest that the genetically monogamous black-legged kittiwake parents flexibly adapt their reproduction and circumvent the costs of suboptimal pairing by manipulating offspring sex.