Assortative pairing by telomere length in king penguins and relationships with breeding success

Telomeres are non-coding genetic repeats protecting the ends of linear chromosomes. Long telomeres are often associated with high individual survival, and inter-individual variation in telomere length has recently been proposed as a proxy for individual quality. Therefore, one might expect individuals of either sex with long telomeres to be of higher intrinsic quality and to be preferred in the context of mate choice. Thus, in sexually monomorphic species where individuals discriminate mates on the basis of signals of intrinsic quality, mate choice should lead to assortative pairing by telomere length, and it should be associated with breeding performance. We tested these two predictions in the king penguin ( Aptenodytes patagonicus , Miller, 1778), a sexually monomorphic seabird. Over 3 years of study and 73 penguin pairs under contrasting environmental conditions, we found strong assortative pairing by telomere length. Interestingly, only female telomere length was positively associated to chick su...