title: Hatching asynchrony aggravates inbreeding depression in a songbird (Serinus canaria): an inbreeding-environment interaction.
abstract: Understanding how the intensity of inbreeding depression is influenced by stressful environmental conditions is an important area of enquiry in various fields of biology. In birds, environmental stress during early development is often related to hatching asynchrony; differences in age, and thus size, impose a gradient in conditions ranging from benign (first hatched chick) to harsh (last hatched chick). Here, we compared the effect of hatching order on growth rate in inbred (parents are full siblings) and outbred (parents are unrelated) canary chicks (Serinus canaria). We found that inbreeding depression was more severe under more stressful conditions, being most evident in later hatched chicks. Thus, consideration of inbreeding-environment interactions is of vital importance for our understanding of the biological significance of inbreeding depression and hatching asynchrony. The latter is particularly relevant given that hatching asynchrony is a widespread phenomenon, occurring in many bird species. The exact causes of the observed inbreeding-environment interaction are as yet unknown, but may be related to a decrease in maternal investment in egg contents with laying position (i.e. prehatching environment), or to performance of the chicks during sibling competition and/or their resilience to food shortage (i.e. posthatching environment).
authors.affiliation: Department of Biology-Ethology, University of Antwerp, Universiteitsplein 1-Campus Drie Eiken C1.25, B-2610, Wilrijk, Belgium. raissa.deboer@uantwerpen.be.
authors.forename: Raïssa A
authors.initials: RA
authors.lastname: de Boer
authors.forename: Marcel
authors.initials: M
authors.lastname: Eens
authors.forename: Erik
authors.initials: E
authors.lastname: Fransen
authors.forename: Wendt
authors.initials: W
authors.lastname: Müller
mesh_terms: D000818:Animals; D002171:Canaries / Q000235:genetics* / Q000254:growth & development; D004777:Environment; D005260:Female; D007178:Inbreeding; D016014:Linear Models; D008297:Male; D009425:Nesting Behavior / Q000502:physiology*; D055703:Reproductive Physiological Phenomena
keywords: Developmental stress; growth rate; maternal effects; sibling competition