Open AccessOffspring fitness and the optimal propagule size in a fluctuating environment
Author(s) -
Kvalnes Thomas,
Røberg Anja Ås,
Jensen Henrik,
Holand Håkon,
Pärn Henrik,
Sæther BerntErik,
Ringsby Thor Harald
Publication year - 2018
Publication title -
journal of avian biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.022
H-Index - 76
eISSN - 1600-048X
pISSN - 0908-8857
DOI - 10.1111/jav.01786
Subject(s) - biology , propagule , offspring , propagule pressure , ecology , avian clutch size , maternal effect , life history theory , phenotypic plasticity , population , zoology , reproduction , demography , biological dispersal , life history , genetics , pregnancy , sociology
Propagule size is an important maternal effect on offspring fitness and phenotype in birds and other oviparous animals. The performance of propagules often increases with size, but a fluctuating environment may introduce temporal variation in the optimal phenotype. Understanding these mechanisms will provide novel insights into the eco‐evolutionary dynamics of life history strategies in parental reproductive investment. We investigated the interaction between propagule size (measured as egg volume) and environmental conditions on offspring mortality and phenotype in a Norwegian house sparrow population. Increased propagule size reduced offspring mortality in early life, with more pronounced effects under heavy precipitation. However, the optimal propagule size for low offspring mortality until recruitment shifted from large to small as temperature increased. Propagule size had no significant effect on fledgling body mass and tarsus length. These results reveal a potential for eco‐evolutionary dynamics in propagule size, as populations adapt to fluctuating environmental conditions. The ultimate outcome of this dynamic process will also depend on variation in parental fitness and tradeoffs with other life‐history traits, particularly clutch size.