Open AccessIntraspecific variation in reproductive physiology and egg quality in the European Starling Sturnus vulgaris
Author(s) -
Christians Julian K.,
Williams Tony D.
Publication year - 2001
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 - 10.1034/j.1600-048x.2001.320105.x
Subject(s) - sturnus , yolk , vitellogenin , oviduct , starling , biology , vitellogenins , intraspecific competition , medicine , endocrinology , reproduction , gizzard , vitellogenesis , zoology , embryo , ecology , oocyte , microbiology and biotechnology , fish <actinopterygii> , fishery
Egg mass shows large intraspecific variation in birds and is repeatable within individuals. The mechanisms underlying this variation are unknown. We hypothesized that measures of egg quality (the mass of yolk protein, yolk lipid, and albumen protein) would be positively correlated with the plasma pools of the yolk precursor vitellogenin, and the masses of the oviduct, metabolic machinery (liver, heart, lungs, kidneys, gizzard, small intestine and pancreas), and endogenous stores of protein and lipid. We tested these predictions in European Starlings Sturnus vulgaris collected at the peak of egg production effort. In contrast to our predictions, both yolk protein and yolk lipid were negatively correlated with plasma vitellogenin levels. Albumen protein was positively related to oviduct mass, but other aspects of body composition failed to explain variation in egg quality. Hence, while we observed correlations between egg composition and peripheral systems (circulating precursor pools and the oviduct), we found no evidence that egg quality is determined by more general processes, i.e., the supply and processing of nutrients.