Data from: Extreme intraclutch egg-size dimorphism in Eudyptes penguins, an evolutionary response to clutch-size maladaptation ...

• Main Authors: Stein, Robert William, Williams, Tony D.
• Format: Dataset
• Language: English
• Published: Dryad 2013
• Subjects: Ecology evolutionary; Aptenodytes forsteri; Phylogenetics comparative; Eudyptes chrysolophus; Eudyptes robustus; Spheniscidae; Spheniscus Magellanicus; Pygoscelis antarctica; Eudyptes sclateri; Pygoscelis adeliae; Eudyptes moseleyi; Reproduction costs; Megadyptes antipodes; Life history evolution; Eudyptes schlegeli; Eudyptes pachyrhynchus; Pygoscelis papua; Spheniscus humboldti; Eudyptula albosignata; Spheniscus demersus; Eudyptula minor; Spheniscus mendiculus; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.5061/dryad.cd233; https://datadryad.org/stash/dataset/doi:10.5061/dryad.cd233

Eudyptes penguins (six species) are uniquely characterized by a two-egg clutch with extreme intraclutch egg-size dimorphism (ESD): the first-laid A-egg is 17.5%–56.9% smaller than the B-egg. Although A-eggs are viable, they almost never produce fledged chicks (genus average <1%). Using classical life-history theory and phylogenetic comparative methods, we demonstrate a marked slowdown in the life history of Eudyptes: age of first reproduction is 52% later and annual fecundity 48% lower compared with other two-egg clutch penguin species. All six Eudyptes species have retained a two-egg clutch, despite this pronounced life-history slowdown; this suggests evolutionary mismatch between clutch size and chicks fledged per clutch. Consistent with this, we show that Eudyptes fledge 43% fewer chicks per clutch than other two-egg clutch penguin species. Extreme intraclutch ESD in Eudyptes is associated primarily with a uniform (5%) increase in relative B-egg size, and B-egg size has evolved in accord with life ... : Life history characteristics of penguin speciesStein and Williams AmNat 53502 Table 1 data.csv ...