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Life Histories

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Related Experiment Video

Updated: Jun 28, 2026

Exploring Life History Choices: Using Temperature and Substrate Type as Interacting Factors for Blowfly Larval and Female Preferences

Exploring Life History Choices: Using Temperature and Substrate Type as Interacting Factors for Blowfly Larval and Female Preferences

Published on: November 17, 2023

Using life-histories to predict and interpret variability in yolk hormones.

O P Love¹, H G Gilchrist, J Bêty

¹Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada. olovea@sfu.ca

General and Comparative Endocrinology

|October 28, 2008

Summary

Maternal yolk corticosterone varies with life history. Altricial and semi-precocial birds show clutch variation, potentially aiding offspring competition, unlike precocial species.

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Published on: October 27, 2016

Area of Science:

Evolutionary biology
Animal reproductive strategies
Endocrinology

Background:

Maternal yolk hormones are thought to enhance offspring plasticity and maternal fitness.
Hormone deposition patterns are expected to correlate with species-specific life histories.
Yolk glucocorticoids can reduce offspring quality and modulate competition or brood reduction.

Purpose of the Study:

To investigate the relationship between life history and intra-clutch variation in yolk corticosterone.
To compare yolk corticosterone patterns across species with different developmental strategies (altricial, semi-precocial, precocial).
To assess the adaptive significance of yolk hormone variation in maternal effects.

Main Methods:

Quantification of intra-clutch yolk corticosterone levels in European starlings, black guillemots, and common eiders.
Analysis of laying sequence effects on hormone deposition within clutches.
Comparison of hormone variation patterns across species representing a developmental continuum.

Main Results:

Yolk corticosterone increased with laying sequence in starlings and guillemots, but not in eiders.
Starlings exhibited the greatest difference in yolk corticosterone between early and late eggs (94.6%).
Individual females within species showed significant variation in hormone deposition patterns.

Conclusions:

Intra-clutch yolk corticosterone variation may be an adaptive maternal effect in species where offspring competition modulation is beneficial (starlings, guillemots).
In precocial species (eiders), intra-clutch yolk hormone variation likely has little adaptive role.
Future research should integrate species-specific life-history hypotheses to understand the evolution of yolk hormone roles.