Translator Disclaimer
3 June 2022 High within-clutch repeatability of eggshell phenotype in Barn Swallows despite less maculated last-laid eggs
Ava-Rose F. Beech, Mattheus C. Santos, Emily B. Smith, Ben W. Berejka, Yujie Liu, Toshi Tsunekage, Iris I. Levin
Author Affiliations +
Abstract

Ecological and life-history variation and both interspecific and intraspecific brood parasitism contribute to diversity in egg phenotype within the same species. In this study, Barn Swallows (Hirundo rustica erythrogaster) laid eggs with high intraclutch repeatability in egg size, shape, and maculation. Despite this high intraclutch repeatability, last-laid eggs had consistently less of the eggshell covered in spots and fewer spots than earlier-laid eggs in the clutch. We examined sources of interclutch and intraclutch variation using both direct measurements and custom software (SpotEgg, NaturePatternMatch) that provide detailed information on egg characteristics, especially maculation measures. In addition to our main findings, maculation on different sides of the egg was highly repeatable; however, only shape, proportion of the eggshell maculated, and average spot size were repeatable between first and replacement clutches. Low intraclutch variation in maculation could allow females to recognize their clutch and this may be adaptive for colonial nesting species, such as the Barn Swallow. Characterizing intraspecific variation in egg size, shape, and maculation is the first step in understanding whether intraclutch variation is low enough—and interclutch variation high enough—such that eggs could serve as identity signals.

LAY SUMMARY

  • Characterizing variation in avian egg size, shape, and speckling can help us understand the mechanistic basis of and functional outcomes for the patterns we see.

  • Photographs of Barn Swallow (Hirundo rustica erythrogaster) eggs showed low within-nest and high between-nest variation in size, shape, and speckling.

  • The most repeatable measure of egg appearance was egg shape, while the least repeatable was average spot size.

  • First and replacement clutch eggs resembled each other only in shape, proportion of the eggshell speckled, and average spot size.

  • The lay order of the eggs explained some of the within-nest variation in egg appearance; last-laid eggs were less spotted than earlier-laid eggs.

La variación ecológica y de la historia de vida, y el parasitismo de nidada tanto inter-específico como intra-específico, contribuyen a la diversidad en el fenotipo de los huevos dentro de la misma especie. En este estudio, individuos de Hirundo rustica erythrogaster pusieron huevos con alta repetibilidad dentro de la nidada en cuanto al tamaño, la forma y el maculado del huevo. A pesar de esta alta repetibilidad dentro de la nidada, los huevos del final de la puesta tuvieron consistentemente menos partes de la cáscara cubiertas de manchas y menos manchas que los huevos puestos al inicio de la puesta. Examinamos las fuentes de variación dentro de la nidada y entre nidadas utilizando mediciones directas y software personalizado (SpotEgg, NaturePatternMatch), que brindan información detallada sobre las características del huevo, especialmente las medidas de maculado. Además de nuestros hallazgos principales, el maculado en diferentes costados del huevo fue altamente repetible; sin embargo, solo la forma, la proporción de la cáscara del huevo maculada y el tamaño promedio de la mancha fueron repetibles entre la primera nidada y las de reemplazo. La baja variación dentro de la nidada en el maculado podría permitir que las hembras reconozcan su nidada y esto puede ser una adaptación para las especies que anidan en colonias, como H. r. erythrogaster. La caracterización de la variación intra-específica en el tamaño, la forma y el maculado de los huevos es el primer paso para comprender si la variación dentro de la nidada es lo suficientemente baja—y la variación entre nidadas lo suficientemente alta—como para que los huevos puedan servir como señales de identidad.

Copyright © American Ornithological Society 2022. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
Ava-Rose F. Beech, Mattheus C. Santos, Emily B. Smith, Ben W. Berejka, Yujie Liu, Toshi Tsunekage, and Iris I. Levin "High within-clutch repeatability of eggshell phenotype in Barn Swallows despite less maculated last-laid eggs," Ornithology 139(4), 1-13, (3 June 2022). https://doi.org/10.1093/ornithology/ukac024
Received: 14 March 2022; Accepted: 17 May 2022; Published: 3 June 2022
JOURNAL ARTICLE
13 PAGES


Share
SHARE
KEYWORDS
egg shape
egg size
eggshell maculation
forma del huevo
Hirundo rustica
Hirundo rustica
intraclutch variation
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top