Presentation Details
| Small, but mighty hummingbirds: high repeatability and accuracy of flight muscle capacity Émilie Gagnon1, Juan Camilo Ríos-Orjuela2, 3, Lacey Pilon1, Percy Hentschel1, Alexa Dansereau1, Paolo S.Segre4, Roslyn Dakin1. 1Biology Department, Carleton University, Ottawa, Ontario, Canada.2Laboratorio de Biología Evolutiva de Vertebrados, Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, Bogotá, Colombia.3Grupo de Morfología y Ecología Evolutiva, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Bogotá, Colombia.4University of Wisconsin - Green Bay, Green Bay, Wisconsin, USA |
Abstract
Muscle performance is thought to determine the outcome of competition. The asymptotic load-lifting assay quantifies maximal muscle power output in vertical flight, and is linked to flight maneuverability and the outcome of competition in small birds. Here, we quantified sources of performance variation within a species, namely repeatability, and we determined the number of trials that accurately capture individual differences. We conducted 124 load-lifting trials on 13 male ruby-throated hummingbirds (Archilochus colubris), testing each individual repeatedly over 3 days. We report large individual differences among males, with a repeatability of 70%. An additional 23% of variation reflected short-term fluctuations, wherein a given male’s performance varies across trials. We found no systematic effects of experience, time, or body mass on load-lifting performance. Using simulation, we show that although sampling protocols with more trials yielded lower repeatabilities, they also increased the accuracy of individual estimates. Overall, our results show that peak flight performance encompasses large individual differences and can closely reflect individuals’ true maximum capacity.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
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