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Zhang J, Santema P, Lin Z, Yang L, Liu M, Li J, Deng W, Kempenaers B. Experimental evidence that cuckoos choose host nests following an egg matching strategy. Proc Biol Sci 2023; 290:20222094. [PMID: 36809803 PMCID: PMC9943643 DOI: 10.1098/rspb.2022.2094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/13/2023] [Indexed: 02/23/2023] Open
Abstract
The arms race between brood parasites and their hosts provides a classic model to study coevolution. Hosts often reject the parasitic egg, and brood parasites should therefore select host nests in which the colour of the eggs best matches that of their own. Although this hypothesis has received some support, direct experimental evidence is still lacking. Here, we report on a study of Daurian redstarts, which show a distinct egg-colour dimorphism, with females laying either blue or pink eggs. Redstarts are often parasitized by common cuckoos, which lay light blue eggs. First, we showed that cuckoo eggs were more similar in spectral reflectance to the blue than to the pink redstart egg morph. Second, we report that the natural parasitism rate was higher in blue than in pink host clutches. Third, we performed a field experiment in which we presented a dummy clutch of each colour morph adjacent to active redstart nests. In this set-up, cuckoos almost always chose to parasitize a blue clutch. Our results demonstrate that cuckoos actively choose redstart nests in which the egg colour matches the colour of their own eggs. Our study thus provides direct experimental evidence in support of the egg matching hypothesis.
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Affiliation(s)
- Jinggang Zhang
- Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China
- Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Seewiesen 82319, Germany
| | - Peter Santema
- Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Seewiesen 82319, Germany
- Edward Grey Institute, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - Zixuan Lin
- Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Lixing Yang
- Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China
- Academy of Forestry Inventory and Planning, National Forestry and Grassland Administration, Beijing 100714, People's Republic of China
| | - Meijun Liu
- Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Jianqiang Li
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, People's Republic of China
| | - Wenhong Deng
- Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Bart Kempenaers
- Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Seewiesen 82319, Germany
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Ruiz-Raya F. Ecophysiology of egg rejection in hosts of avian brood parasites: new insights and perspectives. Curr Zool 2021; 67:631-638. [PMID: 34805540 PMCID: PMC8599070 DOI: 10.1093/cz/zoab042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/09/2021] [Indexed: 12/11/2022] Open
Abstract
Egg rejection is the most effective and widespread defense used by host species to counteract the extreme fitness costs frequently imposed by obligate avian brood parasites. Yet, the proximate mechanisms underlying between- and within-individual variation in host responses remain poorly explored. Emerging evidence suggests that egg rejection is dependent on individual physiological states, and draws attention to the role of hormones as mediators of flexible antiparasitic responses. In this perspective article, I outline recent advances in our understanding of the proximate factors that mediate egg rejection. I also point out some areas where knowledge remains still lacking, especially those related to the development and maintenance of effective cognitive functions, the potential role of oxidative stress, immunological state, and developmental stressors. I propose new hypotheses that stimulate future research on behavioral host responses toward brood parasitism.
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Affiliation(s)
- Francisco Ruiz-Raya
- Centro de Investigación Mariña, Universidade de Vigo, GEA, Vigo 36310, Spain
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Wang Y, Tian M, Liu J, Lu X, Møller AP, Xia C. Testing the Interspecific Function of Female Common Cuckoo “Bubbling” Call. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.725222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Female common cuckoo (Cuculus canorous) predator-like “bubbling” calls distract host parental attention and reduce the egg rejection rate. Such “bubbling” calls are also frequently used to attract males and deter territorial rivals in intraspecies contact, and these calls are an ancestral character in many cuckoo species. Although hosts have had sufficient time to become familiar with this call and evolve anti-parasitic strategies, why are the hosts fooled by this “bubbling” call? We propose two hypotheses. The first hypothesis proposes that call variation reduces the opportunity for host species to correctly assess cuckoo tricks. In contrast, the second hypothesis proposes that the cost of behavior may prevent the antiparasitic strategy from evolving. In the study, we tested the prerequisites of these hypotheses, by investigating whether cuckoo calls vary during the day and testing whether the predator-like calls suppress bird activities. Based on field recordings from three different areas, we found high overlap in the calls generated during different periods. Oriental great reed warblers (Acrocephalus orientalis), a host species, did not show different responses toward the playback of female common cuckoo calls generated before noon or afternoon. Based on bird count data, we found that predator-like call playback is insufficient for suppressing bird activities. Therefore, none of the prerequisites were supported by our field data. We discuss the potential reasons for our findings and hope to inspire more research examining female cuckoo vocalizations.
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Yang C, Wang L, MØller AP, Liang W. Egg polymorphism and highly sensitive egg recognition of cross-phenotypes in rufescent prinias Prinia rufescens as effective defenses against brood parasitism. Integr Zool 2020; 16:280-285. [PMID: 32644219 DOI: 10.1111/1749-4877.12474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Whether escalating egg polymorphism increases the efficiency to reduce the fitness costs of brood parasitism is not supported by empirical studies. Rufescent prinias (Prinia rufescens) laying tetramorphic eggs are highly sensitive to conspecific foreign eggs with different phenotypes that they reject perfectly at 100%, and suffer only 1.4% of plaintive cuckoo (Cacomantis merulinus) parasitism. Our study provided empirical evidence showing that escalation of egg polymorphism in hosts increases their fitness because it reduces successful cuckoo parasitism rate.
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Affiliation(s)
- Canchao Yang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, China
| | - Longwu Wang
- State Forestry Administration of China Key Laboratory for Biodiversity Conservation in Mountainous Areas of Southwest Karst, School of Life Sciences, Guizhou Normal University, Guiyang, China
| | - Anders Pape MØller
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Orsay Cedex, France
| | - Wei Liang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, China
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Ruiz-Raya F, Soler M. Signal detection and optimal acceptance thresholds in avian brood parasite-host systems: implications for egg rejection. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190477. [PMID: 32420851 DOI: 10.1098/rstb.2019.0477] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Signal detection theory addresses the challenge of successfully identifying informative signals in noisy information contexts, allowing optimal behavioural decisions in diverse ecological contexts. The optimal acceptance threshold hypothesis proposed by Reeve (Reeve 1989 Am. Nat. 133, 407-435. (doi:10.1086/284926)) is an elegant theoretical model to predict the flexibility of acceptance thresholds for conspecific discrimination. This model has provided a robust framework used to explore recognition systems in a broad range of contexts such as animal communication, nest-mate discrimination or anti-parasitic host responses. In this review, we discuss key concepts related to the optimal acceptance threshold hypothesis applied to egg rejection decisions in avian brood parasite-host interactions. We explore those factors determining signal detectability in parasitized nests and how hosts adjust their rejection decisions to both the risk of parasitism and the potential costs associated with egg rejection. In addition, we discuss recent results that challenge some traditional assumptions of the optimal acceptance threshold hypothesis and provide a novel perspective to explore rejection decisions, such as the existence of single-threshold decision rules or acceptance decisions. An integrative view combining current evidence with traditional theory is needed to further advance the comprehension of optimal acceptance thresholds. This article is part of the theme issue 'Signal detection theory in recognition systems: from evolving models to experimental tests'.
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Affiliation(s)
- Francisco Ruiz-Raya
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, E-18071 Granada, Spain
| | - Manuel Soler
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, E-18071 Granada, Spain
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Nest defense and egg recognition in the grey-backed thrush (Turdus hortulorum): defense against interspecific or conspecific brood parasitism? Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2759-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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The global distribution of avian eggshell colours suggest a thermoregulatory benefit of darker pigmentation. Nat Ecol Evol 2019; 4:148-155. [DOI: 10.1038/s41559-019-1003-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 09/11/2019] [Indexed: 01/18/2023]
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