1
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Di Giovanni AJ, Villa J, Stanback MT, Thompson CF, Sakaluk SK, Hauber ME, Hanley D. Decision rules for egg-color-based rejection by two cavity-nesting hosts of the brown-headed cowbird. J Exp Biol 2023; 226:jeb245188. [PMID: 37357579 PMCID: PMC10399979 DOI: 10.1242/jeb.245188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 06/21/2023] [Indexed: 06/27/2023]
Abstract
Hosts of obligate avian brood parasites often evolve defense mechanisms to avoid rearing unrelated young. One common defense is egg rejection, for which hosts often rely on eggshell color. Most research has assumed that hosts respond to perceived color differences between their own eggs and parasite eggs regardless of the particular color; however, recent experiments have found that many hosts respond more strongly to brown foreign eggs than to equally dissimilar blue eggs. Yet, none of these prior studies tested a brown-egg-laying species and, with only one exception, all were conducted in open nests where light levels are considered sufficient for effective color-based egg discrimination. Here, we explored how two cavity-nesting hosts of the parasitic brown-headed cowbird (Molothrus ater) - the blue-egg-laying eastern bluebird (Sialia sialis) and the brown-egg-laying house wren (Troglodytes aedon) - respond to experimental eggs painted six distinct colors ranging from blue to brown. Rejection responses of both hosts were best predicted by perceived differences in color between the model egg and their own eggs. Specifically, we found that house wrens preferentially rejected eggs bluer than their own eggs. However, although we found that bluebirds relied on perceived differences in color for their egg rejection decisions, further tests are needed to determine whether they preferentially rejected brown eggs or simply responded to absolute perceived differences in color. These findings demonstrate that these cavity-nesting birds treat perceived color differences in distinct ways, which has important implications on the coevolutionary arms races and the interpretation of avian-perceived color differences.
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Affiliation(s)
| | - Juliana Villa
- Department of Biology, George Mason University, Fairfax, VA 22030, USA
| | - Mark T. Stanback
- Department of Biology, Davidson College, Davidson, NC 28035, USA
| | - Charles F. Thompson
- Behavior, Ecology, Evolution, and Conservation Section, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Scott K. Sakaluk
- Behavior, Ecology, Evolution, and Conservation Section, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Mark E. Hauber
- Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Daniel Hanley
- Department of Biology, George Mason University, Fairfax, VA 22030, USA
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2
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Fulmer AG, Hauber ME. A review of the cues used for rejecting foreign eggs from the nest by the Eurasian blackbird (
Turdus merula
). Ecol Evol 2022; 12:e8886. [PMID: 35571754 PMCID: PMC9077020 DOI: 10.1002/ece3.8886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/07/2022] [Accepted: 04/14/2022] [Indexed: 11/22/2022] Open
Abstract
Avian brood parasitism is reproductively costly for hosts and selects for cognitive features enabling anti‐parasitic resistance at multiple stages of the host's breeding cycle. The true thrushes (genus Turdus) represent a nearly worldwide clade of potential hosts of brood parasitism by Cuculus cuckoos in Eurasia and Africa and Molothrus cowbirds in the Americas. The Eurasian blackbird (Turdus merula) builds an open‐cup nest and is common within much of the common cuckoo's (C. canorus) breeding range. While this thrush is known to be parasitized at most only at low rates by this cuckoo, the species is also a strong rejector of nonmimetic foreign eggs in the nest. Given their open‐cup nesting habits, we predict that Eurasian blackbirds primarily use visual cues in making a distinction between own and parasitically or experimentally inserted foreign eggs in the nest. We then provide a comprehensive and quantitative review of the literature on blackbird egg rejection studies. This review corroborates that vision is the primary sensory modality used by blackbirds in assessing eggs, but also brings attention to some other, less commonly studied cues which appear to influence rejection, including predator exposure, individual experience, stage of clutch completion, and maternal hormonal state. Blackbirds are also able to recognize and eject even highly mimetic eggs (including those of conspecifics) at a moderate rate, apparently relying on many of the same sensory cues. Although the cues involved in foreign egg recognition by Eurasian blackbirds do not appear specialized to nonmimetic cuckoo parasitism, we cannot differentiate between the possibility of egg rejection being selected by mostly conspecific parasitism or by the evolutionary ghost of a now‐extinct, mimetic cuckoo host‐race.
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Affiliation(s)
- Andrew G. Fulmer
- Department of Psychology Fort Lewis College Durango Colorado USA
| | - Mark E. Hauber
- Department of Evolution, Ecology, and Behavior School of Integrative Biology University of Illinois Urbana‐Champaign Urbana Illinois USA
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3
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Stratton JB, Dearborn DC. Nest sanitation behavior does not increase the likelihood of parasitic egg rejection in herring gulls. Curr Zool 2021; 67:675-682. [PMID: 34805545 PMCID: PMC8599063 DOI: 10.1093/cz/zoab046] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/27/2021] [Indexed: 11/19/2022] Open
Abstract
Birds’ behavioral response to brood parasitism can be influenced not only by evolution but also by context and individual experience. This could include nest sanitation, in which birds remove debris from their nests. Ultimately, nest sanitation behavior might be an evolutionary precursor to the rejection of parasitic eggs. Proximately, the context or experience of performing nest sanitation behavior might increase the detection or prime the removal of parasitic eggs, but evidence to date is limited. We tested incubation-stage nests of herring gulls Larus argentatus to ask whether nest sanitation increased parasitic egg rejection. In an initial set of 160 single-object experiments, small, red, blocky objects were usually rejected (18 of 20 nests), whereas life-sized, 3D-printed herring gull eggs were not rejected whether red (0 of 20) or the olive-tan base color of herring gull eggs (0 of 20). Next, we simultaneously presented a red, 3D-printed gull egg and a small, red block. These nests exhibited frequent nest sanitation (small, red block removed at 40 of 48 nests), but egg rejection remained uncommon (5 of those 40) and not significantly different from control nests (5 of 49) which received the parasitic egg but not the priming object. Thus, performance of nest sanitation did not shape individuals’ responses to parasitism. Interestingly, parents were more likely to reject the parasitic egg when they were present as we approached the nest to add the experimental objects. Depending on the underlying mechanism, this could also be a case of experience creating variation in responses to parasitism.
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4
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Samaš P, Hauber ME, Honza M. A Meta-Analysis of Avian Egg Traits Cueing Egg-Rejection Defenses Against Brood Parasitism. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.703208] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The capability of hosts to reject the odd egg from their nest is one of the key defenses against avian brood parasitism. Considerable research effort has been devoted to exploring which phenotypic traits of eggshells facilitate to cue the recognition of the parasitic egg. Here we have reviewed studies addressing salient egg traits involved in the rejection of foreign eggs and used a formal meta-analysis to quantify their relative importance. Hosts appear to rely to a large extent on eggshell color traits, followed by maculation patterns. Hosts respond with similar rates of egg rejection to natural vs. model eggs and when breeding in both closed and open nests. Analyses of experiments on hosts of Cuculus and Molothrus parasites, the two best studied brood parasitic lineages with different co-evolutionary histories, yield similar conclusions. We also identify several poorly studied potential egg recognition cues, such as odor or weight, and recommend exploring even the visual traits in more detail, including chromatic and achromatic contrasts or experimentally manipulated egg maculation characteristics. Recent technological and sensory ecological advances open many new research avenues to experimentally examine the role of diverse egg characteristics in antiparasite defenses.
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5
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Hanley D, López AV, Fiorini VD, Reboreda JC, Grim T, Hauber ME. Variation in multicomponent recognition cues alters egg rejection decisions: a test of the optimal acceptance threshold hypothesis. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180195. [PMID: 30967077 DOI: 10.1098/rstb.2018.0195] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The optimal acceptance threshold hypothesis provides a general predictive framework for testing behavioural responses to discrimination challenges. Decision-makers should respond to a stimulus when the perceived difference between that stimulus and a comparison template surpasses an acceptance threshold. We tested how individual components of a relevant recognition cue (experimental eggs) contributed to behavioural responses of chalk-browed mockingbirds, Mimus saturninus, a frequent host of the parasitic shiny cowbird, Molothrus bonariensis. To do this, we recorded responses to eggs that varied with respect to two components: colour, ranging from bluer to browner than the hosts' own eggs, and spotting, either spotted like their own or unspotted. Although tests of this hypothesis typically assume that decisions are based on perceived colour dissimilarity between own and foreign eggs, we found that decisions were biased toward rejecting browner eggs. However, as predicted, hosts tolerated spotted eggs more than unspotted eggs, irrespective of colour. These results uncover how a single component of a multicomponent cue can shift a host's discrimination threshold and illustrate how the optimal acceptance threshold hypothesis can be used as a framework to quantify the direction and amount of the shift (in avian perceptual units) of the response curve across relevant phenotypic ranges. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.
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Affiliation(s)
- Daniel Hanley
- 1 Department of Biology, Long Island University - Post , Brookville, NY 11548 , USA
| | - Analía V López
- 2 Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires , C1428EGA Buenos Aires , Argentina
| | - Vanina D Fiorini
- 2 Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires , C1428EGA Buenos Aires , Argentina.,3 Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires , C1428EGA Buenos Aires , Argentina
| | - Juan C Reboreda
- 2 Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires , C1428EGA Buenos Aires , Argentina.,3 Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires , C1428EGA Buenos Aires , Argentina
| | - Tomáš Grim
- 4 Department of Zoology, Laboratory of Ornithology, Palacký University , Olomouc 77146 , Czech Republic
| | - Mark E Hauber
- 5 Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign , Urbana, IL 61801 , USA
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6
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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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7
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Hanley D, Gern K, Hauber ME, Grim T. Host Responses to Foreign Eggs across the Avian Visual Color Space. Am Nat 2019; 194:17-27. [DOI: 10.1086/703534] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Yang CC, Wang LW, Liang W, Møller A. High egg rejection rate in a Chinese population of grey-backed thrush ( Turdus hortulorum). Zool Res 2019; 40:226-230. [PMID: 31011133 PMCID: PMC6591160 DOI: 10.24272/j.issn.2095-8137.2019.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
everal previous studies have indicated that nest sanitation behavior is a general adaptation in altricial birds, with egg recognition capacity evolving as a specific response to interspecific brood parasitism (IBP). However, a recent study suggested an alternative hypothesis, concluding that conspecific brood parasitism (CBP) selects for egg rejection in thrushes, with IBP as a by-product. In the present study, we used a spectrophotometer to quantify egg coloration and egg mimicry and performed artificial parasitism experiments in the grey-backed thrush (Turdus hortulorum). We showed that individuals of this species rejected 100% of 12 foreign eggs, without IBP or CBP detected. In a review of previous studies, we also discuss possible explanations for the high egg rejection rate in the grey-backed thrush and suggest areas for future study.
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Affiliation(s)
- Can-Chao Yang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou Hainan 571158, China
| | - Long-Wu 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 Guizhou 550001, China
| | - Wei Liang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou Hainan 571158, China
| | - Anders Møller
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, F-91405 Orsay Cedex, France 3. Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, F-91405 Orsay Cedex, France
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9
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Peer BD, McCleery RA, Jensen WE. Resistance is futile: prohibitive costs of egg ejection in an obligate avian brood parasite host. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Canniff L, Dainson M, López AV, Hauber ME, Grim T, Samaš P, Hanley D. Probing the Limits of Egg Recognition Using Egg Rejection Experiments Along Phenotypic Gradients. J Vis Exp 2018. [PMID: 30199015 DOI: 10.3791/57512] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Brood parasites lay their eggs in other females' nests, leaving the host parents to hatch and rear their young. Studying how brood parasites manipulate hosts into raising their young and how hosts detect parasitism provide important insights in the field of coevolutionary biology. Brood parasites, such as cuckoos and cowbirds, gain an evolutionary advantage because they do not have to pay the costs of rearing their own young. However, these costs select for host defenses against all developmental stages of parasites, including eggs, their young, and adults. Egg rejection experiments are the most common method used to study host defenses. During these experiments, a researcher places an experimental egg in a host nest and monitors how hosts respond. Color is often manipulated, and the expectation is that the likelihood of egg discrimination and the degree of dissimilarity between the host and experimental egg are positively related. This paper serves as a guide for conducting egg rejection experiments from describing methods for creating consistent egg colors to analyzing the findings of such experiments. Special attention is given to a new method involving uniquely colored eggs along color gradients that has the potential to explore color biases in host recognition. Without standardization, it is not possible to compare findings between studies in a meaningful way; a standard protocol within this field will allow for increasingly accurate and comparable results for further experiments.
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Affiliation(s)
| | - Miri Dainson
- Department of Animal Biology, School of Integrative Biology, University of Illinois
| | - Analía V López
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires
| | - Mark E Hauber
- Department of Animal Biology, School of Integrative Biology, University of Illinois
| | - Tomáš Grim
- Department of Zoology and Laboratory of Ornithology, Palacký University
| | - Peter Samaš
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic
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11
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Hanley D, Grim T, Igic B, Samaš P, López AV, Shawkey MD, Hauber ME. Egg discrimination along a gradient of natural variation in eggshell coloration. Proc Biol Sci 2018; 284:rspb.2016.2592. [PMID: 28179521 PMCID: PMC5310612 DOI: 10.1098/rspb.2016.2592] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/10/2017] [Indexed: 11/12/2022] Open
Abstract
Accurate recognition of salient cues is critical for adaptive responses, but the underlying sensory and cognitive processes are often poorly understood. For example, hosts of avian brood parasites have long been assumed to reject foreign eggs from their nests based on the total degree of dissimilarity in colour to their own eggs, regardless of the foreign eggs' colours. We tested hosts' responses to gradients of natural (blue-green to brown) and artificial (green to purple) egg colours, and demonstrate that hosts base rejection decisions on both the direction and degree of colour dissimilarity along the natural, but not artificial, gradient of egg colours. Hosts rejected brown eggs and accepted blue-green eggs along the natural egg colour gradient, irrespective of the total perceived dissimilarity from their own egg's colour. By contrast, their responses did not vary along the artificial colour gradient. Our results demonstrate that egg recognition is specifically tuned to the natural gradient of avian eggshell colour and suggest a novel decision rule. These results highlight the importance of considering sensory reception and decision rules when studying perception, and illustrate that our understanding of recognition processes benefits from examining natural variation in phenotypes.
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Affiliation(s)
- Daniel Hanley
- Department of Biology, Long Island University - Post, Brookville, NY 11548-1300, USA
| | - Tomáš Grim
- Department of Zoology and Laboratory of Ornithology, Palacký University, Olomouc 77146, Czech Republic
| | - Branislav Igic
- Department of Biology, University of Akron, Akron, OH 44325, USA.,Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra 2601, Australia
| | - Peter Samaš
- Department of Zoology and Laboratory of Ornithology, Palacký University, Olomouc 77146, Czech Republic
| | - Analía V López
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA Buenos Aires, Argentina
| | - Matthew D Shawkey
- Department of Biology, University of Akron, Akron, OH 44325, USA.,Department of Biology, Evolution and Optics of Nanostructures Group, Ghent University, Ghent 9000, Belgium
| | - Mark E Hauber
- Department of Psychology, Hunter College and the Graduate Center of the City University of New York, New York, NY 10065, USA.,Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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12
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Trnka A, Samaš P, Grim T. Consistent individual and sex-specific differences in behaviour of common cuckoo chicks: is there a potential impact on host-parasite coevolutionary dynamics? BEHAVIOUR 2018. [DOI: 10.1163/1568539x-00003522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Research on brood parasitism has focused primarily on specific host anti-parasite behaviours and parasite counter-adaptations, and little is known about other aspects of their behaviours such as consistent behavioural differences between individuals. Therefore, we examined consistency in behaviour of nestlings of common cuckoos (Cuculus canorus) raised by great reed warblers (Acrocephalus arundinaceus). Cuckoo chicks showed high repeatability of both aggressive behaviour and breath rate, and both traits were strongly correlated with each other. This represents the first evidence for consistent differences in behaviour among avian brood parasites. Males were consistently more aggressive and less stressed than females. Nestlings of both sexes that hatched later in the season exhibited higher levels of aggression and lower stress responses than nestlings hatched earlier. This suggests that rearing conditions (e.g., food availability and quality) may modulate stress and aggressive phenotypes of brood parasites. We discuss potential effects of the observed patterns on host-parasite dynamics.
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Affiliation(s)
- Alfréd Trnka
- aDepartment of Biology, University of Trnava, Priemyselná 4, 918 43, Trnava, Slovakia
| | - Peter Samaš
- bInstitute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 60365 Brno, Czech Republic
| | - Tomáš Grim
- cDepartment of Zoology and Laboratory of Ornithology, Palacký University, 17. listopadu 50, 77146 Olomouc, Czech Republic
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13
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Dainson M, Hauber ME, López AV, Grim T, Hanley D. Does contrast between eggshell ground and spot coloration affect egg rejection? Naturwissenschaften 2017. [PMID: 28642972 DOI: 10.1007/s00114-017-1476-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Obligate avian brood parasitic species impose the costs of incubating foreign eggs and raising young upon their unrelated hosts. The most common host defence is the rejection of parasitic eggs from the nest. Both egg colours and spot patterns influence egg rejection decisions in many host species, yet no studies have explicitly examined the role of variation in spot coloration. We studied the American robin Turdus migratorius, a blue-green unspotted egg-laying host of the brown-headed cowbird Molothrus ater, a brood parasite that lays non-mimetic spotted eggs. We examined host responses to model eggs with variable spot coloration against a constant robin-mimetic ground colour to identify patterns of rejection associated with perceived contrast between spot and ground colours. By using avian visual modelling, we found that robins were more likely to reject eggs whose spots had greater chromatic (hue) but not achromatic (brightness) contrast. Therefore, egg rejection decision rules in the American robin may depend on the colour contrast between parasite eggshell spot and host ground coloration. Our study also suggests that egg recognition in relation to spot coloration, like ground colour recognition, is tuned to the natural variation of avian eggshell spot colours but not to unnatural spot colours.
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Affiliation(s)
- Miri Dainson
- Department of Psychology, Hunter College and the Graduate Center of the City University of New York, New York, NY, 10065, USA.
| | - Mark E Hauber
- Department of Psychology, Hunter College and the Graduate Center of the City University of New York, New York, NY, 10065, USA.,Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
| | - Analía V López
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA, Buenos Aires, Argentina
| | - Tomáš Grim
- Department of Zoology and Laboratory of Ornithology, Palacký University, 77146, Olomouc, Czech Republic
| | - Daniel Hanley
- Department of Biology, Long Island University - Post, Brookville, New York, NY, 11548, USA
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14
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A test of the nest sanitation hypothesis for the evolution of foreign egg rejection in an avian brood parasite rejecter host species. Naturwissenschaften 2017; 104:14. [PMID: 28251300 DOI: 10.1007/s00114-017-1446-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/20/2016] [Accepted: 02/13/2017] [Indexed: 10/20/2022]
Abstract
Hosts of avian brood parasites have evolved diverse defenses to avoid the costs associated with raising brood parasite nestlings. In egg ejection, the host recognizes and removes foreign eggs laid in its nest. Nest sanitation, a behavior similar in motor pattern to egg ejection, has been proposed repeatedly as a potential pre-adaptation to egg ejection. Here, we separately placed blue 3D-printed, brown-headed cowbird (Molothrus ater) eggs known to elicit interindividual variation in ejection responses and semi-natural leaves into American robins' (Turdus migratorius) nests to test proximate predictions that (1) rejecter hosts should sanitize debris from nests more frequently and consistently than accepter hosts and (2) hosts that sanitize their nests of debris prior to the presentation of a foreign egg will be more likely to eject the foreign egg. Egg ejection responses were highly repeatable within individuals yet variable between them, but were not influenced by prior exposure to debris, nor related to sanitation tendencies as a whole, because nearly all individuals sanitized their nests. Additionally, we collected published data for eight different host species to test for a potential positive correlation between sanitation and egg ejection. We found no significant correlation between nest sanitation and egg ejection rates; however, our comparative analysis was limited to a sample size of 8, and we advise that more data from additional species are necessary to properly address interspecific tests of the pre-adaptation hypothesis. In lack of support for the nest sanitation hypothesis, our study suggests that, within individuals, foreign egg ejection is distinct from nest sanitation tendencies, and sanitation and foreign egg ejection may not correlate across species.
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15
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Samaš P, Rutila J, Grim T. The common redstart as a suitable model to study cuckoo-host coevolution in a unique ecological context. BMC Evol Biol 2016; 16:255. [PMID: 27887566 PMCID: PMC5124271 DOI: 10.1186/s12862-016-0835-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 11/21/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Co-evolutionary arms-races result in spatio-temporally dynamic relationships between interacting species, e.g., brood parasites and their avian hosts. However, majority of avian co-evolutionary studies are limited to "snap-shots" of a single breeding season in an open-nesting host. In a long-term study (11 breeding seasons), we explored a unique system between the brood parasitic common cuckoo (Cuculus canorus) and its host, the common redstart (Phoenicurus phoenicurus) which is exceptional among all cuckoo hosts due to being a cavity nester. Conditions in cavities are different from open nests, e.g., lower risks of predation, more favourable microclimate, increased risks of unsuccessful eviction of host offspring by the cuckoo nestling. Different conditions in cavities thus can be expected to shape parasite-host coevolution differently from what is typically studied in open nesting hosts. RESULTS In our highly parasitised nest-box population (32.5%, n = 569 nests) only 35.7% of cuckoo eggs were laid into the nest cup and incubated by redstarts. Host nests shifted availability to later into the breeding season from 2006 to 2016 and cuckoos followed this trend by also shifting their timing of parasitism. Although previous studies revealed that redstarts selectively eject experimental non-mimetic eggs (desertion was not a specific response to foreign eggs), the hosts never ejected naturally-laid cuckoo eggs or cuckoo eggs cross-fostered into naturally non-parasitised nests. We solve the long-standing debate about the origin of cuckoo eggs found on the nest rim: we gained the first direct video-recording evidence that eggs found on the nest rim were mislaid by parasites and not ejected by hosts. Naturally-parasitised nests were deserted more often (18.6%) than control non-parasitized nests (5.6%) or nests artificially parasitised by us (1.4%). This suggests that the sight of the laying cuckoo female is the primary cue that triggers egg rejection (by desertion) in this host. Review of data from this and other study sites (10 populations, n = 853 experiments) demonstrates high variability in rejection rates and shows that populations facing higher parasitism rates reject parasitic eggs with higher frequencies. Surprisingly, cuckoo chicks either growing solitarily or with redstart chicks did not differ in their fledging success. CONCLUSIONS We suggest that the redstart is an ideal model system to study the flexibility and limits of brood parasite-host co-evolution in an extreme ecological setting.
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Affiliation(s)
- Peter Samaš
- Department of Zoology and Laboratory of Ornithology, Palacky University, 17. listopadu 50, Olomouc, 77146, Czech Republic
| | | | - Tomáš Grim
- Department of Zoology and Laboratory of Ornithology, Palacky University, 17. listopadu 50, Olomouc, 77146, Czech Republic.
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16
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Hanley D, Šulc M, Brennan PLR, Hauber ME, Grim T, Honza M. Dynamic egg color mimicry. Ecol Evol 2016; 6:4192-202. [PMID: 27516874 PMCID: PMC4972242 DOI: 10.1002/ece3.2187] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 11/17/2022] Open
Abstract
Evolutionary hypotheses regarding the function of eggshell phenotypes, from solar protection through mimicry, have implicitly assumed that eggshell appearance remains static throughout the laying and incubation periods. However, recent research demonstrates that egg coloration changes over relatively short, biologically relevant timescales. Here, we provide the first evidence that such changes impact brood parasite–host eggshell color mimicry during the incubation stage. First, we use long‐term data to establish how rapidly the Acrocephalus arundinaceus Linnaeus (great reed warbler) responded to natural parasitic eggs laid by the Cuculus canorus Linnaeus (common cuckoo). Most hosts rejected parasitic eggs just prior to clutch completion, but the host response period extended well into incubation (~10 days after clutch completion). Using reflectance spectrometry and visual modeling, we demonstrate that eggshell coloration in the great reed warbler and its brood parasite, the common cuckoo, changes rapidly, and the extent of eggshell color mimicry shifts dynamically over the host response period. Specifically, 4 days after being laid, the host should notice achromatic color changes to both cuckoo and warbler eggs, while chromatic color changes would be noticeable after 8 days. Furthermore, we demonstrate that the perceived match between host and cuckoo eggshell color worsened over the incubation period. These findings have important implications for parasite–host coevolution dynamics, because host egg discrimination may be aided by disparate temporal color changes in host and parasite eggs.
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Affiliation(s)
- Daniel Hanley
- Department of Zoology and Laboratory of Ornithology Palacký University 17. listopadu 50 Olomouc 771 46 Czech Republic
| | - Michal Šulc
- Institute of Vertebrate Biology Academy of Sciences of the Czech Republicv. v. i., Květná 8603 65 Brno Czech Republic; Department of Ecology Faculty of Science Charles University in Prague Viničná 7128 44 Prague 2 Czech Republic
| | - Patricia L R Brennan
- Department of Biological Sciences Mount Holyoke College South Hadley Massachusetts 01074 USA; Organismic & Evolutionary Biology Graduate Program University of Massachusetts, Amherst Amherst Massachusetts 01003 USA
| | - Mark E Hauber
- Department of Psychology Hunter College and the Graduate Center The City University of New York 695 Park Avenue New York City New York 10065 USA
| | - Tomáš Grim
- Department of Zoology and Laboratory of Ornithology Palacký University 17. listopadu 50 Olomouc 771 46 Czech Republic
| | - Marcel Honza
- Institute of Vertebrate Biology Academy of Sciences of the Czech Republic v. v. i., Květná 8 603 65 Brno Czech Republic
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17
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Wang L, Yang C, Møller AP, Liang W, Lu X. Multiple mechanisms of egg recognition in a cuckoo host. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1988-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Igic B, Nunez V, Voss HU, Croston R, Aidala Z, López AV, Van Tatenhove A, Holford ME, Shawkey MD, Hauber ME. Using 3D printed eggs to examine the egg-rejection behaviour of wild birds. PeerJ 2015; 3:e965. [PMID: 26038720 PMCID: PMC4451021 DOI: 10.7717/peerj.965] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 04/29/2015] [Indexed: 11/20/2022] Open
Abstract
The coevolutionary relationships between brood parasites and their hosts are often studied by examining the egg rejection behaviour of host species using artificial eggs. However, the traditional methods for producing artificial eggs out of plasticine, plastic, wood, or plaster-of-Paris are laborious, imprecise, and prone to human error. As an alternative, 3D printing may reduce human error, enable more precise manipulation of egg size and shape, and provide a more accurate and replicable protocol for generating artificial stimuli than traditional methods. However, the usefulness of 3D printing technology for egg rejection research remains to be tested. Here, we applied 3D printing technology to the extensively studied egg rejection behaviour of American robins, Turdus migratorius. Eggs of the robin’s brood parasites, brown-headed cowbirds, Molothrus ater, vary greatly in size and shape, but it is unknown whether host egg rejection decisions differ across this gradient of natural variation. We printed artificial eggs that encompass the natural range of shapes and sizes of cowbird eggs, painted them to resemble either robin or cowbird egg colour, and used them to artificially parasitize nests of breeding wild robins. In line with previous studies, we show that robins accept mimetically coloured and reject non-mimetically coloured artificial eggs. Although we found no evidence that subtle differences in parasitic egg size or shape affect robins’ rejection decisions, 3D printing will provide an opportunity for more extensive experimentation on the potential biological or evolutionary significance of size and shape variation of foreign eggs in rejection decisions. We provide a detailed protocol for generating 3D printed eggs using either personal 3D printers or commercial printing services, and highlight additional potential future applications for this technology in the study of egg rejection.
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Affiliation(s)
- Branislav Igic
- Department of Biology, University of Akron , Akron, OH , USA
| | - Valerie Nunez
- Department of Psychology, Hunter College, and The Graduate Center of the City University of New York , NY , USA
| | - Henning U Voss
- Citigroup Biomedical Imaging Center, Weill Cornell Medical College , New York, NY , USA
| | - Rebecca Croston
- Department of Biology, University of Nevada-Reno , Reno, NV , USA ; Department of Biology, The Graduate Center of the City University of New York , NY , USA
| | - Zachary Aidala
- Department of Psychology, Hunter College, and The Graduate Center of the City University of New York , NY , USA ; Social and Behavioral Sciences Division, Bloomfield College , Bloomfield, NJ , USA
| | - Analía V López
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires , Buenos Aires , Argentina
| | - Aimee Van Tatenhove
- Department of Ecology and Evolutionary Biology, Cornell University , Ithaca, NY , USA
| | - Mandë E Holford
- Department of Chemistry, Hunter College, The Graduate Center of the City University of New York, and The American Museum of Natural History , NY , USA
| | | | - Mark E Hauber
- Department of Psychology, Hunter College, and The Graduate Center of the City University of New York , NY , USA
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19
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Aidala Z, Croston R, Schwartz J, Tong L, Hauber ME. The role of egg-nest contrast in the rejection of brood parasitic eggs. J Exp Biol 2015; 218:1126-36. [DOI: 10.1242/jeb.108449] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 01/13/2015] [Indexed: 11/20/2022]
Abstract
Abstract
Hosts of avian brood parasites can avoid the reproductive costs of raising genetically unrelated offspring by rejecting parasitic eggs. The perceptual cues and controls mediating parasitic egg discrimination and ejection are well studied: hosts are thought to use differences in egg color, brightness, maculation, size, and shape to discriminate between own and foreign eggs. Most models of brood parasitism implicitly assume that the primary criteria to which hosts attend when discriminating eggs are differences between the eggs themselves. However, this assumption is confounded by the degree to which chromatic and achromatic characteristics of the nest lining co-vary with egg coloration, in that egg-nest contrast per se might be the recognition cue driving parasitic egg detection. Here we systematically tested whether and how egg-nest contrast itself contributes to foreign egg discrimination. In an artificial parasitism experiment, we independently manipulated egg color and nest lining color of the egg-ejector American robin (Turdus migratorius), a host of the obligate brood parasitic brown-headed cowbird (Molothrus ater). We hypothesized that the degree of contrast between foreign eggs and the nest background would affect host egg rejection behavior. We predicted that experimentally decreasing egg-nest chromatic and achromatic contrast (i.e. rendering parasitic eggs more cryptic against the nest lining) would decrease rejection rates, while increasing egg-nest contrast would increase rejection rates. In contrast to our predictions, egg-nest contrast was not a significant predictor of egg ejection patterns. Instead, egg color significantly predicted responses to parasitism. We conclude that egg-egg differences are the primary drivers of egg rejection in this system. Future studies should test for the effects of egg-nest contrast per se in predicting parasitic egg recognition in other host-parasite systems, including those hosts building enclosed nests and parasites laying cryptic eggs, as an alternative to hypothesized effects of egg-egg contrasts.
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Affiliation(s)
- Zachary Aidala
- City University of New York; Bloomfield College, United States
| | - Rebecca Croston
- City University of New York; University of Nevada - Reno, United States
| | | | | | - Mark E. Hauber
- City University of New York; Bloomfield College, United States
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