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Abolins‐Abols M, Peterson M, Studer B, Hale M, Hanley D, Bentley G, Hauber ME. Patterns of stress response to foreign eggs by a rejecter host of an obligate avian brood parasite. Ecol Evol 2023; 13:e9691. [PMID: 36699567 PMCID: PMC9848814 DOI: 10.1002/ece3.9691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 12/08/2022] [Accepted: 12/12/2022] [Indexed: 01/20/2023] Open
Abstract
One of the most effective defenses of avian hosts against obligate brood parasites is the ejection of parasitic eggs from the nests. Despite the clear fitness benefits of this behavior, individuals within so-called "egg-rejecter" host species still show substantial variation in their propensity to eliminate foreign eggs from the nest. We argue that this variation can be further understood by studying the physiological mechanisms of host responses to brood parasitic egg stimuli: independent lines of research increasingly support the hypothesis that stress-related physiological response to parasitic eggs may trigger egg rejection. The "stress-mediated egg rejection" hypothesis requires that hosts activate the stress-response when responding to parasitic egg stimuli. We tested this prediction by asking whether hosts showed differential stress response when exposed to host-like (mimetic) or parasite-like (non-mimetic) eggs. We experimentally parasitized incubating American robins Turdus migratorius, a robust egg-rejecter host to obligate brood parasitic brown-headed cowbirds Molothrus ater, with mimetic or non-mimetic model eggs. To assess the stress response, we measured the heart rate in incubating females immediately after experimental parasitism. We also measured plasma corticosterone and, in a subset of birds, used RNA-sequencing to analyze the expression of proopiomelanocortin (POMC), a precursor of adrenocorticotropic hormone, 2 h after experimental parasitism. We found that egg type had no effect on heart rate. Two hours following experimental parasitism, plasma corticosterone did not differ between the differently-colored model egg treatments or between rejecter and accepter females within the non-mimetic treatment. However, females exposed to non-mimetic eggs showed an upregulation of POMC gene expression (before FDR correction) in the pituitary compared with females treated with mimetic eggs. Our findings suggest that in an egg-rejecter host species, non-mimetic parasitic eggs may increase the activity of the stress-related hypothalamic-pituitary-adrenal axis compared with mimetic eggs, although the temporal dynamics of this response are not yet understood.
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Affiliation(s)
| | | | - Brett Studer
- Department of Evolution, Ecology, and Behavior, School of Integrative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
| | - Mattison Hale
- Department of BiologyUniversity of LouisvilleLouisvilleKentuckyUSA
| | - Daniel Hanley
- Department of BiologyGeorge Mason UniversityFairfaxVirginiaUSA
| | - George Bentley
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyCaliforniaUSA
| | - Mark E. Hauber
- Department of Evolution, Ecology, and Behavior, School of Integrative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
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2
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Mesken J, Beckmann C, McDonald PG. A simple methodology for creating and applying replicable, photograph‐accurate coloration to
3D
‐printed models for animal behavior studies. Ethology 2022. [DOI: 10.1111/eth.13334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Jarrod Mesken
- Centre for Behavioral and Physiological Ecology, Zoology University of New England Armidale New South Wales Australia
| | - Christa Beckmann
- Centre for Behavioral and Physiological Ecology, Zoology University of New England Armidale New South Wales Australia
- School of Science Western Sydney University Penrith New South Wales Australia
- Hawkesbury Institute for the Environment Western Sydney University Penrith New South Wales Australia
| | - Paul G. McDonald
- Centre for Behavioral and Physiological Ecology, Zoology University of New England Armidale New South Wales Australia
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3
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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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4
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Turner AM, Di Giovanni AJ, Hoover JP, Hauber ME. Eggshell texture but not odor treatment affects model egg rejection in American robins (Turdus migratorius). Anim Cogn 2022; 25:1307-1312. [PMID: 35325327 DOI: 10.1007/s10071-022-01614-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/15/2022] [Accepted: 03/12/2022] [Indexed: 11/01/2022]
Abstract
To curb fitness costs associated with obligate avian brood parasitism, some hosts have evolved to reject foreign eggs in the nest. American robins (Turdus migratorius) are among the few hosts of the brown-headed cowbird (Molothrus ater) that mostly remove parasitic eggs from their nests. With the parasite's eggs looking nothing like their own, American robins likely rely most on visual cues when making rejection decisions. However, we still know little about the roles that tactile and olfactory cues play in robin's or other rejecter hosts' rejection decisions. Here, we conducted a set of experiments to test for the use of tactile or olfactory cues in egg rejection by robins. For the tactile experiment, we found that robins were more likely to reject rough rather than smooth eggs. However, our tactile model egg design was not able to fully discriminate between tactile and visual sensory modalities. In the olfaction experiment, we did not find a significant effect of egg scent treatment on rejection rates. Accordingly, future studies on egg rejection should attempt to fully distinguish between tactile and visual cues, as well as examine olfactory cues in other egg rejecter host species.
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Affiliation(s)
- Abbigail M Turner
- Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Alexander J Di Giovanni
- Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jeffrey P Hoover
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61820, USA
| | - Mark E Hauber
- Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61820, USA
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5
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Winnicki SK, Hauber ME, Benson TJ, Abolins‐Abols M. Ground nesting by arboreal American robins ( Turdus migratorius). Ecol Evol 2022; 12:e8489. [PMID: 35127023 PMCID: PMC8794755 DOI: 10.1002/ece3.8489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/02/2021] [Accepted: 12/07/2021] [Indexed: 11/08/2022] Open
Abstract
Animals with dependent and vulnerable young need to decide where to raise their offspring to minimize ill effects of weather, competition, parasitism, and predation. These decisions have critical fitness consequences through impacting the survival of both adults and progeny. Birds routinely place their nest in specific sites, allowing species to be broadly classified based on nest location (e.g., ground- or tree-nesting). However, from 2018 to 2020, we observed 24 American robin (Turdus migratorius) nests placed not on their species-typical arboreal substrates or human-made structures but on the ground at a predator-rich commercial tree-farm in Illinois, USA. This behavior does not appear to be in response to competition and did not affect nest daily survival rate but was restricted to the early half of the breeding season. We hypothesize that ground nesting may be an adaptive response to avoid exposure and colder temperatures at sites above the ground early in the breeding season or a nonadaptive consequence of latent robin nest-placement flexibility.
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Affiliation(s)
- Sarah K. Winnicki
- Department of Evolution, Ecology, and BehaviorSchool of Integrative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- Program in Ecology, Evolution, and ConservationUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
| | - Mark E. Hauber
- Department of Evolution, Ecology, and BehaviorSchool of Integrative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- Program in Ecology, Evolution, and ConservationUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- Illinois Natural History SurveyPrairie Research InstituteUniversity of Illinois at Urbana‐ChampaignChampaignIllinoisUSA
| | - Thomas J. Benson
- Program in Ecology, Evolution, and ConservationUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- Illinois Natural History SurveyPrairie Research InstituteUniversity of Illinois at Urbana‐ChampaignChampaignIllinoisUSA
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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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Turner AM, Hauber ME. The American robin (
Turdus migratorius
): A focal species for anti‐parasitic egg rejection studies among hosts of the brown‐headed cowbird (
Molothrus ater
). Ethology 2021. [DOI: 10.1111/eth.13158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Abbigail M. Turner
- Department of Evolution, Ecology, and Behavior School of Integrative Biology University of Illinois at Urbana‐Champaign Urbana IL USA
| | - Mark E. Hauber
- Department of Evolution, Ecology, and Behavior School of Integrative Biology University of Illinois at Urbana‐Champaign Urbana IL USA
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Hauber ME, Hoover JP, Rhodes OR, Ducay RL, Hanley D. The blunt pole is not a source of more salient recognition cues than the sharp pole for the rejection of model eggs by American robins (Turdus migratorius). JOURNAL OF VERTEBRATE BIOLOGY 2020. [DOI: 10.25225/jvb.20111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Mark E. Hauber
- Department of Evolution, Ecology and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, USA; e-mail:
| | - Jeffrey P. Hoover
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, USA
| | - Oliver R. Rhodes
- Department of Evolution, Ecology and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, USA; e-mail:
| | - Rebecca L. Ducay
- Department of Evolution, Ecology and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, USA; e-mail:
| | - Daniel Hanley
- Department of Biology, George Mason University, Fairfax, USA
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