When are egg-rejection cues perceived? A test using thermochromic eggs in an avian brood parasite host

Hauber, Márk E.; Dainson, Miri; Luro, Alec B.; Louder, Amber A.; Hanley, Daniel

doi:10.1007/s10071-019-01306-w

Cited by 19 publications

(35 citation statements)

References 40 publications

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“…In a subset of the more recent studies of American Robins, visual modeling has been used to estimate the avian‐perceivable differences in color (hereafter, chromatic distances) between robin eggs and natural or experimental model parasitic eggs. In turn, these studies have produced (seemingly) inconsistent findings (e.g., Croston and Hauber 2014a, Hanley et al 2017, Hauber et al 2019b). For example, when the chromatic distances (measured in just noticeable differences, or JNDs) between American Robin and model eggs were experimentally varied along the continuum of natural avian eggshell coloration (from blue through beige to brown), rejections increased with increasing JNDs in the direction of browner eggs (Hanley et al 2017, Hauber et al 2019b).…”

Section: Figmentioning

confidence: 99%

“…In turn, these studies have produced (seemingly) inconsistent findings (e.g., Croston and Hauber 2014a, Hanley et al 2017, Hauber et al 2019b). For example, when the chromatic distances (measured in just noticeable differences, or JNDs) between American Robin and model eggs were experimentally varied along the continuum of natural avian eggshell coloration (from blue through beige to brown), rejections increased with increasing JNDs in the direction of browner eggs (Hanley et al 2017, Hauber et al 2019b). However, some of the same experimental work revealed that rejection behavior was not explained by increasing JNDs in the direction of bluer‐than‐American Robin eggs (Hanley et al 2017).…”

Section: Figmentioning

confidence: 99%

“…Critically, unlike what has been done productively in other study systems (e.g., Stevens et al 2013, Sulc et al 2019), investigators in previous studies of American Robins that utilized perceptual modeling did not account for variation in the appearance of each individual subject’s own egg(s) in their experiments. Instead, a generic set of reflectance spectra of conspecific eggs were applied as the representative basis/template for the robin’s species‐specific egg coloration (e.g., Croston and Hauber 2014a, Hanley et al 2017, Hauber et al 2019b). Therefore, our study has added value because we used the color and shape of one egg of individual female American Robins to assess egg rejection as a function of the perceptual distance between their own and the model eggs (Fig.…”

Section: Figmentioning

confidence: 99%

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Self‐referent phenotype matching is a poor predictor of egg rejection by American Robins

Hauber¹,

Kim²,

Goethe³

et al. 2020

J. Field Ornithol.

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Many hosts of obligate brood‐parasitic birds use variation in the coloration and pattern of eggshells to identify and reject foreign eggs from their nests. However, egg‐rejection behavior of several hosts is not tightly predicted by the modeled output of overall avian‐perceivable chromatic differences between foreign and host eggs. This demands a re‐investigation into the proximate sensory cues and perceptual processes used for egg recognition. One plausible mechanism is that rejection by hosts depends on the relative stimulation of one (or a combination) of their photoreceptors when comparing their own and parasitic eggs (i.e., self‐referencing). To test this, we placed dark‐blue egg models (with a known ~ 50% rejection rate) in nests of American Robins (Turdus migratorius), which are occasional hosts of Brown‐headed Cowbirds (Molothrus ater). We found that relative metrics of individually repeatable size or shape and overall avian‐perceivable differences in color between American Robin eggs and model eggs did not explain the probability of an experimental egg being rejected. However, despite a limited R2 value, hosts were significantly more likely to reject a model egg when the estimated contrast between their own egg and the model egg was greater for the blue (SWS) photoreceptor. These results are consistent with female American Robins using a simple physiological algorithm that would confer widespread benefits by reducing the likelihood of rejecting their own eggs, while still eliminating parasitic eggs because of their dissimilar novel coloration.

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Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

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Self‐referent phenotype matching is a poor predictor of egg rejection by American Robins

Hauber¹,

Kim²,

Goethe³

et al. 2020

J. Field Ornithol.

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“…We studied wild American robins Turdus migratorius, an occasional host to the obligate brood-parasitic 54 brown-headed cowbirds Molothrus ater, at Wandell's Tree Nurserty in Champaign County, IL, USA, 55 during the summer of 2019 (details of the study area are given in [17,18]). We searched for robin nests 56 daily.…”

Section: (A) Field Site and Species 53mentioning

confidence: 99%

Glucocorticoids mediate egg rejection in a brood parasite host

Āboliņš-Ābols

Hauber

2019

Preprint

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10Avian brood parasites and their hosts are engaged in a coevolutionary battle that can result in the 11 evolution of sophisticated trickery by parasites and novel defence behaviours in hosts. Despite the clear 12 evolutionary and ecological significance of host behaviour, however, we know very little about the 13 mechanisms that regulate host defences, which limits our understanding of both inter-and intraspecific 14 variation in host responses to parasitism. Here we tested whether corticosterone, a hormone known to be 15 upregulated in hosts exposed to parasitism, also mediates one of the most frequent host defencesthe 16 rejection of foreign eggs. We experimentally reduced corticosterone levels in free-living brood parasite 17 hosts, American robins Turdus migratorius, using mitotane and found that the likelihood of model egg 18rejection was significantly lower in the mitotane-treated birds relative to the sham-treated birds. These 19 results demonstrate a causal link between glucocorticoids and egg rejection in hosts of avian brood 20 parasites, but the physiological and sensory-cognitive pathways that regulate this effect remain unknown. 21 22

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“…Arguably, avian brood parasitism research to test how birds recognize eggs is at the forefront avian visual perception and discrimination experiments conducted in the wild (Stoddard and Hauber, 2017). Model plaster (Davies and Brooke, 1989;Honza et al, 2007;Rothstein, 1982) or 3D printed eggs (Igic et al, 2015) can be systematically painted with ranges of natural avian colors (Canniff et al, 2018;Hauber et al, 2015) and spotting patterns (Dainson et al, 2017;Hanley et al, 2019;Luro et al, 2018) and placed into host species' nests to test if the attending parents discriminate and recognize the model eggs by touching them (Soler et al, 2017), setting them aside within the nest, or removing them from the nest. Recent work combining visual modeling (Vorobyev and Osorio, 1998) with foreign-egg rejection experiments has demonstrated that 1) birds have a perceptual bias towards responding to natural blue-white-brown egg color gradients (Abolins-Abols et al, 2019;Manna et al, 2020), but do not respond predictably to purple-green color gradients not found among natural eggs (Hanley et al, 2017); 2) egg background color and egg spotting presence (and/or color) combine together as a multicomponent cue and can greatly increase or decrease egg rejection responses, depending on the host species' own egg appearance (Dainson et al, 2017;Hanley et al, 2019;Luro et al, 2018); and 3) host species may use achromatic patterning and spatial features such as egg spotting and scrawling when recognizing and rejecting foreign eggs (Spottiswoode and Stevens, 2010;Stoddard et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Visual acuity and egg spatial chromatic contrast predict egg rejection behavior of American robins

Luro

Fernández‐Juricic

Baumhardt

et al. 2020

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Summary StatementWe used 3D-printed model eggs with checkered patterns of varying dimensions to test how chromatic visual acuity affects egg recognition in an avian brood parasite host species, the American robin. AbstractColor and spatial vision are critical for recognition and discrimination tasks affecting fitness, including finding food and mates and recognizing offspring. For example, as a counter defense to avoid the cost of raising the unrelated offspring of obligate interspecific avian brood parasites, many host species routinely view, recognize, and remove the foreign egg(s) from their nests. Recent research has shown that host species visually attend to both chromatic and spatial pattern features of eggs; yet how hosts simultaneously integrate these features together when recognizing eggs remains an open question. Here, we tested egg rejection responses of American robins (Turdus migratorius) using a range of 3D-printed model eggs covered with blue and yellow checkered patterns differing in relative square sizes. We predicted that robins would reject a model egg if they could visually resolve the blue and yellow squares as separate features or accept it if the squares blended together and appeared similar in color to the natural blue-green color of robin eggs as perceived by the avian visual system. As predicted, the probability of robins rejecting a model egg increased with greater sizes of its blue and yellow squares. Our results suggest that chromatic visual acuity and viewing distance have the potential to limit the ability of a bird to recognize a foreign egg in its nest, thus providing a limitation to host egg recognition that obligate interspecific avian brood parasites may exploit. 409 410 411 412 413 414 Abolins-Abols, M., Hanley, D., Moskát, C., Grim, T. and Hauber, M. E. (2019). Antiparasitic egg rejection by great reed warblers (Acrocephalus arundinaceus) tracks differences along an eggshell color gradient. Stokke, B. G. (2010). Avian colour perception predicts behavioural responses to experimental brood parasitism in chaffinches. J. Evol. Biol. 23, 293-301. Bürkner, P. C. (2017). brms: An R package for Bayesian multilevel models using Stan. J. Stat. Softw. 80, 1-28. Canniff, L., Dainson, M., López, A. V., Hauber, M. E., Grim, T., Samaš, P. and Hanley, D. (2018). Probing the limits of egg recognition using egg rejection experiments along phenotypic gradients. J. Vis. Exp. 2018, e57512. Cassey, P., Honza, M., Grim, T. and Hauber, M. E. (2008). The modelling of avian visual perception predicts behavioural rejection responses to foreign egg colours. Biol. Lett. 4, 515-517. Caves, E. M. and Johnsen, S. (2017). AcuityView: An r package for portraying the effects of visual acuity on scenes observed by an animal. Methods Ecol. Evol. 9, 793-797. Princeton University Press. Croston, R. and Hauber, M. E. (2014). Spectral tuning and perceptual differences do not explain the rejection of brood parasitic eggs by American robins (Turdus migratorius). Behav. Ecol. Sociob...

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When are egg-rejection cues perceived? A test using thermochromic eggs in an avian brood parasite host

Cited by 19 publications

References 40 publications

Self‐referent phenotype matching is a poor predictor of egg rejection by American Robins

Self‐referent phenotype matching is a poor predictor of egg rejection by American Robins

Glucocorticoids mediate egg rejection in a brood parasite host

Visual acuity and egg spatial chromatic contrast predict egg rejection behavior of American robins

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