scholarly journals Egg retrieval versus egg rejection in cuckoo hosts

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180200 ◽  
Author(s):  
Canchao Yang ◽  
Wei Liang ◽  
Anders P. Møller
Keyword(s):  
Brood Parasitism ◽  
Visual Cues ◽  
Egg Rejection ◽  
Egg Recognition ◽  
Theme Issue ◽  
Brood Parasites ◽  
Cavity Nesting ◽  
Series Of Experiments ◽  
Avian Brood Parasitism ◽  
Different Levels

Before complex nests evolved, birds laid eggs on the ground, and egg retrieval evolved as an adaptation against accidental displacement of eggs outside the nest. Therefore, egg retrieval is an ancient, and likely ancestral, widespread behaviour in birds. However, it has received little attention in studies of avian brood parasitism, perhaps because most parasitism occurs in species with complex nests, a context in which egg retrieval seems irrelevant. However, for cavity-nesting hosts of avian brood parasites, egg retrieval may still play an important role in the coevolutionary interactions between obligate brood parasites and hosts, because egg retrieval can be considered to be antagonistic to egg rejection behaviour in hosts, yet both may involve cognition to recognize eggs. We hypothesized that (1) cavity-nesting hosts should retrieve misplaced eggs from outside the nest cup, (2) brood parasitism has modulated egg retrieval behaviour in cavity-nesting hosts and (3) hosts use the same visual cues for decision-making during egg recognition in both egg retrieval and egg rejection actions. To test these hypotheses, we performed a series of experiments in a cavity-nesting host, the green-backed tit (Parus monticolus). Foreign eggs with different levels of mimicry were placed within or outside nest cups of hosts to test their responses. We found that host decisions about whether to retrieve or reject an egg both depended on the degree of mimicry. However, hosts sometimes first retrieved poorly mimetic foreign eggs and then rejected them. Alternatively, hosts sometimes failed to retrieve highly mimetic conspecific eggs. We suggest that egg retrieval in hosts is likely to be a result of the interaction between ancient retrieval behaviour and subsequent adaptation against brood parasitism.This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

scholarly journals The costs of avian brood parasitism explain variation in egg rejection behaviour in hosts

2015 ◽  
Vol 11 (7) ◽  
pp. 20150296 ◽  
Author(s):  
Iliana Medina ◽  
Naomi E. Langmore
Keyword(s):  
Comparative Analysis ◽  
Host Species ◽  
Brood Parasitism ◽  
Large Scale ◽  
Bird Species ◽  
Egg Rejection ◽  
Brood Parasites ◽  
Avian Brood Parasitism ◽  
First Time ◽  
Rejection Rates

Many bird species can reject foreign eggs from their nests. This behaviour is thought to have evolved in response to brood parasites, birds that lay their eggs in the nest of other species. However, not all hosts of brood parasites evict parasitic eggs. In this study, we collate data from egg rejection experiments on 198 species, and perform comparative analyses to understand the conditions under which egg rejection evolves. We found evidence, we believe for the first time in a large-scale comparative analysis, that (i) non-current host species have rejection rates as high as current hosts, (ii) egg rejection is more likely to evolve when the parasite is relatively large compared with its host and (iii) egg rejection is more likely to evolve when the parasite chick evicts all the host eggs from the nest, such as in cuckoos. Our results suggest that the interactions between brood parasites and their hosts have driven the evolution of egg rejection and that variation in the costs inflicted by parasites is fundamental to explaining why only some host species evolve egg rejection.

scholarly journals A Meta-Analysis of Avian Egg Traits Cueing Egg-Rejection Defenses Against Brood Parasitism

2021 ◽  
Vol 9 ◽  
Author(s):  
Peter Samaš ◽  
Mark E. Hauber ◽  
Marcel Honza
Keyword(s):  
Brood Parasitism ◽  
Research Effort ◽  
Meta Analysis ◽  
Phenotypic Traits ◽  
Egg Rejection ◽  
Egg Recognition ◽  
Avian Brood Parasitism ◽  
Egg Traits ◽  
New Research

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.

scholarly journals Avian diet and foraging ecology constrain foreign egg recognition and rejection

2020 ◽  
Vol 13 (1-2) ◽  
pp. 24-31
Author(s):  
Alec B Luro ◽  
Mark E Hauber
Keyword(s):  
Host Species ◽  
Brood Parasitism ◽  
Foraging Ecology ◽  
Foraging Strategies ◽  
Egg Rejection ◽  
Egg Recognition ◽  
Body Sizes ◽  
Bill Morphology ◽  
Avian Brood Parasitism ◽  
Rejection Rates

Egg rejection is a common and effective defense against avian brood parasitism in which the host either marginalizes or removes the parasitic egg or deserts the parasitized clutch. The ability to recognize and reject a parasitic egg depends on bill morphology, sensory systems, and cognition, all of which are also shaped by other selective processes such as foraging. This begs the question whether specific phenotypes associated with different foraging strategies and diets may constrain or facilitate egg recognition and rejection. Here, we propose a novel hypothesis that host species phenotypes related to foraging ecology and diet may impose morphological and visual sensory constraints on the evolution of egg recognition and rejection. We conducted a comparative analysis of the adult diets and egg rejection rates of 165 current host and non-host species. We found that species have significantly higher egg rejection rates when they (1) consume an omnivorous or animal and fruit dominated diet rather than seeds and grains, (2) forage arboreally rather than aerially or on the ground, or (3) possess relatively larger body sizes. Although correlational in nature, as predicted, these results suggest phenotypes related to specific diets and foraging ecologies may differentially constrain or facilitate evolution of host egg rejection defenses against avian brood parasitism.

scholarly journals Avian diet and foraging ecology constrain foreign egg recognition and rejection

2018 ◽  
Author(s):  
Alec B. Luro ◽  
Mark E. Hauber
Keyword(s):  
Host Species ◽  
Brood Parasitism ◽  
Foraging Ecology ◽  
Foraging Strategies ◽  
Egg Rejection ◽  
Egg Recognition ◽  
Body Sizes ◽  
Bill Morphology ◽  
Avian Brood Parasitism ◽  
Rejection Rates

AbstractEgg rejection is the most common defense against avian brood parasitism in which the host either removes the parasitic egg or deserts the parasitized clutch. The ability to recognize and reject a parasitic egg depends on bill morphology, sensory systems, and cognition, all of which are also shaped by other selective processes, such as foraging. This begs the question whether specific phenotypes associated with different foraging strategies and diets may constrain or facilitate egg recognition and rejection. Here, we propose a novel hypothesis that host species phenotypes related to foraging ecology and diet impose morphological and sensory constraints on the evolution of egg rejection. We conducted a comparative analysis of the adult diets and egg rejection rates of 165 current host and non-host species and found species that consume an animal and fruit dominated diet rather than seeds and grains, forage arboreally rather than aerially, and possess relatively larger body sizes have significantly higher egg rejection rates. As predicted, these results suggest that phenotypes related to specific diets and foraging strategies may differentially constrain or facilitate evolution of host egg rejection defenses against avian brood parasitism.

scholarly journals Prolactin mediates behavioural rejection responses to avian brood parasitism

2020 ◽  
Author(s):  
Francisco Ruiz-Raya ◽  
Juan Diego Ibáñez-Álamo ◽  
Charline Parenteau ◽  
Olivier Chastel ◽  
Manuel Soler
Keyword(s):  
Experimental Evidence ◽  
Brood Parasitism ◽  
Parental Attachment ◽  
Positive Association ◽  
Prolactin Secretion ◽  
Host Responses ◽  
Plasma Prolactin ◽  
Egg Rejection ◽  
Brood Parasites ◽  
Avian Brood Parasitism

AbstractEven though adaptations resulting from co-evolutionary interactions between avian brood parasites and their hosts have been well studied, the hormonal mechanisms underlying behavioural host defences remain largely unexplored. Prolactin, the main hormone mediating avian parental behaviour, has been hypothesized to play a key role in the orchestration of host responses to brood parasitic eggs. Based on the positive association between plasma prolactin and parental attachment to eggs, decreasing levels of this hormone are expected to facilitate egg-rejection decisions in parasitized clutches. We tested this prediction by implanting Eurasian blackbirds (Turdus merula) females with an inhibitor of prolactin secretion, bromocriptine mesylate, to experimentally low their prolactin levels. We found that bromocriptine-treated females rejected mimetic model eggs at higher rates than placebo-treated individuals. To our knowledge, this is the first experimental evidence that host responses to brood parasitism are mediated by the primary endocrine pathway that orchestrates the expression of avian parental care.

scholarly journals The Perceptual and Cognitive Processes That Govern Egg Rejection in Hosts of Avian Brood Parasites

2021 ◽  
Vol 9 ◽  
Author(s):  
Daniel Hanley ◽  
Samantha L. Rutledge ◽  
Juliana Villa
Keyword(s):  
Cognitive Processing ◽  
Cognitive Processes ◽  
Selective Pressure ◽  
Null Model ◽  
Egg Rejection ◽  
Egg Recognition ◽  
Brood Parasites ◽  
The Past ◽  
The Cost ◽  
Receptor Noise

Hosts of avian brood parasites are under intense selective pressure to prevent or reduce the cost of parasitism. Many have evolved refined egg discrimination abilities, which can select for eggshell mimicry in their parasite. A classic assumption underlying these coevolutionary dynamics is that host egg recognition depends on the perceivable difference between their own eggs and those of their parasite. Over the past two decades, the receptor noise-limited (RNL) model has contributed to our understanding of these coevolutionary interactions by providing researchers a method to predict a host’s ability to discriminate a parasite’s egg from its own. Recent research has shown that some hosts are more likely to reject brown eggs than blue eggs, regardless of the perceived differences to their own. Such responses suggest that host egg recognition may be due to perceptual or cognitive processes not currently predictable by the RNL model. In this perspective, we discuss the potential value of using the RNL model as a null model to explore alternative perceptual processes and higher-order cognitive processes that could explain how and why some hosts make seemingly counter-intuitive decisions. Further, we outline experiments that should be fruitful for determining the perceptual and cognitive processing used by hosts for egg recognition tasks.

scholarly journals Patterns of host use by brood parasitic Maculinea butterflies across Europe

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180202 ◽  
Author(s):  
András Tartally ◽  
Jeremy A. Thomas ◽  
Christian Anton ◽  
Emilio Balletto ◽  
Francesca Barbero ◽  
...  
Keyword(s):  
Brood Parasitism ◽  
Geographical Variation ◽  
Host Switching ◽  
Host Use ◽  
Theme Issue ◽  
Geographic Mosaic ◽  
New Host ◽  
Brood Parasites ◽  
Comprehensive Survey ◽  
Maculinea Butterflies

The range of hosts exploited by a parasite is determined by several factors, including host availability, infectivity and exploitability. Each of these can be the target of natural selection on both host and parasite, which will determine the local outcome of interactions, and potentially lead to coevolution. However, geographical variation in host use and specificity has rarely been investigated. Maculinea (= Phengaris ) butterflies are brood parasites of Myrmica ants that are patchily distributed across the Palæarctic and have been studied extensively in Europe. Here, we review the published records of ant host use by the European Maculinea species, as well as providing new host ant records for more than 100 sites across Europe. This comprehensive survey demonstrates that while all but one of the Myrmica species found on Maculinea sites have been recorded as hosts, the most common is often disproportionately highly exploited. Host sharing and host switching are both relatively common, but there is evidence of specialization at many sites, which varies among Maculinea species. We show that most Maculinea display the features expected for coevolution to occur in a geographic mosaic, which has probably allowed these rare butterflies to persist in Europe. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

scholarly journals Variation in multicomponent recognition cues alters egg rejection decisions: a test of the optimal acceptance threshold hypothesis

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180195 ◽  
Author(s):  
Daniel Hanley ◽  
Analía V. López ◽  
Vanina D. Fiorini ◽  
Juan C. Reboreda ◽  
Tomáš Grim ◽  
...  
Keyword(s):  
Brood Parasitism ◽  
Response Curve ◽  
Discrimination Threshold ◽  
Single Component ◽  
Decision Makers ◽  
Egg Rejection ◽  
Theme Issue ◽  
Acceptance Threshold ◽  
Behavioural Responses ◽  
Molothrus Bonariensis

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’.

scholarly journals The coevolutionary biology of brood parasitism: a call for integration

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180190 ◽  
Author(s):  
Rose Thorogood ◽  
Claire N. Spottiswoode ◽  
Steven J. Portugal ◽  
Ros Gloag
Keyword(s):  
Parental Care ◽  
Brood Parasitism ◽  
Evolutionary History ◽  
Social Evolution ◽  
Special Issue ◽  
Theme Issue ◽  
Brood Parasites ◽  
History Of ◽  
Ancient Times ◽  
Illuminating System

Obligate brood-parasitic cheats have fascinated natural historians since ancient times. Passing on the costs of parental care to others occurs widely in birds, insects and fish, and often exerts selection pressure on hosts that in turn evolve defences. Brood parasites have therefore provided an illuminating system for researching coevolution. Nevertheless, much remains unknown about how ecology and evolutionary history constrain or facilitate brood parasitism, or the mechanisms that shape or respond to selection. In this special issue, we bring together examples from across the animal kingdom to illustrate the diverse ways in which recent research is addressing these gaps. This special issue also considers how research on brood parasitism may benefit from, and in turn inform, related fields such as social evolution and immunity. Here, we argue that progress in our understanding of coevolution would benefit from the increased integration of ideas across taxonomic boundaries and across Tinbergen’s Four Questions: mechanism, ontogeny, function and phylogeny of brood parasitism. We also encourage renewed vigour in uncovering the natural history of the majority of the world's brood parasites that remain little-known. Indeed, it seems very likely that some of nature’s brood parasites remain entirely unknown, because otherwise we are left with a puzzle: if parental care is so costly, why is brood parasitism not more common?This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

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