scholarly journals Hosts elevate either within-clutch consistency or between-clutch distinctiveness of egg phenotypes in defence against brood parasites

2021 ◽  
Vol 288 (1953) ◽  
pp. 20210326
Author(s):  
Eleanor M. Caves ◽  
Tanmay Dixit ◽  
John F. R. Colebrook-Robjent ◽  
Lazaro Hamusikili ◽  
Martin Stevens ◽  
...  
Keyword(s):  
Individual Variation ◽  
Brood Parasitism ◽  
Negative Relationship ◽  
Empirical Support ◽  
Phenotypic Traits ◽  
Arms Races ◽  
Brood Parasites ◽  
Egg Colour ◽  
Host Parasite

In host–parasite arms races, hosts can evolve signatures of identity to enhance the detection of parasite mimics. In theory, signatures are most effective when within-individual variation is low (‘consistency’), and between-individual variation is high (‘distinctiveness’). However, empirical support for positive covariation in signature consistency and distinctiveness across species is mixed. Here, we attempt to resolve this puzzle by partitioning distinctiveness according to how it is achieved: (i) greater variation within each trait, contributing to elevated ‘ absolute distinctiveness’ or (ii) combining phenotypic traits in unpredictable combinations (‘ combinatorial distinctiveness’). We tested how consistency covaries with each type of distinctiveness by measuring variation in egg colour and pattern in two African bird families (Cisticolidae and Ploceidae) that experience mimetic brood parasitism. Contrary to predictions, parasitized species, but not unparasitized species, exhibited a negative relationship between consistency and combinatorial distinctiveness. Moreover, regardless of parasitism status, consistency was negatively correlated with absolute distinctiveness across species. Together, these results suggest that (i) selection from parasites acts on how traits combine rather than absolute variation in traits, (ii) consistency and distinctiveness are alternative rather than complementary elements of signatures and (iii) mechanistic constraints may explain the negative relationship between consistency and absolute distinctiveness across species.

scholarly journals The ghosts of parasitism past: lingering frontline anti-brood parasite defences in a former host

2021 ◽  
Author(s):  
Matthew H J Chaumont ◽  
Naomi E Langmore ◽  
Justin A Welbergen
Keyword(s):  
Brood Parasitism ◽  
Species Interactions ◽  
Egg Laying ◽  
Arms Race ◽  
Fine Tuning ◽  
Brood Parasite ◽  
Reed Warbler ◽  
Arms Races ◽  
Brood Parasites ◽  
Defensive Behaviors

Abstract Coevolutionary arms races between brood parasites and hosts provide tractable systems for understanding antagonistic coevolution in nature; however, little is known about the fate of frontline antiparasite defences when the host ‘wins’ the coevolutionary arms race. By recreating bygone species-interactions, using artificial parasitism experiments, lingering defensive behaviors that evolved in the context of parasitism can be understood and may even be used to identify the unknown agent of parasitism past. Here we present the first study of this type by evaluating lingering “frontline” nest defences that have evolved to prevent egg laying in a former brood parasite host. The Australian reed warbler Acrocephalus australis, is currently not parasitized but is known to exhibit fine-tuned egg discrimination—a defensive behavior indicative of a past brood parasite-host arms race and common in closely related parasitized species. Here, using 3 D-printed models of adult brood parasites, we examined whether the Australian reed warbler also exhibits frontline defences to adult brood parasites, and whether we could use these defences to identify the warbler’s “ghost of parasitism past”. Our findings provide evidence that the Australian reed warbler readily engages in frontline defences that are considered adaptive specifically in the context of brood parasitism. However, individuals were unable to discriminate between adults of different brood parasite species at their nest. Overall, our results demonstrate that despite a relaxation in selection, defences against brood parasitism can be maintained across multiple stages of the host’s nesting cycle, and further suggest that, in accordance with previous findings, that learning may be important for fine-tuning frontline defence.

scholarly journals Host defences against avian brood parasitism: an endocrine perspective

2018 ◽  
Vol 285 (1886) ◽  
pp. 20180980 ◽  
Author(s):  
Mikus Abolins-Abols ◽  
Mark E. Hauber
Keyword(s):  
Host Responses ◽  
Avian Host ◽  
Shape Variation ◽  
Physiological Mechanisms ◽  
Arms Races ◽  
Brood Parasites ◽  
Avian Brood Parasitism ◽  
Endocrine Factors ◽  
Host Parasite ◽  
Response Traits

Host defences against avian brood parasites are the outcome of well-documented coevolutionary arms races, yet important questions about variation in hosts' antiparasitic response traits remain poorly understood. Why are certain defences employed by some species or individuals and not by others? Here, we propose that understanding variability in and the evolution of host defences can be facilitated by the study of the underlying physiological mechanisms. Specifically, because antiparasitic strategies involve behaviours that have been shown to be hormonally regulated in other contexts, we hypothesize that host responses to brood parasites are likely to be mediated by related endocrine mechanisms. We outline the hallmarks of the endocrine bases of parasite defence-related avian behaviours, review the current understanding of antiparasitic host tactics and propose testable hypotheses about the hormonal mechanisms that may mediate host defences. We consider these mechanisms in a life-history framework and discuss how endocrine factors may shape variation in host defences. By providing a hypothesis-driven mechanistic framework for defences against parasitism, this perspective should stimulate the study of their endocrine bases to enhance our understanding of the intricate arms races in avian host–parasite systems.

scholarly journals Does coevolution with a shared parasite drive hosts to partition their defences among species?

2017 ◽  
Vol 284 (1854) ◽  
pp. 20170272 ◽  
Author(s):  
Eleanor M. Caves ◽  
Martin Stevens ◽  
Claire N. Spottiswoode
Keyword(s):  
Host Species ◽  
Brood Parasitism ◽  
Parasite Species ◽  
Community Context ◽  
Arms Races ◽  
Host Races ◽  
Local Host ◽  
Egg Colour ◽  
Better Than

When mimicry imposes costs on models, selection may drive the model's phenotype to evolve away from its mimic. For example, brood parasitism often drives hosts to diversify in egg appearance among females within a species, making mimetic parasitic eggs easier to detect. However, when a single parasite species exploits multiple host species, parasitism could also drive host egg evolution away from other co-occurring hosts, to escape susceptibility to their respective mimics. This hypothesis predicts that sympatric hosts of the same parasite should partition egg phenotypic space (defined by egg colour, luminance and pattern) among species to avoid one another. We show that eggs of warbler species parasitized by the cuckoo finch Anomalospiza imberbis in Zambia partition phenotypic space much more distinctly than do eggs of sympatric but unparasitized warblers. Correspondingly, cuckoo finch host-races better match their own specialist host than other local host species. In the weaver family, parasitized by the diederik cuckoo Chrysococcyx caprius , by contrast, parasitized species were more closely related and overlapped extensively in phenotypic space; correspondingly, cuckoos did not match their own host better than others. These results suggest that coevolutionary arms races between hosts and parasites may be shaped by the wider community context in which they unfold.

scholarly journals A shared chemical basis of avian host–parasite egg colour mimicry

2011 ◽  
Vol 279 (1731) ◽  
pp. 1068-1076 ◽  
Author(s):  
Branislav Igic ◽  
Phillip Cassey ◽  
Tomáš Grim ◽  
David R. Greenwood ◽  
Csaba Moskát ◽  
...  
Keyword(s):  
Avian Host ◽  
Physiological Mechanisms ◽  
Brood Parasites ◽  
Chemical Basis ◽  
Alternative Phenotypes ◽  
Evolutionarily Conserved ◽  
Egg Colour ◽  
Alternative Scenarios ◽  
Eggshell Colour ◽  
Host Parasite

Avian brood parasites lay their eggs in other birds' nests and impose considerable fitness costs on their hosts. Historically and scientifically, the best studied example of circumventing host defences is the mimicry of host eggshell colour by the common cuckoo ( Cuculus canorus ). Yet the chemical basis of eggshell colour similarity, which impacts hosts' tolerance towards parasitic eggs, remains unknown. We tested the alternative scenarios that (i) cuckoos replicate host egg pigment chemistry, or (ii) cuckoos use alternative mechanisms to produce a similar perceptual effect to mimic host egg appearance. In parallel with patterns of similarity in avian-perceived colour mimicry, the concentrations of the two key eggshell pigments, biliverdin and protoporphyrin, were most similar between the cuckoo host-races and their respective hosts. Thus, the chemical basis of avian host–parasite egg colour mimicry is evolutionarily conserved, but also intraspecifically flexible. These analyses of pigment composition reveal a novel proximate dimension of coevolutionary interactions between avian brood parasites and hosts, and imply that alternative phenotypes may arise by the modifications of already existing biochemical and physiological mechanisms and pathways.

scholarly journals Nest prospecting brown-headed cowbirds ‘parasitize’ social information when the value of personal information is lacking

2017 ◽  
Vol 284 (1861) ◽  
pp. 20171083 ◽  
Author(s):  
David J. White ◽  
Hayden B. Davies ◽  
Samuel Agyapong ◽  
Nora Seegmiller
Keyword(s):  
Personal Information ◽  
Molothrus Ater ◽  
Social Information ◽  
Negative Relationship ◽  
Brood Parasites ◽  
Nest Selection ◽  
Strong Negative Relationship ◽  
Nest Quality ◽  
Cognitive Challenges

Brood parasites face considerable cognitive challenges in locating and selecting host nests for their young. Here, we test whether female brown-headed cowbirds, Molothrus ater , could use information acquired from observing the nest prospecting patterns of conspecifics to influence their own patterns of nest selection. In laboratory-based experiments, we created a disparity in the amount of personal information females had about the quality of nests. Females with less personal information about the quality of two nests spent more time investigating the nest that more knowledgeable females investigated. Furthermore, there was a strong negative relationship between individual's ability to track nest quality using personal information and their tendency to copy others. These two contrasting strategies for selecting nests are equally effective, but lead to different patterns of parasitism.

scholarly journals Foreign Exchange Exposure and Hedging of Turkish Companies: Panel Data Evidence

2016 ◽  
Vol 9 (6) ◽  
pp. 44
Author(s):  
Mahmut Erdogan
Keyword(s):  
Panel Data ◽  
Foreign Exchange ◽  
Positive Relationship ◽  
Negative Relationship ◽  
Empirical Support ◽  
Turnover Ratio ◽  
Time Horizons ◽  
Short Run ◽  
Asset Turnover ◽  
Foreign Exchange Exposure

<p>This study investigates the foreign exchange exposure and determinants of risk for different time horizons of Turkish companies from 1997 to 2011. In order to analyze the effect of the 2001 crisis, the study is split into two sub-periods: pre-crisis, and post-crisis. The empirical findings of the study suggest a negative relationship between exposure and asset turnover ratio, and profit margin, while there was a positive relationship between exposure and leverage. The study also provides empirical support for the fact that the companies with a higher export rate are exposed to higher risk. Finally, large companies are subject to less risk in the short run.</p>

Host–parasite co-evolution

2021 ◽  
pp. 389-416
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Meiotic Recombination ◽  
Evolutionary Process ◽  
Host Switching ◽  
Response To Selection ◽  
Red Queen ◽  
Arms Races ◽  
Migration Rates ◽  
Frequency Changes ◽  
Host Parasite ◽  
Relative Migration

Macroevolutionary patterns concern phylogenies of hosts and their parasites. From those, co-speciation occurs; but host switching is a common evolutionary process and more likely when hosts are close phylogenetically and geographical ranges overlap. Microevolutionary processes refer to allele frequency changes within population. In arms races, traits of hosts and parasites evolve in one direction in response to selection by the other party. With selective sweeps, advantageous alleles rapidly spread in host or parasite population and can become fixed. With antagonistic negative frequency-dependent fluctuations (Red Queen dynamics) genetic polymorphism in populations can be maintained, even through speciation events. A Red Queen co-evolutionary process can favour sexual over asexual reproduction and maintain meiotic recombination despite its other disadvantages (two-fold cost of sex). Local adaptation of host and parasites exist in various combinations; the relative migration rates of the two parties, embedded in a geographical mosaic, are important for this process.

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 Brood parasitism in eusocial insects (Hymenoptera): role of host geographical range size and phylogeny

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180203 ◽  
Author(s):  
Jukka Suhonen ◽  
Jaakko J. Ilvonen ◽  
Tommi Nyman ◽  
Jouni Sorvari
Keyword(s):  
Brood Parasitism ◽  
Range Size ◽  
Geographical Range ◽  
Social Parasite ◽  
Brood Parasite ◽  
Social Parasites ◽  
Brood Parasites ◽  
Eusocial Insects ◽  
Interspecific Brood Parasitism ◽  
Logistic Regressions

Interspecific brood parasitism is common in many animal systems. Brood parasites enter the nests of other species and divert host resources for producing their own offspring, which can lead to strong antagonistic parasite–host coevolution. Here, we look at commonalities among social insect species that are victims of brood parasites, and use phylogenetic data and information on geographical range size to predict which species are most probably to fall victims to brood parasites in the future. In our analyses, we focus on three eusocial hymenopteran groups and their brood parasites: (i) bumblebees, (ii) Myrmica ants, and (iii) vespine and polistine wasps. In these groups, some, but not all, species are parasitized by obligate workerless inquilines that only produce reproductive-caste descendants. We find phylogenetic signals for geographical range size and the presence of parasites in bumblebees, but not in ants and wasps. Phylogenetic logistic regressions indicate that the probability of being attacked by one or more brood parasite species increases with the size of the geographical range in bumblebees, but the effect is statistically only marginally significant in ants. However, non-phylogenetic logistic regressions suggest that bumblebee species with the largest geographical range sizes may have a lower likelihood of harbouring social parasites than do hosts with medium-sized ranges. Our results provide new insights into the ecology and evolution of host–social parasite systems, and indicate that host phylogeny and geographical range size can be used to predict threats posed by social parasites, as well to design efficient conservation measures for both hosts and their parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

Sign in / Sign up

Export Citation Format

Share Document