Anton Antonov

Norwegian University of Science and Technology | NTNU

The evolutionary equilibrium hypothesis was proposed to explain variation in egg rejection rates among individual hosts (intra- and interspecific) of avian brood parasites. Hosts may sometimes mistakenly reject own eggs when they are not parasitized (i.e. make recognition errors). Such errors would incur fitness costs and could counter the evolutio...

Birds are capable of seeing the ultraviolet light (UV) spectrum and as a consequence have evolved UV-reflective structures with signalling functions. Avian eggs also reflect in the UV spectrum but the importance of UV egg matching in egg rejection decisions has been equivocal. Here we conducted egg rejection experiments in the congeneric and sympat...

How do potential hosts escape detrimental interactions with brood parasites? Current consensus is that hole-nesting and granivorous birds avoid brood parasites, like common cuckoos Cuculus canorus, by their inaccessible nest-sites and food unsuitable for parasites, respectively. Any open-nesting insectivorous hosts are believed to remain open to br...

To the memory of A. Antonov who died much too young. Abstract Brood parasitic birds constitute a model system for the study of coevolution. Such parasites are unique by having evolved unusually thick eggshells for their body size. ick eggshells have been hypothesized to evolve as 1) a means of preventing damage to parasite eggs when the brood paras...

Evolution of avian life histories is typically strongly influenced by both altitude and latitude. To date, most studies have investigated the effects of extreme differences in altitude and latitude on variation in reproductive traits. Studies based on small altitude and latitude spans are needed to better understand the resolution of selective pres...

Sex allocation theory and empirical evidence both suggest that natural selection should favour maternal control of offspring sex ratio in relation to their ability to invest in the offspring. Generalist parasites constitute a particularly interesting group to test this theory as different females commonly utilize different host species showing larg...

In this exposé we provide the first review of host use by brood parasitic cuckoos in a multiple-cuckoo system in China, based on our own long-term field data and a compilation of observations obtained from the literature. In total, we found that 11 species of cuckoos utilized altogether 55 host species. These hosts belong to 15 families, in which S...

In avian brood parasitism, egg phenotype plays a key role for both host and parasite reproduction. Several parrotbill species of the genus Paradoxornis are parasitized by the common cuckoo Cuculus canorus, and clear polymorphism in egg phenotype is observed. In this article, we develop a population genetics model in order to identify the key parame...

Avian brood parasites impose strong selection on their hosts leading to the evolution of antiparasite defenses like egg recognition and rejection. Discordance and template-based cognitive mechanisms may form the base for egg recognition by hosts. For discordance, hosts recognize eggs that constitute the minority in a clutch as alien, whereas in tem...

Avian brood parasites and their hosts are involved in complex offence-defense coevolutionary arms races. The most common pair of reciprocal adaptations in these systems is egg discrimination by hosts and egg mimicry by parasites. As mimicry improves, more advanced host adaptations evolve such as decreased intra- and increased interclutch variation...

Although parasites and their hosts often coexist in a set of environmentally differentiated populations connected by gene flow, few empirical studies have considered a role of environmental variation in shaping correlations between traits of hosts and parasites. Here, we studied for the first time the association between the frequency of adaptive p...

We documented brood parasitism by the poorly studied Large Hawk-Cuckoo on a previously unknown host species, the Chinese Babax. Furthermore, we describe a new egg colour for the Large Hawk-Cuckoo. The parasitism rate of Chinese Babax nests over 4 years was 6.9% (11 of 159 nests), with significant temporal variation. The Large Hawk-Cuckoo laid immac...

Many hosts of avian brood parasites such as the common cuckoo (Cuculus canorus) show refined egg discrimination behaviour. Egg recognition in most open-nesting hosts seems to be based entirely on differences in colour. However, hole- and dome-nesting hosts may rely largely on luminance contrasts. Here, we studied egg rejection behaviour in nighting...

We report for the first time on aspects of the breeding biology of the golden parrotbill (Paradoxornis verreauxi), including descriptions of nests, eggs, nestlings and breeding behaviour. The nests were specialized, pensile, semi-domed, attached to bamboo (Fargesia spathacea) branches and constructed from leaves, fibrous roots and moss by both male...

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Generalist parasites regularly evolve host-specific races that each specialize on one particular host species. Many host-specific races originate from geographically structured populations where local adaptations to different host species drive the differentiation of distinct races. However, in sympatric populations where several host races coexist...

There is at present considerable variation in the level of antiparasite defences among different host species of avian brood parasites, but in many potential hosts some individuals reject poorly matching parasite eggs. Here we present unique absence of egg discrimination behaviour backed up by a lack of egg recognition abilities in a suitable commo...

Trait polymorphism can evolve as a consequence of frequency-dependent selection. Coevolutionary interactions between hosts and parasites may lead to selection on both to evolve extreme phenotypes deviating from the norm, through disruptive selection. Here, we show through detailed field studies and experimental procedures that the ashy-throated par...

En la carrera coevolutiva entre Cuculus canorus y sus hospederos han evolucionado varias adaptaciones y contra adaptaciones. Aquí investigamos el parasitismo natural y la sensibilidad al rechazo de huevos de Acrocephalus palustris en Bulgaria. El nivel de parasitismo de C. canorus fue elevado (28%) y el mimetismo promedio de los huevos de C. canoru...

INTERACCIONES COEVOLUTIVAS ENTRE CUCULUS CANORUS Y MILIARIA CALANDRA Aunque los Emberizinae del viejo mundo podrían considerarse hospederos adecuados para Cuculus canorus, en la actualidad no existe evidencia de que alguna de las especies europeas sea parasitada con regularidad. La mayoría de registros históricos de parasitismo se refieren a Emberi...

Given the high costs of avian obligate brood parasitism, host individuals are selected to reject parasitic eggs they recognize as foreign. We show that rejection may not necessarily follow egg discrimination when selective removal of the parasitic egg is difficult. We studied egg rejection behaviour in a small host of the common cuckoo Cuculus cano...

Brood-parasitic birds such as cuckoos and cowbirds lay eggs with unusual by strong shells. Three main hypotheses have been proposed to explain the adaptive significance of this trait. The present study focused on the puncture resistance hypothesis and tested its critical prediction that increased eggshell strength enhances the probability that the...

Capsule Birds select Cotton Thistles as a nesting substrate but these plants provide an unstable support.

Egg discrimination is well documented in many hosts of avian brood parasites, but the proximate mechanisms of egg recognition and rejection decisions are poorly understood. Relevant in this respect is the observation that rejectors of parasite eggs often delay their response. This delay has implications for understanding mechanisms important for eg...

Using multiple logistic regression analysis, we investigated the influence of nest site characteristics, laying date and nest size in marsh warblers Acrocephalus palustris on the risk of parasitism by common cuckoos Cuculus canorus. Marsh warblers breed in more diverse and dense herbaceous vegetation than other cuckoo hosts investigated in comparab...

The breeding ecology of eastern olivaceous warblers Hippolais pallida is poorly known. In this study, we provide data on nest site selection and breeding parameters of the species in a population in northwestern Bulgaria, the only one known to be regularly and heavily parasitized by the common cuckoo Cuculus canorus (hereafter cuckoo). Eastern oliv...

Coevolution is defined as specialized relationships between species that lead to a reciprocal evolutionary change. A particularly suitable model system for studying coevolution is the interactions between obligate avian brood parasites and their hosts. The common cuckoo (Cuculus canorus, hereafter cuckoo) is a well-known brood parasite, which utili...

Although Old World buntings (Emberizinae) may be considered suitable Common Cuckoo (Cuculus canorus) hosts, there is at present no evidence that any of the European species are regularly parasitized. Most historical parasitism records refer to the Yellowhammer (Emberiza citrinella) and Reed Bunting (E. schoeniclus). Both of these species reject alm...

Eggs of several brood parasites have thicker and stronger shells than expected for their size. The present study evaluated the puncture resistance hypothesis for the occurrence of thick-shelled eggs in common cuckoos Cuculus canorus by investigating costs of cuckoo egg ejection in four Acrocephalus warblers—the great reed warbler A. arundinaceus, r...

In the coevolutionary “arms race” between Common Cuckoos (Cuculus canorus) and their hosts, several adaptations and counter-adaptations have evolved. Here, we investigated natural parasitism and host sensitivity to egg rejection in Marsh Warblers (Acrocephalus palustris) in Bulgaria. The level of Common Cuckoo parasitism was high (28%), and average...