共查询到20条相似文献,搜索用时 15 毫秒
1.
J. G. Martinez J. J. Soler M. Soler A. P. Mller T. Burke 《Evolution; international journal of organic evolution》1999,53(1):269-278
The amount of gene flow is an important determinant of population structure and therefore of central importance for understanding coevolutionary processes. We used microsatellite markers to estimate population structure and gene flow rates of the great spotted cuckoo (Clamator glandarius) and its main host in Europe, the magpie (Pica pica), in a number of populations (seven and 15, respectively) across their distribution range in Europe. The genetic analysis shows that there exists a pattern of isolation by distance in both species, although the cuckoo data are only indicative due to a small sample size. Gene flow seems to be extensive between nearby populations, higher for magpies than cuckoos, and especially high for magpie populations within the area of distribution of the great spotted cuckoo. There is no correlation between genetic distances between magpie populations and genetic distances between cuckoo populations. We discuss the implications of extensive gene flow between magpie populations in sympatry with cuckoos for the population dynamics of hosts, in particular for the occurrence of egg rejection behavior in host populations and how the different rates of migration for both species can affect the dynamics of coevolutionary processes. 相似文献
2.
The interaction between hosts and parasites in bird populations has been studied extensively. This paper uses game-theoretic methods to model this interaction. This has been done in previous papers but has not been studied taking into account the detailed sequential nature of this game. We introduce a model allowing the host and parasite to make a number of decisions which will depend on various natural factors. The sequence of events begins with the host forming a nest and laying a number of eggs, followed by the possibility that a parasite bird will arrive at the nest; if it does it can choose to destroy some of the host eggs and lay one of its own. A sequence of events follows, which is broken down into two key stages; firstly the interaction between the host and the parasite adult, and secondly that between the host and the parasite chick. The final decision involves the host choosing whether to raise or abandon the chicks that are in the nest. There are certain natural parameters and probabilities which are central to these various decisions; in particular the host is generally uncertain whether parasitism has taken place, but can assess the likelihood of parasitism based upon certain cues (e.g. how many eggs remain in its nest). We then use this methodology to model two real-world interactions, that of the Reed Warbler with the Common Cuckoo and also the Yellow Warbler with the Brown-headed Cowbird. These parasites have different methods in the way they parasitize the nests of their hosts, and the hosts can in turn have different reactions to these parasites. Our model predictions generally match the real results well, and the model also makes predictions of the effect of changes in various key parameters on the type of parasitic interactions that should occur. 相似文献
3.
The interaction between the Toxoplasma parasitophorous vacuole and vimentin-type intermediate filaments in Vero cells was investigated via immunofluorescence microscopy. A significant rearrangement of host cell vimentin around the Toxoplasma parasitophorous vacuoles occurs throughout the course of infection. Host cell vimentin associates with the parasitophorous vacuoles within an hour after invasion. This vimentin overcoating of the vacuole is initiated at the host cell nuclear surface. During parasite multiplication, vimentin retains a closely defined association with the cytosolic surface of the parasitophorous vacuole. In addition, the vimentin intermediate filaments originating from the host cell nuclear surface are progressively rearranged around the enlarging parasitophorous compartment. During infections, the order of vimentin cytoskeleton is normal throughout the cell and appears redefined only at the vicinity of the parasitophorous vacuole. Depolymerization of the intermediate filaments was achieved with the phosphatase inhibitors okadaic acid and calyculin A. Disruption of the intermediate filament networks resulted in displacement of the parasitophorous vacuoles from the host cell nuclear surface. The data indicate that host cell vimentin binds to the Toxoplasma parasitophorous vacuoles and that the host intermediate filament network serves to dock the parasite compartment to the host cell nuclear surface. 相似文献
4.
Following nest destruction, the laying of physiologically committed eggs (eggs that are ovulated, yolked, and making their way through the oviduct) in the nests of other birds is considered a viable pathway for the evolution of obligate interspecific brood parasitism. While intraspecific brood parasitism in response to nest predation has been experimentally demonstrated, this pathway has yet to be evaluated in an interspecific context. We studied patterns of egg laying following experimental nest destruction in captive zebra finches, Taeniopygia guttata, a frequent intraspecific brood parasite. We found that zebra finches laid physiologically committed eggs indiscriminately between nests containing conspecific eggs and nests containing heterospecific eggs (of Bengalese finches, Lonchura striata vars. domestica), despite the con‐ and heterospecific eggs differing in both size and coloration. This is the first experimental evidence that nest destruction may provide a pathway for the evolution of interspecific brood parasitism in birds. 相似文献
5.
We analysed the spatial and temporal pattern of egg laying in great spotted cuckoo females using microsatellite typing to determine parentage of the eggs and nestlings found in host (magpie) nests. The results showed that there were no exclusive laying territories in the study area. Cases of multiparasitism could be due to single females laying two or more eggs in a nest, or to several females using the same nest. In the latter case multiparasitism was due to a shortage of available host nests. We argue that the need for very large laying areas and the likely small cost of sharing parental care for chicks make the costs of defending territories higher than the benefits, which has constrained the evolution of territoriality in this species. Received: 16 March 1998 / Accepted: 15 June 1998 相似文献
6.
We developed a set of eight polymorphic microsatellite loci for pronghorn, Antilocapra americana. We screened 233 individuals from the National Bison Range in Moiese, MT, and found allele numbers from three to 11 and heterozygosity levels ranging from 0.142 to 0.807. These results suggest that these loci will be useful in paternity analysis and basic population genetics applications. 相似文献
7.
8.
The brown-headed cowbird (Molothrusater) is a generalist obligate brood parasite. Despite intensive study and growing concern over the negative impact of cowbird parasitism on populations of many hosts, very little is known about the factors influencing community-wide patterns of cowbird parasitism. Using systematic nest searches, nest parasitism was studied over two breeding seasons at a study site in northeastern Illinois encompassing grassland, forest-edge, and forest habitat, supporting a diverse avian community. Parasitism was observed for 18 out of 34 altricial bird species found nesting at the study site. A total of 299 cowbird eggs and nestlings were found in 191 of a total of 593 nests. Analyses revealed several ecological and behavioral factors associated with frequency of parasitism and the resulting distribution of cowbird eggs. Much higher frequencies of parasitism were found in edge and forest habitats than in grassland. Within the edge habitat, open nests were parasitized significantly more often than cavity nests. Among open nests in the edge habitat, the two largest species were never parasitized. Host behavior, particularly egg-ejection behavior, was associated with a reduced observed frequency of parasitism, but at least three species known to eject cowbird eggs were sometimes parasitized. For six common hosts capable of rearing cowbirds, we found no correlation between level of parasitism and host nest-survivorship, suggesting that fine-grained assessments of host quality by female cowbirds do not influence patterns of parasitism among acceptable host species, or that differences in host quality are not great and/or predictable enough for such fine-grained assessments. Our results suggest that when a variety of possible nests are available, the level of parasitism on a particular species is a balance between a␣cowbird's preference for a particular species and the effectiveness of host species' defenses. A conceptual model was developed that incorporates the observed correlation of cowbird eggs or nestlings with habitat, nest-type, host species' body mass, and host behavioral defenses. Additional community-wide studies of cowbird parasitism will test if this model is applicable to other avian communities. Received: 20 December 1996 / Accepted: 17 May 1997 相似文献
9.
Traditional ecological theory predicts that specialisation can promote speciation; hence, recently derived species are specialists. However, an alternative view is that new species have broad niches, which become narrower and specialised over time. Here, we test these hypotheses using avian brood parasites and three different measures of host specialisation. Brood parasites provide an ideal system in which to investigate the evolution of specialisation, because some exploit more than 40 host species and others specialise on only one. We find that young brood parasite species are smaller and specialise on a narrower range of host sizes, as expected, if specialisation is linked with the generation of new species. Moreover, we show that highly virulent parasites are more specialised, supporting findings in other host–parasite systems. Finally, we demonstrate that different measures of specialisation can lead to different conclusions, and specialisation indices should be designed taking into account the biology of each system. 相似文献
10.
The brood parasitic habits of the European Cuckoo Cuculus canorus have excited wonder, disbelief and speculation since the fourth century BC. Accurate knowledge of cuckoo biology, however, accumulated only slowly and mostly since 1700. The aim of this study is to review six main topics: (1) the placement of cuckoo eggs in host nests; (2) cuckoo ‘clutch’ size; (3) cuckoo egg characteristics, mimicry and rejection; (4) choice of hosts; (5) eviction of eggs and chicks; and (6) the reasons why cuckoos are brood parasites and are incapable of rearing their own young. Early errors in reporting cuckoo biology were often a consequence of poor or incomplete observations leading to erroneous interpretations. Many of the early observers were egg collectors who focussed almost exclusively on the egg-laying period, thus ignoring cuckoo chick biology. Major landmarks in cuckoo studies included the facts that: (1) cuckoo eggs often resembled those of their hosts (1760s) and that this mimicry was adaptive (1850s); (2) hosts sometimes evicted cuckoo eggs (1770s); (3) female cuckoos laid individually distinctive eggs and that specific cuckoo gentes may exist (1850s); and (4) although well recognised that cuckoo chicks were reared alone, prior to Jenner’s work in the 1780s female cuckoo parents were thought to either eat or evict the host eggs or young. Jenner’s results was more readily accepted in Britain than in Germany. Between 1700 and 1859, cuckoo brood parasitism was difficult to reconcile with the prevalent conceptual framework of physico-theology (later known as the argument from design). Thereafter, Darwin’s idea of natural selection provided a superior conceptual framework, which in conjunction with experimental testing of specific hypotheses has continued to advance our understanding of brood parasitism. Our knowledge of cuckoo biology is far from complete, however, and we predict that continuing research often incorporating new technologies will refine and extend our understanding of the cuckoo’s extraordinary biology. 相似文献
11.
Rose Thorogood Nicholas B. Davies 《Evolution; international journal of organic evolution》2013,67(12):3545-3555
Interactions between avian hosts and brood parasites can provide a model for how animals adapt to a changing world. Reed warbler (Acrocephalus scirpaceus) hosts employ costly defenses to combat parasitism by common cuckoos (Cuculus canorus). During the past three decades cuckoos have declined markedly across England, reducing parasitism at our study site (Wicken Fen) from 24% of reed warbler nests in 1985 to 1% in 2012. Here we show with experiments that host mobbing and egg rejection defenses have tracked this decline in local parasitism risk: the proportion of reed warbler pairs mobbing adult cuckoos (assessed by responses to cuckoo mounts and models) has declined from 90% to 38%, and the proportion rejecting nonmimetic cuckoo eggs (assessed by responses to model eggs) has declined from 61% to 11%. This is despite no change in response to other nest enemies or mimetic model eggs. Individual variation in both defenses is predicted by parasitism risk during the host's egg‐laying period. Furthermore, the response of our study population to temporal variation in parasitism risk can also explain spatial variation in egg rejection behavior in other populations across Europe. We suggest that spatial and temporal variation in parasitism risk has led to the evolution of plasticity in reed warbler defenses. 相似文献
12.
We employ microsatellite markers to assess mating tactics in Lepomis marginatus. Genetic assignments for 1015 progeny in 23 nests indicate that about 95% of the offspring were sired by their respective nest-guardians, a finding consistent with the apparent absence of a brood parasitic morphotype in this species. Allopaternal care was documented in two nests, one resulting from a nest takeover, the other from cuckoldry by an adjoining nest-tender. Clustered de novo mutations also were identified. About 2.5 females (range 1-7) contributed to the offspring pool within a typical nest. Results are compared to those for other Lepomis species. 相似文献
13.
Interspecific brood parasites, like the shiny cowbird (Molothrus bonariensis), lay eggs in nests of other species. Shiny cowbird females peck and puncture eggs when they parasitize host nests. This behavior increases the survival of cowbird chicks when they have to compete for food with larger nestmates. However, cowbird chicks may benefit from smaller nestmates as they increase food provisioning by parents and the cowbird chicks secure most extra provisioning. We investigated whether egg-pecking behavior by female shiny cowbirds might be adjusted to the competition that their chicks face in host nests. We found that more host eggs are destroyed per cowbird egg laid in a larger-bodied host (chalk-browed mockingbird, Mimus saturninus, 70-75 g) than a smaller-bodied host (house wrens, Troglodytes aedon, 12-13 g). We also tested egg-pecking preferences in choice experiments with female cowbirds in captivity and found cowbirds presented with eggs in artificial nests pecked first and more frequently, and punctured more frequently the larger egg when this was a host egg, but not when this was a cowbird egg. Our results are partially consistent with the hypothesis that shiny cowbird females adaptively adjust their egg pecking behavior according to the competition that their chicks face in host nests. 相似文献
14.
Chicks of the brood parasitic common cuckoo (Cuculus canorus) typically monopolize host parental care by evicting all eggs and nestmates from the nest. To assess the benefits of parasitic eviction behaviour throughout the full nestling period, we generated mixed broods of one cuckoo and one great reed warbler (Acrocephalus arundinaceus) to study how hosts divide care between own and parasitic young. We also recorded parental provisioning behaviour at nests of singleton host nestlings or singleton cuckoo chicks. Host parents fed the three types of broods with similar-sized food items. The mass of the cuckoo chicks was significantly reduced in mixed broods relative to singleton cuckoos. Yet, after the host chick fledged from mixed broods, at about 10-12 days, cuckoo chicks in mixed broods grew faster and appeared to have compensated for the growth costs of prior cohabitation by fledging at similar weights and ages compared to singleton cuckoo chicks. These results are contrary to suggestions that chick competition in mixed broods of cuckoos and hosts causes an irrecoverable cost for the developing brood parasite. Flexibility in cuckoos' growth dynamics may provide a general benefit to ecological uncertainty regarding the realized successes, failures, and costs of nestmate eviction strategies of brood parasites. 相似文献
15.
The most virulent avian brood parasites obligately kill host young soon after hatching, thus ensuring their monopoly of host parental care. While the host eviction behaviour of cuckoos (Cuculidae) is well documented, the host killing behaviour of honeyguide (Indicatoridae) chicks has been witnessed only once, 60 years ago, and never in situ in host nests. Here, we report from the Afrotropical greater honeyguide the first detailed observations of honeyguides killing host chicks with their specially adapted bill hooks, based on repeated video recordings (available in the electronic supplementary material). Adult greater honeyguides puncture host eggs when they lay their own, but in about half of host nests at least one host egg survived, precipitating chick killing by the honeyguide hatchling. Hosts always hatched after honeyguide chicks, and were killed within hours. Despite being blind and in total darkness, honeyguides attacked host young with sustained biting, grasping and shaking motions. Attack time of 1-5 min was sufficient to cause host death, which took from 9 min to over 7 h from first attack. Honeyguides also bit unhatched eggs and human hands, but only rarely bit the host parents feeding them. 相似文献
16.
Tomáš Grim 《Journal of Ethology》2008,26(1):9-15
Avian chicks use different begging strategies when soliciting parental care. A novel begging strategy was recently observed in Horsfield’s hawk-cuckoo Hierococcyx hyperythrus (=Cuculus fugax). Chicks of this brood-parasitic species raise and shake their wings and display to fosterers a gape-coloured patch on the undersides of their wings. Although the gape-coloured wing-patch may be a unique trait of Horsfield’s hawk-cuckoo, wing-shaking in the context of begging is virtually universal in both brood parasites and their hosts. A simple qualitative comparison across different avian taxa suggests that wing-shake begging is most probably an ancestral feature of cuckoos and perhaps all altricial birds. The wing-shaking may be an honest signal of chick quality. It could also reduce the risk of predation if wing-shaking was coupled with reduced loudness of begging. Horsfield’s hawk-cuckoo chicks could have exploited the universal pre-existing host responsiveness to wing-shake begging. Evolution could have then further proceeded by making the wing-shaking more conspicuous by addition of another stimulus—the unique colourful wing-patch. I also hypothesize that wing-shake begging may have evolved from pre-fledging restlessness and is used secondarily in courtship displays, threatening postures, and distraction displays by adults. Further discussions and tests of these hypotheses may facilitate research into the so far unstudied phylogenetic history of avian chick-begging strategies. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
Certain kinds of hosts are commonly regarded as being more suitable than other for rearing European cuckoos (Cuculus canorus) – insectivores that lay small eggs and have open, shallow nests – although empirical tests of cuckoo host selection are
lacking. We analysed host use by the European cuckoo in 72 British passerines that are potential hosts and for which there
was information available on life-history variables and variables related to cuckoo-host coevolution, such as rate of parasitism,
rejection rate of non-mimetic model eggs and degree of cuckoo-egg mimicry of host eggs. The relative population size of the
host species affected parasitism rate most strongly, followed by relatively short duration of the nestling period, and the
kind of nest, with cuckoos selecting open-nesting hosts. However, the effect of the nestling period could be related to host
body size and the kind of nest used, because hole-nesting species normally have longer nestling periods than open-nesters.
We re-analysed the data excluding hole nesters and corvid species (species with larger body mass), but the results remained
identical. The European cuckoo may benefit from selecting hosts with short nestling periods because such hosts provide food
for their nestlings at a very high rate. When only those species known as cuckoo hosts were analysed, the variable that best
accounted for the parasitism rate was duration of the breeding season. Therefore, availability of potential hosts in both
time and space is important for cuckoos in selecting hosts.
Received: 16 July 1998 / Accepted: 27 October 1998 相似文献
18.
Mercedes Molina‐Morales Juan G. Martínez David Martín‐Gálvez Deborah A. Dawson Terry Burke Jesús M. Avilés 《Evolution; international journal of organic evolution》2014,68(10):3020-3029
One of the best‐known outcomes of coevolution between species is the rejection of mimetic parasite eggs by avian hosts, which has evolved to reduce costly cuckoo parasitism. How this behavioral adaptation varies along the life of individual hosts remains poorly understood. Here, we identify for the first time, lifetime patterns of egg rejection in a parasitized long‐lived bird, the magpie Pica pica and show that, during the years they were studied, some females accept, others reject, and some others modify their response to model eggs, in all cases switching from acceptance to rejection. Females tested in their first breeding attempt always accepted the model egg, even those individuals whose mothers were egg rejecters. A longitudinal analysis showed that the probability of egg rejection increased with the relative age of the female, but was not related to the risk of parasitism in the population. We conclude that ontogeny plays a fundamental role in the process leading to egg rejection in magpies. 相似文献
19.