Dispersal ecology versus host specialization as determinants of ectoparasite distribution in brood parasitic indigobirds and their estrildid finch hosts

Brood parasitic birds offer a unique opportunity to examine the ecological and evolutionary determinants of host associations in avian feather lice (Phthiraptera). Brood parasitic behaviour effectively eliminates vertical transfer of lice between parasitic parents and offspring at the nest, while at the same time providing an opportunity for lice associated with the hosts of brood parasites to colonize the brood parasites as well. Thus, the biology of brood parasitism allows a test of the relative roles of host specialization and dispersal ecology in determining the host-parasite associations of birds and lice. If the opportunity for dispersal is the primary determinant of louse distributions, then brood parasites and their hosts should have similar louse faunas. In contrast, if host-specific adaptations limit colonization ability, lice associated with the hosts of brood parasites may be unable to persist on the brood parasites despite having an opportunity for colonization. We surveyed lice on four brood parasitic finch species (genus Vidua), their estrildid finch host species, and a few ploceid finches. While Brueelia lice were found on both parasitic and estrildid finches, a molecular phylogeny showed that lice infesting the two avian groups belong to two distinct clades within Brueelia. Likewise, distinct louse lineages within the amblyceran genus Myrsidea were found on estrildid finches and the parasitic pin-tailed whydah (Vidua macroura), respectively. Although common on estrildid finches, Myrsidea lice were entirely absent from the brood parasitic indigobirds. The distribution and relationships of louse species on brood parasitic finches and their hosts suggest that host-specific adaptations constrain the ability of lice to colonize new hosts, at least those that are distantly related.     

A single ancient origin of brood parasitism in African finches: implications for host-parasite coevolution

Robust phylogenies for brood-parasitic birds, their hosts, and nearest nesting relatives provide the framework to address historical questions about host-parasite coevolution and the origins of parasitic behavior. We tested phylogenetic hypotheses for the two genera of African brood-parasitic finches, Anomalospiza and Vidua, using mitochondrial DNA sequence data from 43 passeriform species. Our analyses strongly support a sister relationship between Vidua and Anomalospiza, leading to the conclusion that obligate brood parasitism evolved only once in African finches rather than twice, as has been the conventional view. In addition, the parasitic finches (Viduidae) are not recently derived from either weavers (Ploceidae) or grassfinches (Estrildidae), but represent a third distinct lineage. Among these three groups, the parasitic finches and estrildids, which includes the hosts of all 19 Vidua species, are sister taxa in all analyses of our full dataset. Many characters shared by Vidua and estrildids, including elaborate mouth markings in nestlings, unusual begging behavior, and immaculate white eggs, can therefore be attributed to common ancestry rather than convergent evolution. The host-specificity of mouth mimicry in Vidua species, however, is clearly the product of subsequent host-parasite coevolution. The lineage leading to Anomalospiza switched to parasitizing more distantly related Old World warblers (Sylviidae) and subsequently lost these characteristics. Substantial sequence divergence between Vidua and Anomalospiza indicates that the origin of parasitic behavior in this clade is ancient (approximately 20 million years ago), a striking contrast to the recent radiation of extant Vidua. We suggest that the parasitic finch lineage has experienced repeated cycles of host colonization, speciation, and extinction through their long history as brood parasites and that extant Vidua species represent only the latest iterations of this process. This dynamic process may account for a significantly faster rate of DNA sequence evolution in parasitic finches as compared to estrildids and other passerines. Our study reduces by one the tally of avian lineages in which obligate brood parasitism has evolved and suggests an origin of parasitism that involved relatively closely related species likely to accept and provide appropriate care to parasitic young. Given the ancient origin of parasitism in African finches, ancestral estrildids must have been parasitized well before the diversification of extant Vidua, suggesting a long history of coevolution between these lineages preceding more recent interactions between specific hosts and parasites.     

EVOLUTIONARY ASSOCIATIONS OF BROOD PARASITIC FINCHES (VIDUA) AND THEIR HOST SPECIES: ANALYSES OF MITOCHONDRIAL DNA RESTRICTION SITES

The species-specific associations of the African brood parasitic finches Vidua with their estrildid finch host species may have originated by cospeciation with the host species or by later colonizations of new hosts. Predictions of these alternative models were tested in two species groups of brood parasites (indigobirds, paradise whydahs) and their hosts. Phylogenetic analyses suggested that the brood parasites and their hosts did not speciate in parallel. The parasitic indigobirds share mitochondrial haplotypes with each other, and species limits in both indigobirds and paradise whydahs do not correspond with their gene trees. Different parasite species within a region are more closely related to each other than any is to parasites that are associated with its same host species in other regions of Africa. There is little genetic difference between parasite species D?_i,j < 0.001 in the indigobirds, D?_i,j = 0.01 in the whydahs). Genetic distances D?_i,j between the parasite species are less than the genetic distances between their corresponding host species in all parasite-host comparisons, and average only 7.2% as large in the indigobirds as in their hosts and 42% as large in the paradise whydahs as in their hosts. A phylogenetic model that allows ancestral haplotype polymorphisms to be retained in descendant species was compared to a constraint model of species monophyly requiring all but the one ancestral haplotype to be independently derived within each species. The constraint model increases the length of the indigobird tree by 50% over that of the model of retained ancestral polymorphisms; the difference is statistically significant. Both phylogenetic and distance analyses indicate that the brood parasites have become associated with their host species through host switches and independent colonizations of the hosts, rather than through parallel cospeciation with them. The molecular genetic results are supported by recent discoveries of additional host species that are associated with the indigobirds in the field and by variation in the species-specific song behaviors of the brood parasites.     

Patterns of host–parasite associations in tropical lice and their passerine hosts in Cameroon

Coevolutionary processes that drive the patterns of host–parasite associations can be deduced through congruence analysis of their phylogenies. Feather lice and their avian hosts have previously been used as typical model systems for congruence analysis; however, such analyses are strongly biased toward nonpasserine hosts in the temperate zone. Further, in the Afrotropical region especially, cospeciation studies of lice and birds are entirely missing. This work supplements knowledge of host–parasite associations in lice using cospeciation analysis of feather lice (genus Myrsidea and the Brueelia complex) and their avian hosts in the tropical rainforests of Cameroon. Our analysis revealed a limited number of cospeciation events in both parasite groups. The parasite–host associations in both louse groups were predominantly shaped by host switching. Despite a general dissimilarity in phylogeny for the parasites and hosts, we found significant congruence in host–parasite distance matrices, mainly driven by associations between Brueelia lice and passerine species of the Waxbill (Estrildidae) family, and Myrsidea lice and their Bulbul (Pycnonotidae) host species. As such, our study supports the importance of complex biotic interactions in tropical environments.     

A priori and a posteriori methods in comparative evolutionary studies of host–parasite associations

Brooks parsimony analysis (BPA) and reconciliation methods in studies of host–parasite associations differ fundamentally, despite using the same null hypothesis. Reconciliation methods may eliminate or modify input data to maximize fit of single parasite clades to a null hypothesis of cospeciation, by invoking different a priori assumptions, including a known host phylogeny. By examining the degree of phylogenetic congruence among multiple parasite clades, using hosts as analogs of taxa but not presuming a host phylogeny or any degree of cospeciation a priori, BPA modifies the null hypothesis of cospeciation if necessary to maintain the integrity of the input data. Two exemplars illustrate critical empirical differences between reconciliation methods and BPA: (1) reconciliation methods rather than BPA may select the incorrect general host cladogram for a set of data from different clades of parasites, (2) BPA rather than reconciliation methods provides the most parsimonious interpretation of all available data, and (3) secondary BPA, proposed in 1990, when applied to data sets in which host‐switching produces hosts with reticulate histories, provides the most parsimonious and biologically realistic interpretations of general host cladograms. The extent to which these general host cladograms, based on cospeciation among different parasite clades inhabiting the same hosts, correspond to host phylogeny can be tested, a posteriori, by comparison with a host phylogeny generated from nonparasite data. These observations lead to the conclusion that BPA and reconciliation methods are designed to implement different research programs based on different epistemologies. BPA is an a posteriori method that is designed to assess the host context of parasite speciation events, whereas reconciliation methods are a priori methods that are designed to fit parasite phylogenies to a host phylogeny. Host‐switching events are essential for explaining complex histories of host–parasite associations. BPA assumes coevolutionary complexity (historical contingency), relying on parsimony as an a posteriori explanatory tool to summarize complex results, whereas reconciliation methods, which embody formalized assumptions of maximum cospeciation, are based on a priori conceptual parsimony. Modifications of basic reconciliation methods, embodied in TreeMap 1.0 and TreeMap 2.02, represent the addition of weighting schemes in which the researcher specifies allowed departures from cospeciation a priori, with the result that TreeMap results more closely agree with BPA results than do reconciled tree analysis results.     

When can host shifts produce congruent host and parasite phylogenies? A simulation approach

Congruence between host and parasite phylogenies is often taken as evidence for cospeciation. However, 'pseudocospeciation', resulting from host-switches followed by parasite speciation, may also generate congruent trees. To investigate this process and the conditions favouring its appearance, we here simulated the adaptive radiation of a parasite onto a new range of hosts. A very high congruence between the host tree and the resulting parasite trees was obtained when parasites switched between closely related hosts. Setting a shorter time lag for speciation after switches between distantly related hosts further increased the degree of congruence. The shape of the host tree, however, had a strong impact, as no congruence could be obtained when starting with highly unbalanced host trees. The strong congruences obtained were erroneously interpreted as the result of cospeciations by commonly used phylogenetic software packages despite the fact that all speciations resulted from host-switches in our model. These results highlight the importance of estimating the age of nodes in host and parasite phylogenies when testing for cospeciation and also demonstrate that the results obtained with software packages simulating evolutionary events must be interpreted with caution.     

Biogeography explains cophylogenetic patterns in toucan chewing lice

Historically, comparisons of host and parasite phylogenies have concentrated on cospeciation. However, many of these comparisons have demonstrated that the phylogenies of hosts and parasites are seldom completely congruent, suggesting that phenomena other than cospeciation play an important role in the evolution of host-parasite assemblages. Other coevolutionary phenomena, such as host switching, parasite duplication (speciation on the host), sorting (extinction), and failure to speciate can also influence host-parasite assemblages. Using mitochondrial and nuclear protein-coding DNA sequences, I reconstructed the phylogeny of ectoparasitic toucan chewing lice in the Austrophilopterus cancellosus subspecies complex and compared this phylogeny with the phylogeny of the hosts, the Ramphastos toucans, to reconstruct the history of coevolutionary events in this host-parasite assemblage. Three salient findings emerged. First, reconstructions of host and louse phylogenies indicate that they do not branch in parallel, and their cophylogenetic history shows little or no significant cospeciation. Second, members of monophyletic Austrophilopterus toucan louse lineages are not necessarily restricted to monophyletic host lineages. Often, closely related lice are found on more distantly related but sympatric toucan hosts. Third, the geographic distribution of the hosts apparently plays a role in the speciation of these lice. These results suggest that for some louse lineages biogeography may be more important than host associations in structuring louse populations and species, particularly when host life history (e.g., hole nesting) or parasite life history (e.g., phoresis) might promote frequent host switching events between syntopic host species. These findings highlight the importance of integrating biogeographic information into cophylogenetic studies.     

Song mimicry of Black-bellied Firefinch Lagonosticta rara and other finches by the brood-parasitic Cameroon Indigobird Vidua camerunensis in West Africa

Brood-parasitic finches Vidua spp. mimic songs of their foster species, with most Vidua species both mimicking songs and parasitizing nests of a single estrildid finch species. We describe a behavioural radiation in the Cameroon Indigobird Vidua camerunensis . Local populations are polymorphic in behaviour, each male mimicking songs of a single species, with certain males mimicking songs of one species and other males mimicking songs of another host species. The species most often mimicked in song are Black-bellied Firefinch Lagonosticta rara and African Firefinch L. rubricata ; other species mimicked in song are Brown Twinspot Clytospiza monteiri and Dybowski's Twinspot Euschistospiza dybowskii . Indigobirds in the different mimicry song populations do not differ morphologically in plumage colour or size. The lack of morphological differences between male indigobirds with different mimicry songs is consistent with a recent behavioural radiation through host shifts, perhaps facilitated by environmental change associated with prehistoric cultivation of grain. The mimicry song populations of indigobirds, behaviourally imprinted upon different host species, support the idea of a process of speciation driven by a shift to new host species.     

A Bayesian framework for the analysis of cospeciation

Abstract.— Information on the history of cospeciation and host switching for a group of host and parasite species is contained in the DNA sequences sampled from each. Here, we develop a Bayesian framework for the analysis of cospeciation. We suggest a simple model of host switching by a parasite on a host phylogeny in which host switching events are assumed to occur at a constant rate over the entire evolutionary history of associated hosts and parasites. The posterior probability density of the parameters of the model of host switching are evaluated numerically using Markov chain Monte Carlo. In particular, the method generates the probability density of the number of host switches and of the host switching rate. Moreover, the method provides information on the probability that an event of host switching is associated with a particular pair of branches. A Bayesian approach has several advantages over other methods for the analysis of cospeciation. In particular, it does not assume that the host or parasite phylogenies are known without error; many alternative phylogenies are sampled in proportion to their probability of being correct.     

Evolutionary relationships, cospeciation, and host switching in avian malaria parasites

We used phylogenetic analyses of cytochrome b sequences of malaria parasites and their avian hosts to assess the coevolutionary relationships between host and parasite lineages. Many lineages of avian malaria parasites have broad host distributions, which tend to obscure cospeciation events. The hosts of a single parasite or of closely related parasites were nonetheless most frequently recovered from members of the same host taxonomic family, more so than expected by chance. However, global assessments of the relationship between parasite and host phylogenetic trees, using Component and ParaFit, failed to detect significant cospeciation. The event-based approach employed by TreeFitter revealed significant cospeciation and duplication with certain cost assignments for these events, but host switching was consistently more prominent in matching the parasite tree to the host tree. The absence of a global cospeciation signal despite conservative host distribution most likely reflects relatively frequent acquisition of new hosts by individual parasite lineages. Understanding these processes will require a more refined species concept for malaria parasites and more extensive sampling of parasite distributions across hosts. If parasites can disperse between allopatric host populations through alternative hosts, cospeciation may not have a strong influence on the architecture of host-parasite relationships. Rather, parasite speciation may happen more often in conjunction with the acquisition of new hosts followed by divergent selection between host lineages in sympatry. Detailed studies of the phylogeographic distributions of hosts and parasites are needed to characterize these events.     

Cophylogenetic relationships between penguins and their chewing lice

It is generally thought that the evolution of obligate parasites should be linked intimately to the evolution of their hosts and that speciation by the hosts should cause speciation of their parasites. The penguins and their chewing lice present a rare opportunity to examine codivergence between a complete host order and its parasitic lice. We estimated a phylogeny for all 15 species of lice parasitising all 17 species of penguins from the third domain of the mitochondrial 12S ribosomal rRNA gene, a portion of the mitochondrial cytochrome oxidase subunit 1 gene and 55 morphological characters. We found no evidence of extensive cospeciation between penguins and their chewing lice using TreeMap 2.02beta. Despite the paucity of cospeciation, there is support for significant congruence between the louse and penguin phylogenies due to possible failure to speciate events (parasites not speciating in response to their hosts speciating).     

Song mimicry and species associations of west African indigobirds Vidua with Quail-finch Ortygospiza atricollis, Goldbreast Amandava subflava and Brown Twinspot Clytospiza monteiri

The brood-parasitic indigobirds Vidua spp. mimic the songs of their foster species, which for many species of indigobirds are Lagonosticta firefinches. We report additional associations of indigobirds with estrildid finches in west Africa. Quail-finch Indigobirds Vidua nigeriae in northern Cameroon mimic the songs of Quail-finch Ortygospiza atricollis . Gold-breast Indigobirds Vidua raricola in Cameroon and Sierra Leone mimic the songs of Gold-breast Amandava subflava . Both indigobirds are distinct in male breeding plumage from other indigobirds. Also, a population of blue indigobirds Vidua sp. in Cameroon mimics the songs of Brown Twinspot Clytospiza monteiri . They are similar in colour and size to blue indigobirds associated with Dark Firefinch L. rubricata and Black-bellied Firefinch L. rara . Mouth patterns of fledged young Quail-finch Indigobirds and Goldbreast Indigobirds resemble those of their song-model and presumed foster species, but the mouth pattern of a fledged young associated with the Brown Twinspot mimic was not distinct from the mouth of young Black-bellied Firefinch. The field observations show associations of certain species of indigobirds with finches other than the firefinches. The results are consistent with mitochondrial DNA estimates of greater genetic similarity among indigobirds than among their foster species. The field observations support the hypothesis of evolutionary associations of the brood parasite and foster species by colonization with switching from one foster to another rather than by cospeciation.     

Cospeciation and horizontal transmission of avian sarcoma and leukosis virus gag genes in galliform birds

In a study of the evolution and distribution of avian retroviruses, we found avian sarcoma and leukosis virus (ASLV) gag genes in 26 species of galliform birds from North America, Central America, eastern Europe, Asia, and Africa. Nineteen of the 26 host species from whom ASLVs were sequenced were not previously known to contain ASLVs. We assessed congruence between ASLV phylogenies based on a total of 110 gag gene sequences and ASLV-host phylogenies based on mitochondrial 12S ribosomal DNA and ND2 sequences to infer coevolutionary history for ASLVs and their hosts. Widespread distribution of ASLVs among diverse, endemic galliform host species suggests an ancient association. Congruent ASLV and host phylogenies for two species of Perdix, two species of Gallus, and Lagopus lagopus and L. mutus also indicate an old association with vertical transmission and cospeciation for these ASLVs and hosts. An inference of horizontal transmission of ASLVs among some members of the Tetraoninae subfamily (grouse and ptarmigan) is supported by ASLV monophyletic groups reflecting geographic distribution and proximity of hosts rather than host species phylogeny. We provide a preliminary phylogenetic taxonomy for the new ASLVs, in which named taxa denote monophyletic groups.     

Host-specialization and species diversity in fish parasites: phylogenetic conservatism?

The pattern of parasite species diversification and specialization, appreciated by host range, is investigated in fish parasites. We test whether host range is linked with phylogeny at a high taxonomic level, and if there is a relationship between host range and host species diversification. For this purpose we used two sets of data, one on macro-parasites of marine fishes of the Mediterranean Sea and the other on macro-parasites of marine and freshwater fishes of Canada. Similar patterns of host range among parasitic groups were found. Our findings suggest that habitat (marine vs freshwater) and geographic localization (Canada vs Mediterranean region) play little role in determining the observed patterns of host range. We highlight the potential influence of phylogeny (high-taxonomic level) on the level host range in parasites. We find that parasites with free-swimming larval stages and with direct life cycles have a narrower range of host species than do parasites with indirect life cycle, even if we cannot control for phylogenetic effects because of the lack of variation of life cycles within each parasitic group. Finally, a positive relationship was found between the number of known hosts and parasite species diversity in the case of Mediterranean parasite species. The relationship between host range and species diversification should be related to the mechanism of cospeciation.     

Plasmodium octamerium n. sp., an Avian Malaria Parasite from the Pintail Whydah Bird Vidua macroura*

SYNOPSIS. A new species of avian malaria parasite is described from the pintail whydah Vidua macroura, a very small African finch of the weaver bird family (Ploceidae). Its structure has been studied chiefly in the canary, to which it is easily transmissible by blood inoculation. Since the segmenters most often produce 8 merozoites, the name Plasmodium octamerium n. sp. is proposed. Other characteristics include sexual stages which are usually elongate, often slender, and do not displace the host cell nucleus, and gametocytes indistinguishable from those of many species of Haemoproteus. Erythrocytes are the only blood cells parasitized. The new species resembles Plasmodium fallax in many respects, but gives rise to fewer merozoites and the asexual forms are smaller. Blood-induced infections are also of strikingly different type in some host species. Among susceptible host species are several kinds of finches, pigeons, quail, young chicks, chukars, tree and song sparrows. In most of these hosts infections are mild, but some tree sparrows die as the result of blood infection, and chukars usually die because of massive invasion of the capillary endothelium of the brain by exoerythrocytic forms. These are of the gallinaceum type and may be quite large, producing hundreds of merozoites. Exoerythrocytic stages were sought but not found in other host species.     

Co-evolutionary relationships between the nematode subfamily Cloacininae and its macropodid marsupial hosts

Morphologically based phylogenies of the cloacinine genera Cyclostrongylus, Macropostrongylus, Pharyngostrongylus, Popovastrongylus, Rugopharynx, Thallostonema, Wallabinema, and Zoniolaimus were constructed and compared with the phylogeny of their respective macropodid hosts. These comparisons show some evidence of co-speciation. However, there was little consistency among trees of different nematode genera, parasite species were scattered amongst hosts and basal parasite taxa were, in some instances, parasitic in hosts belonging to derived clades. A cladistic analysis, using as characters 208 cloacinine nematode species found in 23 species of host, produced a tree largely resembling that of the host tree but with significant differences explainable by host switching among macropodids occupying similar habitat. Nematodes were moderately host-specific, but some species occurred in three or more distantly related host species indicating a degree of host switching. The results are more consistent with the hypothesis of a colonisation of macropodid hosts by cloacinine nematodes rather than a prolonged period of co-speciation although alternative interpretations of the data are also considered.     

Low survival of parasite chicks may result from their imperfect adaptation to hosts rather than expression of defenses against parasitism

Host parents exhibit a variety of behaviors toward avian brood parasites, but not all of their actions have necessarily evolved in response to costs imposed by parasites. To investigate whether common waxbills (Estrilda astrild) have evolved defenses specifically against parasitic pin-tailed whydahs (Vidua macroura), I studied the specificity and flexibility of host behaviors toward nestlings at two sites that differed significantly in parasitism rates and intensities. I focused on documenting nestling survival because V. macroura young match the elaborate gape morphology of E. astrild nestlings, a pattern that suggests hosts may possess unique defenses against parasite chicks. Parasite young survived significantly worse than host young in mixed broods. However, this apparent discrimination was not associated with parasitism risk as would be expected if defenses had evolved specifically to counter parasitism. Parasite young may have survived poorly compared to host young because individual chicks were less able to stimulate sufficient care from foster parents or because they were more susceptible to nestling competition, disease, or reduced provisioning by hosts. Mortality may have also been exacerbated by poor timing of parasite egg laying. In nonparasitized and parasitized nests, rates of nestling survival were similar, further suggesting that parenting behaviors that result in chick mortality did not evolve solely in response to parasite young. In addition, orange-breasted waxbills (Amandava subflava) and zebra finches (Taeniopygia guttata), rarely parasitized and nonparasitized relatives of E. astrild, experience similar levels of nestling mortality presumably as a result of phylogenetically widespread parenting strategies. Despite the similarity of parasitic V. macroura nestlings and E. astrild nestlings, I found no evidence that E. astrild parents possess defenses that allow for specific discrimination against parasite chicks during the nestling period. Rather than being subject to host defenses evolved in an arms race, Vidua chicks may simply be imperfectly adapted to life in the nests of their hosts.     

Ecology of congruence: past meets present

Phylogenetic congruence is governed by various macroevolutionary events, including cospeciation, host switching, sorting, duplication, and failure to speciate. The relative frequency of these events may be influenced by factors that govern the distribution and abundance of the interacting groups; i.e., ecological factors. If so, it may be possible to predict the degree of phylogenetic congruence between two groups from information about their ecology. Unfortunately, adequate comparative ecological data are not available for many of the systems that have been subjected to cophylogenetic analysis. An exception is provided by chewing lice (Insecta: Phthiraptera), which parasitize birds and mammals. For a few genera of these lice, enough data have now been published to begin exploring the relationship between ecology and congruence. In general, there is a correspondence between important ecological factors and the degree of phylogenetic congruence. Careful comparison of these genera suggests that dispersal is a more fundamental barrier to host switching among related hosts than is establishment. Transfer experiments show that host-specific lice can survive and reproduce on novel hosts that are similar in size to the native host as long as the lice can disperse to these hosts. To date, studies of parasite dispersal have been mainly inferential. A better understanding of the role of dispersal will require more direct data on dispersal frequency and distances.     

Phylogeny of feather mite subfamily Avenzoariinae (Acari: Analgoidea: Avenzoariidae) inferred from combined analyses of molecular and morphological data.

Phylogenetic relationships among feather mites of the subfamily Avenzoariinae (Acari: Analgoidea: Avenzoariidae) were reconstructed by parsimony analysis of a combined data matrix. We analyzed 41 morphological characters and 246 molecular characters from a fragment of the 16S rDNA. Morphological trees were well supported at deep branches (genera and above), but showed much less support and resolution within genera. Molecular analyses produced trees with better resolution and support on terminal branches and worse support on basal branches. I(MF) index for the combined matrix pointed to the significant congruence of both data subsets with the whole of the data. The topology of the combined tree was close to the morphological tree in the deep branches and had well-resolved terminal branches as in the molecular tree. This suggests a considerable level of complimentarity between the two data sets. An analysis of association patterns of the mites and their hosts was conducted based on the results of the combined analyses for the Avenzoariinae and a phylogeny of their charadriiform hosts (compiled from various bird phylogeny hypotheses). The trees could be reconciled by the invoking of 12-13 cospeciation events, 6-7 duplications, 2 host shifts, and 26-29 sorting events. This suggests a high degree of cospeciation.     

Analytical approaches to measuring cospeciation of host and parasites: through a glass, darkly

Studies of cophylogenetic associations between hosts and parasites have become increasingly common. Historically, congruence between host and parasite phylogenies has been seen as evidence for cospeciation. Analyses of such coevolutionary relationships, however, are made extremely difficult by the complex interplay of cospeciation, host switching, sorting (extinction), duplication (intrahost speciation) and inertia (lack of parasite speciation) events, all of which may produce incongruence between host and parasite phylogenies. Here we review several methods of analysing cospeciation. We illustrate these methods with an example from a Procellariiformes (seabird) and chewing louse (Halipeurus) association.