The evolution of myiasis in humans and other animals in the Old and New Worlds (part II): biological and life-history studies

Myiasis, which is the dipteran parasitism of living vertebrates, occurs in several forms - ranging from benign to fatal, opportunistic to obligate - and seems to have evolved through two distinct routes: saprophagous and sanguinivorous. However, the convergent evolution of morphological and life-history traits seems to have had a major role in confusing the overall picture of how myiasis evolved and this simplistic division is further complicated by the existence of both ectoparasitic and endoparasitic species of myiasis-causing Diptera, the evolutionary affinities of which remain to be resolved. As discussed in part I of this review, if we are to elucidate how the different forms of parasitism arose, it is essential to separate the evolution of the various groups of myiasis-causing flies from the evolution of the myiasis habit per se. Accordingly, whereas we focused on recent landmark phylogenetics studies in part I, we use this framework to analyse relevant biochemical, immunological, behavioural, biogeographical and fossil evidence to elucidate the evolution of myiasis in part II.     

The evolution of myiasis in blowflies (Calliphoridae)

Blowflies (Calliphoridae) are characterised by the ability of their larvae to develop in animal flesh. Where the host is a living vertebrate, such parasitism by dipterous larvae is known as myiasis. However, the evolutionary origins of the myiasis habit in the Calliphoridae, a family which includes the blowflies and screwworm flies, remain unclear. Species associated with an ectoparasitic lifestyle can be divided generally into three groups based on their larval feeding habits: saprophagy, facultative ectoparasitism, and obligate parasitism, and it has been proposed that this functional division may reflect the progressive evolution of parasitism in the Calliphoridae. In order to evaluate this hypothesis, phylogenetic analysis of 32 blowfly species displaying a range of forms of ectoparasitism from key subfamilies, i.e. Calliphorinae, Luciliinae, Chrysomyinae, Auchmeromyiinae and Polleniinae, was undertaken using likelihood and parsimony methods. Phylogenies were constructed from the nuclear 28S large subunit ribosomal RNA gene (28S rRNA), sequenced from each of the 32 calliphorid species, together with suitable outgroup taxa, and mitochondrial cytochrome oxidase subunit I and II (COI+II) sequences, derived primarily from published data. Phylogenies derived from each of the two markers (28S rRNA, COI+II) were largely (though not completely) congruent, as determined by incongruence-length difference and Kishino-Hasegawa tests. However, the phylogenetic relationships of blowfly subfamilies based on molecular data did not concur with the pattern of relationships defined by previous morphological analysis; significantly, molecular analysis supported the monophyly of blowflies (Calliphoridae), distinct from the bot and warble flies (Oestridae). Comparative analysis of the myiasis habit based primarily on the 28S rRNA phylogeny indicated that obligate parasitism, and the ability to initiate myiasis in higher vertebrates, has multiple independent origins across myiasis-causing flies (Calliphoridae and Oestridae) and in at least three subfamilies of blowfly (Calliphoridae). Finally, the general association of various blowfly genera and subfamily clades with particular continental and geographical regions suggests that these groups probably came into existence in the Late Cretaceous period, following the break-up of Gondwana.     

Genetic Approaches for Studying Myiasis-causing Flies: Molecular Markers and Mitochondrial Genomics

“Myiasis-causing flies” is a generic term that includes species from numerous dipteran families, mainly Calliphoridae and Oestridae, of which blowflies, screwworm flies and botflies are among the most important. This group of flies is characterized by the ability of their larvae to develop in animal flesh. When the host is a live vertebrate, such parasitism by dipterous larvae is known as primary myiasis. Myiasis-causing flies can be classified as saprophagous (free-living species), facultative or obligate parasites. Many of these flies are of great medical and veterinary importance in Brazil because of their role as key livestock insect-pests and vectors of pathogens, in addition to being considered important legal evidence in forensic entomology. The characterization of myiasis-causing flies using molecular markers to study mtDNA (by RFLP) and nuclear DNA (by RAPD and microsatellite) has been used to identify the evolutionary mechanisms responsible for specific patterns of genetic variability. These approaches have been successfully used to analyze the population structures of the New World screwworm fly Cochliomyia hominivorax and the botfly Dermatobia hominis. In this review, various aspects of the organization, evolution and potential applications of the mitochondrial genome of myiasis-causing flies in Brazil, and the analysis of nuclear markers in genetic studies of populations, are discussed.     

Morphology and angiosperm systematics in the molecular era

Several ways in which morphology is used in systematic and evolutionary research in angiosperms are shown and illustrated with examples: 1) searches for special structural similarities, which can be used to find hints for hitherto unrecognized relationships in groups with unresolved phylogenetic position; 2) cladistic studies based on morphology and combined morphological and molecular analyses; 3) comparative morphological studies in new, morphologically puzzling clades derived from molecular studies; 4) studies of morphological character evolution, unusual evolutionary directions, and evolutionary lability based on molecular studies; and 5) studies of organ evolution. Conclusions: Goals of comparative morphology have shifted in the present molecular era. Morphology no longer plays the primary role in phylogenetic studies. However, new opportunities for morphology are opening up that were not present in the premolecular era: 1) phylogenetic studies with combined molecular and morphological analyses; 2) reconstruction of the evolution of morphological features based on molecularly derived cladograms; 3) refined analysis of morphological features induced by inconsistencies of previous molecular and molecular phylogenetic analyses; 4) better understanding of morphological features by judgment in a wider biological context; 5) increased potential for including fossils in morphological analyses; and 6) exploration of the evolution of morphological traits by integration of comparative structural and molecular developmental genetic aspects (Evo-Devo); this field is still in its infancy in botany; its advancement is one of the major goals of evolutionary botany.     

The molecular systematics of blowflies and screwworm flies (Diptera: Calliphoridae) using 28S rRNA, COX1 and EF-1α: insights into the evolution of dipteran parasitism

The Calliphoridae include some of the most economically significant myiasis-causing flies in the world - blowflies and screwworm flies - with many being notorious for their parasitism of livestock. However, despite more than 50 years of research, key taxonomic relationships within the family remain unresolved. This study utilizes nucleotide sequence data from the protein-coding genes COX1 (mitochondrial) and EF1α (nuclear), and the 28S rRNA (nuclear) gene, from 57 blowfly taxa to improve resolution of key evolutionary relationships within the family Calliphoridae. Bayesian phylogenetic inference was carried out for each single-gene data set, demonstrating significant topological difference between the three gene trees. Nevertheless, all gene trees supported a Calliphorinae-Luciliinae subfamily sister-lineage, with respect to Chrysomyinae. In addition, this study also elucidates the taxonomic and evolutionary status of several less well-studied groups, including the genus Bengalia (either within Calliphoridae or as a separate sister-family), genus Onesia (as a sister-genera to, or sub-genera within, Calliphora), genus Dyscritomyia and Lucilia bufonivora, a specialised parasite of frogs and toads. The occurrence of cross-species hybridisation within Calliphoridae is also further explored, focusing on the two economically significant species Lucilia cuprina and Lucilia sericata. In summary, this study represents the most comprehensive molecular phylogenetic analysis of family Calliphoridae undertaken to date.     

Phylogeny of the African representatives of the catfish family Clariidae (Teleostei, Siluriformes) based on a combined analysis: independent evolution towards anguilliformity

Clariid catfishes span a broad range of body forms ranging between fusiform and anguilliform morphotypes. Although such variation in body shape has been observed in other families of teleost fishes, amphibians and reptiles, it is rarely as extreme as within the Clariidae. Although the Clariidae were thought to have undergone anagenetic evolution (i.e. progressive evolution within a lineage), more recent studies indicate that anguilliformity evolved several times through a process of cladogenesis (i.e. branching of evolutionary lineages). In this study, it is shown that the phylogenetic analysis of morphological data mainly gives a reflection of the cranial evolution in the Clariidae despite the use of 18 post-cranial characters (out of a total of 53 characters). A combined phylogenetic analysis of both morphological and molecular data rather suggests the derived nature of body elongation. The corresponding morphological changes that co-occur with this elongation can be regarded as an extreme case of convergent evolution at the genus level within the Clariidae.     

Molecular characterization of the mitochondrial cytochrome oxidase I gene of Oestridae species causing obligate myiasis

A 688-bp region of the mitochondrial cytochrome oxidase I gene was sequenced from larvae of 18 species of Oestridae causing obligate myiasis. Larvae belonged to the four Oestridae subfamilies (Cuterebrinae, Gasterophilinae, Hypodermatinae and Oestrinae), which are commonly found throughout the world. Analysis of both nucleotide and amino acid data was performed. Nucleotide sequences included 385 conserved sites and 303 variable sites; mean nucleotide variation between all species was 18.1% and variation within each subfamily ranged from 5.3% to 13.34%. Intraspecific pairwise divergences ranged from 0.14% to 1.59%, and interspecific variation ranged from 0.7% to 27%. Of the 229 amino acids, 76 were variable (60 of which were phylogenetically informative), with some highly conserved residues identified within each subfamily. Phylogenetic analysis showed a strong divergence among the four subfamilies, concordant with classical taxonomy based on morphological and biological features. This study provides the first molecular data set for myiasis-causing Oestridae species, providing an essential database for the molecular identification of these parasites and the assessment of phylogenetic relationships within family Oestridae.     

A molecular phylogenetic framework for the phylum Ctenophora using 18S rRNA genes.

This paper presents the first molecular phylogenetic analysis of the phylum Ctenophora, by use of 18S ribosomal RNA sequences from most of the major taxa. The ctenophores form a distinct monophyletic group that, based on this gene phylogeny, is most closely related to the cnidarians. Our results suggest that the ancestral ctenophore was tentaculate and cydippid-like and that the presently recognized order Cydippida forms a polyphyletic group. The other ctenophore orders that we studied (Lobata, Beroida, and Platyctenida) are secondarily derived from cydippid-like ancestors, a conclusion that is also supported by developmental and morphological data. The very short evolutionary distances between characterized ctenophore 18S rRNA gene sequences suggests that extant ctenophores are derived from a recent common ancestor. This has important consequences for future studies and for an understanding of the evolution of the metazoans.     

More is better: the uses of developmental genetic data to reconstruct perianth evolution

The origin and evolution of the perianth remains enigmatic. While it seems likely that an undifferentiated perianth consisting of tepals arose early in angiosperm evolution, it is unclear when and how differentiated perianths consisting of distinct organs, such as petals and sepals, arose. Phylogenetic reconstructions of ancestral perianth states across angiosperms have traditionally relied on morphological data from extant species, but these analyses often produce equivocal results. Here we describe the use of developmental genetic data as an additional strategy to infer the ancestral perianth character state for different angiosperm clades. By assessing functional data in combination with expression data in a maximum likelihood framework, we provide a novel approach for investigating the evolutionary history of the perianth. Results of this analysis provide new insights into perianth evolution and provide a proof of concept for using this strategy to explore the incorporation of developmental genetic data in character state reconstructions. As the assumptions outlined here are tested and more genetic data are generated, we hope that ancestral state reconstructions based on multiple lines of evidence will converge.     

Positive correlations between molecular and morphological rates of evolution

The existence of positive associations between rates of molecular and morphological evolution (calculated from branch lengths of phylogenetic trees reconstructed using molecular and morphological characters, respectively) is important to issues of neutrality in sequence evolution, phylogenetic reconstructions assuming neutrality, and evolutionary genotype-phenotype mapping. Rates correlate positively when including branches leading to extant species (tips). Excluding tips, trends are similar, but statistical significances decrease systematically. This is due to (a) lower statistical power (excluding tips reduces sample sizes), and (b) rates are solely calculated from inaccurately reconstructed character states of extinct ancestral species, and this noise decreases correlation strengths. Correlations between molecular and morphological rates of evolution increase as more morphological characters are included for phylogenetic reconstruction. Sequence lengths apparently affect correlations along similar principles. Analyses of plant phylogenies confirm those from animals: sampling biases decrease correlations between molecular and morphological rates of evolution. Results confirm that genotype and phenotype are linked, and suggest adaptive components for molecular evolution. The discussion stresses the difficulties associated with analyses and conclusions based on data deduced from phylogenetic reconstruction.     

The evolutionary origins of Syngnathidae: pipefishes and seahorses

Despite their importance as evolutionary and ecological model systems, the phylogenetic relationships among gasterosteiforms remain poorly understood, complicating efforts to understand the evolutionary origins of the exceptional morphological and behavioural diversity of this group. The present review summarizes current knowledge on the origin and evolution of syngnathids, a gasterosteiform family with a highly developed form of male parental care, combining inferences based on morphological and molecular data with paleontological evidence documenting the evolutionary history of the group. Molecular methods have provided new tools for the study of syngnathid relationships and have played an important role in recent conservation efforts. Despite recent insights into syngnathid evolution, however, a survey of the literature reveals a strong taxonomic bias towards studies on the species-rich genera Hippocampus and Syngnathus, with a lack of data for many morphologically unique members of the family. The study of the evolutionary pressures responsible for generating the high diversity of syngnathids would benefit from a wider perspective, providing a comparative framework in which to investigate the evolution of the genetic, morphological and behavioural traits of the group as a whole.     

Understanding phylogenetic incongruence: lessons from phyllostomid bats

All characters and trait systems in an organism share a common evolutionary history that can be estimated using phylogenetic methods. However, differential rates of change and the evolutionary mechanisms driving those rates result in pervasive phylogenetic conflict. These drivers need to be uncovered because mismatches between evolutionary processes and phylogenetic models can lead to high confidence in incorrect hypotheses. Incongruence between phylogenies derived from morphological versus molecular analyses, and between trees based on different subsets of molecular sequences has become pervasive as datasets have expanded rapidly in both characters and species. For more than a decade, evolutionary relationships among members of the New World bat family Phyllostomidae inferred from morphological and molecular data have been in conflict. Here, we develop and apply methods to minimize systematic biases, uncover the biological mechanisms underlying phylogenetic conflict, and outline data requirements for future phylogenomic and morphological data collection. We introduce new morphological data for phyllostomids and outgroups and expand previous molecular analyses to eliminate methodological sources of phylogenetic conflict such as taxonomic sampling, sparse character sampling, or use of different algorithms to estimate the phylogeny. We also evaluate the impact of biological sources of conflict: saturation in morphological changes and molecular substitutions, and other processes that result in incongruent trees, including convergent morphological and molecular evolution. Methodological sources of incongruence play some role in generating phylogenetic conflict, and are relatively easy to eliminate by matching taxa, collecting more characters, and applying the same algorithms to optimize phylogeny. The evolutionary patterns uncovered are consistent with multiple biological sources of conflict, including saturation in morphological and molecular changes, adaptive morphological convergence among nectar‐feeding lineages, and incongruent gene trees. Applying methods to account for nucleotide sequence saturation reduces, but does not completely eliminate, phylogenetic conflict. We ruled out paralogy, lateral gene transfer, and poor taxon sampling and outgroup choices among the processes leading to incongruent gene trees in phyllostomid bats. Uncovering and countering the possible effects of introgression and lineage sorting of ancestral polymorphism on gene trees will require great leaps in genomic and allelic sequencing in this species‐rich mammalian family. We also found evidence for adaptive molecular evolution leading to convergence in mitochondrial proteins among nectar‐feeding lineages. In conclusion, the biological processes that generate phylogenetic conflict are ubiquitous, and overcoming incongruence requires better models and more data than have been collected even in well‐studied organisms such as phyllostomid bats.     

常用核基因序列在双翅目昆虫系统学中的研究进展

双翅目昆虫分为长角亚目和短角亚目,前者主要类群包括蚊、蠓、蛉和蚋,后者主要类群为虻类和蝇类。国内外学者对双翅目昆虫形态分类和分子系统发育关系研究均较多。本文整理总结了几种主要核基因在双翅目昆虫进化和系统发育关系的研究资料,结果显示:双翅目的单系性得到了众多形态学、生物学和分子数据的支持,多数系统发育研究认为传统的长角亚目为并系,短角亚目是一个单系,其主要类群舞虻下目、环裂类、有缝组和有瓣蝇类均为单系,但非环裂类、无缝组为并系,无瓣类可能为并系;基本搞清了有重要医学意义和与环境关系密切的类群,特别是有瓣蝇类各科类群分类系统的进化关系;双翅目昆虫发生辐射进化的三个分支节点时间即:低等双翅目(蚊类)2.2亿年、低等短角亚目(虻类)1.8亿年、有缝组(蝇类)6500万年;大量双翅目昆虫自然生命史历经吸血性、植食性和寄生性,有2.6亿年以上的演化历程。从相关核基因研究中总结出:18SrRNA、28SrRNA和CAD基因能很好的解决高级阶元从目到属的系统发育问题;EF-1ɑ基因和White基因更适合从科到属水平的分类阶元;ITS基因一般应用在从属到种水平的低级分类阶元,并被广泛应用到双翅目昆虫分子系统学研究中。     

Molecular phylogenetics of allodapine bees,with implications for the evolution of sociality and progressive rearing

Allodapine bees have long been regarded as providing useful material for examining the origins of social behavior. Previous researchers have assumed that sociality arose within the Allodapini and have linked the evolution of sociality to a transition from mass provisioning to progressive provisioning of brood. Early phylogenetic studies of allodapines were based on morphological and life-history data, but critical aspects of these studies relied on small character sets, where the polarity and coding of characters is problematic. We used nucleotide sequence data from one nuclear and two mitochondrial gene fragments to examine phylogenetic structure among nine allodapine genera. Our data set comprised 1506 nucleotide positions, of which 402 were parsimony informative. Maximum parsimony, log determinant, and maximum likelihood analyses produced highly similar phylogenetic topologies, and all analyses indicated that the tropical African genus Macrogalea was the sister group to all other allodapines. This finding conflicts with that of previous studies, in which Compsomelissa + Halterapis formed the most basal group. Changing the basal node of the Allodapini has major consequences for understanding evolution in this tribe. Our results cast doubt on the previous hypotheses that progressive provisioning and castelike social behavior evolved among lineages leading to the extant allodapine taxa. Instead, our results suggest that mass provisioning in Halterapis is a derived feature and that social behavior is an ancestral trait for all allodapine lineages. The forms of social behavior present in extant allodapines are likely to have resulted from a long evolutionary history, which may help explain the complexity of social traits found in many allodapine bees.     

Molecular approaches to the study of myiasis-causing larvae

Among arthropod diseases affecting animals, larval infections - myiases - of domestic and wild animals have been considered important since ancient times. Besides the significant economic losses to livestock worldwide, myiasis-causing larvae have attracted the attention of scientists because some parasitise humans and are of interest in forensic entomology. In the past two decades, the biology, epidemiology, immunology, immunodiagnosis and control methods of myiasis-causing larvae have been focused on and more recently the number of molecular studies have also begun to increase. The 'new technologies' (i.e. molecular biology) are being used to study taxonomy, phylogenesis, molecular identification, diagnosis (recombinant antigens) and vaccination strategies. In particular, more in depth molecular studies have now been performed on Sarcophagidae, Calliphoridae and flies of the Oestridae sister group. This review discusses the most topical issues and recent studies on myiasis-causing larvae using molecular approaches. In the first part, PCR-based techniques and the genes that have already been analysed, or are potentially useful for the molecular phylogenesis and identification of myiasis-causing larvae, are described. The second section deals with the more recent advances concerning taxonomy, phylogenetics, population studies, molecular identification, diagnosis and vaccination.     

Phylogeny and evolution of calcareous sponges: monophyly of calcinea and calcaronea,high level of morphological homoplasy,and the primitive nature of axial symmetry

Because calcareous sponges are triggering renewed interest with respect to basal metazoan evolution, a phylogenetic framework of their internal relationships is needed to clarify the evolutionary history of key morphological characters. Morphological variation was scored at the suprageneric level within Calcispongia, but little phylogenetic information could be retrieved from morphological characters. For the main subdivision of Calcispongia, the analysis of morphological data weakly supports a classification based upon cytological and embryological characters (Calcinea/Calcaronea) rather than the older classification scheme based upon the aquiferous system (Homocoela/Heterocoela). The 18S ribosomal RNA data were then analyzed, both alone and in combination with morphological characters. The monophyly of Calcispongia is highly supported, but the position of this group with respect to other sponge lineages and to eumetazoan taxa is not resolved. The monophyly of both Calcinea and Calcaronea is retrieved, and the data strongly rejected the competing Homocoela/Heterocoela hypothesis. The phylogeny implies that characters of the skeleton architecture are highly homoplastic, as are characters of the aquiferous system. However, axial symmetry seems to be primitive for all Calcispongia, a conclusion that has potentially far-reaching implications for hypotheses of early body plan evolution in Metazoa.     

A role for molecular genetics in the recognition and conservation of endangered species

Taxonomies based on morphological traits alone sometimes provide inadequate or misleading guides to phylogenetic distinctions at the subspecies and species levels. Yet taxonomic assignments inevitably shape perceptions of biotic diversity, including recognition of endangered species. Case histories are discussed in which the data of molecular genetics revealed prior systematic errors of the two possible kinds: taxonomic recognition of groups showing little evolutionary differentiation, and lack of taxonomic recognition of phylogenetically distinct forms. In such cases, conservation efforts for 'endangered species' can be misdirected with respect to the goal of protecting biological diversity.     

Somatic musculature of Tardigrada: phylogenetic signal and metameric patterns

Although studies describing molecular‐based phylogenies within tardigrades are now frequently being published, this is not the case for studies combining molecular and morphological characters. Tardigrade phylogeny is still based, from a morphological point of view, almost exclusively on chitinous structures and little attention has been given to detecting and using novel morphological data. Consequently, we analysed the musculature of seven tardigrade species belonging to the main phyletic lines by confocal laser scanning microscopy and compared these morphological results with new molecular analyses (18S+28S rRNA genes). Finally, we analysed all the data with a total evidence approach. A consilience in the phylogenetic relationships among orders and superfamilies of tardigrades was obtained among the evolutionary trees obtained from morphological, molecular and total evidence approaches. Comparative analysis on the musculature allowed the identification of serial homologies and repeated metameric patterns along the longitudinal animal body axis. A phenomenon of mosaic evolution was detected in musculature anatomy, as dorsal musculature was found to be highly modified with respect to the other body muscle groups, probably related to the evolution of dorsal cuticular plates. An understanding of tardigrade musculature anatomy will give fundamental information to understand the evolution of segmental pattern within Panarthropoda. © 2013 The Linnean Society of London     

Probing the Monophyly of the Sphaeropleales (Chlorophyceae) Using Data From Five Genes

Molecular phylogenetic analyses have had a major impact on the classification of the green algal class Chlorophyceae, corroborating some previous evolutionary hypotheses, but primarily promoting new interpretations of morphological evolution. One set of morphological traits that feature prominently in green algal systematics is the absolute orientation of the flagellar apparatus in motile cells, which correlates strongly with taxonomic classes and orders. The order Sphaeropleales includes diverse green algae sharing the directly opposite (DO) flagellar apparatus orientation of their biflagellate motile cells. However, algae across sphaeroplealean families differ in specific components of the DO flagellar apparatus, and molecular phylogenetic studies often have failed to provide strong support for the monophyly of the order. To test the monophyly of Sphaeropleales and of taxa with the DO flagellar apparatus, we conducted a molecular phylogenetic study of 16 accessions representing all known families and diverse affiliated lineages within the order, with data from four plastid genes (psaA, psaB, psbC, rbcL) and one nuclear ribosomal gene (18S). Although single‐gene analyses varied in topology and support values, analysis of combined data strongly supported a monophyletic Sphaeropleales. Our results also corroborated previous phylogenetic hypotheses that were based on chloroplast genome data from relatively few taxa. Specifically, our data resolved Volvocales, algae possessing predominantly biflagellate motile cells with clockwise (CW) flagellar orientation, as the monophyletic sister lineage to Sphaeropleales, and an alliance of Chaetopeltidales, Chaetophorales, and Oedogoniales, orders having multiflagellate motile cells with distinct flagellar orientations involving the DO and CW forms.     

Fine-scale phenotypic change across a species transition zone in the genus neotoma: disentangling independent evolution from phylogenetic history

Zones of secondary contact between closely related species provide a rare opportunity to examine evidence of evolutionary processes that reinforce species boundaries and/or promote diversification. Here, we report on genetic and morphological variation in two sister species of woodrats, Neotoma fuscipes and N. macrotis, across a 30-km transition zone in the Sierra Nevada of California. We assessed whether these lineages readily hybridize, and whether their morphology suggests ecological interactions favoring phenotypic diversification. We combined measurements of body size and 11 craniodental traits from nine populations with genetic data to examine patterns of variation within and between species. We used phylogenetic autocorrelation methods to estimate the degree to which phenotypic variation in our dataset arose from independent evolution within populations versus phylogenetic history. Although no current sympatry or hybridization was evident, craniodental morphology diverged in both lineages near their distributional limits, whereas body size converged. The shift in craniodental morphology arose independently within populations whereas body size retained a strong phylogenetic signal, yet both patterns are consistent with expectations of phenotypic change based on different models of resource competition. Our findings demonstrate the importance of examining a suite of morphological traits across contact zones to provide a more complete picture of potential ecological interactions: competition may drive both diversification and convergence in different phenotypic traits.