Host range evolution in a selected group of osmiine bees (Hymenoptera: Megachilidae): the Boraginaceae‐Fabaceae paradox

Bees are extraordinarily diverse with respect to host plant choice and adaptation. Recent findings suggest that bee host range might be largely governed by evolutionary constraints related to pollen digestion or flower recognition and handling. In the present study, we applied phylogenetic inference to investigate whether such constraints underlie host plant choice in bees of the Annosmia‐Hoplitis group (Megachilidae) and to what extent these bees have evolved specialized adaptations for pollen collection. We demonstrate that most pollen specialist species exclusively exploit either Boraginaceae or Fabaceae, whereas all pollen generalists harvest pollen from both Boraginaceae and Fabaceae. The counterintuitive affinity towards these two plant families, which are neither closely related nor share similar flower morphologies, demonstrates that pollen host choice is considerably constrained in this group of bees. We hypothesize that this Boraginaceae‐Fabaceae paradox might be the result of (1) similar secondary metabolites in the pollen of both families; (2) metabolites that can be detoxified by the same physiological tools; or (3) similar pollen nutrient composition. Contrary to the widely held belief that specialized adaptations for pollen collection are rare among bees, such adaptations are common in the Annosmia‐Hoplitis bees, where they have evolved several times independently to exploit flowers of widely different morphologies. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ●● , ●●–●●.     

You stay,but I Hop: Host shifting near and far co‐dominated the evolution of Enchenopa treehoppers

The importance and prevalence of phylogenetic tracking between hosts and dependent organisms caused by co‐evolution and shifting between closely related host species have been debated for decades. Most studies of phylogenetic tracking among phytophagous insects and their host plants have been limited to insects feeding on a narrow range of host species. However, narrow host ranges can confound phylogenetic tracking (phylogenetic tracking hypothesis) with host shifting between hosts of intermediate relationship (intermediate hypothesis). Here, we investigated the evolutionary history of the Enchenopa binotata complex of treehoppers. Each species in this complex has high host fidelity, but the entire complex uses hosts across eight plant orders. The phylogenies of E. binotata were reconstructed to evaluate whether (1) tracking host phylogeny; or (2) shifting between intermediately related host plants better explains the evolutionary history of E. binotata. Our results suggest that E. binotata primarily shifted between both distant and intermediate host plants regardless of host phylogeny and less frequently tracked the phylogeny of their hosts. These findings indicate that phytophagous insects with high host fidelity, such as E. binotata, are capable of adaptation not only to closely related host plants but also to novel hosts, likely with diverse phenology and defense mechanisms.     

Phylogeny and floral hosts of a predominantly pollen generalist group of mason bees (Megachilidae: Osmiini)

Within the genus Osmia, the three subgenera Osmia, Monosmia, and Orientosmia form a closely‐related group of predominantly pollen generalist (‘polylectic’) mason bees. Despite the great scientific and economic interest in several species of this clade, which are promoted commercially for orchard pollination, their phylogenetic relationships remain poorly understood. We inferred the phylogeny of 21 Osmia species belonging to this clade by applying Bayesian and maximum likelihood methods based on five genes and morphology. Because our results revealed paraphyly of the largest subgenus (Osmia s.s.), we synonymized Monosmia and Orientosmia under Osmia s.s. Microscopical analysis of female pollen loads revealed that five species are specialized (‘oligolectic’) on Fabaceae or Boraginaceae, whereas the remaining species are polylectic, harvesting pollen from up to 19 plant families. Polylecty appears to be the ancestral state, with oligolectic lineages having evolved twice independently. Among the polylectic species, several intriguing patterns of host plant use were found, suggesting that host plant choice of these bees is constrained to different degrees and governed by flower morphology, pollen chemistry or nectar availability, thus supporting previous findings on predominantly oligolectic clades of bees. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 78–91.     

Timing of butterfly parasitization of a plant–ant–scale symbiosis

In the Southeast Asian tropics, Arhopala lycaenid butterflies feed on Macaranga ant-plants inhabited by Crematogaster (subgenus Decacrema) ants tending Coccus-scale insects. A recent phylogenetic study showed that (1) the plants and ants have been codiversifying for the past 20–16 million years (Myr), and that (2) the tripartite symbiosis was formed 9–7 Myr ago, when the scale insects became involved in the plant–ant mutualism. To determine when the lycaenids first parasitized the Macaranga tripartite symbiosis, we constructed a molecular phylogeny of the lycaenids that feed on Macaranga by using mitochondrial and nuclear DNA sequence data and estimated their divergence times based on the cytochrome oxidase I molecular clock. The minimum age of the lycaenids was estimated by the time-calibrated phylogeny to be 2.05 Myr, about one-tenth the age of the plant–ant association, suggesting that the lycaenids are latecomers that associated themselves with the pre-existing symbiosis of plant, ant, and scale insects.     

Molecular phylogeny of the Oriental butterfly genus Arhopala (Lycaenidae,Theclinae) inferred from mitochondrial and nuclear genes

Abstract. We present a phylogeny for a selection of species of the butterfly genus Arhopala Boisduval, 1832 based on molecular characters. We sequenced 1778 bases of the mitochondrial genes Cytochrome Oxidase 1 and 2 including tRNA^Leu, and a 393‐bp fragment of the nuclear wingless gene for a total of 42 specimens of 33 species, representing all major species groups. Analyses of mtDNA and wingless genes show congruent phylogenetic signal. The phylogeny presented here confirms the monophyly of the centaurus, eumolphus, camdeo and epimuta groups and the amphimuta subgroup. It confirms close relationships between species within the agelastus group, that together with the amphimuta subgroup, centaurus and camdeo groups form a monophyletic group. However, incongruencies with previous taxonomic studies also occur; the amphimuta and silhetensis groups are not monophyletic, as is the genus Arhopala itself. One enigmatic species, A. kinabala, was evaluated further for topology and the support for basal placement of this species is due mainly to the wingless gene. However, in the Parsimony analysis, and subsequent Maximum Likelihood evaluations, certain nodes could not be resolved due to insufficient support. The mtDNA shows extreme AT bias with compositional heterogeneity at 3rd codon positions, which may result in saturation. By contrast, the wingless gene does not show compositional bias, suggesting that poor support is not due solely to saturation. The evaluation of morphological characters used in previous studies on Arhopala systematics on the molecular tree indicates that the macular pattern and the absence of tails at the hind wings show extensive homoplasy. A significant phylogenetic signal (as indicated by T‐PTP tests) is present in several of these morphological characters, which are nevertheless of limited use in phylogenetic studies due to their labile nature.     

Ancient association with Fagaceae in the aphid tribe Greenideini (Hemiptera: Aphididae: Greenideinae)

Aphids are intimately associated with their host plants. Evolutionary lability of host association is common within heteroecious aphid lineages, whereas our knowledge of host‐use evolution in non‐host‐alternating aphids is limited. In the present study, we construct the first detailed molecular phylogeny of the monoecious aphid tribe Greenideini based on three mitochondrial genes (COI, COII and Cytb) and one nuclear gene (EF‐1α), and investigated its history of host association. Maximum likelihood and Bayesian phylogenies strongly support the monophyly of Greenideini and most constituent genera. Divergence time estimates and character reconstructions suggest that Greenideini may have originated during the Late Cretaceous to early Paleogene, which accompanies the origin of its ancestral host, members of the family Fagaceae. Colonisation of novel host plants has occurred multiple times during the evolutionary history of Greenideini, thereby leading to current patterns of host association. We suggest that directly shifting to novel hosts, together with expanding host range onto pre‐existing, unused plants, has probably promoted diversification in this tribe.     

An unusual,but not unexpected,evolutionary step taken by syrphid flies: the first record of true primary parasitoidism of ants by Microdontinae

Parasitoidism of ants by flies is known only for Phoridae and Tachinidae. We report the first record of a hoverfly (Syrphidae, Microdontinae, Hypselosyrphus) acting as a true primary parasitoid of ants. Previously, larvae of Microdontinae were known only as obligate predators of ant brood. This is also the first host record for any Hypselosyrphus species, the first reliable record of an association between a syrphid fly and a ponerine ant, and the first record of a dipteran parasitoid developing upon the immature stages of ants. We reared adults of Hypselosyrphus trigonus from cocoons of the arboreal ponerine ant, Pachycondyla villosa, nesting in Aechmea bracteata bromeliads in southern Quintana Roo, Mexico, and we succeeded in determining various aspects of the parasitoid's life history. The findings obtained in the present study provide novel insights into the evolutionary transformation and diversification of the feeding habits of microdontine syrphid larvae, from an obligatory, specific predatory association with the ant brood, to parasitoidism of ant prepupae. We also highlight the need for more detailed studies of the interactions of arboreal ants and their parasites. We conclude with an overview of the evolutionary transitions and diversification of larval feeding habits that have taken place within the family Syrphidae. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 462–472.     

Landscape and oceanic barriers shape dispersal and population structure in the island nematode Pristionchus pacificus

In this study evolutionary host plant patterns at ranks from order to species were analysed using spatial evolutionary and ecological vicariance analysis (SEEVA), based on a multigene phylogeny of 45 ascomycete fungal species. The objective was to understand speciation events and host associations in Ophiognomonia (Gnomoniaceae). Species of this genus are perithecial fungi that occur as endophytes, pathogens, and latent saprobes on plants in the families of Betulaceae, Fagaceae, Juglandaceae, Lauraceae, Malvaceae, Platanaceae, Rosaceae, Salicaceae, and Sapindaceae. A second objective was to determine whether speciation events are influenced by host conservatism, host specialization, or host switching at different taxonomic host ranks. Host differences between sister clades were interpreted using the divergence index (D) from the SEEVA analysis, ranging from 0 for no divergence to 1 for maximum possible divergence. Several fungal subclades showed clear patterns of host order/family conservatism (D = 1.00) for hosts in Betulaceae, Fagaceae, Juglandaceae, and Rosaceae. Clear trends of host specialization at host genus and species ranks (D = 1.00) were suggested within these host families. Independent host jumps were observed for two species at the family rank and three at the order rank. As a result of this study, host specificity and specialization is hypothesized as a mechanism that can strongly contribute to speciation patterns in fungal pathogens. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 1–16.     

Host selectivity,haustorial anatomy and impact of the invasive parasite Parentucellia viscosa on floodplain vegetative communities in Japan

The parasitic plant Parentucellia viscosa has been introduced recently to the Japanese floodplain. Because of its parasitic nature and high fecundity, P. viscosa may well become a major plant invader with a significant impact on floodplain ecosystems. Thus, a knowledge of the host selectivity of P. viscosa will not only provide basic biological information, but will also contribute to the understanding of floodplain vegetation conservation. We evaluated the host selectivity by comparing the observed numbers of haustoria with those expected from the relative below‐ground biomass. In addition, we examined the haustorial anatomy to determine whether haustoria are functional, and compared the above‐ground biomass of three functional plant groups (grasses, legumes and nonleguminous forbs) in intact and parasite removal quadrats. We found that haustoria were nonrandomly distributed amongst host species, suggesting host preference for Poaceae and Fabaceae. In addition, haustoria attached to certain forbs did not penetrate into the stele. The above‐ground biomass of grasses and legumes was increased significantly by the removal of P. viscosa, but the biomass of forbs did not change significantly. These results suggest that host preference depresses the performance of Poaceae and Fabaceae, thus affecting the competitive relationships among plants, meaning that P. viscosa may pose a serious threat to indigenous endangered legumes and grasses. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 69–78.     

Host‐plant use by two Orthomeria (Phasmida: Aschiphasmatini) species feeding on Macaranga myrmecophytes

Myrmecophytes depend on symbiotic ants (plant‐ants) to defend against herbivores. Although these defensive mechanisms are highly effective, some herbivorous insects can use myrmecophytes as their host‐plants. The feeding habits of these phytophages on myrmecophytes and the impacts of the plant‐ants on their feeding behavior have been poorly studied. We examined two phasmid species, Orthomeria alexis and O. cuprinus, which are known to feed on Macaranga (Euphorbiaceae) myrmecophytes in a Bornean primary forest. Our observations revealed that: (i) each phasmid species relied on two closely‐related myrmecophytic Macaranga species for its host‐plants in spite of their normal plant‐ant symbioses; and (ii) there was little overlap between their host‐plant preferences. More O. cuprinus adults and nymphs were found on new leaves, which were attended by more plant‐ants than mature leaves, while most adults and nymphs of O. alexis tended to avoid new leaves. In a feeding choice experiment under ant‐excluded conditions, O. alexis adults chose a non‐host Macaranga myrmecophyte that was more intensively defended by plant‐ants and was more palatable than their usual host‐plants almost as frequently as their usual host‐plant, suggesting that the host‐plant range of O. alexis was restricted by the presence of plant‐ants on non‐host‐plants. Phasmid behavior that appeared to minimize plant‐ant attacks is described.     

Host‐specificity constrains evolutionary host change in the psyllid Prosopidopsylla flava

1. At the higher taxonomic levels Psylloidea have largely co‐evolved with their host plants, and the colonisations of new plant lineages have been relatively few. The mechanisms that have constrained the evolution of host relationships throughout the history of this superfamily are not understood. The host relationships of Prosopidopsylla flava were studied in order to identify possible genetic or ecological constraints to macroevolutionary change in host range, using methodology developed for the host specificity testing of potential biological control agents. 2. The five Prosopis taxa (Leguminosae) tested appeared to be indistinguishable as hosts. Adult feeding required for survival, and for the initiation and continuation of egg production, was specific to Prosopis species. Oviposition occurred on 57 of the 58 non‐Prosopis plant species tested within the Leguminosae and Rosaceae, and was highest on plant species that belonged to the same subfamily. Eggs were inserted into plant tissue by their peduncle but hatched independently of host species. Complete development was restricted to Prosopis, although some early nymphal development was observed on species within the same subfamily as Prosopis (Mimosoideae). 3. Multiple phylogenetic constraints restrict host selection and utilisation by P. flava to Prosopis species, implying a long association between insect and host. Specificity of adult feeding was of special significance, being required for survival, oogenesis, and probably indirectly determining the oviposition host. This supports the hypothesis that genetically set limits in particular aspects of life history are responsible for the inability of some psyllids to readily colonise new plant lineages, rather than stabilising selection.     

Can phylogenetic signal,character displacement,or random phenotypic drift explain the morphological variation in the genus Geonoma (Arecaceae)?

Plant clades may exhibit little or wide morphological variation as a result of (1) the retention of ancestral characteristics or phylogenetic signal, (2) character displacement, or (3) random phenotypic drift or convergence. Understanding the taxonomy and systematics of many plant lineages has been challenging due to continuous intra‐ and interspecific morphological variation. To assess which evolutionary hypothesis could explain the morphological diversity in the genus Geonoma (Arecaceae), we performed a Mantel test between phylogenetic and morphological distances of 54 taxa, and tested for phylogenetic signal using Blomberg's K‐statistic on continuous variables, and a randomization of character states. To obtain a phylogenetic (patristic) distance matrix for Geonoma, we constructed a molecular phylogeny of tribe Geonomateae using three nuclear DNA regions. A positive relationship between the patristic and a 26‐discrete‐character distance matrix (R² = 0.55, P < 0.001) supported the phylogenetic signal hypothesis. The randomization test showed that signal was present in 16 characters. No relationship was evident using a 17‐quantitative‐variable distance matrix (R² = 0.07, P = 0.13), supporting the random drift hypothesis or convergence, and all 17 K‐values were close to 0, suggesting less phylogenetic signal than under the Brownian model. If most morphological variables traditionally used to classify Geonoma evolved randomly or convergently, it might explain Geonoma's challenging taxonomy. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 528–539.     

Use of host plants by Troidini butterflies (Papilionidae, Papilioninae): constraints on host shift

Molecular phylogenetic analyses were conducted to determine relationships and to investigate character evolution for the Troidini/Aristolochia interaction, in an attempt to answer the following questions: (1) what is the present pattern of use of Aristolochia by these butterflies; (2) is the pattern we see today related to the phylogeny of plants or to their chemical composition; (3) can the geographical distribution of Aristolochia explain the host plant use observed today; and (4) how did the interaction between Troidini and Aristolochia evolve? Analyses of character optimization suggest that the current pattern of host plant use of these butterflies does not seem to be constrained by the phylogeny of their food plants, neither by the secondary chemicals in these plants nor by their geographical similarity. The current host plant use in these butterflies seems to be simply opportunistic, with species with a wider geographical range using more species of host plants than those with a more restricted distribution. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90 , 247–261.     

Molecular phylogeny and divergence times of Hormaphidinae (Hemiptera: Aphididae) indicate Late Cretaceous tribal diversification

The aphid subfamily Hormaphidinae is a good candidate for the study of the evolution of insect – plant relationships. Most hormaphidine species depend on woody primary host plants and woody or herbaceous secondary host plants, and represent high host specificity, especially to their primary hosts. No detailed molecular phylogeny of Hormaphidinae has been reported, and the taxonomic positions of some taxa in this group remain unclear. To reconstruct major phylogenetic relationships and to understand the evolution of host association patterns for major lineages, we present the first detailed molecular phylogeny of Hormaphidinae, as inferred from nuclear and mitochondrial DNA sequences, using maximum parsimony, maximum likelihood, and Bayesian methods. The monophyly of Hormaphidinae and its three traditional tribes was supported, and a sister relationship between Hormaphidini and Nipponaphidini was suggested. Most inner relationships within tribes were also supported, and some novel relationships were revealed. Two subtribes of Cerataphidini are proposed. Divergence times estimated using a Bayesian approach indicate that tribal diversifications occurred during the Late Cretaceous and were coincident with the appearance of their primary host plants. The current pattern of secondary host association for the three tribes may have evolved in different time ranges. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 73–87.     

Molecular phylogeny of the ant tribe Myrmicini (Hymenoptera: Formicidae)

The interrelationships within ant subfamilies remain elusive, despite the recent establishment of the phylogeny of the major ant lineages. The tribe Myrmicini belongs to the subfamily Myrmicinae, and groups morphologically unspecialized genera. Previous research has struggled with defining Myrmicini, leading to considerable taxonomic instability. Earlier molecular phylogenetic studies have suggested the nonmonophyly of Myrmicini, but were based on limited taxon sampling. We investigated the composition of Myrmicini with phylogenetic analyses of an enlarged set of taxa, using DNA sequences of eight gene fragments taken from 37 representatives of six of the seven genera (Eutetramorium, Huberia, Hylomyrma, Manica, Myrmica, and Pogonomyrmex), and eight outgroups. Our results demonstrate the invalidity of Myrmicini as currently defined. We recovered sister‐group relationships between the genera Myrmica and Manica, and between Pogonomyrmex and Hylomyrma. This study illustrates that to understand the phylogeny of over 6000 myrmicine species, comprehensive taxon sampling and DNA sequencing are an absolute requisite. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 482–495.     

Association between the African lycaenid,Anthene usamba,and an obligate acacia ant,Crematogaster mimosae

The African lycaenid butterfly, Anthene usamba, is an obligate myrmecophile of the acacia ant, Crematogaster mimosae. Female butterflies use the presence of C. mimosae as an oviposition cue. The eggs are laid on the foliage and young branches of the host plant, Acacia drepanolobium. Larvae shelter in the swollen thorns (domatia) of the host tree, where they live in close association with the acacia ants, and each larva occupies a domatium singly. Anthene usamba are tended by ants that feed from the dorsal nectary organ at regular intervals. Larvae also possess tentacle organs flanking the dorsal nectary organ and appear to signal to ants by everting these structures. Larvae were observed to spend most of their time within the domatia. Stable isotope analysis of matched host plant–ant–butterfly samples revealed that Anthene usamba are δ¹⁵N enriched relative to the ants with which they associate. These data, based on the increase in δ¹⁵N through trophic levels, indicate that the caterpillars of these butterflies are aphytophagous and either exploit the ant brood of C. mimosae within the domatia, or are fed mouth to mouth by adult workers via trophallaxis. This is the first documented case of aphytophagy in African Anthene. Pupation occurs inside the domatium and the imago emerges and departs via the hole chewed by the larva. The adult females remain closely associated with their natal patch of trees, whereas males disperse more widely across the acacia savannah. Females prefer to oviposit on trees with the specific host ant, C. mimosae, an aggressive obligate mutualist, and avoid neighbouring trees with other ant species. Adult butterflies are active during most months of the year, and there are at least two to three generations each year. Observations made over a 5‐year period indicate that a number of different lycaenid species utilize ant‐acacias in East Africa, and these observations are summarized, together with comparisons from the literature. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013 , 109 , 302–312.     

Patterns of morphological evolution of the cephalic region in damselfishes (Perciformes: Pomacentridae) of the Eastern Pacific

Pomacentridae are one of the most abundant fish families inhabiting reefs of tropical and temperate regions. This family, comprising 29 genera, shows a remarkable diversity of habitat preferences, feeding, and behaviours. Twenty‐four species belonging to seven genera have been reported in the Eastern Pacific region. The present study focuses on the relationship between the diet and the cephalic profile in the 24 endemic damselfishes of this region. Feeding habits were determined by means of underwater observations and the gathering of bibliographic data. Variations in cephalic profile were analyzed by means of geometric morphometrics and phylogenetic methods. The present study shows that the 24 species can be grouped into three main trophic guilds: zooplanktivores, algivores, and an intermediate group feeding on small pelagic and benthic preys. Shape variations were low within each genus except for Abudefduf. Phylogenetically adjusted regression reveals that head shape can be explained by differences in feeding habits. The morphometric phylogeny recovered the subfamily Stegastinae and the relationship between Abudefduf troschelii and Chromis species. The cephalic profile of damselfishes contains a clear and strong phylogenetic signal. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 593–613.     

Scale‐dependence of phylogenetic signal in ecological traits of ectoparasites

The non‐independence of traits among closely related species is a well‐documented phenomenon underpinning modern methods for comparative analyses or prediction of trait values in new species. Surprisingly such studies have mainly focused on life‐history or morphological traits of free‐living organisms, ignoring ecological attributes of parasite species in spite of the fact that they are critical for conservation and human health. We tested for a phylogenetic signal acting on two ecological traits, abundance and host specificity, using data for 218 flea species parasitic on small mammals in 19 regions of the Palaearctic and Nearctic, and a phylogenetic tree for these species. We tested for the presence of a phylogenetic signal at both regional and continental scales using three measures (Abouheif/Moran's I, Pagel's λ, and Blomberg et al.'s K). Our results show 1) a consistent positive phylogenetic signal for flea abundance, but only a weaker and erratic signal for host specificity, and 2) a clear dependence on scale, with the signals being stronger at the continental scale and relatively weaker or inconsistent at the regional scale. Whenever values of Blomberg et al.'s K were found significant, they were <1 suggesting that the effects of phylogeny on the evolution of abundance and host specificity in fleas are weaker than expected from a Brownian motion model. The most striking finding is that, within a continental fauna, closely‐related flea species are characterized by similar levels of abundance, though this pattern is weaker within local assemblages, possibly eroded by local biotic or abiotic conditions. We discuss the link between history (represented by phylogeny) and pattern of variation among species in morphological and ecological traits, and use comparisons between the Palaearctic and Nearctic to infer a role of historical events in the probability of detecting phylogenetic signals.     

Evolutionary history of the burnet moth genus Zygaena Fabricius, 1775 (Lepidoptera: Zygaenidae) inferred from nuclear and mitochondrial sequence data: phylogeny, host–plant association, wing pattern evolution and historical biogeography

Burnet moths of the genus Zygaena are a striking group of primarily diurnal Lepidoptera displaying an exceptional phenotypic plasticity. Previous attempts to elucidate the phylogenetic history of the group had been confounded by a perplexing pattern of characters or insufficient taxon sampling. In the present study, we infer a phylogeny of the genus Zygaena by analysing 5.4 kb of their nuclear and mitochondrial DNA. Eighty‐four of the 98 currently recognized species in this genus are considered, including representatives of all described species groups. RNA coding sequences are aligned with reference to zygaenoid moth specific secondary structure models of corresponding molecules. We conduct phylogenetic analyses within a Bayesian framework applying partition specific substitution parameters; covariation of paired sites in RNA gene sequences is accommodated by using doublet substitution models. The molecular data reveal that a considerable number of currently recognized species groups in Zygaena are not monophyletic. The traditional subgeneric classification proves to be artificial as well; Agrumenia and Zygaena (sensu stricto) are polyphyletic. Only the subgenus Mesembrynus can be confirmed as a monophyletic species cluster. Optimization of larval host–plant associations and forewing patterns on sampled trees of the Bayesian analyses suggest convergent evolution of similar wing pattern types in distantly related species clusters and a shift from cyanogenic to acyanogenic host‐plants. The phylogenetic results challenge the classic assumption that early species diversification in Zygaena took place in the Irano–Turkestanian region. Rather, the molecular data point to the western Mediterranean area as the geographical origin of the group and imply a subsequent colonization of the Middle East and Central Asia. We discuss the apparently convergent evolution of similar wing patterns in context with the chemical defence system of burnet moths and suggest a species group concept for the genus Zygaena that accounts for the recent findings. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92 , 501–520.