Diversity and assemblage structure of phytophagous Hemiptera along a latitudinal gradient: predicting the potential impacts of climate change

Aims The aims were (1) to assess the species richness and structure of phytophagous Hemiptera communities along a latitudinal gradient, (2) to identify the importance of rare species in structuring these patterns, and (3) to hypothesize about how phytophagous Hemiptera communities may respond to future climate change. Location East coast of Australia. Methods Four latitudes within the 1150 km coastal distribution of Acacia falcata were selected. The insect assemblage on the host plant Acacia falcata was sampled seasonally over two years. Congeneric plant species were also sampled at the sites. Results Ninety‐eight species of phytophagous Hemiptera were collected from A. falcata. Total species richness was significantly lower at the most temperate latitude compared to the three more tropical latitudes. We classified species into four climate change response groups depending on their latitudinal range and apparent host specificity. Pairwise comparisons between groups showed that the cosmopolitan, generalist feeders and specialists had a similar community structure to each other, but the climate generalists had a significantly different structure. Fifty‐seven species were identified as rare. Most of these rare species were phloem hoppers and their removal from the dataset led to changes in the proportional representation of all guilds in two groups: the specialist and generalist feeders. Main conclusions We found no directional increase in phytophagous Hemiptera species richness. This indicates that, at least in the short term, species richness patterns of these communities may be similar to that found today. As the climate continues to change, however, we might expect some increases in species richness at the more temperate latitudes as species migrate in response to shifting climate zones. In the longer term, more substantial changes in community composition will be expected because the rare species, which comprise a large fraction of these communities, will be vulnerable to both direct climatic changes, and indirect effects via changes to their host's distribution.     

An omics evolutionary perspective on phytophagous insect–host plant interactions in Anastrepha obliqua: a review

Phytophagous insects have a close relationship with their host plants. For this reason, their interactions can lead to important changes in insect population dynamics and evolutionary trajectories. Next generation sequencing (NGS) has provided an opportunity to analyze omics data on a large scale, facilitating the change from a classical genetics approach to a more holistic understanding of the underlying molecular mechanisms of host plant use by insects. Most studies have been carried out on model species in Holarctic and temperate zones. In tropical zones, however, the effects of use of various host plants on evolutionary insect history is less understood. In the current review, we describe how omics methodologies help us to understand phytophagous insect–host plant interactions from an evolutionary perspective, using as example the Neotropical phytophagous insect West Indian fruit fly, Anastrepha obliqua (Macquart) (Diptera: Tephritidae), an economically important fruit crop pest in the Americas. Anastrepha obliqua could adopt a generalist or a specialist lifestyle. We first review the adaptive molecular mechanisms of phytophagous insects to host plants, and then describe the main tools to study phytophagous insect–host plant interactions in the era of omics sciences. The omics approaches will advance the understanding of insect molecular mechanisms and their influence on diversification and evolution. Finally, we discuss the importance of a multidisciplinary approach that integrates the use of omics tools and other, more classical methodologies in evolutionary studies.     

The guest playing host: colonization of the introduced Mediterranean gecko, Hemidactylus turcicus, by helminth parasites in southeastern Louisiana.

Parasite surveys of exotic hosts offer the opportunity to examine parasite colonization on different scales (i.e., host individual, host population, host species, and new geographic locality). Ten helminths (Macracanthorhynchus ingens, Mesocestoides lineatus, Oochoristica javaensis, Haematoloechus varioplexus, Mesocoelium monas, Telorchis corti, Cosmocercoides variabilis, Oswaldocruzia leidyi, Skrjabinoptera sp., and a larval acuariid nematode) were recovered from the exotic Mediterranean gecko Hemidactylus turcicus, in southeastern Louisiana. Only 1 exotic parasite, O. javaensis, colonized a new geographic locality, but 7 local helminths colonized a new host species. Helminth communities of H. turcicus were similar in structure to what has been hypothesized or observed for lizards. Thus, communities were composed of generalists and were depauperate (i.e., colonization of individual geckos or host populations was rare for most of the helminths); however, there was significant variation in community structure among local habitats. Although the gecko's behavioral and physiological attributes predict colonization by monoxenous helminths, only 2, C. variabilis and O. leidyi, were recovered. Eight heteroxenous helminths, 2 of which (the acuariid and O. javaensis) were the most widely distributed and abundant, were the better colonizers. The gecko's generalist diet may have exposed it to a diverse parasite fauna and thus been important in determining the helminths that could colonize.     

Changes in phytophagous insect host ranges following the invasion of their community: Long‐term data for fruit flies

The invasion of an established community by new species can trigger changes in community structure. Invasions often occur in phytophagous insect communities, the dynamics of which are driven by the structure of the host assemblage and the presence of competitors. In this study, we investigated how a community established through successive invasions changed over time, taking the last invasion as the reference. The community included four generalist and four specialist species of Tephritidae fruit flies. We analyzed a long‐term database recording observed numbers of flies per fruit for each species on 36 host plants, over 18 years, from 1991 to 2009. Community structure before the last invasion by Bactrocera zonata in 2000 was described in relation to host plant phylogeny and resource availability. Changes in the host range of each species after the arrival of B. zonata were then documented by calculating diversity indices. The flies in the community occupied three types of niches defined on the basis of plant phylogeny (generalists, Solanaceae specialist, and Cucurbitaceae specialists). After the arrival of B. zonata, no change in the host range of specialist species was observed. However, the host ranges of two generalist species, Ceratitis quilicii and Ceratitis capitata, tended to shrink, as shown by the decreases in species richness and host plant α‐diversity. Our study shows increased host specialization by generalist phytophagous insects in the field following the arrival of an invasive species sharing part of their resources. These findings could be used to improve predictions of new interactions between invaders and recipient communities.     

Generalized host‐plant feeding can hide sterol‐specialized foraging behaviors in bee–plant interactions

Host‐plant selection is a key factor driving the ecology and evolution of insects. While the majority of phytophagous insects is highly host specific, generalist behavior is quite widespread among bees and presumably involves physiological adaptations that remain largely unexplored. However, floral visitation patterns suggest that generalist bees do not forage randomly on all available resources. While resource availability and accessibility as well as nectar composition have been widely explored, pollen chemistry could also have an impact on the range of suitable host‐plants. This study focuses on particular pollen nutrients that cannot be synthesized de novo by insects but are key compounds of cell membranes and the precursor for molting process: the sterols. We compared the sterol composition of pollen from the main host‐plants of three generalist bees: Anthophora plumipes, Colletes cunicularius, and Osmia cornuta, as well as one specialist bee Andrena vaga. We also analyzed the sterols of their brood cell provisions, the tissues of larvae and nonemerged females to determine which sterols are used by the different species. Our results show that sterols are not used accordingly to foraging strategy: Both the specialist species A. vaga and the generalist species C. cunicularius might metabolize a rare C₂₇ sterol, while the two generalist species A. plumipes and O. cornuta might rather use a very common C₂₈ sterol. Our results suggest that shared sterolic compounds among plant species could facilitate the exploitation of multiple host‐plants by A. plumipes and O. cornuta whereas the generalist C. cunicularius might be more constrained due to its physiological requirements of a more uncommon dietary sterol. Our findings suggest that a bee displaying a generalist foraging behavior may sometimes hide a sterol‐specialized species. This evidence challenges the hypothesis that all generalist free‐living bee species are all able to develop on a wide range of different pollen types.     

Host use of a hemiparasitic plant: no trade-offs in performance on different hosts

To examine putative specialization of a hemiparasitic plant to the most beneficial host species, we studied genetic variation in performance and trade-offs between performance on different host species in the generalist hemiparasite, Rhinanthus serotinus. We grew 25 maternal half-sib families of the parasite on Agrostis capillaris and Trifolium pratense and without a host in a greenhouse. Biomass and number of flowers of the parasite were the highest when grown on T. pratense. There were significant interactions between host species and R. serotinus seed-family indicating that the differences in performance on the two hosts and without a host varied among the families. However, we found no significant negative correlations between performance of R. serotinus on the host species or between performance on the two hosts and autotrophic performance. Thus, the genetic factors studied here are not likely to affect the evolution of specialization of R. serotinus to the most beneficial host.     

Host range in phytophagous insects: the potential role of generalist predators

Summary The potential role of generalist natural enemies is presented as one of the important ecological pressures that select for narrow host range in phytophagous insects, and dominant relative to physiological bases for specialization. Experiments are described in three completely different systems indicating that generalist herbivores are more vulnerable to predation than specialist herbivores. The three predators were (a) the vespid waspMischocyttarus flavitarsus, (b) the Argentine antIridomyrmex humilis and (c) the coccinellid beetleHippodamia convergens. It is concluded the predators may provide strong selection pressure for maintenance and perhaps evolution of narrow host range in insect herbivores.     

Local maladaptation in the soft scale insect Saissetia coffeae (Hemiptera: Coccidae)

Local adaptation has often been documented in herbivorous insects. The potential for local maladaptation in phytophagous insects, however, has not been widely considered. I performed a two-generation reciprocal cross-transplant experiment with the generalist soft scale insect Saissetia coffeae (Hemiptera: Coccidae) on two common species of host plants in rain forest habitat in Costa Rica. In this system, S. coffeae showed significant local maladaptation at the level of the host species. Lineages originally collected from Witheringia enjoyed a strong advantage over those collected from Lomariopsis when both sets of lineages were placed on Lomariopsis; however, when both sets of lineages were raised on Witheringia, their fitnesses were statistically indistinguishable. While some aspects of the biology of S. coffeae may impair its ability to adapt to local selection pressures, scale insects are often locally adapted on fine spatial scales, and local maladaptation is therefore especially surprising. Other documented cases of local maladaptation in parasites appear to be due to evolution on the part of the host. The possibility that hosts or natural enemies may place local genotypes at a disadvantage, producing a pattern of local maladaptation, is one that deserves more consideration in the context of plant-insect interactions.     

Ability of a Generalist Seed Beetle to Colonize an Exotic Host: Effects of Host Plant Origin and Oviposition Host

The colonization of an exotic species by native herbivores is more likely to occur if that herbivore is a generalist. There is little information on the life-history mechanisms used by native generalist insects to colonize exotic hosts and how these mechanisms are affected by host properties. We examined the ability of the generalist seed beetle Stator limbatus Horn to colonize an exotic species. We compared its host preference, acceptability, performance, and egg size when ovipositing and developing on two native (Pithecellobium dulce (Roxb.) Benth and Senegalia riparia (Kunth)) and one exotic legume species (Leucaena leucocephala (Lam.)). We also analyzed the seed chemistry. We found that females recognize the exotic species as an unfavorable host for larval development and that they delayed oviposition and laid fewer and larger eggs on the exotic species than on the native species. Survivorship on the exotic host was 0%. Additionally, seeds of the native species contain five chemical compounds that are absent in the exotic species, and the exotic species contains three sterols, which are absent in the native legumes. Genetically based differences between beetles adapted to different hosts, plastic responses toward new hosts, and chemical differences among seeds are important in host colonization and recognition of the exotic host. In conclusion, the generalist nature of S. limbatus does not influence its ability to colonize L. leucocephala. Explanations for the colonization of exotic hosts by generalist native species and for the success of invasive species must be complemented with studies measuring local adaptation and plasticity.     

Interactions between phytophagous insects and their Opuntia hosts

Abstract.

• 1 The cactophagous insect community on opuntias is analysed to show the number of insect species in different taxa. An extension of this analysis gives the average species complement on large and small opuntias.
• 2 A highly significant positive correlation is found between the total number of phytophagous insect species on individual Opuntia species and a measure of the overall ‘architecture’ of their host plants.
• 3 The specificity of the phytophagous insects on opuntias is briefly considered and the community as a whole analysed by guilds. The co-evolution of the Opuntia-feeding insects and their hosts has culminated in a community of specialist insects to the exclusion of nearly all generalist phytophages.
• 4 The life history strategies of the Opuntia-feeding insects are reviewed. Common to all developmental stages are morphological and behavioural adaptations that reduce the risk of attack by natural enemies. This is clearly the consequence of living on structurally simple host plants where there is little place to hide.
• 5 The possible influence of insect herbivores on Opuntia evolution is discussed.
• 6 An understanding of the interactions between the phytophagous insect community and opuntias has clear implications for the biological control of alien Opuntia weeds.

     

Pattern and process in the evolution of insect-plant associations: Yponomeuta as an example

Phylogenetic studies are increasing our understanding of the evolution of associations between phytophagous insects and their host plants. Sequential evolution, i.e. the shift of insect herbivores onto pre-existing plant species, appears to be much more common than coevolution, where reciprocal selection between interacting insects and plants is thought to induce chemical diversification and resistance in plants and food specialization in insects.Extreme host specificity is common in phytophagous insects and future studies are likely to reveal even more specialization. Hypotheses that assume that food specialists have selective advantages over generalists do not seem to provide a general explanation for the ubiquity of specialist insect herbivores. Specialists are probably committed to remain so, because they have little evolutionary opportunity to reverse the process due to genetically determined constraints on the evolution of their physiology or nervous system. The same constraints might result in phylogenetic conservatism, i.e. the frequent association of related insect herbivores with related plants. Current phylogenetic evidence, however, indicates that there is no intrinsic direction to the evolution of specialization.Historical aspects of insect-host plant associations will be illustrated with the small ermine moth genus Yponomeuta. Small ermine moths show an ancestral host association with the family Celastraceae. The genus seems to be committed to specialization per se rather than to a particular group of plants. Whatever host shift they have made in their evolutionary past (onto Rosaceae, Crassulaceae, and Salicaceae), they remain monophagous. The oligophagous Y. padellus is the only exception. This species might comprise a mosaic of genetically divergent host-associated populations.     

Comparative demography of a specialist and generalist fruit fly: Implications for host use and pest management

Host plants used by phytophagous insects can have significant consequences on demography parameters, overall lifetime fitness and their subsequent population dynamics. Here, we conduct a comparative demographic study between the specialist Zeugodacus cucumis (French) and generalist Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) to determine whether the host plants used by these fly species play any role in their overall lifetime fitness and explains current host use patterns. These two fly species are pests within the north-eastern region of Australia and we further aimed to use complete life-history data to determine the population parameters and models that would help identify the sensitive life-history stage that could be targeted for effective field management. Eggs collected from laboratory-reared flies were inoculated into organically grown fruits of both the primary and alternate host plant cultivars of both fly species. The proportion surviving each life stage from egg through to adult and fecundity were monitored for all cohorts from the different plant cultivars. Complete stage-base life-tables for cohorts of each fly species developing from each fruit cultivar were constructed, and the key demographic parameters and population models were analysed using PopTools matrix model programme. Our results showed that the host used by each fly species had significant consequences on fly demographic parameters and hence their overall lifetime fitness. The generalist B. tryoni was able to compensate for the fitness loss experienced at the pre-adult stage by having adults with higher fecundity, but this was not the case for the specialist Z. cucumis. Stage-base population models revealed that the population growth rate of both species was highly sensitive at the adult reproductive stage, indicating that manipulating probability of survival at this life stage would effectively manage populations of these pest species. This study provides the empirical evidence of undertaking complete life history demography studies of phytophagous insects to accurately understand their lifetime fitness consequences of using a certain host, their observed host use patterns, and overall population dynamics. We suggest that any efforts to manage dacine fruit fly pest population should consider life-history consequences of host use.     

Host plant preference and performance of the sibling species of butterflies <Emphasis Type="Italic">Leptidea sinapis</Emphasis> and <Emphasis Type="Italic">Leptidea reali</Emphasis>: a test of the trade-off hypothesis for food specialisation

A large proportion of phytophagous insect species are specialised on one or a few host plants, and female host plant preference is predicted to be tightly linked to high larval survival and performance on the preferred plant(s). Specialisation is likely favoured by selection under stable circumstances, since different host plant species are likely to differ in suitability—a pattern usually explained by the “trade-off hypothesis”, which posits that increased performance on a given plant comes at a cost of decreased performance on other plants. Host plant specialisation is also ascribed an important role in host shift speciation, where different incipient species specialise on different host plants. Hence, it is important to determine the role of host plants when studying species divergence and niche partitioning between closely related species, such as the butterfly species pair Leptidea sinapis and Leptidea reali. In Sweden, Leptidea sinapis is a habitat generalist, appearing in both forests and meadows, whereas Leptidea reali is specialised on meadows. Here, we study the female preference and larval survival and performance in terms of growth rate, pupal weight and development time on the seven most-utilised host plants. Both species showed similar host plant rank orders, and larvae survived and performed equally well on most plants with the exceptions of two rarely utilised forest plants. We therefore conclude that differences in preference or performance on plants from the two habitats do not drive, or maintain, niche separation, and we argue that the results of this study do not support the trade-off hypothesis for host plant specialisation, since the host plant generalist Leptidea sinapis survived and performed as well on the most preferred meadow host plant Lathyrus pratensis as did Leptidea reali although the generalist species also includes other plants in its host range. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The genetic architecture of a niche: variation and covariation in host use traits in the Colorado potato beetle

The genetic basis of host plant use by phytophagous insects can provide insight into the evolution of ecological niches, especially phenomena such as specialization and phylogenetic conservatism. We carried out a quantitative genetic analysis of multiple host use traits, estimated on five species of host plants, in the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae). Mean values of all characters varied among host plants, providing evidence that adaptation to plants may require evolution of both behavioral (preference) and post-ingestive physiological (performance) characteristics. Significant additive genetic variation was detected for several characters on several hosts, but not in the capacity to use the two major hosts, a pattern that might be caused by directional selection. No negative genetic correlations across hosts were detected for any 'performance' traits, i.e. we found no evidence of trade-offs in fitness on different plants. Larval consumption was positively genetically correlated across host plants, suggesting that diet generalization might evolve as a distinct trait, rather than by independent evolution of feeding responses to each plant species, but several other traits did not show this pattern. We explored genetic correlations among traits expressed on a given plant species, in a first effort to shed light on the number of independent traits that may evolve in response to selection for host-plant utilization. Most traits were not correlated with each other, implying that adaptation to a novel potential host could be a complex, multidimensional 'character' that might constrain adaptation and contribute to the pronounced ecological specialization and the phylogenetic niche conservatism that characterize many clades of phytophagous insects.     

Do canal‐cutting behaviours facilitate host‐range expansion by insect herbivores?

According to the escalation–radiation model of co-evolution, insect herbivores that acquire the ability to circumvent a plant defence enter a new adaptive zone and increase in species. How herbivore counter-adaptations to plant defences might lead to speciation is poorly understood. Studies of nymphalid butterflies suggest that the evolution of a broadened host range may be a critical step. This paper examines if leaf-feeding insects capable of deactivating defensive plant canals with canal cutting often have broad host ranges. A total of 94 species of canal-cutting insects were identified from the literature, including eight new canal cutters described in this paper. Only 27% of canal cutters with known host ranges are generalists that feed on plants in multiple families. The proportion of generalist canal cutters is similar or lower than estimates of generalists among phytophagous insects overall. Only five species, at most, of the canal-cutting generalists feed exclusively on plants with secretory canals. The paucity of generalists can be attributed in part to the considerable taxonomic distance separating canal-bearing plant families and to their corresponding chemical distinctiveness. The dependence of many canal-cutting species on host chemicals for defence would also favour specialization.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 715–731.     

Testing the trend towards specialization in herbivore-host plant associations using a molecular phylogeny of Tomoplagia (Diptera: Tephritidae)

Herbivorous insects are abundant and diverse and insect-host plant associations tend to be specialized and evolutionarily conserved. Some authors suggested that generalist insect lineages tend to become specialists, with host specialization leading to an evolutionary dead-end for the parasite species. In this paper, we have examined this tendency using a phylogenetic tree of Tomoplagia (Diptera: Tephritidae), a parasite of asteracean plants. We have tested the trend towards specialization in different hierarchical degrees of host specialization. The topology of the tree, the inference of ancestral hosts, and the lack of directional evolution indicated that specialization does not correspond to a phylogenetic dead-end. Although most Tomoplagia species are restricted to a single host genus, specialization does not seem to limit further host range evolution. This work emphasizes the advantages of the use of different levels of specialization and the inclusion of occasional hosts to establish a more detailed scenario for the evolution of this kind of ecological association.     

Specificity and host predictability: a comparative analysis among monogenean parasites of fish

1. This article compares generalist (parasite species found on two or more host species) and specialist (found on only one host species) monogenean parasite species of fish. The reduction of the host range – that is an increase in host specificity – may correspond with a better adaptation of the parasite to a more predictable host environment. A more predictable environment may allow the parasite species to develop specific adaptations.
2. We assume that the more predictable host environment can be evaluated by host body size, since numerous life-traits, such as longevity, are positively correlated with size.
3. We found that specialist parasites parasitize larger hosts species than generalist parasites. We also found a good relationship between host body size and parasite body size for specialist parasite species.
4. An adaptation to the mechanical problems encountered in the host's gill chamber may lead to an increase in parasite body size. The infection of a larger part of the host population in order to decrease the chances of local extinction due to fluctuations of host abundance may be another adaptive mechanism.
5. We found a negative correlation between parasite body size and prevalence for generalist parasite species. This relationship disappeared when using the comparative method controlling for phylogeny, which proved that it was a phylogenetic effect.     

Molecular characterization of trophic ecology within an island radiation of insect herbivores (Curculionidae: Entiminae: Cratopus)

The phytophagous beetle family Curculionidae is the most species‐rich insect family known, with much of this diversity having been attributed to both co‐evolution with food plants and host shifts at key points within the early evolutionary history of the group. Less well understood is the extent to which patterns of host use vary within or among related species, largely because of the technical difficulties associated with quantifying this. Here we develop a recently characterized molecular approach to quantify diet within and between two closely related species of weevil occurring primarily within dry forests on the island of Mauritius. Our aim is to quantify dietary variation across populations and assess adaptive and nonadaptive explanations for this and to characterize the nature of a trophic shift within an ecologically distinct population within one of the species. We find that our study species are polyphagous, consuming a much wider range of plants than would be suggested by the literature. Our data suggest that local diet variation is largely explained by food availability, and locally specialist populations consume food plants that are not phylogenetically novel, but do appear to represent a novel preference. Our results demonstrate the power of molecular methods to unambiguously quantify dietary variation across populations of insect herbivores, providing a valuable approach to understanding trophic interactions within and among local plant and insect herbivore communities.     

Multilocus models of sympatric speciation: Bush versus Rice versus Felsenstein

Abstract. In populations of phytophagous insects that use the host plant as a rendezvous for mating, divergence in host preference could lead to sympatric speciation. Speciation requires the elimination of "generalist" genotypes, that is, those with intermediate host preference. This could occur because such genotypes have an inherent fitness disadvantage, or because preference alleles become associated with alleles that are oppositely selected on the two hosts. Although the former mechanism has been shown to be plausible, the latter mechanism has not been studied in detail. I consider a multilocus model (the "Bush model") in which one set of biallelic loci affects host preference, and a second set affects viability on the hosts once chosen. Alleles that increase viability on one host decrease viability on the other, and all loci are assumed to be unlinked. With moderately strong selection on the viability loci, preference alleles rapidly become associated with viability alleles, and the population splits into two reproductively isolated host specialist populations. The conditions for speciation to occur in this model, as measured by the strength of selection required, are somewhat more stringent than in a model in which preference and viability are controlled by the same loci (one-trait model). In contrast, the conditions are much less stringent than in a model in which speciation requires buildup of associations between viability loci and loci controlling a host-independent assortative mating trait (canonical two-trait model). Moreover, in the one-trait model, and to a lesser extent the Bush model, the strength of selection needed to initiate speciation is only slightly greater than that needed to complete it. This indicates that documenting instances of sympatric species that are reproductively isolated only by host or habitat preference would provide evidence for the plausibility of sympatric speciation in nature.     

Cryptic species of mites (Uropodoidea: Uroobovella spp.) associated with burying beetles (Silphidae: Nicrophorus): The collapse of a host generalist revealed by molecular and morphological analyses

Uroobovella (Mesostigmata: Uropodoidea: Urodinychidae) species are among the most common mites associated with carrion-feeding Nicrophorus (Silphidae) beetles. Previous taxonomic understanding suggests that a single host generalist, U. nova, disperses and lives with Nicrophorus species worldwide (reported from at least seven host species). Using morphometrics and morphological characteristics, as well as partial cytochrome oxidase I (COI) and the entire internal transcribed spacer 2 (ITS2) markers, we tested whether this apparent generalist is truly a generalist or rather a complex of cryptic species with narrower host ranges. Based on deutonymph mites collected from 14 host species across six countries and 17 provinces or states, we show that U. nova represents at least five morphologically similar species with relatively restricted host ranges. Except for one species which yielded no molecular data (but did exhibit morphological differences), both molecular and morphological datasets were congruent in delimiting species boundaries. Moreover, comparing the mite phylogeny with the known ecology and phylogenetic relationships of their host species suggests that these mites are coevolving with their silphid hosts rather than tracking ecologically similar species.