Host Plant Use Research Articles

Host plant use by two distinct lineages of the tomato red spider mite, Tetranychus evansi, differing in their distribution range

The tomato red spider mite, Tetranychus evansi, is an emerging pest of solanaceous crops. Two distinct genetic lineages (I and II) have been identified, lineage I having a much wider geographic distribution than lineage II. This has been attributed to differences in cold hardiness that make lineage I better adapted to colonize the coldest parts of the invaded area. However, other factors such as the ability to exploit different hosts may also be involved. In this work, we compared the performance of the Nice (lineage I) and Perpignan (lineage II) strains of T. evansi on two frequent host plants for this species: black nightshade, Solanum nigrum, and cultivated tomato, S. lycopersicum. In general, Nice strain mites performed better (higher fecundity, lower offspring mortality, bigger egg size and lower percentage of males) than Perpignan strain mites when both: (1) they were reared and tested on the same host plant (S. lycopersicum or S. nigrum); and (2) when shifted from S. nigrum to S. lycopersicum and vice versa. Digestive proteases showed also higher expression in Nice strain mites than in Perpignan strain mites, independently of their plant host, potentially reflecting a more efficient proteolytic digestion of plant proteins. However, no differences in detoxification enzyme (P450, esterases and glutathione S-transferases) activities were found when the two strains were compared. In conclusion, our results demonstrate that Nice strain mites exhibited life history traits leading to higher fitness on two different hosts, which may be related with the higher invasive potential and outbreak risks of mites from lineage I.

Museum archives revisited: Central Asiatic hawkmoths reveal exceptionally high late Pliocene species diversification (Lepidoptera, Sphingidae)

Three high‐elevation Hyles species of Central Asia have proven difficult to sample, and thus, only a limited number of specimens are available for study. Ancient DNA techniques were applied to sequence two mitochondrial genes from ‘historic’ museum specimens of Hyles gallii, Hyles renneri and Hyles salangensis to elucidate the phylogenetic relationships of these species. This approach enabled us to include the holotypes and paratypes. The status of H. salangensis as a species endemic to a mountain range north of Kabul in Afghanistan is confirmed by this study. It is most closely related to Hyles nicaea and H. gallii, and quite distant from the clade comprising the species from Hyles vespertilio to Hyles tithymali, despite this group and H. salangensis both completely lacking an arolium on the pretarsus. Our results show that the samples assigned to H. renneri and Hyles livornica tatsienluica are conspecific and so we reinstate Hyles tatsienluica stat. nov. as the valid name for this species and synonymize H. renneri syn. nov. with it. This study shows that the distribution range postulated for H. tatsienluica extends from Nepal well into the mountains of south‐western China. The distribution ranges of H. livornica and H. tatsienluica overlap. The study confirms the previously proposed synonymies of Hyles nepalensis, Hyles gallii intermedia and Hyles gallii tibetanica with H. gallii. Extensive species sampling (over 80% of Hyles species) in this study allowed additional analyses. The dated phylogeny reveals the global Hyles hawkmoth radiation to be much more recent than previously thought: it began in the Late Miocene and culminated in a Pleistocene burst of diversification in the Northern Hemisphere. Ancestral ranges of basal nodes were reconstructed as highly equivocal, but the Neotropics has the highest probability in the two oldest nodes. Although the origins of the Madagascan and Australian species also remain ambiguous, a large crown clade of fifteen species was reconstructed to have originated in the Palaearctic. The wide distribution ranges of the two migratory species, H. livornica and H. gallii, appear to blur any traces of the biogeographic origin of the clades containing these species. Specialization in larval host plant use onto particular plant families from the ancestral condition ‘polyphagous’ may have led to an increased rate of speciation and phylogenetic diversification in three subgroups of Hyles (the Hawaiian clade, the Hyles centralasiae group and the Hyles euphorbiae complex).

Ants visiting extrafloral nectaries and pyrrolizidine alkaloids may shape how a specialist herbivore feeds on its host plants

The presence of extrafloral nectaries (EFNs) attracts predators and parasitoids, and protects the plant against herbivorous insects. By improving plant defences, EFNs reduce the fitness of herbivores. The use of similar host plants with no EFNs or adaptations in response to predators and parasitoids may enhance herbivore fitness. In this context, we studied the feeding habit (on leaves or on unripe seeds inside the pods) of larvae of the specialist moth Utetheisa ornatrix in two Crotalaria host plant species in which EFNs are present (C. micans) or absent (C. paulina). We hypothesized that the moths’ feeding habit was influenced by its natural enemies via their presence on EFNs. In C. micans, we found more larvae feeding inside the pods rather than on the leaves, while in C. paulina, larvae were found in both parts of the plant. There was greater activity of natural enemies in C. micans than in C. paulina. The moth sequesters enough pyrrolizidine alkaloid (PAs) to defend against predators in the leaves and seeds of C. paulina, but only in seeds of C. micans. Therefore, a change in the feeding habit in U. ornatrix larvae is a plastic response that depends on whether EFNs are present or not, or whether PA concentrations are low or high. This change does not affect overall moth performance. However, other factors, such as pod hardness, predation by organisms other than those visiting EFNs or even parasitoids cannot be ruled out as being responsible for the change in feeding habit. To date, both the EFNs and PAs in Crotalaria species are a parsimonious explanation of how larvae of U. ornatrix use different species of Crotalaria for feeding.

Parasitoids follow herbivorous insects to a novel host plant, generalist predators less so

AbstractThe ‘enemy‐free space’ hypothesis predicts that herbivorous insects can escape their natural enemies by switching to a novel host plant, with consequences for the evolution of host plant specialisation. However, if natural enemies follow herbivores to their novel host plants, enemy‐free space may only be temporary. We tested this by studying the colonisation of the introduced tree Eucalyptus grandis (Hill) Maiden (Myrtaceae) by insects in Brazil, where various species of herbivores have added eucalyptus to their host plant range, which consists of native myrtaceous species such as guava. Some herbivores, for example, Thyrinteina leucoceraea Ringe (Lepidoptera: Geometridae), cause outbreaks in eucalyptus plantations but not on guava, possibly because eucalyptus offers enemy‐free space. We sampled herbivores (mainly Lepidoptera species) and natural enemies on eucalyptus and guava and assessed parasitism of Lepidoptera larvae on both host plant species during ca. 2 years. Overall, predators were encountered more frequently on guava than on eucalyptus. In contrast, parasitoids were encountered equally and parasitism rates of Lepidoptera larvae were similar on both host plants. This indicates that herbivores may escape some enemies by moving to a novel host plant. However, this escape may be temporary and may vary with time. We argue that studying temporal and spatial patterns of enemy‐free space and the response of natural enemies to host use changes of their herbivorous prey is essential for understanding the role of natural enemies in the evolution of host plant use by herbivorous arthropods.

The Effects of Bean Leafroll Virus on Life History Traits and Host Selection Behavior of Specialized Pea Aphid (Acyrthosiphon pisum, Hemiptera: Aphididae) Genotypes.

Intraspecific specialization by insect herbivores on different host plant species contributes to the formation of genetically distinct "host races," but the effects of plant virus infection on interactions between specialized herbivores and their host plants have barely been investigated. Using three genetically and phenotypically divergent pea aphid clones (Acyrthosiphon pisum L.) adapted to either pea (Pisum sativum L.) or alfalfa (Medicago sativa L.), we tested how infection of these hosts by an insect-borne phytovirus (Bean leafroll virus; BLRV) affects aphid performance and preference. Four important findings emerged: 1) mean aphid survival rate and intrinsic rate of population growth (Rm) were increased by 15% and 14%, respectively, for aphids feeding on plants infected with BLRV; 2) 34% of variance in survival rate was attributable to clone × host plant interactions; 3) a three-way aphid clone × host plant species × virus treatment significantly affected intrinsic rates of population growth; and 4) each clone exhibited a preference for either pea or alfalfa when choosing between noninfected host plants, but for two of the three clones tested these preferences were modestly reduced when selecting among virus-infected host plants. Our studies show that colonizing BLRV-infected hosts increased A. pisum survival and rates of population growth, confirming that the virus benefits A. pisum. BLRV transmission affected aphid discrimination of host plant species in a genotype-specific fashion, and we detected three unique "virus-association phenotypes," with potential consequences for patterns of host plant use by aphid populations and crop virus epidemiology.

Patterns of microhabitat and larval host-plant use by an imperiled butterfly in northern Florida

The quality of habitat for a given species is fundamental to its persistence in that habitat space. Herbivorous insects often require a specific combination of host plants, floral resources, and physical features such as shelter. Identifying these different habitat features is a focus of ecology and conservation, particularly for managing rare or imperiled taxa. We investigated the patterns of microhabitat and host plant use of the rare frosted elfin butterfly, Callophrys irus, a larval host-plant specialist found in frequently disturbed sand plains, barrens, and sandhill pine-oak forests of the eastern United States. Previous studies have been conducted on populations in the Northeastern and Midwestern US, but the southern part of its range remains unstudied. Our efforts focused on a persistent C. irus colony in northeastern Florida, resulting in a geographically referenced census of larval host-plant Lupinus perennis, along with a multiple year survey of microhabitat features relevant to both C. irus adults and immatures. Results of the larval host-plant census revealed that the highest densities of host plants were located distant to the highest densities of C. irus. Hot-spot analysis confirmed the significance of this pattern, suggesting different habitat requirements for larval host-plant L. perennis and C. irus individuals in order to achieve maximum potential densities. Our survey of C. irus immatures showed a similar pattern of microhabitat affinity that was previously recorded in the Northeast and Midwestern US, including large larval host-plants, low amounts of ground cover vegetation, and the presence of some shade. Unique to our study we found that the presence of other herbivores of L. perennis such as larvae of the crambid moth Uresiphita reversalis had a negative effect on encountering C. irus immatures. Our results suggest that management that aims to conserve these species needs to include habitat factors that favor the overlap of these species and to consider where their densities are the highest.

Novel Observations of Larval Fire Survival, Feeding Behavior, and Host Plant Use in the Regal Fritillary,Speyeria idalia(Drury) (Nymphalidae)

ABSTRACT. Speyeria idalia is a prairie specialist that has experienced dramatic population declines throughout its range. Speyeria idalia is nearly extirpated from the eastern portion of its former range; however, populations within Kansas are relatively stable. We made several previously undescribed field observations of late-instar larvae and post-diapause female S. idalia in northeastern Kansas during 2014–2016. We report finding late-instar larvae at locations that were burned within weeks of detection. The observations of larvae shortly following a burn suggests that S. idalia larvae are capable of surviving fire and contradicts our current knowledge of this species. Additionally, we describe a feeding behavior characteristic of late-instar larvae. Larvae observed in the field and lab stripped leaves of host plants leaving only stems. This strip-style feeding behavior provided unique feeding evidence that was valuable to detecting the presence of larvae in the field. Finally, we documented larvae and...

Phylogeography of the Wheat Stem Sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae): Implications for Pest Management.

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a key pest of wheat in the northern Great Plains of North America, and damage resulting from this species has recently expanded southward. Current pest management practices are inadequate and uncertainty regarding geographic origin, as well as limited data on population structure and dynamics across North America impede progress towards more informed management. We examined the genetic divergence between samples collected in North America and northeastern Asia, the assumed native range of C. cinctus using two mitochondrial regions (COI and 16S). Subsequently, we characterized the structure of genetic diversity in the main wheat producing areas in North America using a combination of mtDNA marker and microsatellites in samples collected both in wheat fields and in grasses in wildlands. The strong genetic divergence observed between North American samples and Asian congeners, in particular the synonimized C. hyalinatus, did not support the hypothesis of a recent American colonization by C. cinctus. Furthermore, the relatively high genetic diversity both with mtDNA and microsatellite markers offered additional evidence in favor of the native American origin of this pest. The genetic diversity of North American populations is structured into three genetic clusters and these are highly correlated with geography. Regarding the recent southern outbreaks in North America, the results tend to exclude the hypothesis of recent movement of damaging wheat stem sawfly populations from the northern area. The shift in host plant use by local populations appears to be the most likely scenario. Finally, the significance of these findings is discussed in the context of pest management.

Losing a battle but winning the war: moving past preference-performance to understand native herbivore-novel host plant interactions.

Introduced plants can positively affect population viability by augmenting the diet of native herbivores, but can negatively affect populations if they are subpar or toxic resources. In organisms with complex life histories, such as insects specializing on host plants, the impacts of a novel host may differ across life stages, with divergent effects on population persistence. Most research on effects of novel hosts has focused on adult oviposition preference and larval performance, but adult preference may not optimize offspring performance, nor be indicative of host quality from a demographic perspective. We compared population growth rates of the Baltimore checkerspot butterfly, Euphydryas phaeton, on an introduced host, Plantago lanceolata (English plantain), and the native host Chelone glabra (white turtlehead). Contrary to the previous findings suggesting that P. lanceolata could be a population sink, we found higher population growth rates (λ) on the introduced than the native host, even though some component parameters of λ were higher on the native host. Our findings illustrate the importance of moving beyond preference-performance studies to integrate vital rates across all life stages for evaluating herbivore-host plant relationships. Single measures of preference or performance are not sufficient proxies for overall host quality nor do they provide insights into longer term consequences of novel host plant use. In our system, in particular, P. lanceolata may buffer checkerspot populations when the native host is limiting, but high growth rates could lead to crashes over longer time scales.

Performance of Western Tent Caterpillar (Malacosoma californicum) on Two Common Host Plants, Including a New Host Plant Record

ABSTRACT. Tent caterpillars are generalists across their full host range, but display local host plant preferences. We present evidence for a new host plant record, wax currant (Ribes cereum), for western tent caterpillars (Malacosoma californicum) along the Colorado Front Range. We tested the suitability of wax currant as a host plant for western tent caterpillars as compared to chokecherry (Prunus virginiana), an abundant and commonly used host plant. We measured the density of tent caterpillar tents in areas where both host plants occur to assess host plant use. We reared tent caterpillar larvae on both host plants and measured fitness effects due to host plant quality (survival, pupal mass) and natural enemies (parasitism). We did not find a relationship between host plant abundance and use by tent caterpillars and found no evidence for a preference for either host plant. We found that western tent caterpillars do not differ in pupal mass when reared on chokecherry and on wax currant in a laboratory s...

Integrative data helps the assessment of a butterfly within the Udranomia kikkawai species complex (Lepidoptera: Hesperiidae): Immature stages, natural history, and molecular evidence

The immature stages of the skipper butterfly Udranomia kikkawai from Brazil are described, including information on host plant use in cerrado savanna, shelter building behavior, and barcode sequences. The caterpillars feed on young leaves of two host food plants, Ouratea spectabilis and Ouratea hexasperma (Ochnaceae). The duration from egg hatching to adult eclosion averaged 30 days. Immature stages of U. kikkawai morphologically resemble those of other Hesperiidae by lacking head horns and complete lack of body scoli, and having a fusiform pupa with uniform color (except for mimetic false eye spots) and no projections. The young-leaf color of Udranomia caterpillars contrasts with that observed in the sister genus Drephalys, whose larvae are conspicuously colored. The food plant of Udranomia is also very uniform: all records are Ochnaceae across the distribution range of Udranomia. Based on molecular data, Brazilian populations correspond to the true U. kikkawai, which is part of a species complex that includes at least two additional undescribed species from Costa Rica. Our paper shows that free access to exchangeable database platforms can raise natural history studies to an integrative level that helps clarify patterns of diversity within taxonomically problematic groups.

Immature Stages ofArchonias brassolis tereas(Godart) (Pieridae: Pierini), with Notes on Interspecific Interactions between Mistletoe Butterflies

ABSTRACT. The immature stages of the Neotropical mistletoe butterfly Archonias brassolis tereas (Godart) (Pieridae: Pierini) are described and illustrated for the first time from the Atlantic Forest of Southeast Brazil. Eggs are laid in clusters on leaves of the mistletoe Phoradendron sp. (Viscaceae). Larvae are gregarious and underwent five instars. Mature caterpillars present yellow aposematic color pattern; pupae are yellow with black dorsal projections. Morphology, host plant use and behavior of immature stages are similar to species in the Catasticta group. An additional species of mistletoe butterfly, Brangas sp. (Lycaenidae), with gregarious and aposematic yellow caterpillars was found in sympatry on the same leaves of the host plant. These findings suggest that both interspecific competition and larval mimicry are important traits in the ecology and evolution of mistletoe butterflies.

Oviposition site selection of the Alcon blue butterfly at the northern range margin

Female oviposition decisions in insects may strongly affect offspring growth and survival, and thus determine population performance. In this study, we examined oviposition site selection in the xerophilous ecotype of the endangered myrmecophilous butterfly Phengaris (=Maculinea) alcon (Lepidoptera, Lycaenidae) in Estonia, at the northern distribution margin of both the butterfly and its host plant, Gentiana cruciata L. Egg distribution on individual host plants appeared to be highly uneven: plants carrying high egg loads contrasted to a high proportion of host plants without any or with a few eggs. Host plant use for oviposition was strongly dependent on plant characteristics and environmental context. Host plant height relative to the surrounding vegetation rather than the absolute height of host plants was a key factor determining the use of particular host plant individuals for oviposition. In particular, plants protruding above surrounding vegetation had a higher probability of being used for oviposition, and carried more eggs. Additionally, the number of eggs laid on individual host plants was positively associated with the presence of flowers and the number of shoots. More aggregated host plants received fewer eggs than those with less conspecifics around. Feeding damage by wild herbivores, found in a substantial proportion of the butterfly’s host plants, strongly reduced the number of eggs on individual plants. Our results underline the need to assure that butterfly’s host plants do not become overgrown by surrounding vegetation. Best practices for opening vegetation around host plants may need further studies that explicitly account for butterfly’s host ants—their abundance in relation to vegetation height and their response to opening vegetation.

A new species of Leurocephala Davis & Mc Kay (Lepidoptera, Gracillariidae) from the Azapa Valley, northern Chilean Atacama Desert, with notes on life-history

The Neotropical micromoth genus Leurocephala Davis & Mc Kay, 2011 (Lepidoptera, Gracillariidae) was originally described to include only the type species, L. schinusae Davis & Mc Kay, 2011, whose leaf miner larvae are associated with Anacardiaceae in Argentina, Brazil and Paraguay. An integrative analysis including morphology, life history and DNA barcode sequences revealed that specimens collected on Schinus molle L. (Anacardiaceae) in the coastal valleys of the Atacama Desert of northern Chile belong to a second species of this formerly monotypic genus. Adults of Leurocephala chilensis Vargas & Moreira sp. nov. are herein described and illustrated in association with the immature stages and life history, and corresponding phylogenetic relationships are assessed based on DNA barcode sequences. This finding provides the first record of Leurocephala from west of the Andes Range, expanding remarkably its geographic range. It is suggested that the extent of diversity within Leurocephala is much greater and that variation in geographic factors and host plant use may have modeled it, an evolutionary hypothesis that should be assessed in further studies.

Host-plants of leaf-miners in Australian subtropical rainforest

Leaf-miners are endophytic insect herbivores that are considered to be relatively host-specific compared with other types of insect herbivores, often depending on one or a few congeneric hosts. Because of their degree of host-specificity, they may be particularly vulnerable to environmental change. Despite this, little is known about the host-plants and life histories of the Australian leaf-mining fauna. Here we present new information on the host-plant use of leaf-miners occurring in Australian subtropical rainforest. We repeatedly hand-collected leaf-miners at 14 sampling sites in the ‘Tweed Caldera’ subtropical rainforest region of south-eastern Queensland and north-eastern New South Wales, Australia. Leaf-miners and their host-plants were identified to species (or morphospecies in the case of some leaf-miners). Within the region, a total of 106 plant species was recorded as leaf-miner hosts, on which a total of 12 679 individual leaf-miners was counted, belonging to 50 different species. We measured the local host-plant range of each leaf-miner species for which we had reliable incidence records across sampling sites (24 species). Local host-specificity was relatively high with 66.7 % of species recorded from a single or two congeneric host-plants. 16.7 % of species were restricted to a single plant family and 16.7 % were recorded on a few to several plants of the same plant order or across a range of unrelated host-plants.

Timing and host plant associations in the evolution of the weevil tribe Apionini (Apioninae, Brentidae, Curculionoidea, Coleoptera) indicate an ancient co-diversification pattern of beetles and flowering plants

Host plant shifts of insects can lead to a burst of diversification driven by their arrival in a new adaptive zone. In this context, our study aims to explore timing and patterns in the evolution of the weevil tribe Apionini (Brentidae, Curculionoidea, Coleoptera), particularly in relation to affiliations with their host plants. The classification of Apionini is difficult because of their relatively uniform appearance. Most taxa live mono- or oligophagously on members of Asteraceae or Fabaceae, but many are associated with other plant families, like Lamiaceae, Malvaceae and Polygonaceae. However, a comprehensive hypothesis of the phylogenetic relationships within the tribe Apionini is still missing. In the present study, we reconstructed trees and estimated divergence times among tribes. These results were further used to reconstruct the ancestral host plant use in Apionini weevils and to infer if the divergence timing of putative subtribes corresponds with the occurrence and radiation of their specific host plant groups. Phylogenetic analyses confirm the monophyly of most subtribes, with the exceptions of Oxystomatina, Kalcapiina and Aspidapiina. The subribe Aplemonina is inferred to be sister to all remaining Apionini. Divergence time estimates indicate the first occurrence of Apionini in the Upper Cretaceous and a simultaneous occurrence of several families of flowering plants and the occupation by Apionini weevil herbivores. These conspicuous coincidences support either an ancient co-diversification scenario or an escalating diversification in weevils induced by the radiation of flowering plants.

Insect symbionts in food webs.

Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont presence might affect food web structure. Many symbionts are now known to help their hosts escape or resist natural enemy attack, and others can allow their hosts to withstand abiotic stress or affect host plant use. In addition to the direct effect of symbionts on aphid phenotypes there may be indirect effects mediated through trophic and non-trophic community interactions. We believe that by using data from barcoding studies to identify bacterial symbionts, this extra, microbial dimension to insect food webs can be better elucidated.This article is part of the themed issue ‘From DNA barcodes to biomes’.

Frugivorous Flies (Diptera: Tephritidae, Lonchaeidae) Associated with Fruit Production on Ilha de Santana, Brazilian Amazon

We conducted a survey of the species of frugivorous flies (Tephritidae and Lonchaeidae), their hosts, and their parasitoids found on Ilha de Santana, Amapa State, Brazilian Amazon. We also assessed host plant use by Bactrocera carambolae Drew & Hancock. Fruits were collected from various plant species, at 30 d intervals, from Jan to Jul 2015. In total, 149 fruit samples were collected (3,142 fruits, 76.3 kg), belonging to 20 plant species (9 native and 11 introduced) in 13 botanical families. Infestation by fruit flies was observed in 86 samples (11 species in 8 botanical families). Specimens of 5 species of Tephritidae and 4 species of Lonchaeidae fruit flies were obtained, as well as 3 species of braconid parasitoids. The most important fruit fly species on Ilha de Santana are: B. carambolae, for being a species of quarantine importance; and Anastrepha obliqua (Macquart) and Anastrepha striata Schiner, for infesting plant species of local socioeconomic importance. Averrhoa carambola (Oxalidaceae), Eugenia uniflora (Myrtaceae), Malpighia emarginata (Moc. & Sesse) ex DC. (Malpighiaceae), and Psidium guajava (Myrtaceae) are the host plants responsible for sustaining the population of B. carambolae.

Population differences in olfaction accompany host shift in Drosophila mojavensis.

Evolutionary shifts in plant-herbivore interactions provide a model for understanding the link among the evolution of behaviour, ecological specialization and incipient speciation. Drosophila mojavensis uses different host cacti across its range, and volatile chemicals emitted by the host are the primary cue for host plant identification. In this study, we show that changes in host plant use between distinct D. mojavensis populations are accompanied by changes in the olfactory system. Specifically, we observe differences in olfactory receptor neuron specificity and sensitivity, as well as changes in sensillar subtype abundance, between populations. Additionally, RNA-seq analyses reveal differential gene expression between populations for members of the odorant receptor gene family. Hence, alterations in host preference are associated with changes in development, regulation and function at the olfactory periphery.

Geography and major host evolutionary transitions shape the resource use of plant parasites

The evolution of resource use in herbivores has been conceptualized as an analog of the theory of island biogeography, assuming that plant species are islands separated by phylogenetic distances. Despite its usefulness, this analogy has paradoxically led to neglecting real biogeographical processes in the study of macroevolutionary patterns of herbivore-plant interactions. Here we show that host use is mostly determined by the geographical cooccurrence of hosts and parasites in spider mites (Tetranychidae), a globally distributed group of plant parasites. Strikingly, geography accounts for most of the phylogenetic signal in host use by these parasites. Beyond geography, only evolutionary transitions among major plant lineages (i.e., gymnosperms, commelinids, and eudicots) shape resource use patterns in these herbivores. Still, even these barriers have been repeatedly overcome in evolutionary time, resulting in phylogenetically diverse parasite communities feeding on similar hosts. Therefore, our results imply that patterns of apparent evolutionary conservatism may largely be a byproduct of the geographic cooccurrence of hosts and parasites.