Caterpillar Species Research Articles

Response of lepidopteran herbivore communities to crop management in coffee plantations

Although the conservation potential of low input coffee plantations has been widely proved, the effect of management intensity on insect herbivores and particularly caterpillar communities has been scarcely studied. We used a management intensity quantitative index to assess changes in leaf damage, abundance of all herbivores and caterpillar species richness, abundance, evenness and community species composition along a management intensity gradient in coffee plantations.There was no correlation between management intensity and the abundance of all herbivore guilds, but there was a negative relationship between management intensity and caterpillar abundance and species richness. Management intensity was positively related to caterpillar species evenness but did not influence species composition, which was rather influenced by climatic seasonality. We found 202 lepidopteran morphospecies, of which 128 fed on coffee plants. Despite a greater caterpillar abundance and richness, mean leaf damage to coffee plants was lower in plantations with a low management intensity index. Overall, we suggest that low and intermediate management intensity and the preservation of a diverse shade canopy can contribute to the conservation of Lepidoptera, without representing significant amounts of leaf damage to coffee plants.

Caterpillar Pests of Tiki Huts and Other Thatched Structures

Two species of caterpillars that eat dried sabal palm leaves have been causing problems with thatched structures. If you’ve got a chickee or are planning to get one, you can take steps to protect the thatch. Learn how to identify and manage the two caterpillar pests in this 4-page fact sheet written by Stephen H. Brown and Lyle J. Buss and published by the UF/IFAS Entomology and Nematology Department.https://edis.ifas.ufl.edu/in1213

Associational Interactions Between Urban Trees: Are Native Neighbors Better Than Non-Natives?

This project investigated associational interactions (associational resistance or susceptibility) between native and non-native trees commonly found in urban landscapes in the southeastern United States. Non-native plants offer limited ecological services because few native herbivore species are capable of feeding on them. In a 2-yr field study, abundance and species richness of caterpillars, plant damage, and herbivore natural enemies were evaluated in plots where a native red maple (Acer rubrum L. [Sapindales: Aceraceae]) was planted singly (no neighbors) or interplanted with either non-native non-congeneric crepe myrtles (Lagerstroemia indica L. [Myrtales: Lythraceae]), non-native congeneric Norway maples (Acer platanoides L. [Sapindales: Aceraceae]), or other red maples. Dryocampa rubicunda Fabricius (Lepidoptera: Saturniidae) accounted for most of the damage and caterpillar abundance. There were few significant differences between treatment groups in the establishment year of 2014, but in 2015 there was greater tree defoliation, caterpillar abundance, and caterpillar species richness when red maples were surrounded by crepe myrtles. We describe this as a biological fence effect in which the presence of crepe myrtle causes caterpillars to accumulate on the focal red maples over multiple generations. Red maples interplanted with Norway maple neighbors hosted an intermediate abundance and species richness of caterpillars compared to red maples interplanted with crepe myrtles and those with other red maples, indicating a spillover of herbivores to the related maple. No significant trends in insect natural enemy abundance or diversity between treatment groups were detected. These results highlight the necessity of considering plant associational interactions in context of species origin to alleviate pest outbreaks and develop sustainable landscape designs.

Diversity of Noctuid Caterpillars belonging to Subfamily Amphipyrinae, Catocalinae, Cuculiinae, Heliothinae, Noctuinae and Plusiinae on Host Crops/Plants of Jammu & Kashmir State (India)

This paper deals with a total of 22 species of 14 genera, belonging to noctuid moth caterpillars, under subfamily Amphipyrinae (2 spp.), Catocalinae (1sp.), Cuculiinae (3 spp.), Heliothinae (2 spp.), Noctuinae (8 spp.) and Plusiinae (6 spp.). These noctuid species have been found to be feeding on 56 spp. of agricultural crops, economically important plants and water weed. Of the total caterpillar species, under 6 sub-families, 14 spp. of various sub-families, excepting Cuculiinae, are associated with different agricultural crops. This accounts for 63.63% of noctuid-fauna studied. The highest number of caterpillar species i.e. 13 (Cuculines, Heliothines, Noctuines and Plusiines), feed on 28 spp. of medicinal / aromatic plants. This is followed by8 spp. of noctuids, devouring vegetable crops (9 spp.). 6 spp. of caterpillars are associated with 4 spp. of cereal / food crops, 4 spp. with legumes (5spp.), 3 spp. feeding fodder crops (3 spp.), 2 spp. each associated with fruit crop/tree (2 spp.), ornamental plants (2 spp.) and rape seed, and 1 sp. each of caterpillar feeding on mulberry and common water hyacinth, belonging to different subfamilies of noctuid moths. An up-to-date systematic Checklist of noctuids, associated with crops and plant species, has been provided. Besides, species diversity of noctuid-fauna on host crops/ plants, has been included.

An Updated Systematic Checklist and Biodiversity of Caterpillars of Butterfly-Fauna (Insecta) on Food/ Host Plant Species in Jammu and Kashmir State (India) - Papilionoidea: Papilionidae, Nymaphalidae

This paper deals with 38 species under 25 genera of butterfly caterpillars, belonging to family Papilionidae and Nymphalidae, feeding on more than 35 host plant species, under 28 genera of 18 families. The food / host plants of caterpillars include agricultural crops and other economically important plant and tree species. The Papilionid caterpillars covered a total of 9 species, associated with 9 species of food/ host species. The 30 species of Nymphalid caterpillars, were found to be having 25 species as their food plants. The highest number of Nymphalid caterpillar species i.e. 9, are associated with family Poaceae (grasses, cereal). This is followed by Papilionids (6 spp.), feeding on aromatic and ornamental plants, and fruit crops (Rutaceae). The highest number of caterpillar species i.e., 15 Nymphalids, Papilionids), is found to be feeding on medicinal plants (18 spp.). An up-to-date systematic checklist, with host plants, has been provided. Besides, species diversity of caterpillar-fauna on food / host plant species has been studied.

An Update on the Systematic Checklist and Biodiversity of Caterpillars of Butterfly-Fauna on Food /Host Plant Species of Jammu & Kashmir State (India) - Papilionoidea: Hesperiidae, Lycaenidae and Pieridae

This paper deals with 23 species, under 15 genera of butterfly caterpillars, belonging to family Hesperiidae, Lycaenidae and Pieridae, associated with 33 species of food / host plant species (agricultural crops and economically important plant species), covering 14 families. The highest number of caterpillar species i.e. 8 (Lycaenids, Pierids) has been found on medicinal plants, followed by 6 spp. (Hesperiids, Pierids) on vegetable crop species. The food crops, fruit crops and ornamental plant species, served as food / host plants for 4 spp. each, pertaining to family Hesperiidae, Lycaenidae and Pieridae. The lowest number of caterpillar species i.e. 2 (Lycaenid, Pierid), is known to be on forest / timber trees. An-up-to date systematic checklist of butterfly caterpillar species, with food/ host plant species, have been provided. Besides, species diversity of caterpillar-fauna on host plant species has been discussed.

THE EFFECTS OF THE ALKALOID SCOPOLAMINE ON THE PERFORMANCE AND BEHAVIOR OF TWO CATERPILLAR SPECIES.

Plants have evolved many defenses against insect herbivores, including numerous chemicals that can reduce herbivore growth, performance, and fitness. One group of chemicals, the tropane alkaloids, is commonly found in the nightshade family (Solanaceae) and has been thought to reduce performance and fitness in insects. We examined the effects of the tropane alkaloid scopolamine, the alkaloid constituent of Datura wrightii, which is the most frequent host plant for the abundant and widespread insect herbivore Manduca sexta in the southwestern United States. We exposed caterpillars of two different species to scopolamine: M. sexta, which has a shared evolutionary history with Datura and other solanceous plants, and Galleria mellonella, which does not. We showed that the addition of ecologically-realistic levels of scopolamine to both the diet and the hemolymph of these two caterpillar species (M. sexta and G. mellonella) had no effect on the growth of either species. We also showed that M. sexta has no behavioral preference for or against scopolamine incorporated into an artificial diet. These results are contrary to other work showing marked differences in performance for other insect species when exposed to scopolamine, and provide evidence that scopolamine might not provide the broad-spectrum herbivore resistance typically attributed to it. It also helps to clarify the coevolutionary relationship between M. sexta and one of its main host plants, as well as the physiological mechanism of resistance against scopolamine.

Ecological diversity of edible insects and their potential contribution to household food security in Haut‐Katanga Province, Democratic Republic of Congo

AbstractDemocratic Republic of the Congo (DR Congo) has a wide diversity of edible insects making it one of the most important biodiversity hot spots in Africa. The aim of this study was to give the first insight into the food plant range, seasonal availability of edible insects, community preference and willingness to consume them. The study revealed a list of eleven edible insect species belonging to four families. Twenty‐six plant species were recorded as food plants of nine edible caterpillar species. Seasonal availability of these insects coincided with the rainy season and was strongly linked to relatively high level of consumption. The caterpillars Elaphrodes lactea Gaede, Lobobunaea saturnus Fabricius and Cinabra hyperbius (Westwood) as well as the termites Macrotermes falciger Gerstäcker were the most dominant species of edible insects preferred and consumed among the different communities. Our study demonstrates that entomophagy is a common practice among the ethnic populations with married, tertiary and university‐level individuals recording significantly higher consumption of edible caterpillars. Populations between the ages of 18 and 45 years as well as the Bemba tribe were also more actively involved in entomophagy. Further research would be necessary to exploit edible insect biodiversity and ethno‐entomophagy and initiate actions for food plant conservation in DR Congo.

Does Aphid Infestation Interfere with Indirect Plant Defense against Lepidopteran Caterpillars in Wild Cabbage?

Attraction of parasitoids to plant volatiles induced by multiple herbivory depends on the specific combinations of attacking herbivore species, especially when their feeding modes activate different defense signalling pathways as has been reported for phloem feeding aphids and tissue feeding caterpillars. We studied the effects of pre-infestation with non-host aphids (Brevicoryne brassicae) for two different time periods on the ability of two parasitoid species to discriminate between volatiles emitted by plants infested by host caterpillars alone and those emitted by plants infested with host caterpillars plus aphids. Using plants originating from three chemically distinct wild cabbage (Brassica oleracea) populations, Diadegma semiclausum switched preference for dually infested plants to preference for plants infested with Plutella xylostella hosts alone when the duration of pre-aphid infestation doubled from 7 to 14 days. Microplitis mediator, a parasitoid of Mamestra brassicae caterpillars, preferred dually-infested plants irrespective of aphid-infestation duration. Separation of the volatile blends emitted by plants infested with hosts plus aphids or with hosts only was poor, based on multivariate statistics. However, emission rates of individual compounds were often reduced in plants infested with aphids plus hosts compared to those emitted by plants infested with hosts alone. This effect depended on host caterpillar species and plant population and was little affected by aphid infestation duration. Thus, the interactive effect of aphids and hosts on plant volatile production and parasitoid attraction can be dynamic and parasitoid specific. The characteristics of the multi-component volatile blends that determine parasitoid attraction are too complex to be deduced from simple correlative statistical analyses.

Plant‐mediated species networks: the modulating role of herbivore density

1. When herbivores of distinct feeding guilds, such as phloem feeders and leaf chewers, interact, the outcome of these interactions often shows facilitation. However, whether this facilitation turns into competition at stronger herbivory pressure remains unknown.2. Using an integrative approach that links ecological processes (behavioural choices of insects) with physiological plant mechanisms (nutrient and phytohormone levels) for the wild crucifer Brassica nigra (L.) Koch., this study evaluates preferences of leaf chewers for plants previously infested with several densities of the specialist aphid Brevicoryne brassicae L. (Hemiptera, Aphididae). As leaf chewers, four species of caterpillars (Lepidoptera) were selected that differ in their degree of specialisation in crucifers.3. These results show that, whereas at low and medium aphid densities caterpillars displayed a preference for aphid‐infested plants or no preference, at high aphid infestation density, all four species of caterpillar preferred uninfested plants, with a significant difference for Pieris rapae and Mamestra brassicae.4. In contrast to our expectation, the consistent preference for uninfested plants at a high aphid density could not be associated with a decrease in plant nutrition. However, while jasmonate concentrations [i.e. 12‐oxo‐phytodienoic acid and jasmonic acid (JA)] at medium aphid‐density infestation decreased compared with low levels of infestation, at high infestation level, the jasmonates JA as well as JA conjugated with the amino acid isoleucine were present at higher levels compared with low‐infestation treatments.5. This work provides evidence that positive interactions observed in herbivore communities can be transient, leading to negative interactions mediated by changes in plant defences rather than in plant nutrition.

Nonpreference ofCeratomia catalpae(Lepidoptera: Sphingidae) to Invertebrate Predators

Aposematic traits such as bright contrasting coloration and gregarious feeding are often signals to predators that a potential prey is unpalatable. Larvae of Ceratomia catalpae (Boisduval) (Lepidoptera: Sphingidae), the catalpa sphinx, show aposematic traits and sequester catalpol, a secondary compound from their host plant Catalpa spp. (Bignoniaceae). Catalpol sequestration by other caterpillar species has been shown to deter both invertebrate and vertebrate predators, but the palatability of C. catalpae has not been explicitly tested. Choice tests were performed with spiders (Hogna carolinensis Walckenaer, Araneae: Lycosidae) and predatory hemipterans (Podisus maculiventris [Say], Hemiptera: Pentatomidae). These tests showed that predators naive to both C. catalpae and the alternate prey Trichoplusia ni (Hubner) (Lepidoptera: Noctuidae) and Manduca sexta (L.) (Lepidoptera: Sphingidae) preferred the alternate species, and that P. maculiventris that were exposed previously to T. ni also preferred T. ni. In nonchoice tests, P. maculiventris grew significantly more slowly upon C. catalpae compared to M. sexta. These results suggest that C. catalpae, like other caterpillars that sequester catalpol, is less palatable to invertebrate predators compared to nonsequestering caterpillar species.

Microbiological Load of Edible Insects Found in Belgium.

Edible insects are gaining more and more attention as a sustainable source of animal protein for food and feed in the future. In Belgium, some insect products can be found on the market, and consumers are sourcing fresh insects from fishing stores or towards traditional markets to find exotic insects that are illegal and not sanitarily controlled. From this perspective, this study aims to characterize the microbial load of edible insects found in Belgium (i.e., fresh mealworms and house crickets from European farms and smoked termites and caterpillars from a traditional Congolese market) and to evaluate the efficiency of different processing methods (blanching for all species and freeze-drying and sterilization for European species) in reducing microorganism counts. All untreated insect samples had a total aerobic count higher than the limit for fresh minced meat (6.7 log cfu/g). Nevertheless, a species-dependent blanching step has led to a reduction of the total aerobic count under this limit, except for one caterpillar species. Freeze-drying and sterilization treatments on European species were also effective in reducing the total aerobic count. Yeast and mold counts for untreated insects were above the Good Manufacturing Practice limits for raw meat, but all treatments attained a reduction of these microorganisms under this limit. These results confirmed that fresh insects, but also smoked insects from non-European trades, need a cooking step (at least composed of a first blanching step) before consumption. Therefore, blanching timing for each studied insect species is proposed and discussed.

Habitat richness and tree species richness of roundabouts: effects on site selection and the prevalence of arboreal caterpillars

This study examined the relationship between the habitat and tree species richness of roundabouts and the abundance and species richness of tree-dwelling caterpillars, and thus the potential of urban roundabouts to support breeding populations. Total tree species number on sites was related to an increase in caterpillar abundance and a greater number of habitats was associated with a higher number of caterpillar species. An increase in the total number of trees was not correlated with a greater abundance of tree-feeding Lepidoptera; nor were native trees found to support proportionally more caterpillar species than all tree species, including introduced. This could be due to differences in species accumulation, the prevalence of generalist species or a statistical sampling effect. The occupancy and average abundance of caterpillar species was generally low, which does not support the theory that Lepidoptera in urban areas tend towards mono-dominance. It may, however, represent the presence of ‘accidental’ species on roundabouts. Habitat management and planting to increase tree species diversity and density on roundabouts has the potential to increase the species diversity and abundance of arboreal Lepidoptera, and increase abundance of butterfly and moth urban populations.

Proximate Composition and Amino Acids of Four Species of Pine Caterpillars (Lepidoptera: Lasiocampidae)

The objectives of the study were to analyze the nutritional composition of some species of pine caterpillars and to encourage utilization of these forest insect pests, therefore, the study constituted part of IPM (Integrated Pest Management) for these forest pests in China. The results showed that the crude protein (CP) content of the pupae of 4 species ranged from 53.55% to 61.26%. The CP content of the adults of 2 species was 58.04% and 68.30% respectively. The fat and the energy content ranged from 19.75 to 26.46% and from 406 to 473 kcal per 100g for the pupae; 6.56 to 24.63% and 327 to 454 kcal per 100g for the adults respectively. As compared with the essential amino acids according to WHO/FAO/UNU pattern, some of the essential amino acids for human adult nutrition are found to be higher than the levels as recommended by WHO/FAO/UNU.

Impact of different preparations on the nutritional value of the edible caterpillar Imbrasia epimethea from northern Angola

In contrast to most European countries, raw and processed insects are a part of the traditional diet in Africa, especially among poor people in rural areas. This paper presents a first nutritional analysis of the caterpillar species Imbrasia epimethea (Drury), which is widely collected and eaten in the Uige Province, northern Angola. Major nutrients were analysed with focus on the impact of different traditional preparation techniques (evisceration, cooking and/or drying). The native larvae revealed similar nutritional values (protein and fat content, amino and fatty acid composition) as Gonimbrasia belina, another member of Lepidoptera, and a higher quality than mealworms and crickets. With respect to more “Western” diets, the protein content of I. epimethea was found to be similar to tuna, chicken and beef, while essential amino acid were lower, resulting in lower essential amino acid indices. Fat contents were lower than in chicken, tuna and beef. Its fatty acid profile, with high percentages of polyunsaturated fatty acids, makes it a valuable contribution to human nutrition. The different preparation methods had only limited impact on the nutritional composition of the caterpillars. The removal of the gut reduced carbohydrates originating from the leaves of the host plant, and thus significantly raised protein and (non-significantly) fat contents. Thermal processing had no significant negative effect on the nutritional value except for the decrease of monounsaturated fatty acids. Thus, I. epimethea represents a valuable traditional alternative to food from other animal sources, especially with regard to its fatty acid composition.

Non-target effects of grass-specific herbicides differ among species, chemicals and host plants in Euphydryas butterflies

Habitat modification by invasive species places numerous butterfly species at risk of extinction. Grass-specific herbicides, graminicides, are a sought-after tool to reduce invasive grasses, augment forbs and enhance butterfly populations. However, possible non-target effects raise concern. We investigated non-target effects of graminicides on three species of caterpillars in the genus Euphydryas (Nymphalidae), a taxon with numerous species in decline worldwide. In one experiment, we compared the effects of three graminicides (clethodim, sethoxydim and fluazifop-p-butyl) on E. colon. In a second experiment, we assessed the effects of fluazifop-p-butyl, the most commonly used graminicide in prairies in the Northwest USA, on three Euphydryas species (E. colon, E. editha and E. phaeton), each raised on two different hostplants. In the first experiment, fluazifop-p-butyl did not affect survivorship of pre-diapause larvae, sethoxydim reduced survivorship by 20 % relative to controls, and effects of clethodim were inconclusive. Graminicides did not change the total concentration of iridoid glycosides in the caterpillars, but all three graminicides increased the concentration of aucubin to almost double the level in control treatments. In the second experiment, the effects of fluazifop-b-butyl were not consistent across butterfly and host plant species. However, fluazifop-b-butyl reduced group size of gregarious pre-diapause larvae under all conditions. Our results suggest that if managers use graminicides over the short-term to control invasive grasses, fluazifop-p-butyl has the most promise for minimal effects. However, efforts should be paired with demographic and behavioral monitoring to quantify context-dependent impacts.

Micro- and Macroevolutionary Trade-Offs in Plant-Feeding Insects.

A long-standing hypothesis asserts that plant-feeding insects specialize on particular host plants because of negative interactions (trade-offs) between adaptations to alternative hosts, yet empirical evidence for such trade-offs is scarce. Most studies have looked for microevolutionary performance trade-offs within insect species, but host use could also be constrained by macroevolutionary trade-offs caused by epistasis and historical contingency. Here we used a phylogenetic approach to estimate the micro- and macroevolutionary correlations between use of alternative host-plant taxa within two major orders of plant-feeding insects: Lepidoptera (caterpillars) and Hemiptera (true bugs). Across 1,604 caterpillar species, we found both positive and negative pairwise correlations between use of 11 host-plant orders, with overall network patterns suggesting that different host-use constraints act over micro- and macroevolutionary timescales. In contrast, host-use patterns of 955 true bug species revealed uniformly positive correlations between use of the same 11 host plant orders over both timescales. The lack of consistent patterns across timescales and insect orders indicates that host-use trade-offs are historically contingent rather than universal constraints. Moreover, we observed few negative correlations overall despite the wide taxonomic and ecological diversity of the focal host-plant orders, suggesting that positive interactions between host-use adaptations, not trade-offs, dominate the long-term evolution of host use in plant-feeding insects.

Caterpillar assemblages onChusqueabamboos in southern Ecuador: abundance, guild structure, and the influence of host plant quality

1. Information on the guild structure of foliage-associated tropical insects is scarce, especially as caterpillars are mostly considered only as herbivores feeding on living leaves. However, many caterpillar species display alternative trophic associations, feeding on dead or withered leaves or epiphylls (‘non-herbivores’). 2. To determine the contribution of these non-herbivores, caterpillar communities associated with Chusquea Kunth (Poaceae) in the Andes of southern Ecuador were investigated. Caterpillars were collected at two elevation levels (montane rainforest ∼2000 m and elfin forest at ∼3000 m a.s.l.) and assigned to three feeding guilds (strict herbivores, non-herbivores, and switchers) based on feeding trials. Foliage quality and leaf area were recorded to test for their influence on guild composition and caterpillar density. 3. Three hundred and eighty-nine individuals belonging to 175 Lepidoptera species associated with Chusquea bamboos were found. The species richness of caterpillars was similarly high at both elevation levels but varied between feeding guilds. Approximately half (46.5%) displayed an alternative feeding association, i.e. were non-herbivores (31.1%) or switchers (15.4%). 4. Caterpillar density was nearly two-fold higher in the elfin forest, but only strict herbivores and switchers increased significantly with elevation. Leaf area positively influenced the density of strict herbivores and switchers; foliage quality only affected strict herbivores. The density of non-herbivores did not differ significantly between the forest types and was not related to leaf area or foliage quality. 5. The present study underpins that non-herbivores make up a considerable fraction of caterpillar communities in tropical mountain ecosystems and demonstrates that elevation, foliage quality and available plant biomass further shape feeding guild composition.

Interactive Effects of Cabbage Aphid and Caterpillar Herbivory on Transcription of Plant Genes Associated with Phytohormonal Signalling in Wild Cabbage.

Plants are commonly attacked by a variety of insect herbivores and have developed specific defenses against different types of attackers. At the molecular level, herbivore-specific signalling pathways are activated by plants in response to attackers with different feeding strategies. Feeding by leaf-chewing herbivores predominantly activates jasmonic acid (JA)-regulated defenses, whereas feeding by phloem-sucking herbivores generally activates salicylic acid (SA)-regulated defenses. When challenged sequentially by both phloem-sucking and leaf-chewing herbivores, SA-JA antagonism may constrain the plant’s ability to timely and adequately divert defense to the second herbivore that requires activation of a different defensive pathway. We investigated the effect of the temporal sequence of infestation by the aphid Brevicoryne brassicae and three caterpillar species, Plutella xylostella, Pieris brassicae, and Mamestra brassicae, on the interaction between JA and SA signal-transduction pathways in three wild cabbage populations. We found no support for SA-JA antagonism, irrespective of the temporal sequence of herbivore introduction or the identity of the caterpillar species based on the transcript levels of the JA- and SA-regulated marker genes LOX and PR-1, respectively, at the examined time points, 6, 24, and 48 h. In general, infestation with aphids alone had little effect on the transcript levels of the two marker genes, whereas the three caterpillar species upregulated not only LOX but also PR-1. Transcriptional changes were different for plants from the three different natural cabbage populations.

Intraspecific phytochemical variation shapes community and population structure for specialist caterpillars.

Summary Chemically mediated plant–herbivore interactions contribute to the diversity of terrestrial communities and the diversification of plants and insects. While our understanding of the processes affecting community structure and evolutionary diversification has grown, few studies have investigated how trait variation shapes genetic and species diversity simultaneously in a tropical ecosystem.We investigated secondary metabolite variation among subpopulations of a single plant species, Piper kelleyi (Piperaceae), using high‐performance liquid chromatography (HPLC), to understand associations between plant phytochemistry and host‐specialized caterpillars in the genus Eois (Geometridae: Larentiinae) and associated parasitoid wasps and flies. In addition, we used a genotyping‐by‐sequencing approach to examine the genetic structure of one abundant caterpillar species, Eois encina, in relation to host phytochemical variation.We found substantive concentration differences among three major secondary metabolites, and these differences in chemistry predicted caterpillar and parasitoid community structure among host plant populations. Furthermore, E. encina populations located at high elevations were genetically different from other populations. They fed on plants containing high concentrations of prenylated benzoic acid.Thus, phytochemistry potentially shapes caterpillar and wasp community composition and geographic variation in species interactions, both of which can contribute to diversification of plants and insects.