Raymond V. Barbehenn's research while affiliated with University of Michigan and other places

Publications (50)

Article
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The rapid growth and prolific reproduction of many insect herbivores depend on the efficiencies and rates with which they acquire nutrients from their host plants. However, little is known about how nutrient assimilation efficiencies are affected by leaf maturation or how they vary between plant species. Recent work showed that leaf maturation can...
Article
The growth rates of insect herbivores commonly decrease when they feed on mature leaves due to the combined effects of several nutritional and physiological mechanisms. Environmental stresses during leaf development may also decrease herbivore performance. The present study tests two main hypotheses to help clarify the importance of these factors f...
Article
The efficient aquisition of nutrients from leaves by insect herbivores increases their nutrient assimilation rates and overall fitness. Caterpillars of the gypsy moth (Lymantria dispar L.) have high protein assimilation efficiencies (PAE) from the immature leaves of trees such as red oak (Quercus rubra) and sugar maple (Acer saccharum) (71–81%) but...
Article
Full-text available
In plant–ant–hemipteran interactions, ants visit plants to consume the honey-dew produced by phloem-feeding hemipterans. If genetically based differences in plant phloem chemistry change the chemical composition of hemipteran honeydew, then the plant's genetic constitution could have indirect effects on ants via the hemipterans. If such effects cha...
Article
Lymantria dispar L. caterpillars have a decreased ability to assimilate protein from mature leaves of red oak (Quercus rubra) compared with young, expanding leaves. The present study determines whether the drop in protein assimilation efficiency (PAE) occurs during the rapid phase of leaf maturation. Several mechanisms that might account for decrea...
Article
Synergistic combinations of plant allelochemicals are commonly believed to increase their effectiveness as defenses against insect herbivores. For example, temperate deciduous trees produce large amounts of phenolic compounds (primarily tannins), but many of these trees also produce smaller amounts of other potentially toxic compounds. This study t...
Article
Sulfur amino acids [cysteine (Cys) and methionine (Met)] play two major roles during animal development: protein synthesis for growth and glutathione synthesis for defense. For caterpillars, the levels of sulfur amino acids found in foliar protein can be especially low relative to their nutritional needs. Previous work has measured concentrations o...
Article
The nutritional value of alternative host plants for leaf-feeding insects such as caterpillars is commonly measured in terms of protein quantity. However, nutritional value might also depend on the quality of the foliar protein [i.e., the composition of essential amino acids (EAAs)]. A lack of comparative work on the EAA compositions of herbivores...
Article
The essential amino acids (EAAs) arginine, histidine, lysine, and methionine, as well as cysteine (semiessential), are believed to be susceptible to reactions with reactive oxygen species (ROS) in biological systems. The decreased availability of these EAAs could harm insect nutrition, since several of them can also be limiting for protein synthesi...
Article
The rapid growth of insects that feed on tree leaves in the spring is believed to be due to high nutritional quality. This study tested the hypothesis that both high nutritional quality and low levels of oxidative stress (i.e., toxicological effects) benefit caterpillars that feed in the spring. Fourth-instar larvae of Lymantria dispar (Lepidoptera...
Article
Silicon (Si) is a useful indigestible marker in plants for measuring food consumption and nutritional indices. Si concentrations in HF:HCl extracts of small (5–20 mg) samples may be measured easily using atomic emission spectroscopy. The Si marker and gravimetric methods were compared using Lymantria dispar (L.) larvae fed artificial diet with 2.5%...
Article
Tannins are the most abundant secondary metabolites made by plants, commonly ranging from 5% to 10% dry weight of tree leaves. Tannins can defend leaves against insect herbivores by deterrence and/or toxicity. Contrary to early theories, tannins have no effect on protein digestion in insect herbivores. By contrast, in vertebrate herbivores tannins...
Article
Full-text available
Peroxidases (PODs) are believed to act as induced and constitutive defenses in plants against leaf-feeding insects. However, little work has examined the mode of action of PODs against insects. Putative mechanisms include the production of potentially antinutritive and/or toxic semiquinone free radicals and quinones (from the oxidation of phenolics...
Article
The high levels of tannins in many tree leaves are believed to cause decreased insect performance, but few controlled studies have been done. This study tested the hypothesis that higher foliar tannin levels produce higher concentrations of semiquinone radicals (from tannin oxidation) in caterpillar midguts, and that elevated levels of radicals are...
Article
The ability of foliar tannins to increase plant resistance to herbivores is potentially determined by the composition of the tannins; hydrolyzable tannins are much more active as prooxidants in the guts of caterpillars than are condensed tannins. By manipulating the tannin compositions of two contrasting tree species, this work examined: (1) whethe...
Article
Tannins are believed to function as plant defenses against caterpillars, in part, as a result of their oxidation in the midgut lumen. One putative mode of action that has not been examined in leaf-feeding larvae is oxidative stress in midgut tissues that results from tannin oxidation in the midgut lumen. The test species used in this study, Malacos...
Article
Full-text available
Ascorbate is the major water-soluble antioxidant in plants and animals, and it is an essential nutrient for most insect herbivores. Therefore, ascorbate oxidase (AO) has been proposed to function as a plant defense that decreases the availability of ascorbate to insects. This hypothesis was tested by producing transgenic poplar (Populus tremula x P...
Article
Tannins are believed to function as antiherbivore defenses, in part, by acting as prooxidants. However, at the high pH found in the midguts of caterpillars, the oxidative activities of different types of tannins vary tremendously: ellagitannins > galloyl glucoses > condensed tannins. Ingested ascorbate is utilized by caterpillars to minimize phenol...
Chapter
Plant polyphenol oxidases (PPOs) are widely distributed and well-studied oxidative enzymes, and their effects on discoloration in damaged and diseased plant tissues have been known for many years. The discovery in C.A. Ryan's laboratory in the mid-1990s that tomato PPO is induced by the herbivore defense signals systemin and jasmonate, together wit...
Article
Polyphenol oxidase (PPO) is commonly believed to function as an effective antiherbivore defense in plants. PPO is induced in plants following herbivory, and insect performance is often negatively correlated with PPO levels. However, induced defenses create numerous changes in plants, and very little work has been done to test the direct effects of...
Article
We examined whether tannin composition plays an important role in explaining the oxidative activities of tree leaves of Acer saccharum (sugar maple) and Quercus rubra (red oak). Sugar maple leaves contained substantial amounts of ellagitannins, condensed tannins, and galloyl glucoses, whereas red oak leaves contained almost exclusively condensed ta...
Article
Plants synthesize a diversity of tannin structures but little is known about whether these different types have different oxidative activities in herbivores. Oxidative activities of hydrolyzable and condensed tannins were compared at pH 10 with two methods: EPR spectrometry was used to quantify semiquinone radicals in anoxic conditions and a spectr...
Article
Leaf-chewing insects are commonly believed to be unable to crush the nutrient-rich bundle sheath cells (BSC) of C4 grasses. This physical constraint on digestion is thought to reduce the nutritional quality of these grasses substantially. However, recent evidence suggests that BSC are digested by grasshoppers. To directly assess the ability of gras...
Article
Peroxides are formed in the midgut fluids of caterpillars when ingested tannins and other phenolic compounds oxidize. If these peroxides broke down in the presence of redox-active metal ions, they would form damaging free radicals (Fenton-type reactions). Elemental iron is present in relatively large amounts in leaves and artificial diets, but litt...
Article
Phenolic compounds are generally believed to be key components of the oxidative defenses of plants against pathogens and herbivores. However, phenolic oxidation in the gut fluids of insect herbivores has rarely been demonstrated, and some phenolics could act as antioxidants rather than prooxidants. We compared the overall activities of the phenolic...
Article
The peritrophic envelope (PE) is an extracellular matrix that is secreted by the midgut epithelium in most arthropods. In addition to protecting the midgut epithelium from abrasive food particles and microbial pathogens, in vitro experiments have suggested that the PE functions as a radical-scavenging antioxidant in caterpillars. This study tested...
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Grasses with the C3 photosynthetic pathway are commonly considered to be more nutritious host plants than C4 grasses, but the nutritional quality of C3 grasses is also more greatly impacted by elevated atmospheric CO2 than is that of C4 grasses; C3 grasses produce greater amounts of nonstructural carbohydrates and have greater declines in their nit...
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It is plausible that the nutritional quality of C3 plants will decline more under elevated atmospheric CO2 than will the nutritional quality of C4 plants, causing herbivorous insects to increase their feeding on C3 plants relative to C4 plants. We tested this hypothesis with a C3 and C4 grass and two caterpillar species with different diet breadths...
Article
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The increasing CO2 concentration in Earth's atmosphere is expected to cause a greater decline in the nutritional quality of C3 than C4 plants. As a compensatory response, herbivorous insects may increase their feeding disproportionately on C3 plants. These hypotheses were tested by growing the grasses Lolium multiflorum C3) and Bouteloua curtipendu...
Article
The seasonal decline in foliar nutritional quality in deciduous trees also effects the availability of essential micronutrients, such as ascorbate and α-tocopherol, to herbivorous insects. This study first examined whether there are consistent patterns of seasonal change in antioxidant concentrations in deciduous tree leaves. α-Tocopherol concentra...
Article
Polyphagous grasshoppers consume plants that contain markedly greater amounts of potentially prooxidant allelochemicals than the grasses eaten by graminivorous grasshoppers. Therefore, levels of antioxidant defenses maintained by these herbivores might be expected to differ in accordance with host plant ranges. Antioxidant levels were compared in m...
Article
The biological activity of phenolic compounds ingested by caterpillars is commonly believed to result from their oxidation, although the products of oxidation have been well-characterized in only a few cases. The initial oxidation products of phenols (semiquinone or phenoxyl radicals) can be measured with electron paramagnetic resonance (EPR) spect...
Article
Graminivorous species of grasshoppers develop lethal lesions in their midgut epithelia when they ingest tannic acid, whereas polyphagous grasshoppers are unaffected by ingested tannins. This study tests the hypothesis that polyphagous species are defended by higher activities of antioxidant enzymes (constitutive or inducible) in their guts than are...
Article
Four mechanisms by which peritrophic membranes (PMs) potentially protect herbivorous insects from ingested allelochemicals are reviewed: adsorption, ultrafiltration, polyanion exclusion, and the capacity of PMs to act as antioxidants. Most of the research on the protective roles of PMs against ingested allelochemicals has focused on their impermeab...
Article
Tomato ( Lycopersicon esculentum ) cultivars were transformed with genes that encode bacterial chitinolytic enzymes (i.e., endochitinase and chitobiosidase) from Streptomyces albidoflavus . Transgenic tomato plants producing these enzymes were found to have enhanced resistance to cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), co...
Article
This study demonstrates that an ascorbate-recycling system in the midgut lumen can act as an effective antioxidant defense in caterpillars that feed on prooxidant-rich foods. In tannin-sensitive larvae of the forest tent caterpillar, Malacosoma disstria (Lasiocampidae), ingested tannic acid is oxidized in the midgut lumen, generating significant qu...
Article
The role of the peritrophic envelope in the non-absorption of three allelochemicals ingested by generalist grasshoppers was examined. This study tested the hypothesis that the association of lipophilic and amphiphilic allelochemicals with lipid aggregates (mixed micelles) reduces their permeability through the peritrophic envelope, a process simila...
Article
Magnesium and calcium ions, in concentrations comparable to those reported in the midgut fluids of lepidopteran larvae, bring about the precipitation of most of the tannic acid present in simple solutions buffered at pH 8.0 and 10.0, but not at pH 6.5. In contrast, when tannic acid is added to Manduca sexta midgut fluid, less than 31% of the tannic...
Article
We tested the hypothesis that the permeability of the peritrophic envelope in herbivorous insects is greatly reduced for polyanions as a result of an extensive network of anionic sites in the proteoglycans of the matrix. 14C-Dextran sulfate (polyanionic, 8000 M(w)) and fluorescein isothiocyanate-labeled (FITC) dextran (monoanionic, 9400 M(w)) were...
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We examined several of the mechanisms that have been reported to enable polyphagous grasshoppers (Orthoptera: Acrididae) to tolerate ingested hydrolyzable tannins: hydrolysis, adsorption on the peritrophic envelope, and peritrophic envelope impermeability. None of these mechanisms explain the tolerance of Melanoplus sanguinipes to ingested tannic a...
Article
The ninhydrin method has been used widely for measuring amino acids in hydrolysed purified proteins. It is also a useful method of measuring the total amino acid or protein content of hydrolysed plant samples. In this study the conditions used in a modified ninhydrin method were found to incompletely hydrolyse protein. Therefore, standard condition...
Article
A sensitive method was developed for measuring the size and flux of marker substances that permeate the peritrophic envelopes (PEs) of insects. Seven species of herbivorous insects were fed polydisperse fluorescein isothiocyanate-labeled dextrans (FITC-dextrans), and the average size and amount of FITC-dextrans that diffused through their PEs were...
Article
Final-instar Malacosoma disstria fed artificial diets containing tannic acid develop lethal pupal deformities. We examined some of the factors potentially underlying tannin sensitivity in this species, including the permeability of the peritrophic envelope to tannic acid and the chemical fate of tannic acid in the gut. Tannic acid does not penetrat...
Article
Tannic acid had no detrimental effect on the growth rates or digestion efficiencies of Orgyia leucostigma larvae. We examined three potential mechanisms which might allow these larvae to tolerate ingested tannic acid. (1) Little chemical modification of ingested tannic acid was found. Less than 10% of the tannic acid ingested by O. leucostigma was...
Article
Full-text available
We tested the hypothesis that C 4 grasses are inferior to C 3 grasses as host plants for herbivorous insects by measuring the relative performance of larvae of a graminivorous lepidopteran, Paratrytone melane (Hesperiidae), fed C 3 and C 4 grasses. Relative growth rates and final weights were higher in larvae fed a C 3 grass in Experiment I. Howeve...
Article
Cynodon dactylon (Poaceae) leaf pieces recovered from the frass of final-instar Paratrytone melane larvae (Lepidoptera: Hesperiidae) were composed of 14–22 percent crushed cells and 78–86 percent uncrushed cells, yet approximate digestibilities of soluble carbohydrates and protein averaged 78 and 88 percent, respectively. Therefore, nutrients from...
Article
Full-text available
Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/42714/1/10667_2004_Article_BF00185646.pdf
Article
Larvae ofUresiphita reversalis feed almost exclusively on legumes in the tribe Genisteae, which characteristically contain a variety of quinolizidine alkaloids. The larvae are aposematic, and onGenista monspessulana, a major host in California, they feed on the youngest leaves, at the periphery of the plant. These leaves, which were preferred over...
Article
A preliminary assessment was made of a variety of approaches to dosing insects with compounds that normally deter feeding. Enclosing water-soluble compounds in liposomes has promise for strong deterrents, although in drinking assays many deterrents lose their potency anyway. Microencapsulating compounds by embedding them in a polymer matrix to form...
Article
Feeding preference assays that lasted 6 hours were used to test a range of plant secondary compounds for deterrence to Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae), a grass-feeding armyworm. Preference was determined by relative amounts of treated and control material consumed. In these assays, about half of the compounds were deterrent...

Citations

... Previous studies reported on variations of macroelement concentrations (N, P, K, Ca, Na) in leaves of different pedunculate oak genotypes as a result of the interaction of a certain genotype and environmental factors [55]. Furthermore, foliar nutritional quality changes greatly during leaf maturation, as well as insect assimilation efficiency of compounds such as carbohydrates and proteins [56]. Along with these differences, the variability in nutrient amounts between plant species and even within a single plant (leaf maturity, for example) suggests that most insect herbivores facing heterogeneous nutritional sources regulate their nutrient intake [23]. ...
... The fibers in the leaves themselves are formed during growth. Pandan leaves with older age will have a higher fiber content compared to young leaves as a result of metabolism [22]. WAC ability of pandan leaves powder dependent on the amount and nature of the water / hydrophilic binding component [23]. ...
... Diet quality and quantity are key determinants of insect development and immunity (Klemola et al., 2007;Mason et al., 2014;Barbehenn et al., 2015;Borzoui et al., 2017). Nutrient balance, protein, carbohydrate, secondary metabolites, and water are among the factors determining the diet quality (Kraus et al., 2019). ...
... Furthermore, host plant identity and quality influence the outcome of ant-hemipteran associations. Plant secondary metabolites and nutrients vary among and within plant species, affecting hemipterans not only directly but also indirectly through effects on honeydew composition and thus hemipteran ability to attract ants (Pringle et al. 2014). For instance, although ants increase the average abundance of the aphid Aphis asclepiadis on milkweed (Asclepias syriaca) by 59%, such effects depend strongly on milkweed genotype, and ants are even antagonists (i.e., they reduce aphid abundance) on more than one-third of plant genotypes due to varying concentrations of plant toxins in aphid honeydew (Züst & Agrawal 2017). ...
... Preference and performance of folivorous insects vary depending on plant leaf quality [3,46]. Due to generalist feeding habit and high mobility, GM larvae encounter large inter-and intra-specific variation in nutritional, allelochemical, and morphological attributes of their hosts [22,33,35,[47][48][49][50]. High quality plants that are nutritionally adequate and contain low level of toxic secondary metabolites are commonly preferred by GMs, improve their fitness, affect interaction with other environmental factors, and thus population dynamics and probability of outbreaks [8,51,52]. ...
... It was fascinating to discover that small weevils could have most of their body protein tied up in the cuticle! With a postdoc and a German chemist, we showed that quinolizidine alkaloids were important in a caterpillar species, Uresiphita reversalis, on the weed French broom (62). We had worked on it as a potential weed control agent, but the ecology demonstrated that its sensitivity to high levels and intensity of rainfall limited its ability to control spread of the plant. ...
... The glutathione level was affected by the combined treatment of phenolics with a saponin and an alkaloid, supporting the fact that a "combination" of secondary metabolites can be more useful for plant protection. Test larvae which were exposed to ellagitannins and phenolics showed a greatly enhanced reactive oxygen level in their midgut [54] (Table 1). ...
... Despite the highest SLM, high nitrogen and low C/N ratio in Turkey oak partly explain why it is an optimal host compared to beech and hornbeam. Barbehenn et al. [61] showed that decreased nitrogen during leaf maturation was related with decreased GM performance. Numerous literature data show that hornbeam and beech leaves contain secondary metabolites [22,[62][63][64] which provoke avoidance behavior in GM larvae [32,65] and negatively affect GM larval growth and nutritional indices [22,33,34,37,66]. ...
... Due to the relative toxicity of this sulphur-containing amino acid [24], free cysteine makes up only a small proportion of total free amino acids, about 0.3% for the control larvae and even less in Brassicaceae-fed larvae. It is suggested that in lepidopteran caterpillars more than 20% of the insect s total cysteine is allocated to GSH [25], making this an invaluable and limiting substance. Hence, the limitations in cysteine availability consequently limit GSH for detoxification; however, critical minimal levels must be maintained for a balanced metabolism to ensure redox homeostasis, on the one hand, and the formation of new proteins for growth or enzymes for essential bioreactions, on the other. ...
... Apis mellifera adult workers have higher peritrophic matrix permeability (70 kDa) than M. quadrifasciata (40 kDa). Differences in the pore size of the peritrophic matrix in different species of the same insect order have been reported in Diptera, which have pores between 4 and 10 nm (Peters and Wiese, 1986;Terra and Ferreira, 1993;Casu et al., 1997) and in Lepidoptera with pores between 24 and 650 nm (Adang and Spence, 1983;Santos et al., 1986;Barbehenn and Martin, 1995;Lehane, 1997;Toprak et al., 2013). In R. americana only digestive enzymes 70 kDa with a diameter of 5.8-5.9 ...