Beetle Feeding Research Articles

Evaluation of a <i>Brassica napus</i> Auxin-Repressed Gene Induced by Flea Beetle Damage and <i>Sclerotinia sclerotiorum</i> Infection

Biotic stresses negatively affect canola growth and production. Flea beetle damage and Sclerotinia sclerotiorum (S. sclerotiorum) infection are two of the worst biotic stresses for canola. Auxin Repressed Proteins (ARPs) responsive to several abiotic stresses have been reported. However, information about ARPs induced by Flea beetle damage and S. sclerotiorum infection, their roles in biotic stress tolerance are still lacking in canola. ESTs for an Auxin Repressed Protein 1 (BnARP1) were highly represented (expressed) in a Brassica napus subtractive library developed after leaf damage by the crucifer flea beetle (Phyllotreta cruciferae). Expression of this gene was under different developmental control in B. napus, and it was co-induced in B. napus by flea beetle feeding, S. sclerotiorum infection, drought and cold. A total of 25 BnARP genes were represented in different B. napus stress and development EST libraries and indicated larger, diversified families than known earlier. Dwarf phenotypes, primary root growth inhibition, lateral root enhancement, reduced sensitivity to 2, 4-D, and reduced PIN1 and LOX expression in transgenic Arabidopsis expression lines suggest that BnARP1 is an auxin repressor that prevents auxin transport and supports an interaction between the auxin and jasmonate signalling pathways. And the increased survival after S. sclerotiorum infection in transgenic over-expression Arabidopsis suggests that BnARP1 could play a role in S. sclerotiorum tolerance through connecting auxin and jasmonate signalling pathways.

Sound-Triggered Production of Antiaggregation Pheromone Limits Overcrowding ofDendroctonus valensAttacking Pine Trees

For insects that aggregate on host plants, both attraction and antiaggregation among conspecifics can be important mechanisms for overcoming host resistance and avoiding overcrowding, respectively. These mechanisms can involve multiple sensory modalities, such as sound and pheromones. We explored how acoustic and chemical signals are integrated by the bark beetle Dendroctonus valens to limit aggregation in China. In its native North American range, this insect conducts nonlethal attacks on weakened trees at very low densities, but in its introduced zone in China, it uses mixtures of host tree compounds and the pheromone component frontalin to mass attack healthy trees. We found that exo-brevicomin was produced by both female and male D. valens, and that this pheromone functioned as an antiaggregating signal. Moreover, beetles feeding in pairs or in masses were more likely than were beetles feeding alone to produce exo-brevicomin, suggesting a potential role of sound by neighboring beetles in stimulating exo-brevicomin production. Sound playback showed that an agreement sound was produced by both sexes when exposed to the aggregation pheromone frontalin and attracts males, and an aggressive sound was produced only by males behaving territorially. These signals triggered the release of exo-brevicomin by both females and males, indicating an interplay of chemical and sonic communication. This study demonstrates that the bark beetle D. valens uses sounds to regulate the production of an antiaggregation pheromone, which may provide new approaches to pest management of this invasive species.

Degradation capacities of bacteria and yeasts isolated from the gut of Dendroctonus rhizophagus (Curculionidae: Scolytinae).

Bark beetles (Curculionidae: Scolytinae) feed on the xylem and phloem of their host, which are composed of structural carbohydrates and organic compounds that are not easily degraded by the insects. Some of these compounds might be hydrolyzed by digestive enzymes produced by microbes present in the gut of these insects. In this study, we evaluated the enzymatic capacity of bacteria (Acinetobacter lwoffii, Arthrobacter sp., Pseudomonas putida, Pseudomonas azotoformans, and Rahnella sp.) and yeasts (Candida piceae, Candida oregonensis, Cyberlindnera americana, Zygoascus sp., and Rhodotorula mucilaginosa) isolated from the Dendroctonus rhizophagus gut to hydrolyze cellulose, xylan, pectin, starch, lipids, and esters. All isolates, with the exception of C. piceae, showed lipolytic activity. Furthermore, P. putida, P. azotoformans, C. americana, C. piceae, and R. mucilaginosa presented amylolytic activity. Esterase activity was shown by A. lwoffii, P. azotoformans, and Rahnella sp. Cellulolytic and xylanolytic activities were present only in Arthrobacter sp. and P. azotoformans. The pectinolytic activity was not recorded in any isolate. This is the first study to provide evidence on the capacity of microbes associated with the D. rhizophagus gut to hydrolyze specific substrates, which might cover part of the nutritional requirements for the development, fitness, and survival of these insects.

Toxicity and efficacy of novel biopesticides for organic management of cucumber beetles on Galia muskmelons

Spotted (Diabrotica undecimpunctata howardi) and striped (Acalymma vittata) cucumber beetles are significant pests of cucurbits, and organic management options are limited. Beetle feeding results in aesthetic damage and reduction in marketable yields as well as transmission of bacterial wilt resulting in plant mortality. Biopesticides are formulated from naturally occurring organisms such as fungi and bacteria that are pathogenic or toxic to insect pests and may be used in organic production systems. These products are thought to have lower risk to non-target organisms including mammals and beneficial insects. This research examined the potential of novel microbial products and fungal organisms to reduce cucumber beetle damage on melons. Laboratory bioassays were performed to evaluate the efficacy of a bacterial extract of Chromobacterium subtsugae and two common strains of entomopathogenic fungi, Beauveria bassiana and Isaria fumosorosea, on cucumber beetles in a controlled environment. Trials were performed against adult beetles in organic field experiments on muskmelon (Cucumis melo L. cv. reticulatus Ser.). Prior to testing in the field, anti-feedant effects were observed when beetles were exposed to leaves with Chromobacterium subtsugae and Beauveria bassiana in the laboratory. However, in field applications, we did not observe a reduction in beetle populations below the economic threshold levels, and subsequently, there was no yield increase compared to the control. Additional research is needed to improve biopesticide efficacy through formulation and timing of delivery, determine efficacy on multiple life stages of the pest, and understand interactions of microbial biopesticides in the environment and potential for non-target impacts in organic systems.

Trade‐offs and tritrophic consequences of host shifts in specialized root herbivores

Summary Trade‐offs in an herbivore's ability to feed, avoid predation and succeed on alternative hosts are thought to be major driving factors in host specialization. In this study, we compared how two closely related milkweed beetles (Tetraopes spp.) that have specialized on separate Asclepias species respond to host switching to alternative milkweed plants. By additionally examining effects on the beetles’ entomopathogenic natural enemies, we test whether host plant specialization is driven by plant–herbivore interactions alone or whether there is a role for the tritrophic interactions. Tetraopes beetles feed on milkweed roots as larvae and on milkweed shoots as adults, and they sequester toxic cardenolides from their host plants. We predicted that growth and sequestration would be compromised on alternative hosts as a consequence of specialization. Larvae of each Tetraopes species were reared on their native host plant, the host plant of the other species and two closely related Asclepias species that do not typically host Tetraopes. Regardless of beetle specialization, survival of both beetles was highest on A. syriaca, which has the second‐to‐lowest levels of root cardenolides and is the native host for T. tetraophthalmus. Larval growth was not affected by host plant for T. texanus, but T. tetraophthalmus grew best on A. exaltata, a close relative of A. syriaca that does not typically experience beetle feeding. We found that larval sequestration of cardenolides largely mirrored host plant values in the roots, with the exception of T. texanus on A. asperula, which sequestered a low proportion of the cardenolides from this host. Although all larvae were susceptible to entomopathogenic nematodes (EPNs), the number of EPNs emerging from cadavers depended on the beetle–plant combination, with more EPNs produced when beetles were feeding on native compared to non‐native hosts. The observed consequences for tritrophic interactions did not fit expectations for specialized herbivores (i.e. EPN predation was highest when beetles were on their native hosts), suggesting that specialization may be driven primarily by a plant–herbivore interaction in this system, not by a tritrophic effect. A Lay Summary is available for this article.

Phylogeny of the Gondwanan beetle family Ulodidae (Tenebrionoidea).

Ulodidae is a small family of saproxylic and fungus feeding beetles restricted to New Zealand, Australia, Chile and New Caledonia. The phylogeny of this family is presented for the first time, based on a cladistic analysis of 53 adult characters from 16 ulodid genera, rooted with Parahelops Waterhouse (Promecheilidae). The topology shows Arthopus Sharp at the base of the tree and confirms the placement of Meryx Latreille as a member of Ulodidae and closely related to the Chilean genus Trachyderas Philippi & Philippi. The extinct New Zealand genus Waitomophylax Leschen & Rhode was placed among a clade consisting of Brouniphylax Strand, Exohadrus Broun, and Pteroderes Germain. Two new genera and two new species are described: Ulobostrichus gen. n. (type species: Ulobostrichus monteithi sp. n.) and Ulocyphaleus gen. n. (type species: Cyphaleus valdivianus Philippi & Philippi, 1864, now U. valdivianus (Philippi & Philippi) n. comb.; U. laetus sp. n.). Dipsaconia pyritosa Pascoe is designated as the type species of Dipsaconia Pascoe and a lectotype was designated for C. valdivianus. A fully illustrated key to the genera and a checklist of the 16 genera and 42 species is included. Based on the phylogeny, the following characters are derived in the family: tuberculate body surface and the presence of scales and /or encrustations. The presence of pore-fields in the abdominal cuticle has evolved at least three times in Meryx Latreille (Australia), Syrphetodes Pascoe (New Zealand) and Trachyderastes Kaszab (New Caledonia).

Management of Chinese Rose Beetle (Adoretus sinicus) Adults Feeding on Cacao (Theobroma cacao) Using Insecticides.

The Chinese rose beetle (Adoretus sinicus Burmeister (Coleoptera: Scarabaeidae)) is an introduced, widely-established pest in Hawai’i. The adult beetles feed on the leaves of cacao (Theobroma cacao L.), which can lead to defoliation and even death of young trees. We evaluated the impact of five commercially available products with different active ingredients (imidacloprid, azadirachtin, Beauveria bassiana (Bals.-Criv.) Vuill., kaolin clay, and pyrethrin) and the presence or absence of weed mat cover in reducing adult beetle feeding on sapling cacao in the field. The use of weed mat cover reduced feeding damage compared to the untreated control, as did foliar application of imidacloprid, azadirachtin, and B. bassiana. In the laboratory, field-collected adult beetles were presented cacao leaf samples dipped in one of the five products and compared to a control. Beetles exposed to pyrethrin died rapidly. Among the other treatments, only exposure to imidacloprid significantly reduced survival relative to the control. Beetles fed very little on leaf samples with azadirachtin but their longevity was not significantly reduced. Imidacloprid, azadirachtin, and weed mat application had the most promise for reducing adult Chinese rose beetle feeding damage in young cacao and deserve further investigation for successful management of this significant pest.

Reflective Polyethylene Mulch Reduces Mexican Bean Beetle (Coleoptera: Coccinellidae) Densities and Damage in Snap Beans.

Mexican bean beetle, Epilachna varivestis Mulsant, is a serious pest of snap beans, Phaseolus vulgaris L., in the eastern United States. These beetles are intolerant to direct sunlight, explaining why individuals are typically found on the undersides of leaves and in the lower portion of the plant canopy. We hypothesized that snap beans grown on reflective, agricultural polyethylene (plastic mulch) would have fewer Mexican bean beetles and less injury than those grown on black plastic or bare soil. In 2014 and 2015, beans were seeded into beds of metallized, white, and black plastic, and bare soil, in field plots near Blacksburg, VA. Mexican bean beetle density, feeding injury, predatory arthropods, and snap bean yield were sampled. Reflected light intensity, temperature, and humidity were monitored using data loggers. Pyranometer readings showed that reflected light intensity was highest over metallized plastic and second highest over white plastic; black plastic and bare soil were similarly low. Temperature and humidity were unaffected by treatments. Significant reductions in Mexican bean beetle densities and feeding injury were observed in both metallized and white plastic plots compared to black plastic and bare soil, with metallized plastic having the fewest Mexican bean beetle life stages and injury. Predatory arthropod densities were not reduced by reflective plastic. Metallized plots produced the highest yields, followed by white. The results of this study suggest that growing snap beans on reflective plastic mulch can suppress the incidence and damage of Mexican bean beetle, and increase yield in snap beans.

Efficacy of Entomopathogenic Nematodes and Sprayable Polymer Gel Against Crucifer Flea Beetle (Coleoptera: Chrysomelidae) on Canola.

The crucifer flea beetle, Phyllotreta cruciferae (Goeze), is a key pest of canola (Brassica napus L.) in the northern Great Plains of North America. The efficacies of entomopathogenic nematodes (Steinernema spp. and Heterorhabditis spp.), a sprayable polymer gel, and a combination of both were assessed on canola for flea beetle management. Plots were treated soon after colonization by adult flea beetles, when canola was in the cotyledon to one-leaf stage. Ten plants along a 3.6-m section of row were selected and rated at pre-treatment and 7 and 14 d post treatment using the damage-rating scheme advanced by the European Plant Protection Organization, where 1 = 0%, 2 = 2%, 3 = 5%, 4 = 10%, and 5 = 25% leaf area injury. Under moderate flea beetle feeding pressure (1-3.3% leaf area damaged), seeds treated with Gaucho 600 (Bayer CropScience LP Raleigh, NC) (imidacloprid) produced the highest yield (843.2 kg/ha). Meanwhile, Barricade (Barricade International, Inc. Hobe Sound, FL) (polymer gel; 1%) + Scanmask (BioLogic Company Inc, Willow Hill, PA) (Steinernema feltiae) resulted in the highest yields: 1020.8 kg/ha under high (2.0-5.3% leaf area damaged), and 670.2 kg/ha at extremely high (4.3-8.6 % leaf area damaged) feeding pressure. Our results suggest that Barricade (1%) + Scanmask (S. feltiae) can serve as an alternative to the conventional chemical seed treatment. Moreover, Scanmask (S. feltiae) can be used to complement the effects of seed treatment after its protection has run out.

Modification of plant‐induced responses by an insect ecosystem engineer influences the colonization behaviour of subsequent shelter‐users

Summary Herbivores that modify plant morphology, such as gall‐forming insects, can disproportionately impact arthropod community on their host plants by providing novel habitats and shelters from biotic and abiotic stresses. These ecosystem engineers could also modify plant chemical properties, but how such changes in plant quality affect the behaviour of subsequent colonizers has rarely been investigated. We explored how an initial infestation of the tall goldenrod (Solidago altissima) by an ecosystem engineer, the rosette gall‐midge (Rhopalomyia solidaginis), affects colonization behaviour of a shelter‐using beetle (Microrhopala vittata) through plant‐induced responses in the field. Beetles preferentially colonized plants with galls and exhibited a clumped distribution on those plants, which suggested a possible advantage for aggregating on galled plants. Accordingly, we found that beetles remained longer on galled plants with previous beetle damage than those without beetle damage. No such effect of beetle damage was found on plants without a gall. Similar interactions between galler infestation and beetle damage were found in beetle's feeding choice, leaf diterpene and serine protease inhibitor production, and volatile organic compound (VOC) emission. These plant metabolic induction and herbivore response patterns indicated that the gall‐midge can alter how plants respond to the beetle damage and that gall presence coupled with beetle damage improves leaf palatability for the beetle. Finally, we found reciprocal effects of beetles on gall‐midge performance to be neutral to slightly positive, suggesting that the observed field association of the two herbivores could be formed by plant‐mediated facilitation. Synthesis. Our study suggests that an ecosystem engineer could have significant impact on herbivore community not only by changing plant morphology, but also by altering host quality and modifying plant‐induced responses to subsequent herbivory. As such, R. solidaginis also functions as a keystone herbivore that has disproportionate effects on community dynamics and composition meditated by induced plant growth and metabolic responses.

Field growth traits and insect-host plant interactions of two transgenic canola (Brassicaceae) lines with elevated trichome numbers

AbstractPlant growth and insect resistance characteristics were determined for two Brassica napus Linnaeus (Brassicaceae) lines, AtGL3+ and K-5-8, developed for enhanced trichome densities relative to their parental cultivar Westar. In the field, both transgenic lines had glabrous cotyledons that curled upwards at emergence but flattened with time, and young leaves with elevated trichome density. Flea beetle (Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (Fabricius); Coleoptera: Chrysomelidae) feeding was reduced on true leaves of both lines by 30–50% compared with insecticide-free Westar. Flea beetle feeding levels on cotyledons of the two hairy-leaved lines were lower than on unprotected Westar and similar to those seen on insecticide-treated Westar. Antixenosis and antibiosis resistance was observed when diamondback moths (Plutella xylostella (Linnaeus); Lepidoptera: Plutellidae) interacted with the hairy AtGL3+ and K-5-8 lines in the laboratory. Although the numbers of eggs laid by female diamondback moths on the transformed lines were similar to or higher than on Westar, in feeding bioassays larvae moved off AtGL3+ plants and larval feeding injury decreased on the transformed lines compared with Westar leaves. No agronomic or seed yield penalties were found for plants of K-5-8. These data highlight the utility of manipulating trichome regulatory genes to increase plant resistance against brassicaceous insect pests.

Herbivore dung as food for dung beetles: elementary coprology for entomologists

1. How do dung beetles and their larvae manage to subsist on herbivore dung consisting of plant remains that are at least partly indigestible, mixed with various metabolic waste products? To clarify what is known and not known about this basic aspect of dung beetle biology, the present review summarises information on dung composition and discusses the feeding of beetles (food: fresh dung) and larvae (food: older dung) in relation to this information.2. There is 70–85% water in typical fresh dung, and undigested lignocellulose or ‘fibre’ constitutes about 70% of the organic matter which also contains 1.5–3%N. About 75% of this is ‘metabolic faecal nitrogen’, mostly associated with dead and alive microbial biomass. As all essential amino acids and cholesterol are probably present, additional synthesis by microbial symbionts may not be needed by the beetles.3. Beetles minimise the intake of lignocellulose by filtering fibre particles out of their food which is probably microbial biomass/debris with much smaller particle size. Excess fluid may be squeezed out of this material by the mandibles before ingestion.4. All larvae are bulk feeders and unable to filtrate, but little is known about the composition of their food, i.e. older dung in pats or underground brood masses. Larvae in dung pats may depend on easily digestible dung components, probably microbial biomass, whereas the nutritional ecology of larvae in brood masses is still not understood. Unravelling the composition of their food might answer some of the so far unanswered questions.

Beetle community response to residual forest patch size in managed boreal forest landscapes: Feeding habits matter

Forest fragmentation by management activities has been implicated in the decline of forest biodiversity. Even though boreal ecosystems are generally deemed quite resilient to disturbance effects, high contemporary levels of disturbance might push forest-interior species toward decline or extinction. In this study, we examined beetle communities in forest patches of different sizes, including clearcuts, residual postharvest patches from 0.03 to 50ha in size, and large mature forest tracts (>1000ha). Overall, community structure follows a gradient between clearcuts and large mature forest tracts, even if patch size effects were more difficult to detect among patches >2.5ha. Beetles were most abundant in clearcuts, and species richness was highest in small tree groups (0.03–0.05ha). The effects of fragmentation were strongly conditioned by beetle feeding habits. Predators and xylophagous beetles were mostly associated with clearcuts or smaller patches (i.e., small tree groups or large tree groups [0.3–0.5ha]), whereas fungivorous beetles were associated with forest-interior habitats. Although many forest-interior species were still present in relatively small patches 1–5years after harvesting, negative effects of habitat fragmentation on these species might increase in the long-term.

Effects of food source quality on the adults of Melolontha melolontha and M. hippocastani

Abstract This paper presents the results of studies on the life span, survival, weight and fecundity of the forest cockchafer (Melolontha hippocastani, Fabricius, 1801) and the common cockchafer (Melolontha melolontha, Linnaeus, 1758) beetle feeding on Alnus glutinosa (L.) Gaertn., Betula pendula Roth., Carpinus betulus L., Fagus sylvatica L., Larix decidua Mill., Prunus serotina (Ehr.) Borkh., Quercus petraea (Matt.) Liebl., Quercus robur L., Robinia pseudoacacia L., Sambucus nigra L. and Sorbus aucuparia L. em. Hedl. The lifespan and weight of beetles as well as female fertility were examined in 2011 and 2013. Specimen for laboratory tests were collected in the field shortly after leaving their overwintering sites in the soil and identical experimental protocols were applied to both examined species. 576 and 432 beetles were tested in 2011 and 2013, respectively. In 2011, beetles were feeding on A. glutinosa, B. pendula, F. sylvatica, L. decidua Q. petraea leaves and on C. betulus, P. serotina, R. pseudoacacia, S. aucuparia and S. nigra in 2013. Both years, beetles feeding on Q. robur leaves were examined as a control. Our results showed that feeding on leaves of Q. robur and Q. petraea had the largest positive impact on the life time, weight and fecundity of the studied beetles. Leaves of F. sylvatica and L. decidua also constituted an adequate food source for the development of M. melolontha. M. hippocastani, however, did not perform as well when feeding on these two tree species. Females of M. melolontha reared on leaves of B. pendula did not lay eggs. The following plant species had a negative impact on the survival and development of the collected specimen and female fertility: A. glutinosa, S. nigra, P. serotina and R. pseudoacacia. Neither beetle species fed on the leaves of A. glutinosa or S. nigra.

Genetic architecture underlying host choice differentiation in the sympatric host races of Lochmaea capreae leaf beetles.

Speciation in herbivorous insects has received considerable attention during the last few decades. Much of this group's diversity originates from adaptive population divergence onto different host plants, which often involves the evolution of specialized patterns of host choice behaviour. Differences in host choice often translates directly into divergence in mating sites, and therefore positive assortative mating will be created which will act as a strong barrier to gene flow. In this study, we first explored whether host choice is a genetically determined trait in the sympatric willow and birch host races of the leaf feeding beetle Lochmaea capreae, or whether larval experience influences adult host choice. Once we had established that host choice is a genetically based trait we determined its genetic architecture. To achieve this, we employed a reciprocal transplant design in which offspring from pure willow and birch cross-types, F1, F2 and backcrosses were raised on each host plant and their preference was determined upon reaching adulthood. We then applied joint-scaling analysis to uncover the genetic architecture of host preference. Our results suggest that rearing host does not have a pronounced effect on adult's host choice; rather the segregation pattern implies the existence of genetic loci affecting host choice in these host races. The joint-scaling analysis revealed that population differences in host choice are mainly influenced by the contribution of additive genetic effects and also maternally inherited cytoplasmic effects. We explore the implications of our findings for evolutionary dynamics of sympatric host race formation and speciation.

Direction of interaction between mountain pine beetle (Dendroctonus ponderosae) and resource-sharing wood-boring beetles depends on plant parasite infection.

Plant pathogens can have cascading consequences on insect herbivores, though whether they alter competition among resource-sharing insect herbivores is unknown. We experimentally tested whether the infection of a plant pathogen, the parasitic plant dwarf mistletoe (Arceuthobium americanum), on jack pine (Pinus banksiana) altered the competitive interactions among two groups of beetles sharing the same resources: wood-boring beetles (Coleoptera: Cerambycidae) and the invasive mountain pine beetle (Dendroctonus ponderosae) (Coleoptera: Curculionidae). We were particularly interested in identifying potential mechanisms governing the direction of interactions (from competition to facilitation) between the two beetle groups. At the lowest and highest disease severity, wood-boring beetles increased their consumption rate relative to feeding levels at moderate severity. The performance (brood production and feeding) of mountain pine beetle was negatively associated with wood-boring beetle feeding and disease severity when they were reared separately. However, when both wood-boring beetles and high severity of plant pathogen infection occurred together, mountain pine beetle escaped from competition and improved its performance (increased brood production and feeding). Species-specific responses to changes in tree defense compounds and quality of resources (available phloem) were likely mechanisms driving this change of interactions between the two beetle groups. This is the first study demonstrating that a parasitic plant can be an important force in mediating competition among resource-sharing subcortical insect herbivores.

The (w)hole story: Facilitation of dead wood fauna by bark beetles?

Facilitation between species is thought to be a key mechanism in community assembly and diversity, as certain species create microhabitats for others. A profound characteristic of forest ecosystems is a large amount of dead wood which is colonised by a vast array of invertebrate species. Bark beetles (Scolytinae) feed and breed on dying or dead trees, puncturing holes into the bark and engraving inner bark and outer wood with their galleries. These holes and galleries might facilitate other invertebrates by providing access to the inner bark for shelter, feeding and reproduction. We tested this hypothesised facilitative interaction during the early decomposition phase of coarse woody debris of spruce (Picea abies L. Karst.) incubated in two environmentally contrasting forest sites in the ‘common garden’ experiment LOGLIFE. We sampled invertebrates in 25 cm diameter logs at different degrees of colonisation by bark beetles. Our results indicated that (1) bark beetles facilitated the entrance into spruce logs of other invertebrates with body width that matched the size of bark-beetle holes, and (2) the abundance of invertebrates was often positively related to the proportional surface area of inner bark consumed by bark beetles, but more so in the nutrient-rich site than in the nutrient poor site. This study provides the first quantitative test of facilitation between invertebrate clades in dead wood communities. Including facilitative interaction in community assembly studies may change some predictions about relationships between tree functional traits and invertebrate diversity and will lead to a more accurate and comprehensive understanding of dead wood communities.

Evaluation of Kaolin Clay as an Alternative Management Tactic for Japanese Beetle Feeding Damage in Grape Vineyards

The Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), is an exotic, introduced Scarab that has become one of the most widespread and destructive insect pest of turf, landscapes and nursery crops in the eastern United States. It also damages various fruit, garden and field crops. Evaluation of certain conventional and non-conventional control agents in a Wisconsin vineyard revealed that bifenthrin, a fourth generation synthetic pyrethroid, provided the greatest Japanese beetle adult control in choice and no-choice feeding bioassays. Bacillus thuringiensis gallariae (Btg) was also effective in both bioassays. However, Btg residual activity was relatively limited; its performance decreased five days after treatment. Kaolin clay provided effective Japanese beetle adult management via consistent adult feeding damage mitigation in both study years. Field tests showed that various application Kaolin clay rates were effective in minimizing feeding damage by Japanese beetle adults, and no adverse effects were observed on several important fruit quality characteristics such as sugar content (Brix), acidity, number of fruit produced per plant and fruit weight. Kaolin clay is an alternative, non-insecticide management tactic that can be employed by grape growers to minimize feeding damage by Japanese beetle adults and reduce the amount of conventional insecticide input needed to maintain grape quality.

Wplyw wodnych wyciag�w z bylicy piolunu (Artemisia absinthium L.) na zerowanie wybranych szkodnik�w roslin uprawnych i ich reakcje na zapach tej rosliny

The aim of this study was to determine the effect of water extracts from fresh and dry matter of Artemisia absinthium L. on the feeding of selected pests. Moreover their reactions on the smell of this plant by using the olfactometer were examined. Beetles feeding intensity assessment was carried out by measuring the surface of feeds caused by Sitona lineatus L. In the case of Acyrthosiphon pisum Harris contact poisoning on mortality of adults and larvae were tested. In determining the effect of extracts of A. absinthium L. on Leptinotarsa decemlineata Say. food weight eaten by adult beetles and larvae and changes in larvae body weight were established. In studies on the olfactory reaction of above mentioned insects, for S. lineatus and L. decemlineata glass olfactometer Y-tube was used and for winged A. pisum females - 4-armed arena olfactometer. The results of the experiment showed that extract from dry matter of A. absinthium L. at concentration of 10% greatly reduced feeding of Sitona lineatus L. The highest mortality of A. pisum Harris was observed in objects in which extracts from dry and fresh matter of the highest concentrations (10% and 30% respectivelly) were applied. Extract from fresh matter in concentration of 30% made the greatest contribution to reduce feeding of L. decemlineata Say, while extract made from the dry matter at concentration of 10% significantly contributed to reduce the weight of food eaten by the larvae of this pest. Studies using the olfactometer showed a strong deterring reaction of odors derived from A. absinthium L. in relation to S. lineatus (both males and females) and males of L. decemlineata Say.

Structure of Phoretic Mite Assemblages Across Subcortical Beetle Species at a Regional Scale.

Mites associated with subcortical beetles feed and reproduce within habitats transformed by tree-killing herbivores. Mites lack the ability to independently disperse among these habitats, and thus have evolved characteristics that facilitate using insects as transport between resources. Studies on associations between mites and beetles have historically been beetle-centric, where an assemblage of mite species is characterized on a single beetle species. However, available evidence suggests there may be substantial overlap among mite species on various species of beetles utilizing similar host trees. We assessed the mite communities of multiple beetle species attracted to baited funnel traps in Pinus stands in southern Wisconsin, northern Arizona, and northern Georgia to better characterize mite dispersal and the formation of mite-beetle phoretic associations at multiple scales. We identified approximately 21 mite species totaling 10,575 individuals on 36 beetle species totaling 983 beetles. Of the mites collected, 97% were represented by eight species. Many species of mites were common across beetle species, likely owing to these beetles' common association with trees in the genus Pinus. Most mite species were found on at least three beetle species. Histiostoma spp., Iponemus confusus Lindquist, Histiogaster arborsignis Woodring and Trichouropoda australis Hirschmann were each found on at least seven species of beetles. While beetles had largely similar mite membership, the abundances of individual mite species were highly variable among beetle species within each sampling region. Phoretic mite communities also varied within beetle species between regions, notably for Ips pini (Say) and Ips grandicollis (Eichhoff).