Scarabaeid Larvae Research Articles

Exploring interactions between Beauveria and Metarhizium strains through co-inoculation and responses of perennial ryegrass in a one-year trial.

Perennial ryegrass (Lolium perenne L.) possesses a high level of nutritional quality and is widely used as a forage species to establish permanent pastures in southern Chile. However, the productivity of most such pastures is limited by various environmental agents, such as insect pests and drought. In this context, our work stresses the need for elucidating the ability of fungal endophytes to establish interactions with plants, and to understand how these processes contribute to plant performance and fitness. Therefore, we evaluated the colonization and impact of two native strains of the endophytic insect-pathogenic fungus (EIPF) group isolated from permanent ryegrass pastures in southern Chile. Roots and seeds of ryegrass and scarabaeid larvae were collected from nine different ryegrass pastures in the Los Ríos region of southern Chile to specifically isolate EIPFs belonging to the genera Beauveria and Metarhizium. Fungal isolations were made on 2% water agar with antibiotics, and strains were identified by analyzing the entire internal transcribed spacer (ITS) 1-5.8S-ITS2 ribosomal DNA region. Four strains of Beauveria and 33 strains of Metarhizium were isolated only in scarabaeid larvae from ryegrass pastures across four sites. Experimental mini-pastures that were either not inoculated (control) or co-inoculated with conidia of the strains Beauveria vermiconia NRRL B-67993 (P55_1) and Metarhizium aff. lepidiotae NRRL B-67994 (M25_2) under two soil humidity levels were used. Ryegrass plants were randomly collected from the mini-pastures to characterize EIPF colonization in the roots by real-time PCR and fluorescence microscopy. Aboveground biomass was measured to analyze the putative impact of colonization on the mini-pastures’ aboveground phenotypic traits with R software using a linear mixed-effects model and the ANOVA statistical test. Seasonal variation in the relative abundance of EIPFs was observed, which was similar between both strains from autumn to spring, but different in summer. In summer, the relative abundance of both EIPFs decreased under normal moisture conditions, but it did not differ significantly under water stress. The aboveground biomass of ryegrass also increased from autumn to spring and decreased in summer in both the inoculated and control mini-pastures. Although differences were observed between moisture levels, they were not significant between the control and inoculated mini-pastures, except in July (fresh weight and leaf area) and October (dry weight). Our findings indicate that native strains of B. vermiconia NRRL B-67993 (P55_1) and M. aff. lepidiotae NRRL B-67994 (M25_2) colonize and co-exist in the roots of ryegrass, and these had little or no effect on the mini-pastures’ aboveground biomass; however, they could have other functions, such as protection against root herbivory by insect pests.

Variability in nestling diet of European hoopoes: annual and sampling effect

The aim of the study is to get a representative picture of the diet composition of hoopoes in vineyards as specific man made habitats in Central Europe. Therefore diet composition and its interannual variability and the representativeness of two sampling techniques have been studied in hoopoe nestlings, Upupa epops during two breeding periods. Altogether, 1081 prey items were identified and classified into ca. 90 species, 32 families and 11 orders of invertebrates. Regarding interannual variation, the number of prey items per nestbox did not differ between years in the same nestboxes. A within-nest comparison between the two sampling methods revealed a significant difference in the number of prey items for four categories, namely orthopterans, “other beetles”, arachnids and lepidopterans. Comparing the two sampling methods, revealed reversed results regarding the proportion of the main prey categories; e.g. scarabaeid larvae, abundant in the camera samples, were less frequent in faeces, whereas “other beetles” were common in faeces, but were only occasionally detected in the camera recordings. The occurrence of the earthworms in the hoopoe's food is novel. We finally discuss advantages as well as the drawbacks of both methods and the possibility to use both these contrasting, but non-invasive techniques.

Glycolytic Activities in the Larval Digestive Tract of Trypoxylus dichotomus (Coleoptera: Scarabaeidae).

The larvae of the Japanese horned beetle, Trypoxylus dichotomus (Coleoptera: Scarabaeidae: Dynastinae), are an example of a saprophage insect. Generally, Scarabaeid larvae, such as T. dichotomus, eat dead plant matter that has been broken down by fungi, such as Basidiomycota. It is thought that β-1,3-glucan, a constituent polysaccharide in microbes, is abundant in decayed plant matter. Studies of the degradation mechanism of β-1,3-glucan under these circumstances are lacking. In the current study, we sought to clarify the relationship between the capacity to degrade polysaccharides and the food habits of the larvae. The total activities and optimum pH levels of several polysaccharide-degrading enzymes from the larvae were investigated. The foregut, midgut and hindgut of final instar larvae were used. Enzymatic activities were detected against five polysaccharides (soluble starch, β-1,4-xylan, β-1,3-glucan, pectin and carboxymethyl cellulose) and four glycosides (p-nitrophenyl (PNP)-β-N-acetylglucosaminide, PNP-β-mannoside, PNP-β-glucoside and PNP-β-xyloside). Our results indicate that the digestive tract of the larvae is equipped with a full enzymatic system for degrading β-1,3-glucan and β-1,4-xylan to monomers. This finding elucidates the role of the polysaccharide-digesting enzymes in the larvae, and it is suggested that the larvae use these enzymes to enact their decomposition ability in the forest environment.

Cloning and characterization of a novel cry8Ab1 gene from Bacillus thuringiensis strain B-JJX with specific toxicity to scarabaeid (Coleoptera: Scarabaeidae) larvae

Isolation of Bacillus thuringiensis (Bt) strain or its cry gene encoding insecticidal crystal protein (ICP) with specific toxicity is of great importance to biological control of insect pests. In this study, by screening 66 strains of Bt isolated from soil samples collected in Shandong Province, China, a new cry8-type gene from Bt strain B-JJX was identified via PCR-RFLP method. This novel gene, cry8Ab1, was cloned from the Bt strain B-JJX and expressed in an acrystalliferous mutant strain HD-73−. The open reading frame of the cry8Ab1 gene consists of 3543bp with a G+C content of 37.99% and encodes a protein of 1180 amino acids with a putative MW of 133.3kDa which was confirmed by SDS-PAGE analysis. The Cry8Ab1 protein was expressed and released as spherical parasporal crystals from Bt acrystalliferous mutant strain HD-73− along with the presence of spores. In bioassays, this protein was toxic to 3-day-old larvae of the scarabaeid pests, Holotrichia oblita and H. parallela, with an LC50 of 5.72 and 2.00μgtoxing−1soil, respectively. The results are in accordance with the insecticidal activities of the original Bt strain B-JJX, which had an LC50 of 1.72 and 0.96μgtoxing−1soil against H. oblita and H. parallela, respectively.

Multilocus sequence analysis (MLSA) of ‘Rickettsiella costelytrae' and ‘Rickettsiella pyronotae’, intracellular bacterial entomopathogens from New Zealand

Larvae of scarab beetles live in the soil and are frequently hosts for microbial pathogens. In New Zealand, larvae of the grass grub, Costelytrae zealandica (Coleoptera: Scarabaeidae), and manuka beetles, Pyronota spp. (Coleoptera: Scarabaeidae), have been collected from field populations showing loss of vigour and a whitened appearance. Diagnosis indicated an intracellular infection of fat body tissues by Rickettsiella-like micro-organisms. Rickettsiella bacteria are under evaluation as a possible new source of insect bio-control agents for important agricultural pests as, e.g. scarabaeid and elaterid larvae. The present study aimed at the unequivocal molecular taxonomic identification and comparison of the bacteria associated with Costelytra and Pyronota. Electron microscopy and phylogenetic reconstruction using a multilocus sequence analysis approach based on the 16S ribosomal RNA gene together with four protein-encoding markers (ftsY, gidA, rpsA, and sucB) demonstrated that both bacteria from New Zealand are phylogenetically closely related, but not identical, and belong to the taxonomic genus Rickettsiella. The bacteria under study should be referred to as pathotypes 'Rickettsiella costelytrae' and 'Rickettsiella pyronotae', respectively. Moreover, on the basis of the currently accepted systematic organization of the genus Rickettsiella, both pathotypes should be considered synonyms of the nomenclatural type species, Rickettsiella popilliae. The study demonstrates that Rickettsiella bacteria are geographically widespread pathogens of scarabaeid larvae. Implications of the phylogenetic findings presented for the stability of host adaptation by Rickettsiella bacteria are critically discussed.

Microphthalma europaea Egger (Diptera: Tachinidae), a new record for Turkey

Microphthalma europaea Egger (Diptera: Tachinidae) is recorded as a parasitoid of the last instar larvae of Polyphylla fullo (Linnaeus) (Coleoptera: Scarabaeidae). The adult male and female were used for identification, and this is the first known record of this species in Turkey. This is also a first report of a tachinid obtained from scarabaeid larvae in Turkey.

Below-ground host location by Campsomeriella annulata (Hymenoptera: Scoliidae), a parasitoid of scarabaeid grubs

Scoliid wasps are ectoparasitoids that attack soil-dwelling scarabaeid larvae, and little is known about their host-searching behavior. In this study we investigated the cues used in host location by Campsomeriella annulata (Fabricius) and examined whether or not these wasps can detect hosts in the soil from the surface. In a dual-choice test with a Y-tube, female wasps were attracted to sand with host odor, sand with host feces, and sand used for rearing the host, the larvae of Anomala rufocuprea Motschulsky (Coleoptera: Scarabaeidae). In a dual-choice test for cues presented at a distance, the wasps did not discriminate between the Y-tube arms with and without cues. In an experimental arena in which host products and a host grub were buried 0.5 cm below the surface the wasps did not respond to the cues from the surface in terms of the burrowing frequencies and antennal tapping rates. Our results indicate that C. annulata searches for the host grubs by using kairomones, residual cuticular substances, or feces deposited in the soil as the grubs move through it, and that wasps cannot perceive the host in the soil from the surface. We discuss how scoliid wasps search for soil-dwelling hosts using cues that are reliable but not highly detectable.

BACILLUS THURINGIENSIS SPECIFIC TO SCARABAEID BEETLES: A REVIEW

Since the first report of Bacillus sotto by Ishiwata in 1901, thousands of related papers about Bacillus thuringiensis have been documented. In the field of biocontrol of insect pests by this bacterium, after the initial discovery of several B. thuringiensis isolates specific for lepidopteran insects, the isolation of B. thuringiensis israelensis, specific to dipteran larvae by Goldberg and Margalit, and B. thuringiensis tenebrionis, specific to some group of coleopteran insects by Krieg et al. were epoch making advances. In 1992, Ohba et al. isolated B. thuringiensis ja ponensis strain Buibui, which was specific to only scarabaeid larvae. This isolate is the main target of our discussion in this review. These discoveries by which not only B. thuringiensis sciences, but also applied biological control strategies have been enriched, which inspirit us to screen novel isolates. On the other hand, the fields of molecular biology and biochemistry studies on the structural elucidation of toxin proteins and mechanism of action have also tremendously progressed. But the complete mechanism has yet to be solved. For instance, interaction between receptor proteins locating on the plasma membrane of insect midgut epithelial cells and insecticidal proteins has not been fully sketched- In a way, this field is still in chaos. Addressing these exciting and enigmatic subjects will eventually lead to the construction of sustainable agriculture in the 21st century.

Soil dwelling macro-invertebrates in intensively grazed dairy pastures in Pennsylvania, New York and Vermont

This study estimates the relative contributions of environment and farm management strategies in influencing soil faunal assemblages and attempts to identify the species with potential to affect sustainability of intensive grazing management systems in the north-eastern USA. It arises because of the change from confinement feeding of dairy cattle, consequent upon concerns about negative environmental effects, the rising costs for machinery and housing, and reduced profit margins, together with the absence of data from which the consequences of such change on the soil fauna may be predicted. Macro-invertebrates were sampled in soil from seventy-eight grazed pastures on twenty-one dairy farms in Pennsylvania, USA, in the spring of 1994. On five of these farms, macro-invertebrates were sampled (four pastures per farm) in the spring, summer and autumn seasons of 1994, 1995 and 1996. In 1997, macro-invertebrates were sampled in soil during spring, summer and autumn from (four pastures per farm) on three farms in New York, and during spring and summer on three farms in Vermont. Species richness ranged from two to twelve species (mean 6·4) per pasture site in Pennsylvania and five to eighteen species (mean 10·7) in New York and Vermont. The communities were dominated at most sites by earthworms. Earthworms were correlated with soil basal and substrate-induced respiration/carbon ratio, and soil moisture, but were negatively correlated with cows per hectare and herbage biomass in Pennsylvania. Sitona larvae were recorded at nineteen of the twenty-one farms during the spring of 1994 across Pennsylvania and occurred at populations >5 m−2 in 68% of the sampled pastures. Sitona larvae were less abundant in New York and Vermont. Elaterid larvae comprised a complex of seven species of which Aeolus melillus (Say) and Melanotus communis (Gyllenhal) comprised 35% and 39%, respectively, of the elaterids collected in Pennsylvania. Agriotes mancus (Say) and Ctenicera destructor (Brown) comprised 41% and 26%, respectively, of four species collected in New York and Vermont. Scarabaeid larvae, comprising a complex of eight species, were detected at only 27% of the seventy-eight pastures sampled in spring 1994 in Pennsylvania. Five species were collected in ten of the twelve New York pastures and four species in nine of the twelve Vermont pastures. Populations of scarabaeid larvae averaged <25 m−2 in all three states, except in three Pennsylvania pastures in spring 1994. Detrended canonical correspondence analysis (DCCA) showed pasture standing biomass, legume diversity, pre-winter stubble height, white clover pasture content, and soil phosphorus levels influenced numbers of invertebrate species more than climatic factors, such as temperature, rainfall, altitude, latitude and seasonal water table. DCCA also showed most pastures to be close to the average of environmental factors. The extremely low density of herbivorous macro-invertebrates in soil and the absence of pest outbreaks may indicate a stable soil ecosystem.

Bacillus thuringiensis Strain Buibui for Control of Cupreous Chafer, Anomala cuprea (Coleoptera: Scarabaeidae), in Turfgrass and Sweet Potato

Abstract The efficacy of the toxin from Bacillus thuringiensis serovar japonensis (strain Buibui), which is specific to scarabaeid larvae, was evaluated in turfgrass pots. The toxin controlled first and second instars of the cupreous chafer, Anomala cuprea , at 2 mg protein/pot and the greenness of the turfgrass did not deteriorate. On the other hand, the efficacy against the third instar was less than that against the first and second instars, and the greenness and dry weight of the turfgrass were reduced. However, the mortality against the third instar was 48% compared with 8% for the control. In the field, the effectiveness of the Buibui toxin was evaluated in sweet potato plots. The ratio of damaged potatoes in the treated plots with the Buibui toxin was 31% compared with 69% for the control plots. The index of damage to sweet potato in the treated and untreated plots was 23 and 55, respectively. These results suggest that the toxin at 100 mg/m 2 effectively controlled the cupreous chafer in the sweet potato fields.

Milky Disease Bacterium as a Stressor to Increase Susceptibility of Scarabaeid Larvae to an Entomopathogenic Nematode

Mortality of Cyclocephala hirta by the entomopathogenic nematode Heterorhabditis bacteriophora was enhanced in grubs infected with the milky disease bacterium, Bacillus popilliae (Bp). In concentration-response assays with the nematode, LC50 values and 95% fiducial limits were 4.0 (<0.1, 14.6) infective juveniles per grub for Bp-infected insects and 47.7 (32.0, 64.7) for non-Bp-infected insects. The increased mortality of Bp-infected insects was partially attributed to rapid penetration of H. bacteriophora through the midgut wall. In in vitro assays with ligated midguts, the time required for H. bacteriophora to penetrate the midgut wall of Bp-infected grubs was 0.6 ± 0.1 hr, whereas the time required in non-Bp-infected grubs was 1.3 ± 0.1 hr. Total nematode progeny production per milligram grub tissue did not differ significantly between Bp-infected and non-Bp-infected grubs. However, the proportion of progeny remaining trapped in the non-Bp-infected cadavers at the end of the assay was greater than the proportion remaining in Bp-infected cadavers (0.52 ± 0.04 vs 0.13 ± 0.05, respectively). These data indicate that coexistence of these two pathogens within a host can occur and that B. popilliae could be used as a stressor on C. hirta to increase its susceptibility to H. bacteriophora.

Insecticidal spectrum of a novel isolate of Bacillus thuringiensis serovar japonensis

A newly isolated strain, designated Buibui, belonging to Bacillus thuringiensis serovar japonensis had potent larvicidal activity against the scarabaeids Anomala cuprea Hope and Popillia japonica Newman. Preliminary tests indicated that other scarabaeid larvae including A. albopilosa Hope, A. rufocuprea Motschulsky, A. daimiana Harold, A. schonfeldti Ohaus, Mimela splendens (Gyllenhal), and Blitopertha orientalis (Waterhouse) were equally susceptible to strain Buibui. However, the strain showed no insecticidal activity against larval lepidopteran insects including Bombyx mori (L.) (Bombycidae), Plutella xylostella (L.) (Plutellidae), Spodoptera litura Fabricius, S. exigua Hübner (Noctuidae), and Adoxophyes sp. (Tortricidae) and coleopterans, Allomyrina dichotoma L. (Scarabaeidae) and Henosepilachna vigintioctopunctata Fabricius (Coccinellidae). At 14 days post-treatment, the LC 50 and LC 95 of the δ-endotoxin against the cupreous chafer, A. cuprea , were estimated by probit analysis as 0.098 ± 0.019 and 0.29 ± 0.086 μg protein/g compost, respectively. Strain Buibui showed no β-exotoxin activity.

Control of scarabaeid larvae in groundnut fields by soil applying cow-compost and cow-dungs with pesticides

Control of scarabaeid larvae in groundnut fields by soil applying cow-compost and cow-dungs with pesticides

Effect of application of green wheats and a pesticide &ldquo;MPP&rdquo; into ridges for controlling scarabaeid larvae in a sweet potato field

Effect of application of green wheats and a pesticide &ldquo;MPP&rdquo; into ridges for controlling scarabaeid larvae in a sweet potato field

Evidence of Enhanced Degradation of Isofenphos in Turfgrass Thatch and Soil

Supernatant from aqueous dispersions of turfgrass thatch and soil from four Ohio golf courses where spring application of isofenphos (Oftanol) failed to control summer-generation scarabaeid larvae, were injected into a buffered nutrient solution of 10 ppm isofenphos. High-pressure liquid chromatography analysis showed that isofenphos disappeared (91 to ≥99%) in ≤3 d, whereas no degradation occurred with samples from an untreated site. Methods described may be useful in elucidating the enhanced degradative potential of certain other pesticides.

Biomass of Larval Scarabaeidae (Coleoptera) in Relation to Grazing Pressures in Temperate, Sown Pastures

SUMMARY (1) Four years' data on the biomass of scarabaeid larvae in eighteen 1.2 ha pastures were obtained by a plough technique. The pastures were grazed continuously with approximately eight, twelve and sixteen sheep ha-', using two breeds and three lambing times, in factorial combination. (2) A highly significant quadratic relation was found to exist between total scarabaeid biomass (log scale) and 'grazing pressure'. This was defined as the number of Merino ewes ha-' multiplied by 1. 15 if the lambing time was spring, and again by 1-15 if instead the sheep were Dorset Horn. These factors were determined from the data for total scarabaeid biomass. (3) The total biomass of scarabaeids peaked at a grazing pressure of 12.9, which was equivalent to approximately twelve breeding Merino ewes ha-', on pastures sown to Phalaris aquatic L. and Trifolium repens L. However, over the range from ten to fifteen in grazing pressure there was little systematic variation in scarabaeid biomass. (4) The dominant genera Anoplognathus and Sericesthis each showed significant quadratic relations to grazing pressure, but Antitrogus numbers were insufficient to exhibit any systematic effect. (5) The clover content of the pastures, although affected by grazing pressures, appeared to have no significant effect on the biomass of larval scarabaeids.

Effect of application of green wheat to control scarabaeid larvae in the field of sweet potato, with special reference to weather conditions

Effect of application of green wheat to control scarabaeid larvae in the field of sweet potato, with special reference to weather conditions

LABORATORY STUDIES OF THE FOOD PREFERENCES OF SOME ORCHARD CARABIDS (COLEOPTERA: CARABIDAE)

AbstractLaboratory studies of the food preferences of several adult carabids showed thatAmara aeneaDeG.,Anisodactylus sanctaecrucisF.,Harpalus affinisSchr., andStenolophus commaF. were polyphagous and readily fed on the seeds of several weeds as well as on young codling moth larvae and apple maggot pupae.H. affinisalso attacked 4th and 5th instar codling moth larvae and pupae more readily than the other species.Pterostichus melanariusIII. showed a strong preference for the larger prey such as 5th instar codling moth larvae, earthworms, and scarabaeid larvae. The potential of these species as predators of the codling moth and the apple maggot is discussed.

First record of transantarctic relationships in the Tachinidae (Diptera, Muscoidea, Calyptratae)

The Trichoprosopini (Tachinidae, Tachininae) from Southern Chile are considered in this paper a sister group tribe of the New Zealand Cccisorini, both tribes being parasitic on Scarabaeid larvae. This is a new evidence of transan-tarctic relationships in the Calyptrate Muscoidea.

The influnce of the application of organic matters to sweet potato field on the occurrence of scarabaeid larvae

The influnce of the application of organic matters to sweet potato field on the occurrence of scarabaeid larvae