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Methyl benzoate is a natural product (floral volatile organic compound) that is currently used as a food flavoring ingredient. This compound has shown to be insecticidal in laboratory studies against agricultural and urban pests, including spotted wing drosophila Drosophila suzukii, brown marmorated stink bug Hyalomorpha halys, the diamondback moth Plutella xylostella, and the common bed bug Cimex lectularius, to name several insect taxa. In this study we topically treated adult Aedes aegypti females with methyl benzoate and analogs and determined their toxicities. We found that among adult females, 4 analogs—butyl benzoate, n-pentyl benzoate, vinyl benzoate, and methyl 3-methoxybenzoate—were more toxic than the parent compound, methyl benzoate.

We evaluated a botanical compound, methyl benzoate, which was previously shown to have insecticidal activity on several agricultural pests, for its behavioral action on the common bed bug, Cimex lectularius L. Methyl benzoate, along with acetophenone and Cirkil™, a commercially available bed bug control product, exhibited repellent action against bed bugs in an EthoVision video system designed to track the movement of individuals.

Nutrition is important in honey bee (Apis mellifera L.) colony decline. While the honey bee is incapable of converting dietary plant sterols to cholesterol, the sterol 24-methylenecholesterol has b...

Common bed bug Cimex lectularius (L.) (Hemiptera: Cimicidae) infestations are on the rise and due to the development of pesticide resistance they are becoming more difficult to control, affordably. We evaluated a naturally occurring compound methyl benzoate (MB) and related analogs, previously reported to have insecticidal activity on several agricultural pests, for its fumigant action on the common bed bug, C. lectularius L. A discriminating concentration was used to determine the effectiveness of MB, and several of its analogs as fumigants in a laboratory assay. It was found that MB provided >90% control of adult bed bugs in this laboratory fumigant assay. LC50 values were calculated for MB against both a pyrethroid-susceptible and a pyrethroid-resistant strain of common bed bugs. It was determined that both strains were susceptible in this laboratory assay. However, when MB was tested in a field-like assay and compared to a commercially available bed bug control product, it was found to be significantly less effective compared to the commercial product. Our study has found that while MB has the potential to be used as a bed bug control agent, refinements in the delivery system will be needed to increase efficacy under field-like conditions.

Flonicamid is a systemic pesticide that inhibits the feeding of certain greenhouse pests and certain hemipteran pests of agricultural crops. In a laboratory study directed at the common bed bug (Cimex lectularius L.), flonicamid (as Aria®) was evaluated for its ability to either kill or inhibit the feeding of this blood-sucking pest. After flonicamid was applied topically (by spray), as a residual (to bed bug harborages), or fed directly to bed bugs by incorporating the insecticide into the bloodmeal, mortality assessments were made and surviving bed bugs were given the opportunity to feed on untreated blood. At the recommended label rates and at rates that approached the solubility limits of the product in water, it was concluded that this insecticide would be ineffective in a bed bug control program.

Accurate and timely surveillance of bed bug infestations is critical for the development of effective control strategies. Although the bed bug-produced volatiles (E)-2-hexenal and (E)-2-octenal are considered as defensive secretions, the present study demonstrates, using ethovision® video-tracking software (Noldus Information Technology Inc., Leesburg, Virginia), that low amounts of these commercially-obtained aldehydes function as attractants, and high amounts function as local repellents, against the common bed bug Cimex lectularius L. In behavioural assays, both males and female C. lectularius are attracted to 0.04 µg of an aldehyde blend (1 : 1) for up to 1 h after initial treatment of filter paper disks. Males differ from females in their response to higher amounts of aldehydes, with females and males exhibiting maximum local repellency at 40 µg and 400 µg, respectively. The results suggest that these bed bug secretions may be candidates for lures and monitors.

To determine whether volatiles from bed bug eggs were similar to the defensive secretions from nymphs and adults, headspace volatiles from eggs of the common bed bug (Cimex lectularius L.) were collected by aeration, daily until hatch, and subsequently analyzed by gas chromatography-mass spectrometry. We now report that eucalyptol (1,8-epoxy-p-menthane) was identified from all egg samples. Blank control samples containing no eggs had no evidence of eucalyptol. Positive controls, containing nymphs, adults, and fecal deposits, showed the presence of the defensive secretions (E)-2-hexenal and (E)-2-octenal, but no eucalyptol. The lack of detectable (E)-2-hexenal and (E)-2-octenal in viable egg samples and the detection of eucalyptol are discussed in relation to canine detection of bed bugs.

The two major aldehydes (E)-2-hexenal and (E)-2-octenal emitted as defensive secretions by bed bugs Cimex lectularius L. (Hemiptera: Cimicidae), inhibit the in vitro growth of an isolate of Metarhizium anisopliae sensu lato (s.l.) (Metsch.) Sokorin (Hypocreales: Clavicipitaceae) (ARSEF 1548). These chemicals inhibit fungal growth by direct contact and via indirect exposure (“fumigation”). Fumigation with (E)-2-octenal for as little as 0.5 h was sufficient to inhibit all fungal growth. Bed bugs placed on filter paper treated with an isolate of M. anisopliae s.l. conidia in the absence of (E)-2-octenal exhibited 99 % mortality after one week. However, bed bugs placed on fungal-treated filter paper and exposed to (E)-2-octenal at 1 h experienced 10 % mortality. The inhibition of fungal growth by bed bug aldehydes is discussed in the context of other biotic and abiotic barriers to infection.

Certain plant-derived essential oils are classified as ‘minimum risk' pesticides that require no registration with the Environmental Protection Agency and, therefore, have become attractive in formulations of pest-control products. In Petri dish assays, fumigation of a pyrethroid-susceptible strain of bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), with various essential oils results in mortality that approaches or equals 100% after 5 d. However, when bed bugs were exposed to the same essential oils in sealed, commercial trash bags for 5 d, only rosemary oil killed greater than 99% of the bed bugs. These results are compared with a commercial product that contains cold-pressed neem oil that killed 100% of the exposed bed bugs in both the Petri dish and trash bag studies.

Bed bugs Cimex lectularius L. were exposed to conidia (spores) of the entomopathogenic fungus Metarhizium anisopliae by feeding, aerosol spray, or contact with a treated surface. Feeding experiments demonstrated that bed bugs were innately susceptible to this fungus. However, only at 98% humidity were mortality rates high, regardless of whether bed bugs were sprayed with a fungal solution or contacted a treated surface. Mortality in treated bed bugs at ambient humidity did not increase when these bed bugs were kept in aggregation with other bed bugs that had recently blood fed to repletion. Based on these laboratory studies, we conclude that M. anisopliae is a poor pathogen for use in control of bed bugs, particularly at humidities that would likely be encountered under field conditions.

Releaser pheromones have direct behavioural effects to arrest, attract or disperse insects, whereas interactions within groups of social insects are often influenced by primer pheromones. The behaviour of insects displaying intermediate levels of sociality is largely unexplored in this context. In the present study, both the gregariousness and arrestment (settling near the odour source) of bed bugs Cimex lectularius L. (Hemiptera: Cimicidae) in response to conspecific exuvial extracts are described. Adult males are arrested on filter papers with extracts derived from exuviae of fifth-instar nymphs. Adult females and nymphs display no significant evidence for such behaviour. Adults of both sexes show no preference for extracts of male versus female fifth-instar exuviae. Arrestment of adult males does not occur on papers treated with fourth-instar exuvial extracts. Because the insects are assayed behaviourally in groups, an index is calculated describing how far bugs are away from being located independently of one another, as a measure of gregariousness. Adult males have lower values for this index (i.e. locations are closer to independence). Adult females, nymph cohorts and mixed age groups all have higher values for this index, which tend to increase over time. Females exhibit a clear increasing dose-dependent relationship for this index. It is concluded that the extracts of fifth-instar nymphal exuvia arrest males on refuges that possess the odour source. However, gregariousness is induced in females, without evidence of a tendency to assemble near the odour source.

Analyses of the dorsal abdominal glands of fourth- and fifth-instar nymphs of the bed bud, Cimex lectularius L. (Hemiptera: Cimicidae), indicated the predominant constituents were (E)-2-hexenal and (E)-2-octenal, with lesser amounts of 4-oxo-(E)-2-hexenal and 4-oxo-(E)-2-octenal. The latter two compounds have not been reported previously as occurring in bed bugs. There were no differences in the chemical composition of the dorsal abdominal glands excised from exuviae left behind by either male or female adults, nor from glands excised from fourth-instar exuviae. Because the two oxo-aldehydes made up at least 16% of the gland contents, further study of the functional role of these chemicals seem advisable.

Bed bugs Cimex lectularius L. were exposed to conidia (spores) of the entomopathogenic fungus Metarhizium anisopliae by feeding, aerosol spray, or contact with a treated surface. Feeding experiments demonstrated that bed bugs were innately susceptible to this fungus. However, only at 98% humidity were mortality rates high, regardless of whether bed bugs were sprayed with a fungal solution or contacted a treated surface. Mortality in treated bed bugs at ambient humidity did not increase when these bed bugs were kept in aggregation with other bed bugs that had recently blood fed to repletion. Based on these laboratory studies, we conclude that M. anisopliae is a poor pathogen for use in control of bed bugs, particularly at humidities that would likely be encountered under field conditions.

SummaryTylosin has been isolated from pollen samples by adsorption on acidic mixed-mode solid-phase extraction cartridges, with subsequent determination using a disk-diffusion microbiological assay. While not providing identification of individual antibiotics present, the presence of a zone of inhibition provides a simple indication of the presence of bacteriostatic/bactericidal residues. Use of Paenibacillus larvae gave reproducible sensitivity to 0.2 mg/kg tylosin, but not reliably below that level. Of the strains of bacteria tested, P. larvae and Micrococcus luteus gave the greatest sensitivity and inhibition zone diameter; M. luteus was sensitive to some component of pollen, giving large blanks, and less sensitive than other strains to low concentrations of tylosin. Sampling provides the greatest source of error in the analysis of pollen.

Transmission mechanisms of six honeybee viruses, including acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Kashmir bee virus (KBV), and sacbrood bee virus (SBV), in honey bee colonies were investigated by reverse transcription-PCR (RT-PCR) methods. The virus status of individual queens was evaluated by examining the presence of viruses in the queens' feces and tissues, including hemolymph, gut, ovaries, spermatheca, head, and eviscerated body. Except for head tissue, all five tissues as well as queen feces were found to be positive for virus infections. When queens in bee colonies were identified as positive for BQCV, DWV, CBPV, KBV, and SBV, the same viruses were detected in their offspring, including eggs, larvae, and adult workers. On the other hand, when queens were found positive for only two viruses, BQCV and DWV, only these two viruses were detected in their offspring. The presence of viruses in the tissue of ovaries and the detection of the same viruses in queens' eggs and young larvae suggest vertical transmission of viruses from queens to offspring. To our knowledge, this is the first evidence of vertical transmission of viruses in honeybee colonies.

Individual honey bee Apis mellifera L. queens were examined for the presence of six honey bee viruses including acute bee paralysis virus, chronic bee paralysis virus, black queen cell virus, deformed wing virus, Kashmir bee virus, and sacbrood virus. All viruses, except ABPV, were detected in the samples. Among queens examined for virus infections, 93% had multiple virus infections. The detection of viruses in queens raises the possibility of a vertical transmission pathway wherein infected queens can pass virus through their eggs to their offspring.

Using uniplex RT-PCR we screened honey bee colonies for the presence of several bee viruses, including black queen cell virus (BQCV), deformed wing virus (DWV), Kashmir bee virus (KBV), and sacbrood virus (SBV), and described the detection of mixed virus infections in bees from these colonies. We report for the first time that individual bees can harbor four viruses simultaneously. We also developed a multiplex RT-PCR assay for the simultaneous detection of multiple bee viruses. The feasibility and specificity of the multiplex RT-PCR assay suggests that this assay is an effective tool for simultaneous examination of mixed virus infections in bee colonies and would be useful for the diagnosis and surveillance of honey bee viral diseases in the field and laboratory. Phylogenetic analysis of putative helicase and RNA-dependent RNA polymerase (RdRp) encoded by viruses reveal that DWV and SBV fall into a same clade, whereas KBV and BQCV belong to a distinct lineage with other picorna-like viruses that infect plants, insects and vertebrates. Results from field surveys of these viruses indicate that mixed infections of BQCV, DWV, KBV, and SBV in the honey bee probably arise due to broad geographic distribution of viruses.

SUMMARYThe sublethal effects of coumaphos on developing queens were investigated. Young honey bee larvae were transferred into beeswax cups containing known concentrations (0 to 1000 mg/kg) of coumaphos. The cups with larvae were placed in queenless colonies for rearing and 10 days later acceptance was determined by recording mature queen cells. The queen cells were placed in small mating colonies for 21 days, when the queens were collected after being rated for commercial acceptability. The queens were then either introduced to production colonies and monitored for six months or dissected to determine mating success. All but one queen failed to develop at 1000 mg/kg of coumaphos, and greater than 50% of cells were rejected at 100 mg/kg coumaphos. The queens that were reared were lighter in weight as pre-emergence pupae. The effects on other characters related to queen performance are discussed. The presence of coumaphos in queen rearing cells can reduce the number of queens still functioning in colonies ...

SUMMARYThe antibiotic tylosin was found to be effective in controlling oxytetracycline-resistant American foulbrood (Paenibacillus larvae) in honey bee (Apis mellifera) colonies, while not affecting adult and larval honey bee mortality. An optimal rate of 200 mg tylosin, applied in 20 g of confectioners' sugar at weekly intervals for three weeks, resulted in complete remission of detectable disease symptoms 45 days after initial treatment. No detectable disease symptoms were observed seven months after treatment with this rate. Various higher doses of tylosin (600 mg and 1000 mg per 20 g confectioners' sugar) applied over three honey bee brood cycles, resulted in no significant increase in adult and larval bee mortality when compared with controls. Discussion is given as to long term American foulbrood control and tactics for resistance management.

Pentane extracts of male and female bed bugs were analyzed by gas chromatography and mass spectrometry in an effort to identify cuticular hydrocarbons. Seventeen hydrocarbons accounting for nearly 99% of the compounds eluting in the cuticular hydrocarbon region were identified. The sample contained mostly n-alkanes of 24 to 34 carbons, with odd numbered components predominating. The second major type of hydrocarbon were the 2-methylalkanes.

International audience; The organophosphate insecticide coumaphos has recently received emergency approval in the United States for control of fluvalinate-resistant Varroa destructor and the small hive beetle, Aethina tumida Murray. We investigated the transfer of coumaphos from wax into syrup and honey, using adsorption of coumaphos from diluted syrup or honey onto a solid-phase extraction cartridge, elution, and subsequent analysis. Coumaphos in syrup was quantitated using HPLC with UV detection, and we found that coumaphos migrates from wax into syrup, with low concentrations increasing over a few months. Concentrations reached 200-300 ppb in 100 g of syrup in contact with 10 g of wax containing 1000 ppm of coumaphos; contact with wax containing 100 and 10 ppm led to lower amounts. Impurities made HPLC determination of coumaphos in honey impossible, but the solid phase extract could be analyzed by gas chromatography/mass spectrometry. Concentrations in honey were similar to those in syrup, reaching 430 ppb after 26 weeks at 1000 ppm in wax.

Five neuropeptides with known allatotropic or allatostatic activity in other insect species were examined for their effects on honey bee corpora allata. Using an in vitro radiochemical assay, we assessed the ability of these peptides to affect the biosynthesis of juvenile hormone III and its immediate precursor methyl farnesoate, as well as their effects on the conversion of methyl farnesoate into juvenile hormone. None of the allatostatins tested affected JH biosynthesis during the last larval instar of honey bee workers. Manduca sexta allatotropin, however, stimulated JH biosynthesis in a stage-specific and dose-dependent manner. Analysis of intraglandular contents of juvenile hormone and its precursor revealed that the allatotropin significantly increased JH precursor but did not overcome the stage-specific block in the terminal step of JH biosynthesis that is typical for early fifth-instar worker larvae. Studies also indicated that the allatotropic effect was reversible at the level of methyl farnesoate production.

The tau-fluvalinate content of 13 lot numbers of Apistan® strips was determined by high performance liquid chromatography (HPLC). The average percent tau-fluvalinate in strips from each lot number ranged from 9.95 to 10.64 %, which falls within the range specified in the Confidential Statement of Formula (CSF) on file with the Environmental Protection Agency. It is not likely that the reduced efficacy in parasitic mite (Varroa jacobsoni) control reported in certain areas of the US is due to the tau-fluvalinate content of Apistan® strips. © Inra/DIB/AGIB/Elsevier, Paris

Les insectes doivent tirer les sterols de leurs aliments et de nombreux insectes phytophages sont capables de convertir les sterols a 28 et 29 carbones, couramment presents dans les plantes, en cholesterol. D'autres insectes, tels que l'abeille mellifere, sont incapables de faire cette conversion et renferment peu, si ce n'est aucun, cholesterol. Nous avons voulu comparer les sterols des tissus de la grande teigne de la ruche, Galleria mellonella, avec les sterols des rayons de couvain usages que l'insecte parasite. A l'aide d'une separation solvant:solvant suivie d'une serie de chromatographies sur colonne, nous avons pu isoler et purifier les sterols des prenymphes de G mellonella et des rayons sur lesquels elles etaient elevees. Les analyses par chromatographie gazeuse sur capillaire et par chromatographie gazeuse-spectrometrie de masse ont montre que le rayon de couvain comportait principalement du 24-methylene-cholesterol et d'autres 24-alkylsterols et renfermait moins d' 1 % de cholesterol (tableau I). Nous avons suppose que ces sterols provenaient des residus de pollen et/ou des exuvies d'abeilles. Pourtant, d'apres l'analyse des prenymphes de G mellonella, cholesterol representait plus de 85 % des sterols totaux des tissus. Nous avons attribue ce resultat a la capacite de G mellonella de dealkyler les sterols alimentaires en cholesterol. Ces resultats montrent que les composes qui inhibent le systeme enzymatique implique dans la conversion des 24-alkylsterols en cholesterol pourraient etre utilises a l'avenir dans les programmes de lutte contre la grande teigne de la ruche.

SUMMARYTwo antibiotics were both shown to be effective in controlling American foulbrood (Paenibacillus larvae larvae) in honey bee (Apis mellifera) colonies. Two dosages (100 or 200 mg) of tylosin tartrate or lincomycin hydrochloride were evaluated. Each antibiotic was applied in 20 g of confectioner's sugar three times at 7-day intervals. The higher dosage of both antibiotics gave consistent control after 45 days. The lower dose of 100 mg did not result in complete control in the colonies treated with tylosin; one of the 10 colonies still had detectable disease after 45 days. Thus, a dose of 200 mg applied three times over three weeks in dust form was highly effective in controlling American foulbrood and represents an appropriate dose for either of these antibiotics.

Exposure of a pyrethroid-susceptible strain of bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae) to varying concentrations of deltamethrin for 24 h indicated no significant difference in mortality between males, females, and nymphs at 24 nor at 168 h postexposure when bed bugs were removed to untreated surfaces at 24 h. In addition, many bed bugs classified as morbid or moribund at 24 h and removed to untreated surfaces at this time, recovered by 336 h (2 wk) and were capable of feeding when given the opportunity. Adult female bed bugs that survived were able to lay eggs and the resulting nymphs blood-fed. By contrast, all bed bugs classified as morbid or moribund at 24 h that remained on deltamethrin-treated surfaces for 336 h either died or were still classified as morbid or moribund at the end of this time. No bed bugs classified as morbid or moribund blood-fed when given the opportunity at 2 wk, regardless of whether they remained on the treated surfaces or were removed to untreated surfaces. A power analysis demonstrated we would have detected even moderate differences in mortality between males and females, had differences existed. Therefore, using males exclusively in efficacy assays is a suitable strategy to preserve females for laboratory colony purposes. Results also indicated there is little reason to assess efficacy beyond 1 wk, even when bed bugs are exposed for only 24 h.

Technologies to detect bed bugs have not kept pace with their global resurgence. Early detection is critical to prevent infestations from spreading. Detection based exclusively on bites is inadequate, because reactions to insect bites are non-specific and often misdiagnosed. Visual inspections are commonly used and depend on identifying live bugs, exuviae, or fecal droplets. Visual inspections are inexpensive, but they are time-consuming and unreliable when only a few bugs are present. Use of a dog to detect bed bugs is gaining in popularity, but it can be expensive, may unintentionally advertise a bed bug problem, and is not foolproof. Passive monitors mimic natural harborages; they are discreet and typically use an adhesive to trap bugs. Active monitors generate carbon dioxide, heat, a pheromone, or a combination to attract bed bugs to a trap. New technologies using DNA analysis, mass spectrometry, and electronic noses are innovative but impractical and expensive for widespread use.

The larval midgut of the tobacco hornworm, Manduca sexta, has high ecdysone 20-monooxygenase (EZOMO) activity, located both in the mitochondria and in the microsomes. The apparent kinetic parameters for E20MO in mitochondria and microsomes were determined. The K,s (for ecdysone) of the rnitochondrial and microsomal enzymes were 1.63 x 1 0-5 and 3.67 x 1 O-’ M, respectively. The V,,, was 82.7 prnol/min/rng protein for mitochondria and 32.0 pmol/min/mg protein for microsomes. Although the mitochondria1 E20MO has the higher V,,,, at physiological ecdysone concentrations (1 0-’ ~ 1 O-’ M) it is only one-eighth to one-tenth as active as the rnicrosornal enzyme. It is concluded that the rnicrosornal E20MO is the primary, if not the only, enzyme involved in ecdysone 20-hydroxylation in M. 5exta midgut. o 1996 Wey-Liss, Inc *

The tritium-labeled bis-norleucine analog of Helicoverpa zea pheromone biosynthesis-activating neuropeptide ([3H]NLPBAN) was incubated in vitro with hemolymph from Manduca sexta or H. zea adult females. The incubations resulted in the formation of several tritium-labeled degradation products. At a [3H]NLPBAN concentration of 0.9 microM the degradation proceeded at a very slow but physiologically plausible rate (2-10 fmol/min/microliters hemolymph). The primary [3H]NLPBAN degradation reaction in M. sexta hemolymph was not inhibited by 20 microM leupeptin, 0.1 mM amastatin, 1 mM EDTA, 1 mM EGTA, 1 mM 1,10-phenanthroline, or 2 mM 4-(2-aminoethyl)benzenesulfonyl fluoride; but secondary reactions may have been affected, as some of the inhibitors changed the radio-HPLC profile of the degradation products. It is concluded that hemolymph of M. sexta and H. zea contains peptidase(s) capable of inactivating circulating PBAN.

Background There has been a worldwide resurgence of bedbug infestations. Bites by these insects may cause mild or severe cutaneous reactions, and anaphylaxis has been reported. Little is known about the most severe cutaneous reactions, termed bullous or complex reactions. Objective To study the time course and histopathologic findings of complex (bullous) cutaneous reactions to bedbugs in order to determine the optional treatment for them. Design, Setting, and Participants We prospectively photographed bullous reactions to observed bedbug bites at 30 minutes; 6, 12, 24, 36, 48, and 72 hours; 1, 2, 3, and 4 weeks, and biopsied reactions at 30 minutes, and 6, 12, and 24 hours. We also reviewed Internet postings and the available medical literature on bullous reactions after bedbug bites. Main Outcomes and Measures Correlations between clinical and histologic findings using both routine and immunofluorescent techniques. Results Bullous reactions to bedbugs are not rare. Of 357 photographs of bedbug bites posted on the Internet, 6% were bullous. In an individual with previous bullous reactions, experimental bedbug bites were associated with a progression of cutaneous responses at bite sites from immediate, pruritic, edematous lesions to a late-in-time macule, which evolved into bullous reactions by 24 hours. Bullous lesions eventually lysed but took weeks to heal. Histopathologic evaluation of bullous reactions showed a polymorphous picture with histologic evidence of an urticarial-like reaction early on that rapidly developed into a hybrid leukocytoclastic vasculitis. This vasculitis was initially neutrophilic but developed into a destructive, necrotizing, eosinophil-rich vasculitis with prominent infiltration of CD 68+ histiocytes and collagen necrobiosis. This histologic picture is similar to the dermal vasculitis in patients with Churg-Strauss vasculitis. Conclusion Historically, bedbug bite reactions have been considered to be of minor medical significance. However, the findings presented here demonstrate that the not-uncommon bullous reactions to bedbug bites reflect the presence of a local, highly destructive, cutaneous vasculitis. The histologic features of these reactions resemble those occurring in the Churg-Strauss syndrome. Therefore, efforts to prevent further bites and monitor for evidence of systemic vasculitis should be made in patients with bullous reactions to bedbug bites. Topical treatment with high potency corticosteroids may be useful in the treatment of bullous reactions.

The activities of ecdysone oxidase (EO), 3-oxoecdysteroid 3α-reductase (3α-R), and 3-oxoecdysteroid 3β-reductase (3β-R) were determined for epidermis, hemolymph, and fat body of wandering fifth instar Manduca sexta larvae and for midguts of various developmental stages between 3 days after the last larval and 14 days after the pupal ecdysis. The larval midgut was the only organ showing substantial specific activities of EO and 3α-R, and both increased up to the seventh day after ecdysis. Hemolymph and fat body had only moderate to high 3β-R and low EO activites, and the epidermis did not contain significant activity of any of the enzymes. On the ninth day after the last larval ecdysis the larval midgut epithelium was replaced by a new pupal midgut epithelium. After this event only 3β-R was restored to high activities, whereas EO and 3α-R showed only low to marginal activities. It is concluded that only the larval midgut has a role in the inactivation of ecdysteroids by 3-epimerization. © 1993 Wiley-Liss, Inc. 1

Using high performance liquid chromatography in conjunction with radioimmunoassay and mass spectrometry, the major ecdysteroid of the solitary cactus bee, Diadasia rinconis, was determined to be 20-hydroxyecdysone, with lesser amounts of makisterone A. Another 28-carbon ecdysteroid thought to be the 24-epimer of makisterone A was also detected. The neutral sterols of Diadasia consisted primarily of 24-methylenecholesterol (92.2%) with lesser amounts of other C28 and C29 sterols. Cholesterol accounted for less than 0.1% of the total tissue sterols. The occurrence of 20-hydroxyecdysone in a phytophagous hymenopteran is discussed in relation to the low level of cholesterol encountered. © 1993 Wiley-Liss, Inc. 1

Since they are unable to biosynthesize sterols, many phytophagous and omnivorous insects satisfy their cholesterol requirement by side chain dealkylation of the C-24 alkyl group of dietary C28 and C29 phytosterols. However, not all insects that can dealkylate the phytosterol side chain produce cholesterol. In addition, certain insects,e.g., some Hymenoptera, Hemiptera, and Diptera, are unable to dealkylate the sterol side chain. Although C27 ecdysteroids (molting hormones), which are biosynthesized from cholesterol, are the major ecdysteroids in most insects, many of those species that are unable to dealkylate phytosterols utilize campesterol as a precursor for the C28 ecdysteroid makisterone A. The considerable diversity of steroid utilization between certain insect species makes it difficult to generalize about insect steroid biochemistry. The ability to disrupt certain unique aspects of steroid utilization and metabolism in insects might be exploited for developing new insect control technology.

Larvae of the house fly, Musca domestica were reared aseptically on diets which contained either cholesterol, campesterol or sitosterol as the dietary sterol at a concentration of 0.1% dry wt. Analysis of puraria (24 h post-pupariation) reared on campesterol or sitosterol diets revealed they contained from 2.7 to 4.6% cholesterol, indicating an ability to accumulate this sterol even where it is present in only minute quantities. Purparia on all diets produced the 27-carbon molting hormones, ecdysone and 20-hydroxyecdysone. When the concentration of campesterol was increased to 0.2% dry wt, puparia also contained the 28-carbon ecdysteroid, makisterone A, although it accounted for only 20.7% of the total ecdysteroid produced.

Measurements of both juvenile hormone and ecdysteroid haemolymph titres were made from the same individuals to explore the possibility that there is an interaction between these hormones in the regulation of adult honey bee behaviour and physiology. Queens, egg-laying workers, and workers engaged in brood care (nurses) had low titres of juvenile hormone whereas foragers had significantly higher titres, as in previous studies. In contrast, ecdysteroid titres were undetectably low in both nurses and foragers, higher in laying workers, and higher still in laying queens. Measurements of juvenile hormone titres are consistent with previous findings demonstrating that this hormone regulates worker age polyethism but does not play a typical role in reproduction. Comparison of juvenile hormone and edcysteroid titres suggests that ecdysteroids are not involved in the regulation of age polyethism but may play a role in the regulation of reproduction in honey bees.

An ecdysteroid RIA was used to determine the ecdysteroid titer in developing embryos of Dysdercus fasciatus and revealed that peak titer occurred approximately 120 h post-oviposition. Analysis of neutral sterols at this time indicated sitosterol to be the predominant neutral sterol with lesser amounts of campesterol. Embryonic sterols were highly reflective of the sterols found in the cotton seed diet upon which previous generations of the bugs had fed. Analysis of the embryonic extract for ecdysteroids indicated the presence of both makisterone A and the 29-carbon ecdysteroid makisterone C. Isolation of these compounds was accomplished by reversed-phase and silica HPLC in conjunction with RIA, and the identification of both compounds was confirmed by mass spectrometry. No ecdysone or 20-hydroxyecdysone was detected in the embryonic sample.

Gut chitin synthase was characterized and the sterols and ecdysteroids in the sugarcane rootstalk borer weevil, Diaprepes abbreviatus, were identified. An in vitro cell-free chitin synthase assay was developed using larval gut tissues from D. abbreviatus. Subcellular fractionation experiments showed that the majority of chitin synthase activity was located in 10,000g pellets. The gut chitin synthase requires Mg2+ to be fully active: 7–8-fold increases in activity were obtained with 10 mM Mg2+ present in reaction mixture. Calcium also stimulated activity (4–5-fold with 10 mM Ca2+), while Cu+2 completely inhibited at 1 mM. Other monovalent and divalent cations had little or no effect on activity. The pH and temperature optima were 7 and 25°C, respectively. Gut chitin synthesis was activated ca. 50% by trypsin treatments. GlcNAc stimulated chitin synthase activity, but Glc, GlcN and glycerin did not. Polyoxin D, UDP, and ADP inhibited the chitin synthase reaction with I50's of 75 μM, 2.3 mM, and 3.6 mM, respectively. Nikkomycin Z was a potent inhibitor of chitin synthase (91% inhibition at 10 μM). Tunicamycin and diflubenzuron had no effect on the enzyme. The apparent Km and Vmax for the gut chitin synthase were, respectively, 122.5 ± 7.4 μM and 426 ± 19.7 pmol/h/mg protein utilizing UDP-GlcNAc as the substrate. Sterol analyses indicated that cholesterol was the major dietary and larval sterol. HPLC/RIA data indicated that 20-hydroxyecdysone was the major molting hormone.

Release of mature sperm from the testes of the gypsy moth, Lymantria dispar , into the seminal ducts occurs in a daily rhythmic pattern. The rhythm of sperm release is initiated in developing pharate adults 3–4 days after spermatogenesis and development of the reproductive tract has been completed. At that time a significant decline occurs in the blood titre of RIA-detectable ecdysteroids. Infusion of 20-hydroxyecdysone into male pupae inhibits the release of sperm from the testis in a dose-dependent and age-dependent fashion. The decline in haemolymph ecdysteroid levels seems essential for the initiation of the rhythmic release of sperm from the testis, but does not appear to play a role in determining the phase of this rhythm.

The most crucial stage in the dynamics of virus infections is the mode of virus transmission. In general, transmission of viruses can occur through two pathways: horizontal and vertical transmission. In horizontal transmission, viruses are transmitted among individuals of the same generation, while vertical transmission occurs from mothers to their offspring. Because of its highly organized social structure and crowded population density, the honey bee colony represents a risky environment for the spread of disease infection. Like other plant and animal viruses, bee viruses use different survival strategies, including utilization of both horizontal and vertical routes, to transmit and maintain levels in a host population. In this review, we explore the current knowledge about the honey bee viruses and transmission routes of bee viruses. In addition, different transmission strategies on the persistence and dynamics of host-pathogen interactions are also discussed.

Worldwide, American foulbrood (AFB) is the most devastating bacterial disease of the honey bee (Apis mellifera). Because the distinction between AFB and powdery scale disease is no longer considered valid, the pathogenic agent has recently been reclassified as one species Paenibacillus larvae, eliminating the subspecies designations Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens. The creamy or dark brown, glue-like larval remains of infected larvae continue to provide the most obvious clinical symptom of AFB, although it is not conclusive. Several sensitive and selective culture media are available for isolation of this spore-forming bacterium, with the type of samples that may be utilized for detection of the organism being further expanded. PCR methods for identification and genotyping of the pathogen have now been extensively developed. Nevertheless, biochemical profiling, bacteriophage sensitivity, immunotechniques and microscopy of suspect bacterial strains are entirely adequate for routine identification purposes., Facultad de Ciencias Agrarias y Forestales, Centro de Investigaciones de Fitopatología

Deformed wing virus (DWV) can cause wing deformity and premature death in adult honeybees, although like many other bee viruses, DWV generally persists as a latent infection with no apparent symptoms. Using reverse transcription (RT)-PCR and Southern hybridization, we detected DWV in all life stages of honeybees, including adults with and without deformed wings. We also found DWV in the parasitic mite Varroa destructor , suggesting that this mite may be involved in the transmission of DWV. However, the detection of the virus in life stages not normally associated with mite parasitism (i.e., eggs and larvae) suggests that there are other modes of transmission. The levels of DWV in different life stages of bees were investigated by using TaqMan real-time quantitative RT-PCR. The amounts of virus varied significantly in these different stages, and the highest levels occurred in pupae and in adult worker bees with deformed wings. The variability in virus titer may reflect the different abilities of bees to resist DWV infection and replication. The epidemiology of DWV is discussed, and factors such as mite infestation, malnutrition, and climate are also considered.

Beekeepers apply various dusts to honey bee, Apis mellifera L., colonies to dislodge parasitic mites and control bacterial brood diseases. Anecdotal reports by beekeepers indicate that the antibiotic oxytetracycline (OTC) can be toxic when applied in powdered sugar to cells containing immature bee brood, but it was not known whether the purported toxicity is caused by the antibiotic or the sugar carrier. Additionally, the toxicity of various dusts, proposed for parasitic mite control, is poorly known. In the current studies, we tested OTC and two other antibiotics (tylosin and lincomycin, candidate compounds for use in honey bee colonies) in a powdered sugar carrier for larval toxicity. We also tested for larval toxicity, several dusts that have been proposed for mite control. OTC caused significant brood mortality of approximately 80% at the concentrations used in the hive (200 mg in 20 g sugar). In contrast, tylosin and lincomycin at the 200 mg dose were both similar to untreated controls, and only five times that concentration (1000 mg) caused significant brood mortality of approximately 65%. The addition of dusts, wheat flour, talc, and a commercially available protein supplement, BeePro, resulted in mortality levels between 65 and 80%, similar to that seen with OTC. The common antibiotic carrier, powered confectioners sugar, was nontoxic. The use of 100 unsealed brood cells was demonstrated to be a reliable means of assessing potential adverse affects of dry compounds on larval honey bees. Two new candidate antibiotics for use in honey bee colonies were less toxic to larval bees than the currently labeled antibiotic, OTC.

International audience; Young honey bee larvae were transferred into the queen cups containing known concentrations (0 to 1000 mg/kg) of the organophosphate pesticide coumaphos. These larvae were placed in queenless colonies and examined ten days later to determine the rate of rejection or acceptance as indicated by a mature sealed queen cell. All queens failed to develop at 1000 mg/kg, and greater than 50% of the queen cells were rejected at the 100 mg/kg concentration. Additionally, queens that survived exposure to100 mg/kg coumaphos weighed significantly less than control queens. The implications of exposure of developing queens to sublethal amounts of pesticides are discussed.