Development of semiochemical attractants for monitoring bean seed beetle, Bruchus rufimanus

BACKGROUND: Bruchus rufimanus is a serious pest of field beans. The objective here was to develop a semiochemical‐baited trapping system to facilitate monitoring of the pest. RESULTS: Volatile compounds that were electrophysiologically active with the antennae of B. rufimanus females were identified from headspace samples of Vicia faba flowers and from male B. rufimanus. Selected headspace samples and synthetic compounds were tested in olfactometer bioassays. The semiochemicals were then formulated in lures for traps and evaluated in a field trapping experiment. Cone traps baited with a three‐component blend of floral volatiles, releasing (R)‐linalool (17.7 mg day^?1), cinnamyl alcohol (0.4 mg day^?1) and cinnamaldehyde (0.77 mg day^?1), caught significantly more of both sexes of B. rufimanus than unbaited control traps. A male volatile, 1‐undecene, was EAG active with female antennae. It was attractive to females in an olfactometer, indicating that it is a sex pheromone. However, in the field it only enhanced trap catches if it was released together with the floral volatiles. CONCLUSION: The blends of semiochemicals identified were shown to be attractive in cone traps under field conditions. The prototype trapping system developed could be used as a monitoring tool to determine infestation levels of B. rufimanus in bean fields. Copyright © 2011 Society of Chemical Industry     

Effects of Nicotine and Tobacco-Related Products on the Feeding Behavior of the German Cockroach (Blattodea: Blattellidae)

Animals use olfaction to detect developmentally significant volatile organic compounds (VOCs) in their local environment. As part of a wider study aiming to demonstrate that the olfactory responses of animals to VOCs can be modified through the creation of a drug-addicted status and association with a selected VOC, we investigated nicotine and tobacco smoke particulate (TSP) extract as possible addictive compounds for male German cockroaches, Blattella germanica (Linnaeus). In feeding experiments using an artificial food stimulus, food treated with TSP extract was preferred over untreated food. Surprisingly, nicotine, which was expected to be the most important addictive tobacco component, did not induce noticeable effects on cockroach behavior. Both TSP extract and nicotine were shown to be phagostimulants. Olfactometry assays that measured odor-mediated insect behavior demonstrated that male B. germanica did not choose TSP-extract-treated food even when attempts were made specifically to train them via this modality. These results support a hypothesis that B. germanica needs to consume TSP-containing food to show a clear preference for this stimulus and that gustatory mechanisms are involved due to compounds present in the TSP extract.     

Dynamics of the free-living stages of sheep intestinal parasites on pasture in the North Island of New Zealand. 1. Patterns of seasonal development

Abstract

AIM: To describe the seasonal pattern of development of third-stage infective larvae (L3) from eggs of Teladorsagia (=Ostertagia) circumcincta, Trichostrongylus colubriformis and Haemonchus contortus on pasture in the North Island of New Zealand.

METHODS: Sheep faeces containing known numbers of eggs of all three nematode species were deposited on, or buried in, pasture plots at three sites, viz coastal Manawatu, Upper Hutt Valley, and East Cape hill country. Development was measured by recovering L3 from faeces, herbage and soil 28–31 days after deposition on 13–18 occasions, between January 2005 and July 2006. Analysis of the number of larvae recovered used a mixed model including number of eggs deposited, weight of faeces recovered (an assumed indicator of earthworm activity), site, contamination date, and position of deposited faeces, i.e. on the surface or buried.

RESULTS: There was a significant effect of contamination date on development of all three species, with maximum numbers ofL3 developing between late spring (November) and early autumn (March), and minimum numbers in June and July. There were large differences between species, with H. contortus exhibiting a long period (April to October) where development was close to zero, whereas T. circumcincta developed to some extent all year round. Development of T. colubriformis was intermediate between the other two species.

Burying faeces containing nematode eggs increased the number of L3 recovered compared with surface deposition (p≤0.001), although there were a small number of exceptions involving only T. colubriformis. The weight of faeces recovered at harvest, which was assumed to be an indication of earthworm activity, was correlated with the number of L3 recovered for all species (p<0.001). In a separate analysis, earthworms were assumed tohave been active if <5 g faeces remained at harvest. Where this occurred, the number of L3 of T. colubriformis and T.circumcincta recovered was reduced by 56% and 58%, respectively (p<0.001).

CONCLUSIONS: A marked seasonal pattern of development was observed for all three species, with the most larvae developing in spring-early autumn and the least in winter. This seasonal pattern was most pronounced in H. contortus and least obvious in T. circumcincta. Burying faeces containing eggs generally resulted in more L3 being recovered, whilst the apparent activity of earthworms resulted in fewer larvae being recovered.     

Effect of dietary carbohydrate and monensin on expression of gluconeogenic enzymes in liver of transition dairy cows

Thirty-four multiparous Holstein cows were used in a randomized block design to evaluate the effects of feeding nonforage fiber sources (NFFS), monensin, or their combination on expression of gluconeogenic enzymes in the liver during the transition to lactation. The addition of 0 or 300 mg/d of monensin to a conventional (CONV) or NFFS prepartum diet was evaluated in a 2 x 2 factorial arrangement of treatments. The NFFS diet was formulated by replacing 30% of the forage component of the CONV diet with cottonseed hulls and soyhulls. The CONV and NFFS basal diets were fed at dry-off and continued through parturition. Monensin was fed from -28 d relative to calving (DRTC) through parturition. At calving, all cows were placed on the same diet. Liver biopsy samples obtained at -28, -14, +1, +14, and +28 DRTC were used to determine pyruvate carboxylase (PC) and cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) mRNA expression. Feeding NFFS resulted in greater (P < 0.05) prepartum DMI compared with the CONV diet. There was no effect of prepartum diets on postpartum DMI or average milk production to 56 d of lactation. Expression of PC mRNA was elevated (P < 0.05) at 1 d postpartum, but there was no effect of NFFS or monensin on PC mRNA abundance. Expression of PEPCK-C mRNA at calving was increased (P < 0.05) with prepartum monensin feeding. The data indicate that feeding monensin to transition cows induces hepatic PEPCK-C mRNA expression before calving. The increased expression of hepatic PEPCK-C mRNA with monensin feeding suggests a feed-forward mechanism of metabolic control in ruminants that links molecular control of gluconeogenesis with the profile of rumen fermentation end products.     

An Experimental Model to Study Resistance Index and Systolic/Diastolic Ratio of Uterine Arteries in Adverse Canine Pregnancy Outcome

The aim of this study was to describe the changes in the resistance index (RI) and systolic/diastolic ratio ( S / D ) of the uterine arteries during mid-pregnancy abortion induction in the dog. Sixteen 30–35 day pregnant bitches were randomly assigned to either a pharmacological protocol to interrupt gestation (n = 8) or were used as untreated control group (n = 8). Doppler assessments of uterine arteries blood flow were carried out before the initiation of the protocol and then every other day up to abortion (treated group) or parturition (control group). All treated bitches aborted 6 ± 1.2 days after initiation of the treatment (while none of the non-treated bitches aborted). Pre-treatment RI and S / D did not differ between groups (p > 0.2) while average post-treatment indexes were (mean ± SD): 0.62 ± 0.1 vs 0.53 ± 0.1 (p < 0.01) and 2.96 ± 0.9 vs 2.23 ± 0.3 (p = 0.01), for the treated and non-treated group respectively. Correlations between days to abortion and RI or S / D were 0.75 (p < 0.01) and 0.79 (p < 0.01) and, −0.78 (p < 0.01) and −0.73 (p < 0.01) for the treated and non-treated groups respectively. In the treated group, correlations between serum progesterone (P₄) concentrations and RI and S / D were −0.76 (p < 0.01) and −0.59 (p < 0.01) respectively. It is concluded that, during induction of abortion, RI and S / D of uterine arteries progressively increased while P₄ decreased.     

Phytic acid represents 10 to 15% of total phosphorus in alfalfa root and crown

Phytic acid, myo‐inositol 1,2,3,4,5,6 hexakisphosphate. the major storage form of phosphorus (P) in seeds, comprises 60 to 90% of total seed P. Phytic acid has also been observed in other vegetative and reproductive tissue including roots although no studies to date have unequivocally demonstrated that phytic acid is indeed present in roots. Three methods (ferric precipitation, ion‐exchange chromatography, and high voltage paper electrophoresis) were used to demonstrate that phytic acid is a P‐containing compound within the root and crown tissue of alfalfa (Medicago sativa L.). Phytic acid P was found to represent from 10 to 15% of total root and crown P.     

Arthritis and panuveitis as manifestations of Borrelia burgdorferi infection in a Wisconsin pony

Infection with Borrelia burgdorferi caused panuveitis and arthritis in a pony. Spirochetes were detected by direct immunofluorescence in the anterior chamber of the eye. The carpal joints had severe degenerative joint disease, with synovial proliferation. The synovium and serum had B burgdorferi antibody titers of 1:1024. The pony lived in an area of Wisconsin where infection with B burgdorferi is endemic in human beings. Previously, serum antibodies to B burgdorferi had been found in horses, but disease had not been reported.     

A note on the mosquito oviposition pheromone

Mosquitoes of the genus Culex, e.g. Culex quinquefasciatus, release a volatile pheromone from their eggs that induces gravid females to oviposit around the pheromone source. Enantioselective synthesis by the Sharpless epoxidation method and chiral gas chromatography showed the major pheromone component to be (?)-(5R,6S)-6-acetoxy-5-hexadecanolide. Shortening the alkyl chain resulted in a loss of behavioural activity, whereas perfluorination of the alkyl chain or substitution of the acetoxy groups with the trifluoroacetoxy group gave active analogues. A simple large scale synthesis was devised to provide material for a fìeld trial. The pheromone, formulated in effervescent tablets, was used to concentrate oviposition in specific breeding sites where the larvae were controlled with a juvenoid-type insecticide.