Field validation of senesced banana leaf extracts for trapping banana weevils on smallholder banana/plantain farms

Palm wine alcohol extract of senesced banana leaf material, Musa spp., was tested for its efficacy in open field trapping of the banana weevil, Cosmopolites sordidus in Ghana from June to August 2015. Modified pitfall and bottle traps were baited with either individual treatments, that is palm alcohol extract, C. sordidus aggregation pheromone or pseudostem or with combinations of extract plus aggregation pheromone or extract plus pseudostem. The combination of extract plus aggregation pheromone was able to lure more weevils into traps compared with the respective individual lures. There was a 2.1-fold increase in mean catch per week when the palm alcohol extract was used in combination with pheromone compared with using pheromone alone, and a corresponding 2.6-fold increase when the extract was used with pseudostem in traps. There was no statistically significant interaction between the palm alcohol extract (presence or absence) and treatment (pheromone or pseudostem), but the best combination for maximal catches of adult banana weevils was a combination of palm alcohol extract with aggregation pheromone. Management of banana weevils with attractive banana leaf extract has important practical applications in parts of the world where other management options are too expensive or commercial treatments are in short supply, but where leaf material is cheap and readily available for local use by smallholder farmers.     

Different bioassays for investigating orientation responses of the banana weevil, Cosmopolites sordidus, show additive effects of host plant volatiles and a synthetic male-produced aggregation pheromone

Abstract Three different bioassay methods to investigate the orientation behaviour of the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), to host plant volatiles and a synthetic pheromone (cosmolure+) were compared. A locomotion compensator was used to separately record walking tracks in response to three odour sources. The data show that C. sordidus uses odour‐conditioned anemotaxis in its orientation to the odour sources tested. Of the two olfactometers tested, a dual port olfactometer using a continuous airflow showed stronger discrimination by C. sordidus to the different odours compared with a double pitfall olfactometer. The results of all three bioassays indicate that C. sordidus responds in an additive way to the combination of fermentation plant volatiles and the synthetic pheromone.     

Sampling communities of ground-foraging ants: Pitfall catches compared with quadrat counts in an Australian tropical savanna

The relative abundances of ant species captured in pitfall traps was compared with those obtained by direct counts in quadrats at a savanna site in Kakadu National Park, Northern Territory. Two measures of abundance in traps were used, one based on total numbers of ants, the other on species frequency of occurrence. All species commonly recorded in quadrats were collected in traps, and their relative abundances were highly correlated on all occasions. Of the 20 most common species in quadrats, five occurred with a significantly different (in all cases lower) frequency in pitfall traps, but these species represented only 1.8–3.1% of total quadrat counts. Results from quadrats and pitfall traps were particularly similar (r > 0.8) when species-were classified into functional groups. Frequency data from traps may sometimes overestimate the abundance of widespread, solitary foraging species (e.g. ‘Chelaner’ and Tetramorium spp.) and underestimate species with large colony sizes (e.g. Iridomyrmex spp.). Data based on total numbers of ants in traps may be more prone to distortion arising from species differences in locomotor behaviour. Species counts in traps could be scaled to reduce these distortions. The finding that pitfall traps gave results comparable with those from quadrat counts provides support for the use of pitfall traps in studies of Australian ant communities in open habitats.     

Tillage differentially affects the capture rate of pitfall traps for three species of carabid beetles

The influence of tillage, gender, and microclimate on capture rates of pitfall traps for the beetles Poecilus scitulus LeConte, Poecilus lucublandus (Say), and Pterostichus melanarius Illiger (Coleoptera: Carabidae) were assessed in mark–release–recapture experiments in spring pea and spring wheat. Experiments were conducted during June, July, and August of 2003 in the Palouse region of northern Idaho, USA. Rates of capture in pitfall traps for the three carabid species were differentially affected by crop‐tillage systems. Capture rates for P. scitulus and P. lucublandus were higher in no‐till (NT) than in conventional tillage (CT) peas, whereas capture rates for P. scitulus and Pt. melanarius were higher in CT than in NT wheat. Ground‐level temperatures and relative humidity (r.h.) differed little among tillage systems. Nevertheless, capture rates were generally positively correlated with ground‐level temperature and negatively correlated with r.h., with correlations more often significant in NT than in CT systems. The response of the thermophilic Poecilus spp. to temperature provides a possible mechanistic explanation for capture rate patterns in legumes during June, but not in other months for peas or any month in wheat during the experiments. Movement impedance due to residue could explain lower capture rates of P. scitulus and Pt. melanarius in NT than in CT spring wheat. These results suggest that researchers using pitfall trapping for carabid populations should take into account potential capture biases their treatments can introduce.     

Comparison of reptile sampling in Iran with pitfall versus double-ended funnel traps

In north Khorasan province, Iran, we compared the effectiveness of two types of traps for collecting reptiles: funnel traps and pitfall traps. Three stations were monitored over three 10-day periods and in total 544 individuals (including 200 recaptures) belonging to 5 species and 4 families of lizards (Lacertidae) were collected. Funnel traps with 280 captures were more efficient than pitfall traps with 264 captures, but the differences between the two traps are not significant. Three species were captured most often in the three different stations respectively: station 1, Bunopus crassicauda (22% relative frequency); station 2, Eremias fasciata (29% relative frequency); and station 3, Trapelus agilis (32% relative frequency). Shannon species richness indices were higher for pitfall than funnel traps (i.e., 1.45 vs. 1.40), but the difference was not significant. Pitfall traps were better for capturing species that search widely for food, while the funnel traps preferentially captured species that climb plants, such as Trapelus agilis. We recommend using both types of trap to capture the various types of species in any one region.     

Too hot to handle? Balancing increased trapability with capture mortality in hot weather pitfall trapping

Trapping at air temperatures close to, or exceeding, critical thermal maxima is important for comprehensive sampling of vertebrate assemblages and collection of sufficient data for impact assessment. However, pitfall trapping on hot days also potentially exposes trapped animals to stress or death through overheating or desiccation. We investigate causes of mortality from 14 305 captures over a 22‐year pitfall trap study in arid South Australia and compared mortality rates with maximum temperatures, solar radiation and rainfall. Overall mortality rate was 3.2% with chewing by rodents and handling accidents the most influential cause of death recorded. The highest mortality rates were experienced by the tiny skink, Lerista labialis, which was difficult to detect in traps each day and hence problematic to assess the effect of weather variables on capture mortality. For all other abundant species, high maximum temperature was only a significant explanatory variable for increased death rates of the house mouse Mus domesticus, and increased solar radiation was positively related to capture mortality for the house mouse, the frog Neobatrachus sudelli and the small skink Ctenotus schomburgkii. However, capture rates for these taxa and eight other common species would have been significantly lower if trapping did not occur on days of 40 °C or more. We conclude that trapping in hot weather is both desirable and justifiable and suggest techniques for further reducing mortality rates in pitfall studies.     

Evaluation of a CO2‐free commercial mosquito attractant to capture triatomines in the laboratory

Efforts have been made to develop vertebrate odor‐based attractants to lure hematophagous triatomines into traps. However, more work is needed to reach a practical, cheap, and efficient odor lure. We carried out attraction and capture tests in a dual‐choice olfactometer and a pitfall trap. Here we report that a three‐component, CO₂‐free, synthetic blend of vertebrate odor (consisting of ammonia, L(+) lactic acid and hexanoic acid, and known as Sweetscent®) significantly induces 3^rd‐instar Rhodnius prolixus and Triatoma infestans nymphs to fall into the test capture‐tube of the olfactometer. Blend constituents presented singly or in two‐component blends did not evoke a response and, therefore, we propose that the insects respond specifically to the three‐component blend in a synergistic way. When tested in a pitfall trap in an experimental arena, this blend induced capture in 37.5% of the lured traps, whereas 9% of the nymphs tested were captured in a single night. No insects were captured in control traps. Our work represents a proof‐of‐concept regarding capture of triatomines using host odor‐based, CO₂‐free synthetic mixtures as lures for pitfall traps. CO₂‐free lures are more practical for field work than natural or CO₂‐containing synthetic blends.     

Evaluation of trap designs and food attractants for trapping Eucryptorrhynchus scrobiculatus (Coleoptera: Curculionidae)*

Eucryptorrhynchus scrobiculatus (Motschulsky) is a serious pest of tree of heaven, Ailanthus altissima (Mill.) Swingle in China. Laboratory choice tests were conducted to compare attractiveness of vinegar, ethanol, apple juice, the vinegar-ethanol mixture (VE), vinegar-apple mixture (VA), ethanol-apple mixture (EA) and vinegar-ethanol-apple mixture (VEA) to E. scrobiculatus. VEA showed significantly higher attractiveness to E. scrobiculatus than vinegar, ethanol, apple juice alone, VE, VA or EA. The field experiments were conducted to evaluate the efficiency of commercial pitfall traps baited with different ratios of VEA (Apple: VE, m:m) for trapping E. scrobiculatus. Field evaluations showed that the number of marked and wild E. scrobiculatus in traps baited with the VEA (Apple: VE, 30:70 ratio, m:m) was significantly higher than traps baited with other ratios of VEA. Further testing of four types of trap baited with this VEA (Apple: VE, 30:70 ratio, m:m) indicated that captures in homemade pitfall trap design were significantly higher than in any other trap design (commercial pitfall traps, cross-vane versus traps and six-unit-funnel traps). The results demonstrated that homemade pitfall traps baited with the VEA (Apple: VE, 30:70 ratio, m:m) have potential for E. scrobiculatus monitoring.     

The Integrated Effect of the Nematode-Bacteria Complex and Neem Plant Extracts Against Plutella Xylostella (L.) Larvae (Lepidoptera: Yponomeutidae) on Chinese Cabbage

The compatibility of the nematode-bacteria complex of Steinernema carpocapsae, Steinernema abbasi, and Heterorhabditis bacteriophora with neem plant extracts (seeds and leaves) to control diamondback moth, Plutella xylostella (L.) on Chinese cabbage plants was investigated under laboratory conditions. The initial treatment of Chinese plant leaves with neem plant extracts resulted in more susceptibility of P. xylostella to neem seeds extract than neem leaves extract. The combination studies resulted in a higher synergistic effect of nematode-bacteria complex of H. bacteriophora, S. abbasi and S. carpocapsae with neem seeds extract compared with that of S. abbasi with neem leaves extract. In contrast, the combination of nematode-bacteria complex of S. carpocapsae and H. bacteriophora with neem leaves extract gave an antagonistic effect. On the other hand, the time-mortality response was more reduced with neem seeds extract than with neem leaves extract, besides it was a concentration dependant factor. We conclude from these investigations that the combination of entomopathogenic nematodes with neem plant extracts could be of success in controlling P. xylostella on Chinese cabbage plants in the field.     

Evaluation and optimization of ethanol production from carob pod extract by <Emphasis Type="Italic">Zymomonas mobilis</Emphasis> using response surface methodology

In this research, ethanol production from carob pod extract (extract) using Zymomonas mobilis with medium optimized by Plackett–Burman (P–B) and response surface methodologies (RSM) was studied. Z. mobilis was recognized as useful for ethanol production from carob pod extract. The effects of initial concentrations of sugar, peptone, and yeast extract as well as agitation rate (rpm), pH, and culture time in nonhydrolyzed carob pod extract were investigated. Significantly affecting variables (P = 0.05) in the model obtained from RSM studies were: weights of bacterial inoculum, initial sugar, peptone, and yeast extract. Acid hydrolysis was useful to complete conversion of sugars to glucose and fructose. Nonhydrolyzed extract showed higher ethanol yield and residual sugar compared with hydrolyzed extract. Ethanol produced (g g⁻¹ initial sugar, as the response) was not significantly different (P = 0.05) when Z. mobilis performance was compared in hydrolyzed and nonhydrolyzed extract. The maximum ethanol of 0.34 ± 0.02 g g⁻¹ initial sugar was obtained at 30°C, initial pH 5.2, and 80 rpm, using concentrations (g per 50 mL culture media) of: inoculum bacterial dry weight, 0.017; initial sugar, 5.78; peptone, 0.43; yeast extract, 0.43; and culture time of 36 h.     

Potential of a synthetic aggregation pheromone for integrated pest management of Colorado potato beetle

Abstract

• 1 The relative number of colonizing adult Colorado potato beetles (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) coming to pitfall traps baited with the aggregation pheromone (S)‐3,7‐dimethyl‐2‐oxo‐oct‐6‐ene‐1,3‐diol [(S)‐CPB I] and the use of the pheromone in a trap crop pest management strategy were evaluated in the field for the first time.
• 2 More than five‐fold more adult L. decemlineata were caught in pitfall traps baited with the pheromone compared with controls. However, attraction to the pheromone diminished after 5 days in the field.
• 3 In the trap crop management strategy, more colonizing adults were present in pheromone‐treated rows of potatoes compared with untreated middle rows.
• 4 Significantly fewer L. decemlineata egg masses and larvae were found in potato plots that were bordered by pheromone‐treated rows, or bordered by imidacloprid + pheromone‐treated rows, or rows treated at‐planting with imidacloprid compared with untreated (control) potato plots.
• 5 Densities of L. decemlineata egg masses and larvae and percentage defoliation were significantly lower, and marketable tuber yield significantly higher, in conventional imidacloprid‐treated potatoes compared with all other treatments.
• 6 Although our results demonstrate the potential for use of the aggregation pheromone in the management of L. decemlineata in the field, more research is needed to optimize the release rates of the attractant and incorporate control methods for cohabiting pests.

     

Pitfall trapping of scarce Orthoptera at a coastal nature reserve in Essex, UK

The value of pitfall trapping was questioned in a recent review of methods for sampling Orthoptera in grassland ecosystems. However, subsequent to the publication of this review, interesting data has become available from pitfall trapping at Colne Point, an important coastal nature reserve in Essex, UK. As a result of this trapping, the nationally scarce and Essex Red Data List species, Platycleis albopunctata, was rediscovered in the county. This tettigoniid was believed to be extinct in Essex as previous visual searches for the insect at Colne Point had failed to locate it. Large numbers of the Essex Red Data List species, Myrmeleotettix maculatus, were also captured, as were specimens of the nationally scarce cockroach, Ectobius panzeri (Dictyoptera). Systematic pitfall trapping at Colne Point was therefore pivotal in recording scarce species such as P. albopunctata which had proved difficult to locate by visual searching methods.     

Preparation of novel authentication film by screen printing of anthocyanin biomolecular extract: Thermochromism and vapochromism

Novel thermochromic and vapochromic paper substrates were prepared via screen printing with anthocyanin extract in the presence of ferrous sulfate mordant, resulting in multi-stimuli responsive colorimetric paper sheets. Environmentally friendly anthocyanin extract was obtained from red-cabbage (Brassica oleracea var. capitata L.) to function as spectroscopic probe in coordination with ferrous sulfate mordant. Pink anthocyanin/resin nanocomposite films immobilized onto paper surface were developed by well-dispersion of anthocyanin extract as a colorimetric probe in a binding agent without agglomeration. As demonstrated by CIE colorimetric studies, the pink (λ_max = 418 nm) film deposited onto paper surface turns greenish-yellow (λ_max = 552 nm) upon heating from 25 to 75°C, demonstrating new thermochromic film for anti-counterfeiting applications. The thermochromic effects were investigated at different concentrations of the anthocyanin extract. Upon exposure to ammonia gas, the color of the anthocyanin-printed sheets changes rapidly from pink to greenish-yellow, and then immediately returns to pink after taking the gaseous ammonia stimulus away, demonstrating vapochromic effect. The current sensor strip showed a detection limit for ammonia gas in the range 50–300 ppm. Both thermochromism and vapochromism showed high reversibility without fatigue. In addition to studying the rheological properties of the prepared composites, the morphological and mechanical properties of the printed cellulose substrates were also studied.     

Should I stay or should I go? Modelling dispersal strategies in saproxylic insects based on pheromone capture and radio telemetry: a case study on the threatened hermit beetle <Emphasis Type="Italic">Osmoderma eremita</Emphasis>

To predict how organisms cope with habitat fragmentation we must understand their dispersal biology, which can be notoriously difficult. We used a novel, multi-pronged approach to study dispersal strategies in the endangered saproxylic hermit beetle Osmoderma eremita, exploiting its pheromone system to intercept high numbers of dispersing individuals, which is not possible with other methods. Mark-release-recapture, using unbaited pitfall traps inside oak hollows and pheromone-baited funnel traps suspended from tree branches, was combined with radio telemetry (in females only) to record displacements. Dispersal, modelled as a probability distribution of net displacement, did not differ significantly between sexes (males versus females recaptured), observation methods (females recaptured versus radio-tracked), or sites of first capture (pitfall trap in tree versus pheromone trap – distance from original dispersal point unknown). A model including all observed individuals yielded a mean displacement of 82 m with 1% dispersing > 1 km. Differences in body length were small between individuals captured in pitfall versus pheromone traps, indicating that dispersal is rarely a condition-dependent response in O. eremita. Individuals captured in pheromone traps were consistently lighter, indicating that most dispersal events occur relatively late in life, which agrees with trap catch data. In addition, most (79%) females captured in pheromone traps were mated, showing that females typically mate before leaving their natal tree. Our data show that integrating odour attractants into insect conservation biology provides a means to target dispersing individuals and could greatly improve our knowledge of dispersal biology in threatened species.     

Is pitfall trapping a valuable sampling method for grassland Orthoptera?

Common methods to assess diversity and abundance of Orthoptera are sweep netting, transect counts and box-quadrat sampling. Pitfall trapping, by contrast, is rarely used, and the value of this method is still being questioned. In 2008, we studied Orthoptera species richness and abundance in five vegetation types along a gradient of dune succession on the Baltic Sea island of Hiddensee (NE Germany) by comparing transect-count and pitfall-trapping data. Using transect counts, 12 species were detected in the study area. With pitfall traps, three chorto- and thamnobiont Ensifera species (C. dorsalis, M. roeselii and T. viridissima) were not caught at all, and it was only in low-growing and sparsely-vegetated grey dunes that all present species were detected. With pitfall traps, the proportion of present species recorded strongly declined with increasing height and density of the vegetation type. Assuming that transect counts are a good proxy for relative Orthoptera densities, densities ascertained by pitfall traps are strongly biased by vegetation structure and locomotive behaviour of the species. More than 80% of all individuals were caught in sparsely-vegetated grey dunes. Frequency patterns of the species also differed. Using pitfall traps, especially chortobiont species were significantly underrepresented. Qualitative and quantitative sampling of Orthoptera using pitfall traps seems only reasonable in habitats with low and sparse vegetation and a high proportion of geobiont species.     

An investigation into the effects of stimulators of fluid production on Locusta Malpighian tubule intracellular elemental composition

The intracellular elemental concentrations of Na, K, P, S, Cl and Mg in the type 1 cells of Malpighian tubules of Locusta migratoria L. have been measured using electron probe X-ray microanalysis. The effects of in vitro stimulation with 1 mM cAMP and corpora cardiaca extract (CC-extract) on the elemental concentrations have been quantified. The distribution of elements, particularly Na, K and Cl is not homogeneous in control cells, and concentration gradients exist within the cytoplasm. Dibutyryl-cAMP (DB-cAMP) caused a decrease in [K]_i without disrupting the gradient which increased from the basal to the apical surface, the apical [Na]_i was increased as was the [Cl]_i. In contrast, in vitro application of CC-extract did not cause changes to the intracellular elemental composition as compared with control cells These data are consistent with the interpretation that exogenous cAMP only partially activated the full stimulatory response of Malpighian tubule cells observed with CC-extract. The changes observed in the density and elemental composition of the `dark bodies' in response to DB-cAMP and CC-extract stimulation suggest that these structures have a role in the ionic economy of Malpighian tubule cells. Accepted: 6 April 1999     

Microsilica as antigen carrier and adjuvant in the Atlantic salmon (Salmo salarL.)

Bovine serum albumin and a glycine/HCl extract fromAeromonas salmonicidawere most effectively adsorbed to microsilica particles at pH 5·0 compared with pHs of 6·0, 7·0, 8·0 and 9·0. Atlantic salmon were immunised by intraperitoneal injection of the glycine/HCl extract fromA. salmonicidaadsorbed to microsilica. Antibody titres againstA. salmonicidaantigens demonstrated a prominent adjuvant effect of the microsilica 8 weeks after immunisation compared with soluble antigens. The duration of the antibody response suggests that microsilica may have some depot effect. The antibody response was, however, lower than the response obtained with Freund's complete adjuvant. Microsilica stimulated the respiratory burst activity in cultured Atlantic salmon head kidney macrophages. Some side effects of the microsilica were observed. Adhesions between abdominal organs and between the organs and the peritoneum were distinct. In addition, a dark greyish pigmentation at the sites of adhesion was evident. Cultured macrophages in the presence of high concentrations of microsilica resulted in toxic effects on the cells.     

Highly Responsive Bioinspired AgNPs Probe for the Precise Colorimetric Detection of the Mn(II) in Aqueous Systems

A green, rapid, and cost-effective probe for the precise colorimetric detection of Mn(II) ions has been investigated. The AgNPs were prepared via heating method by utilizing the extract obtained from Bhilwa (Semecarpus anacardium Linn) nuts (B−AgNPs). The Mn(II) ions induce the aggregation of B−AgNPs, resulting in color changes from yellowish brown to dark red along with the red shift in the surface plasmon resonance (SPR) peak from 404 to 432 nm. The aggregation of B−AgNPs was further confirmed by FTIR, HRTEM, and DLS techniques. The developed probe displayed an excellent linear response towards Mn(II) ions in the linear range from 20 to 0.001 ppm. In comparison to the currently available methods for the detection of Mn(II), the proposed probe provides an enhanced detection limit, i.e., 0.001 ppm. The developed colorimetric probe can be successfully applied for the detection of Mn(II) ions in water samples (pond water), thus demonstrating its potential use in field applications.

     

Catches in pitfall traps in relation to mean densities of carabid beetles

Summary Based on continuous pitfall catches summed over the whole activity period for the carabid beetles Pterostichus versicolor Sturm and Calathus melanocephalus L., a satisfactorily linear relationship is presented between the mean densities in several habitats and in different years and the numbers of beetles trapped. This means that with the help of continuous pitfall sampling a reliable relative measure of the sizes of carabid populations can be obtained.Simulation experiments show that for individuals of P. versicolor the distances covered each day should be represented by strips of some width instead of by lines to obtain numbers trapped that equal the field data. The influence on numbers trapped of the high mobility of beetles in unfavorable habitats is probably not significant. Simulation experiments with C. melanocephalus indicate that a much lower capture efficiency than for P. versicolor has to be programmed to fit the simulation results with the field data.The catch from different types of pitfalls is not always proportional to trap perimeter due to different vegetation cover of the immediate trap surroundings and to different kinds of roofs placed over the pitfalls. For the same species the capture efficiency of a pitfall can also change throughout the season.Simulation experiments show that the number and shape of the pitfalls need not influence the catches, provided that the traps keep the same total perimeter and are broadly spaced.Remodelling of some data from the literature reveals that the linear relationship between mean densities and year-catches in pitfalls is probably a general one among carabid species. This leads to the hypothesis that carabid beetles have to work through a fixed reproductive program each year by means of an almost constant total amount of locomotory activity which is realized step by step during spells of suitable weather.Some recommendations are given for intraspecific and interspecific comparisons of pitfall catches between sites and years.Communication no. 196 of the Biological Station of the Agricultural University (Wageningen), Wijster (Drenthe), The Netherlands     

Assessment of the effects of transgenic Bt cotton Bollgard II on the abundance of nontarget arthropods in Burkina Faso

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