Trap style influences wild pig behavior and trapping success

Despite the efforts of many natural resource professionals, wild pig (Sus scrofa) populations are expanding in many areas of the world. Although many creative techniques for controlling pig populations are being explored, trapping has been and still is the most commonly used method of population control for many public and private land managers. We conducted an observational study to examine the efficiency of 2 frequently used trap styles: a small, portable box-style trap and a larger, semi-permanent, corral-style trap. We used game cameras to examine patterns of trap entry by wild pigs around each style of trap, and we conducted a trapping session to compare trapping success between trap styles. Adult female and juvenile wild pigs entered both styles of trap more readily than did adult males, and adult males seemed particularly averse to entering box traps. Less than 10% of adult male visits to box traps resulted in entries, easily the least percentage of any class at any style of trap. Adult females entered corral traps approximately 2.2 times more often per visit than box traps and re-entered corral traps >2 times more frequently. Juveniles entered and re-entered both box and corral traps at similar rates. Overall (all-class) entry-per-visit rates at corral traps (0.71) were nearly double that of box traps (0.37). Subsequent trapping data supported these preliminary entry data; the capture rate for corral traps was >4 times that of box traps. Our data suggest that corral traps are temporally and economically superior to box traps with respect to efficiency; that is, corral traps effectively trap more pigs per trap night at a lower cost per pig than do box traps. © 2011 The Wildlife Society.     

Electronic Trap States in Methanofullerenes

The trap states in three fullerene derivatives, namely PC₆₁BM ([6,6]‐phenyl C₆₁ butyric acid methyl ester), bisPC₆₁BM (bis[6,6]‐phenyl C₆₁ butyric acid methyl ester) and PC₇₁BM ([6,6]‐phenyl C₇₁ butyric acid methyl ester), are investigated by means of thermally stimulated current measurements (TSC). Thereby, the lower limit of the trap densities for all studied methanofullerenes is on the order of 10²² m^?3, with the highest trap density in bisPC₆₁BM and the lowest in PC₆₁BM. Fractional TSC measurements on PC₆₁BM reveal a broad trap distribution instead of discrete trap levels, with activation energies ranging from 15 meV to 270 meV and the maximum at about 75 meV. The activation energies of the most prominent traps in the other two fullerene derivatives are significantly higher, at 96 meV and 223 meV for PC₇₁BM and 184 meV for bisPC₆₁BM, respectively. The influence of these findings on the performance of organic solar cells is discussed.     

Exploring Mouse Trap History

Since intelligent design (ID) advocates claimed the ubiquitous mouse trap as an example of systems that cannot have evolved, mouse trap history is doubly relevant to studying material culture. On the one hand, debunking ID claims about mouse traps and, by implication, also about other irreducibly complex systems has a high educational value. On the other hand, a case study of mouse trap history may contribute insights to the academic discussion about material culture evolution. Michael Behe argued that mouse traps cannot trap mice with any part missing; therefore, they cannot have a precursor with one part less, therefore, cannot have a continuous history, and therefore, cannot have evolved. The patented and seminal precursor of current flat snap traps, however, had one part less, because spring and striker were formed of one wire. Secondly, historical records that reach back into the Bronze Age suggest that its history continued for a very long time. Thirdly, all prerequisites for evolution (variation, transmission, and selection) abound in mouse trap populations. Hence, Behe’s triple-jump conclusion about mouse traps is false each step. There is no, in principle, impossibility for mouse traps to evolve. An evolutionary account of mouse trap history also has academic merits beyond its educational value. Three important conclusions can be drawn: (1) reticulate phylogenies of artifact systems may be resolvable as overlapping, but branching, phylogenies of parts; (2) homologous ideas may be realized by analogous material, that is, phylogenies of information do not necessarily coincide with those of material parts; (3) recombination of parts between different artifact systems increases the cumulative nature of cultural evolution.     

分泌蛋白特异性基因陷阱的设计与验证

蛋白质分子向细胞外分泌的过程有赖于信号肽的介导.基因陷阱是功能性基因克隆的一种有效方法,经典的基因陷阱以geo作为报告基因,对所克隆的基因类型没有选择性.将绿脓杆菌外毒素、2A序列、IL-2受体穿膜区以及新霉素磷酸转移酶的基因依次融合构建新型报告基因——peo,该报告基因能够特异性地甄别具有信号肽编码序列的基因.为验证peo对信号肽编码序列的特异性甄别作用,以peo为报告基因,构建了3种质粒载体,分别模拟用基因陷阱载体进行筛选时可能出现的3种情况,通过转染HeLa细胞、G418筛选以及碱性磷酸酶检测,证明peo能够有效地区分信号肽和非信号肽编码序列,以peo为报告基因改造的基因陷阱载体可以用于分泌蛋白基因的筛选.     

A Single-Sampling Hair Trap for Mesocarnivores

Abstract Although techniques to analyze and quantify DNA-based data have progressed, methods to noninvasively collect samples lag behind. Samples are generally collected from devices that permit coincident sampling of multiple individuals. Because of cross-contamination, substantive genotyping errors can arise. We developed a cost-effective (US$4.60/trap) single-capture hair trap for American martens (Martes americana). In the field, traps effectively targeted martens; >75% of all hair samples were identified as marten. Eighty percent of marten hair (n = 180) contained sufficient quality for DNA-based analyses. This effective and affordable trap can be used by managers to monitor mesocarnivore populations noninvasively.     

A Microfluidic-based Hydrodynamic Trap for Single Particles

The ability to confine and manipulate single particles in free solution is a key enabling technology for fundamental and applied science. Methods for particle trapping based on optical, magnetic, electrokinetic, and acoustic techniques have led to major advancements in physics and biology ranging from the molecular to cellular level. In this article, we introduce a new microfluidic-based technique for particle trapping and manipulation based solely on hydrodynamic fluid flow. Using this method, we demonstrate trapping of micro- and nano-scale particles in aqueous solutions for long time scales. The hydrodynamic trap consists of an integrated microfluidic device with a cross-slot channel geometry where two opposing laminar streams converge, thereby generating a planar extensional flow with a fluid stagnation point (zero-velocity point). In this device, particles are confined at the trap center by active control of the flow field to maintain particle position at the fluid stagnation point. In this manner, particles are effectively trapped in free solution using a feedback control algorithm implemented with a custom-built LabVIEW code. The control algorithm consists of image acquisition for a particle in the microfluidic device, followed by particle tracking, determination of particle centroid position, and active adjustment of fluid flow by regulating the pressure applied to an on-chip pneumatic valve using a pressure regulator. In this way, the on-chip dynamic metering valve functions to regulate the relative flow rates in the outlet channels, thereby enabling fine-scale control of stagnation point position and particle trapping. The microfluidic-based hydrodynamic trap exhibits several advantages as a method for particle trapping. Hydrodynamic trapping is possible for any arbitrary particle without specific requirements on the physical or chemical properties of the trapped object. In addition, hydrodynamic trapping enables confinement of a "single" target object in concentrated or crowded particle suspensions, which is difficult using alternative force field-based trapping methods. The hydrodynamic trap is user-friendly, straightforward to implement and may be added to existing microfluidic devices to facilitate trapping and long-time analysis of particles. Overall, the hydrodynamic trap is a new platform for confinement, micromanipulation, and observation of particles without surface immobilization and eliminates the need for potentially perturbative optical, magnetic, and electric fields in the free-solution trapping of small particles.Download video file.^{(62M, mov)}     

The Annotation of Zebrafish Enhancer Trap Lines Generated with PB Transposon

An enhancer trap (ET) mediated by a transposon is an effective method for functional gene research. Here, an ET system based on a PB transposon that carries a mini Krt4 promoter (the keratin4 minimal promoter from zebrafish) and the green fluorescent protein gene (GFP) has been used to produce zebrafish ET lines. One enhancer trap line with eye-specific expression GFP named EYE was used to identify the trapped enhancers and genes. Firstly, GFP showed a temporal and spatial expression pattern with whole-embryo expression at 6, 12, and 24 hpf stages and eye-specific expression from 2 to 7 dpf. Then, the genome insertion sites were detected by splinkerette PCR (spPCR). The Krt4-GFP was inserted into the fourth intron of the gene itgav (integrin, alpha V) in chromosome 9 of the zebrafish genome, with the GFP direction the same as that of the itgav gene. By the alignment of homologous gene sequences in different species, three predicted endogenous enhancers were obtained. The trapped endogenous gene itgav, whose overexpression is related to hepatocellular carcinoma, showed a similar expression pattern as GFP detected by in situ hybridization, which suggested that GFP and itgav were possibly regulated by the same enhancers. In short, the zebrafish enhancer trap lines generated by the PB transposon-mediated enhancer trap technology in this study were valuable resources as visual markers to study the regulators and genes. This work provides an efficient method to identify and isolate tissue-specific enhancer sequences.     

Capture and Mortality Rates of Ducks in Selected Trap Types

ABSTRACT We evaluated different trap styles and related mortality of trapped ducks (Anas spp.) for 3 field seasons as part of the United States-Canada Cooperative Waterfowl Banding Program. During 2002, we evaluated 4 trap designs and caught 10,966 ducks. Trap style affected capture rates (P = 0.018, F₅ = 9.02), with Benning II and oval traps catching more ducks than cloverleaf and star traps. In 2003, we tested 3 trap styles and caught 10,849 ducks. Trap style affected duck capture rates (P < 0.01, F₅ = 15.16), with oval traps with 6-m lead panels catching more ducks than Benning II traps and cloverleaf traps. During 2004, we tested 3 trap styles and caught 11,737 ducks. Trap style affected capture rates (P < 0.01, F₅ = 11.23), with oval traps with 6-m leads catching more ducks than either the oval trap without leads or Benning II traps. Trap style affected mortality rates of ducks, but overall mortality of trapped ducks was low with a rate of 1.16% in 2002, 0.32% in 2003, and 0.17% in 2004; mortality was not a major problem in our study. Waterfowl managers may be able to catch more ducks using oval traps with leads without increasing mortality of captured ducks.     

Efficiency Evaluation of Nozawa-Style Black Light Trap for Control of Anopheline Mosquitoes

House-residual spraying and insecticide-treated bed nets have achieved some success in controlling anthropophilic and endophagic vectors. However, these methods have relatively low efficacy in Korea because Anopheles sinensis, the primary malaria vector, is highly zoophilic and exophilic. So, we focused our vector control efforts within livestock enclosures using ultraviolet black light traps as a mechanical control measure. We found that black light traps captured significantly more mosquitoes at 2 and 2.5 m above the ground (P < 0.05). We also evaluated the effectiveness of trap spacing within the livestock enclosure. In general, traps spaced between 4 and 7 m apart captured mosquitoes more efficiently than those spaced closer together (P > 0.05). Based on these findings, we concluded that each black light trap in the livestock enclosures killed 7,586 female mosquitoes per trap per night during the peak mosquito season (July-August). In May-August 2003, additional concurrent field trials were conducted in Ganghwa county. We got 74.9% reduction (P < 0.05) of An. sinensis in human dwellings and 61.5% reduction (P > 0.05) in the livestock enclosures. The black light trap operation in the livestock enclosures proved to be an effective control method and should be incorporated into existing control strategies in developed countries.     

Random versus Game Trail-Based Camera Trap Placement Strategy for Monitoring Terrestrial Mammal Communities

Camera trap surveys exclusively targeting features of the landscape that increase the probability of photographing one or several focal species are commonly used to draw inferences on the richness, composition and structure of entire mammal communities. However, these studies ignore expected biases in species detection arising from sampling only a limited set of potential habitat features. In this study, we test the influence of camera trap placement strategy on community-level inferences by carrying out two spatially and temporally concurrent surveys of medium to large terrestrial mammal species within Tanzania’s Ruaha National Park, employing either strictly game trail-based or strictly random camera placements. We compared the richness, composition and structure of the two observed communities, and evaluated what makes a species significantly more likely to be caught at trail placements. Observed communities differed marginally in their richness and composition, although differences were more noticeable during the wet season and for low levels of sampling effort. Lognormal models provided the best fit to rank abundance distributions describing the structure of all observed communities, regardless of survey type or season. Despite this, carnivore species were more likely to be detected at trail placements relative to random ones during the dry season, as were larger bodied species during the wet season. Our findings suggest that, given adequate sampling effort (> 1400 camera trap nights), placement strategy is unlikely to affect inferences made at the community level. However, surveys should consider more carefully their choice of placement strategy when targeting specific taxonomic or trophic groups.     

Evaluation of Live-Capture Techniques for Free-Ranging Wolverines

Abstract: Wolverines (Gulo gulo) are a rare carnivore and live-capture efforts often comprise a significant component of field research projects. Wolverine studies have used aerial, snowmobile, hand-capture, and live-trap capture techniques. We reviewed existing wolverine live-capture data to evaluate sex-related biases associated with capture technique. We modified round log live traps, developed a new portable wooden live trap, and evaluated effects of live trap type, trap-site selection, and seasonal timing of trapping on wolverine capture success. Aerial capture techniques had a positive bias for capture of male wolverines. Live-capture rates were highest for portable wooden traps and lowest for barrel traps. Trapping success was highest during March when snow conditions were amenable to wolverine travel and temperatures improved bait effectiveness. Traps in corridor habitats were more successful than traps in noncorridor habitats. This difference was more pronounced in environments with rugged topography. We provide guidance for live-trap operation, describe animal handling procedures, and provide detailed instructions for construction of modified round log and portable wooden wolverine live traps. These will benefit future wolverine studies by increasing trap effectiveness and reducing risk of injury and mortality to captured wolverines.     

Development of a Gravid Trap for Collecting Live Malaria Vectors Anopheles gambiae s.l.

Background

Effective malaria vector control targeting indoor host-seeking mosquitoes has resulted in fewer vectors entering houses in many areas of sub-Saharan Africa, with the proportion of vectors outdoors becoming more important in the transmission of this disease. This study aimed to develop a gravid trap for the outdoor collection of the malaria vector Anopheles gambiae s.l. based on evaluation and modification of commercially available gravid traps.

Methods

Experiments were implemented in an 80 m² semi-field system where 200 gravid Anopheles gambiae s.s. were released nightly. The efficacy of the Box, CDC and Frommer updraft gravid traps was compared. The Box gravid trap was tested to determine if the presence of the trap over water and the trap’s sound affected catch size. Mosquitoes approaching the treatment were evaluated using electrocuting nets or detergents added to the water in the trap. Based on the results, a new gravid trap (OviART trap) that provided an open, unobstructed oviposition site was developed and evaluated.

Results

Box and CDC gravid traps collected similar numbers (relative rate (RR) 0.8, 95% confidence interval (CI) 0.6–1.2; p = 0.284), whereas the Frommer trap caught 70% fewer mosquitoes (RR 0.3, 95% CI 0.2–0.5; p < 0.001). The number of mosquitoes approaching the Box trap was significantly reduced when the trap was positioned over a water-filled basin compared to an open pond (RR 0.7 95% CI 0.6–0.7; p < 0.001). This effect was not due to the sound of the trap. Catch size increased by 60% (RR 1.6, 1.2–2.2; p = 0.001) with the new OviART trap.

Conclusion

Gravid An. Gambiae s.s. females were visually deterred by the presence of the trapping device directly over the oviposition medium. Based on these investigations, an effective gravid trap was developed that provides open landing space for egg-laying Anopheles .     

Trap diversity and evolution in the family Droseraceae

We review trapping mechanisms in the carnivorous flowering plant family Droseraceae (order Caryophyllales). Its members are generally known to attract, capture, retain and digest prey animals (mainly arthropods) with active snap-traps (Aldrovanda, Dionaea) or with active sticky flypaper traps (Drosera) and to absorb the resulting nutrients. Recent investigations revealed how the snap-traps of Aldrovanda vesiculosa (waterwheel plant) and Dionaea muscipula (Venus’ flytrap) work mechanically and how these apparently similar devices differ as to their functional morphology and shutting mechanics. The Sundews (Drosera spp.) are generally known to possess leaves covered with glue-tentacles that both can bend toward and around stuck prey. Recently, it was shown that there exists in this genus a higher diversity of different tentacle types and trap configurations than previously known which presumably reflect adaptations to different prey spectra. Based on these recent findings, we finally comment on possible ways for intrafamiliar trap evolution.     

Effect of nestbox construction and colour on the occupancy and breeding success of nesting tits Parus spp.

Capsule Breeding performance was not affected, although variation in nestbox occupancy may result from perceived differences in protection from predators and insulation properties.

Aim To assess if nestboxes of different construction and colour were occupied differently by breeding tits and affected breeding success.

Methods A total of 292 nestboxes of different construction and colour were placed in a range of habitats and their occupancy, and the clutch size, brood size and number of young fledged of the birds that used them were measured.

Results Overall 272 tit nests were included in the analysis. Although there were species-related differences in the occupancy of the different types of nestboxes, more tits nested in the boxes constructed from woodcrete (64% of nests) compared to the wooden boxes (36%). More tits nested in green (72%) rather than brown boxes (28%) and in boxes with entrance holes (68%) rather than wedges (32%). The clutch size, brood size and number of young fledged did not vary in relation to nestbox type.

Conclusion Within the parameters of the experimental design of this study, tits are more likely to nest in woodcrete boxes than in wooden boxes, and in wooden boxes that are green and have holes rather than brown boxes with wedge entrances. It is likely that the smaller internal volume, internal darkness, insulating properties and perceived protection from predation were the reasons for these differences.     

A quantitative study of tissue dynamics in Venus's flytrap Dionaea muscipula (Droseraceae). II. Trap reopening

Changes in normalized cell length (NCL) and tissue volume densities (V_v) of five trap tissues were studied during reopening of fully closed traps of Venus's flytrap (Dionaea muscipula Ellis). Four trap-reopening stages were identified based on morphological changes observed in time-lapse video: (1) Sealed—the last stage of trap closure before the trap began to reopen; (2) Deappressed—characterized by a convex bulge in the upper region of the trap; (3) Release—in which the bulge region moved closer to the trap margins initiating lobe separation while the marginal tynes remained interdigitated; (4) Fully opened—the trap lobes assumed a morphology similar to that of a nonstimulated trap. Morphological changes associated with trap reopening occurred as a series of relatively fast (l-5h) and slow (10-15 h) movements and appeared to be a reversal of the morphologies observed during trap closure. However, comparison of changes in NCL of trap tissues during closure and reopening showed very little statistical correlation indicating that the tissue dynamics associated with trap closure were not simply reversed during reopening. Although the precise cell movements that provided driving force for trap morphological change were not delineated in this study, comparison of NCL data suggested that tissues in the trap lobe were alternately “active” and “quiescent” in temporally and regionally complex patterns. Changes in the NCL of analogous tissues on opposite sides of the mid-trap tissues within a trap region showed high positive correlation values, which indicated the possibility of coordinated activity in opposing tissues.     

Environmental impacts of wooden,plastic, and wood-polymer composite pallet: a life cycle assessment approach

Purpose

Waste recycling is one of the essential tools for the European Union’s transition towards a circular economy. One of the possibilities for recycling wood and plastic waste is to utilise it to produce composite product. This study analyses the environmental impacts of producing composite pallets made of wood and plastic waste from construction and demolition activities in Finland. It also compares these impacts with conventional wooden and plastic pallets made of virgin materials.

Methods

Two different life cycle assessment methods were used: attributional life cycle assessment and consequential life cycle assessment. In both of the life cycle assessment studies, 1000 trips were considered as the functional unit. Furthermore, end-of-life allocation formula such as 0:100 with a credit system had been used in this study. This study also used sensitivity analysis and normalisation calculation to determine the best performing pallet.

Result and discussion

In the attributional cradle-to-grave life cycle assessment, wood-polymer composite pallets had the lowest environmental impact in abiotic depletion potential (fossil), acidification potential, eutrophication potential, global warming potential (including biogenic carbon), global warming potential (including biogenic carbon) with indirect land-use change, and ozone depletion potential. In contrast, wooden pallets showed the lowest impact on global warming potential (excluding biogenic carbon). In the consequential life cycle assessment, wood-polymer composite pallets showed the best environmental impact in all impact categories. In both attributional and consequential life cycle assessments, plastic pallet had the maximum impact. The sensitivity analysis and normalisation calculation showed that wood-polymer composite pallets can be a better choice over plastic and wooden pallet.

Conclusions

The overall results of the pallets depends on the methodological approach of the LCA. However, it can be concluded that the wood-polymer composite pallet can be a better choice over the plastic pallet and, in most cases, over the wooden pallet. This study will be of use to the pallet industry and relevant stakeholders.

     

Trap closure and prey retention in Venus flytrap (Dionaea muscipula) temporarily reduces photosynthesis and stimulates respiration

Background and Aims

The carnivorous plant Venus flytrap (Dionaea muscipula) produces a rosette of leaves: each leaf is divided into a lower part called the lamina and an upper part, the trap, with sensory trigger hairs on the adaxial surface. The trap catches prey by very rapid closure, within a fraction of a second of the trigger hairs being touched twice. Generation of action potentials plays an important role in closure. Because electrical signals are involved in reduction of the photosynthetic rate in different plant species, we hypothesized that trap closure and subsequent movement of prey in the trap will result in transient downregulation of photosynthesis, thus representing the energetic costs of carnivory associated with an active trapping mechanism, which has not been previously described.

Methods

Traps were enclosed in a gas exchange cuvette and the trigger hairs irritated with thin wire, thus simulating insect capture and retention. Respiration rate was measured in darkness (R_D). In the light, net photosynthetic rate (A_N), stomatal conductance (g_s) and intercellular CO₂ concentration (c_i) were measured, combined with chlorophyll fluorescence imaging. Responses were monitored in the lamina and trap separately.

Key Results

Irritation of trigger hairs resulted in decreased A_N and increased R_D, not only immediately after trap closure but also during the subsequent period when prey retention was simulated in the closed trap. Stomatal conductance remained stable, indicating no stomatal limitation of A_N, so c_i increased. At the same time, the effective quantum yield of photosystem II (Φ_PSII) decreased transiently. The response was confined mainly to the digestive zone of the trap and was not observed in the lamina. Stopping mechanical irritation resulted in recovery of A_N, R_D and Φ_PSII.

Conclusions

We put forward the first experimental evidence for energetic demands and carbon costs during insect trapping and retention in carnivorous plants, providing a new insight into the cost/benefit model of carnivory.     

The Tauber Pollen Trap,a Discussion of Its Usefulness in Pollen Deposition Studies

In connection with pollen deposition studies some discrepancies between Tauber traps and open collectors were discovered. Field observations showed that the aerodynamic lid of the Tauber trap itself acted as a pollen trap by redeposition e.g. because of rainsplash. In an experiment coal dust in the size range of pollen was introduced in a turbulent air stream passing over the trap. Great quantities of coaldust were captured on the aerodynamic lid. By exposure to artificial rain it was observed that the splashing effect of raindrops brought coal dust into the sampler. By application of Corylus pollen on the aerodynamic lid and exposure to rain, it was found that great amount of pollen is transferred by raindrop splash to the trap. This contamination of the pollen contents of the trap is so serious that the usefulness of the Tauber trap for quantitative evaluation of the pollen deposition is doubted unless the trap is protected in some way. Further tests of this effect have been planned.     

Trap catches of the sweetpotato whitefly （Homoptera： Aleyrodidae） in the Imperial Valley, California, from 1996 to 2002

An outbreak of the sweetpotato whitefly, Bemisia tabaci （Gennadius）, biotype B occurred in the Imperial Valley, California in 1991. The insects destroyed melon crops and seriously damaged other vegetables, ornamentals and row crops. As a result of the need for sampling technology, we developed a whitefly trap （named the CC trap） that could be left in the field for extended time periods. We used the traps to monitor populations ofB. tabaci adults during year-round samplings from 1996 to 2002 to study variations in the weekly trap catches of the insect. The greatest number ofB. tabaci adults was recorded in 1996, followed by a continuing annual decrease in trap catches each year through 2002. The overall decline of B. tabaci is attributed in part to the adoption of an integrated pest management （IPM） program initiated in 1992 and reduced melon hectares from 1996 to 2002. Other factors may also have contributed to the population reductions. Seasonally, B. tabaci trap catches decreased during the late summer and fall concurrent with decreasing minimum tempera- tares that are suggested to be a significant factor affecting seasonal activity and reproduction.     

Trap cropping effect on oviposition behaviour of the leek moth Acrolepiopsis assectella and the diamondback moth Plutella xylostella

The potential of trap cropping as a pest control strategy was explored for two specialist moth species, where oviposition behaviour determines larval distribution. Oviposition behaviour was studied at three different scales: Individual plants in the laboratory, small scale field experiments with and without cages, and medium scale field trials. The study insects were the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), a specialist on Brassica species and the leek moth, Acrolepiopsis assectella (Z.) (Lepidoptera: Acrolepiidae), a specialist on Allium species. The diamondback moth preferred Indian mustard, Brassica juncea (L.) over white cabbage, B. oleracea var alba (L.). The leek moth did not show preference when offered leek, Allium porrum (L.) and chives, A. schoenoprasum (L.). However, the leek moth did prefer to oviposit on plants of a larger biomass over smaller plants. In both the small scale and the medium scale field studies the trap crops reduced the number of eggs laid on the primary crop. The total number of eggs laid in the monoculture and the trap crop treatments were the same in the small scale field cage study, but the females distributed their eggs differently. More eggs were laid on trap crops compared with primary crops and this pattern was also validated in the medium scale field trials. In this study only the direct effects of trap cropping were considered. Indirect effects of vegetation diversity such as enhancement of natural enemies could potentially increase the efficacy of trap cropping.