The investigations were financially supported by the Division for Earth and Life Sciences of the Netherlands Organization for Scientific Research (grant 833.13.004), the Sci-Tech Landing Projection of Higher Education of Jiangxi Province (KJLD14030) and The Cultivation Plan for Young Scientists of Jiangxi Province (Jinggang star 20153BCB23014). We thank Daomeng Fu, Zhigang Li and Xiaolong Huang for their help in producing the movie.

1. Modification of a Leaf Blower-vac for Suction Sampling
<ol>
	<li>Collect all parts listed in the Materials List.</li>
	<li>Connect all polyvinyl chloride (PVC) pipes with unplasticized polyvinyl chloride (U-PVC) glue (pipes 1-2-3-4-5 and 6-7).</li>
	<li>Drill three holes that are evenly distributed around the suction mouth of the machine.</li>
	<li>Connect the machine to the end 1 of PVC pipe 1-5 by inserting one screw into each of the three holes. Do not use glue to connect pipe end 1 to the machine because the connection should be reversible to clean the fan. 
	Note: In case the diameter of the suction mouth of the machine differs from the model described here, the diameter of pipe end 1 should be adjusted to fit the machine seamlessly.</li>
	<li>Add 2 layers of thread seal tape to pipe ends 5 and 6.</li>
	<li>Put the piece of metal gauze between the hose and the mouth part (PVC pipes 6 and 7) to prevent the sampling net from being sucked into the machine. Use metal gauze with a mesh diameter between 0.5 mm and 0.5 cm.</li>
	<li>Connect the hose to pipe ends 5 and 6 with metal clamp hoops.</li>
</ol>
2. Prepare the Sampling Enclosure
<ol>
	<li>Remove the bottom from a plastic bucket (50 L, 40 cm bottom diameter). This size of the enclosure covers 2-4 rice hills in a&#160;transplanted rice field, depending on crop stage24.</li>
	<li>Attach a nylon mesh sleeve, with a length of 1 m, to the top of the bucket using a rubber band. For this sleeve, use a mesh size that is small enough to prevent the escape of the smallest target arthropods. Use a diameter less than 0.5 mm.</li>
</ol>
3. Field Application of the Modified Leaf Blower-vac for Suction Sampling
<ol>
	<li>Use two persons to operate the device in the field. One person operates the blower-vac and the other handles the bucket enclosure and the sampling nets.</li>
	<li>Start the machine.</li>
	<li>Insert a sampling net into the mouth part of the blower-vac and fix it with a rubber band. For the net, use a mesh size that is small enough to catch the smallest target arthropods, but does not create obvious airflow resistance. Use the light nylon material with a mesh diameter between 0.2-0.5 mm.</li>
	<li>Place the enclosure quickly over the plants at a random location in the field and push the bottom of the bucket firmly into the soil. Make sure that the sleeve is closed to prevent arthropods from escaping from the top of the enclosure.</li>
	<li>Remove all arthropods from inside the enclosure in a top-down spiraling way, for a standardized sampling duration. For rice crops in the vegetative and reproductive stages, use sampling durations of 1 and 2 min, respectively.</li>
	<li>After finishing the sample, remove the rubber band from the sampling net, quickly close the net and take it out of the mouth part of the blower-vac and close it with a knot, while keeping the machine running.</li>
	<li>Repeat steps 3.2 to 3.5 at random locations in the field for the next samples. The number of replications depends on the variation in the spatial distribution of arthropods in the field, the required accuracy of the estimate and the purpose of the study. Typically, six replicates will give a good impression of the arthropod community and species abundances.</li>
</ol>

<ol>
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New. 17, 30-31 (1992).</li><li>Domingo, I., Schoenly, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+suction+apparatus+for+sampling+invertebrate+communities+in+flooded+rice.">An improved suction apparatus for sampling invertebrate communities in flooded rice.</a> Int. Rice Res. New. 23 (2), 38-39 (2012).</li><li>Moorman, C. E., Plush, C. J., Orr, D. B., Reberg-Horton, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beneficial+Insect+Borders+Provide+Northern+Bobwhite+Brood+Habitat.">Beneficial Insect Borders Provide Northern Bobwhite Brood Habitat.</a> PLoS ONE. 8 (12), e83815 (2013).</li><li>Bambaradeniya, C. N. 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The authors have nothing to disclose.

Suction sampling is one of many possible methods to sample arthropod communities in crops. For scientific research in rice systems, suction sampling is an appropriate option because the method provides absolute estimates of arthropod densities, it is non-destructive, and &#8212; in contrast to visual counts &#8212; allows collection and storage of samples for later processing. Compared to the commercially available D-vac, the blower-vac is smaller, lighter and easier to handle in (flooded) rice fields and also easier to combine with an enclosure. For example, a blower-vac weighs about 6 kg, whereas the backpack D-vac model, presented as the international standard for insect sampling, has a weight 12 kg11. More importantly, the sampling efficiency of the blower-vac is higher than the D-vac16,17, while the cost of the blower-vac is less. The modification of a leaf blower-vac into a suction sampler does not require special skills or equipment and takes less than an hour after all additional parts have been collected. The blower-vac described here is easier to construct and operate than versions described previously in the literature16,17, and the required parts (Table 1) are standard construction materials that are widely available. This makes the blower-vac also accessible to researchers with small budgets in developing countries.
The power and displacement of the engine determines the suction force of the blower-vac. Here we recommend a machine with a power between 0.7-1.2 kW and a displacement between 25-35 cc, which is adequate for sampling the plant-dwelling arthropod community in rice. The length of the flexible plastic hose and the diameter of the sucking mouth part (pipe 7) are critical for a good sampling performance. A hose that is too long will reduce the suction power, whereas a hose that is too short will be inconvenient to use during sampling. Similarly, a mouth part with too large a diameter will reduce the suction power, whereas a diameter that is too small will reduce the sampling efficiency due to the small surface. The sampling efficiency depends critically on the sampling duration. If sampling is conducted throughout the growing season, the sampling duration may have to be adjusted to the plant size, structure, and planting density to maintain a similar level of efficiency. Sampling efficiency should be checked by careful visual inspection of the enclosed area after sampling. If there are still arthropods present, the sampling duration must be increased. The recommended sampling durations for rice crops in the vegetative stage is 1 minute&#160;and in the reproductive and ripening stages it is 2 minutes.
Suction sampling with the blower-vac can be conducted in flooded fields, while alternative methods, such as pitfall and beat sheet sampling are not feasible in standing water. The blower-vac can also be used to sample the arthropod community on the water surface of flooded rice fields (e.g., predatory water bugs), as the machine is capable of sucking in some water. However, it is not recommended for sampling aquatic arthropods as the motor may stop running when the mouth part is inserted deeply into the water and the airflow is blocked. Apart from rice, the blower-vac can also be used in other crops and non-crop habitat, as long as the height and structure of the vegetation allows proper placement of the enclosure25.
Our blower-vac suction sampling method is non-destructive. Almost all arthropods collected in the sampling net survived, including those soft bodies such as mosquitos and damselflies. The application of this method, however, has some limitations and drawbacks. The blower-vac needs to be operated by two persons. Carrying the blower-vac in the field will result in some disturbance, and therefore this method may underestimate disturbance-sensitive species such as grasshoppers. Fast and abrupt placement of the enclosure in a relatively undisturbed area in the forward direction of movement may limit this potential bias. The loud noise of the blower-vac machine may also cause disturbance, and sampling at night in residential areas is not recommended. The method is not suitable for sampling highly mobile flying insects, such as predatory Odonata or larger hymenopterous parasitoids. As with any sampling method, the combination of the blower-vac with other methods, such as sweep net sampling or destructive harvesting of plants, can provide a more complete and balanced assessment of the arthropod community26.

Repeated assessment of the abundance and diversity of phytophagous and entomophagous arthropods in crops is needed for ecological studies of population dynamics and species interactions, including the study of biological control. Rice is a major staple food, with a high potential for biocontrol by entomophagous arthropods1,2, but which can be disrupted by insecticides3. The diversity of arthropods in rice crops can be high, and arthropod species occupy various crop strata (e.g., ground, stem, canopy, flowers), differ in mode of movement (e.g., walking, jumping, flying) and foraging strategy (e.g., sessile sucking insects, hunting predators and flower visiting pollinators)4.
There is a wide range of arthropod sampling techniques, each with strengths and weaknesses. For instance, pitfall traps can be used to sample ground-dwelling arthropods, but provide activity-dependent relative population estimates5,6. Sweep nets can be used to sample fast-flying insects in the canopy7-9, but give relative estimates of arthropod abundance. The beat sheet method can be used to sample the plant-dwelling arthropod community and provides absolute estimates of arthropod abundance, but it cannot be used effectively in flooded crop fields such as rice paddies10.
Suction sampling, when conducted in combination with an enclosure covering a standardized area of the field, provides absolute estimates of the densities of plant-dwelling arthropods. This method can also be used in flooded rice. Samples can be stored for later processing and identification. The Dietrick vacuum (D-vac)11 is the first commercially developed suction sampler. Although D-vacs are still widely used12-14, they are relatively expensive, have a limited suction force15 and are relatively heavy, which makes them hard to handle in flooded rice fields16. Arida and Heong 16 developed a suction sampler using a petrol-driven leaf blower-vac, and this prototype was further refined by Domingo and Schoenly 17. Advantages of the blower-vac suction sampler as compared to the D-vac are that it is much cheaper and easier to handle.
Although the blower-vac suction sampling method has been used in many ecological studies18-23, the instructions for its modification and application have not been clearly described. Here we present a video-based, detailed description of the modification and application of a petrol-powered leaf blower-vac for suction sampling of arthropod populations in flooded rice fields. The modification is inspired by Arida and Heong 16 and Domingo and Schoenly 17, but the design has been further simplified compared to these original publications, facilitating construction and use.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Machine</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Leaf blower-vac</td>
			<td>We used Oleo-Mac BV300, Made in Italy</td>
			<td>Power: 1.0 kW, Displacement: 30.5 cc, Max air volume: 720 m&#179;/h, Max air speed: 70 m/sec, Weight: 4.5 kg, Diameter of suction mouth: 113 mm&#160;</td>
			<td>There are many different brands and models available. For comparable performance, the specifications concerning power and air speed should be similar to those presented here.&#160;</td>
		</tr>
		<tr>
			<td colspan="2">Additional parts for modification</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PVC pipe 1</td>
			<td></td>
			<td>Outer &#248; of end connected to the machine: 112 mm, Inner &#248; of end connected to PVC pipe 2: 110 mm</td>
			<td>This is the cover of a &#248; 110 mm PVC pipe</td>
		</tr>
		<tr>
			<td>PVC pipe 2</td>
			<td></td>
			<td>Outer &#248;: 110 mm, Length: 10 cm</td>
			<td>Normal outer &#248; 110 mm PVC pipe; to connect PVC pipe 1 and 3</td>
		</tr>
		<tr>
			<td>PVC pipe 3</td>
			<td></td>
			<td>Inner &#248; of big end: 110 mm, Inner &#248; of small end: 50 mm</td>
			<td>PVC &#248; 110 mm to &#248; 50 mm downpipe reducer</td>
		</tr>
		<tr>
			<td>PVC pipe 4</td>
			<td></td>
			<td>Outer &#248;: 50 mm, Length: 5 cm</td>
			<td>Normal &#248; 50 mm PVC pipe; to connect PVC pipe 3 and 5</td>
		</tr>
		<tr>
			<td>PVC pipe 5</td>
			<td></td>
			<td>Inner &#248;: 50 mm and 32 mm, Outer &#248; of small part: 38 mm</td>
			<td>PVC &#248; 50 mm to &#248; 32 mm downpipe reducer</td>
		</tr>
		<tr>
			<td>Hose</td>
			<td></td>
			<td>Outer &#248;: 40 mm</td>
			<td>Wire-fortified, flexible plastic hose&#160;</td>
		</tr>
		<tr>
			<td>Metal gauze</td>
			<td></td>
			<td>Mesh &#248;: 1 mm, &#248;: 60 mm</td>
			<td>Prevent the sampling net from being sucked into the machine</td>
		</tr>
		<tr>
			<td>PVC pipe 6</td>
			<td></td>
			<td>Outer &#248; of small end: 38 mm, Inner &#248; of big end: 63 mm</td>
			<td>PVC &#248; 32 mm to &#248; 63 mm reducer</td>
		</tr>
		<tr>
			<td>PVC pipe 7</td>
			<td></td>
			<td>Outer &#248;: 63 mm, Length: 25 cm</td>
			<td>Normal outer &#248; 63mm PVC pipe</td>
		</tr>
		<tr>
			<td>U-PVC glue</td>
			<td></td>
			<td></td>
			<td>U-PVC glue; to connect PVC parts</td>
		</tr>
		<tr>
			<td colspan="2">Metal clamp hoops (2)</td>
			<td>Flexible between &#248; 35 mm - 51 mm</td>
			<td>To connect the hose with the PVC pipes</td>
		</tr>
		<tr>
			<td colspan="2">Thread seal tape</td>
			<td>Width: 18mm</td>
			<td>Seal the hose-PVC connections</td>
		</tr>
		<tr>
			<td>Screws (3)</td>
			<td></td>
			<td>Length: 25mm</td>
			<td>To connect PVC pipe 1 with the suction mouth of the machine</td>
		</tr>
		<tr>
			<td colspan="2">Sampling net and enclosure</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="2">Sampling net</td>
			<td>Mesh size &#248;: 0.3 mm, Width of the mouth: 10 cm, Height: 30 cm</td>
			<td>The sampling net has a conical shape.</td>
		</tr>
		<tr>
			<td>Bucket</td>
			<td></td>
			<td>Bottom &#248;: 40 cm, Volume: 50 L</td>
			<td>Cut the bottom</td>
		</tr>
		<tr>
			<td>Nylon sleeve</td>
			<td></td>
			<td>Mesh size &#248;: 0.3 mm, Length: 1 m</td>
			<td>To cover the bucket as enclosure</td>
		</tr>
	</tbody>
</table>

modification and application of a leaf blower-vac for field sampling of arthropods

Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropod populations in rice. When used in combination with an enclosure, application of this sampling device provides absolute estimates of the populations of arthropods as numbers per standardized sampling area. The sampling efficiency depends critically on the sampling duration. In a mature rice crop, a two-minute sampling in an enclosure of 0.13 m2 yields more than 90% of the arthropod population. The device also allows sampling of arthropods dwelling on the water surface or the soil in rice paddies, but it is not suitable for sampling fast flying insects, such as predatory Odonata or larger hymenopterous parasitoids. The modified blower-vac is simple to construct, and cheaper and easier to handle than traditional suction sampling devices, such as D-vac. The low cost makes the modified blower-vac also accessible to researchers in developing countries.

A total of 295 arthropods were collected in 8 three-minute blower-vac samples from a rice crop in the ripening stage in Jiangxi Province, China, in September 2015. To determine the relationship between relative yield (proportion of the arthropods collected in the sample) and sampling duration, each sample was divided into six sub-samples of 30 seconds each. The mean number of individuals per sample was 36.9 &#177; 4.1 (mean &#177; SEM). A total of eight arthropod orders were found, with Hemiptera (28.8%), Araneae (27.5%) and Diptera (17.6%) being dominant (Figure 1). The relative yield, expressed as a percentage of the number of collected arthropods after three minutes, was 52.9% &#177; 5.1, 92.4% &#177; 1.9 and 97.3% &#177; 0.9 after 30 seconds, 2 and 2.5 minutes, respectively (Figure 2).
<img alt="Figure 1" src="/files/ftp_upload/54655/54655fig1.jpg" /> 
Figure 1. Species composition (at the order level) of arthropod samples in the suburbs of Nanchang city in Jiangxi Province, China. Eight samples were taken with a blower-vac of three-minutes each. Error bars represent the standard error of the mean. <a href="https://www.jove.com/files/ftp_upload/54655/54655fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/54655/54655fig2.jpg" /> 
Figure 2. Cumulative relative yield as a function of total sampling duration based on sub-samples of 30 seconds each. The total number of arthropods collected over a sampling duration of three minutes is set at 100%. No arthropods were found upon visual inspection after the last blower-vac sample. Error bars represent standard errors of the mean of eight three-minute samples. <a href="https://www.jove.com/files/ftp_upload/54655/54655fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

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Modification and Application of a Leaf Blower-vac for Field Sampling of Arthropods

Assessment of arthropod abundance in crops is critical for investigating population dynamics and species interactions. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropods in rice.

Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the ...

modification-application-leaf-blower-vac-for-field-sampling

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8.7K Views.  Wageningen University. Assessment of arthropod abundance in crops is critical for investigating population dynamics and species interactions. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropods in rice.

Video: Modification and Application of a Leaf Blower-vac for Field Sampling of Arthropods

Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation

Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals is often not well understood. Here we demonstrate an integrated field lysimetry and porewater sampling method for evaluating the mobility of chemicals applied to soils and established vegetation. Lysimeters, open columns made of metal or plastic, are driven into bareground or vegetated soils. Porewater samplers, which are commercially available and use vacuum to collect percolating soil water, are installed at predetermined depths within the lysimeters. At prearranged times following chemical application to experimental plots, porewater is collected, and lysimeters, containing soil and vegetation, are exhumed. By analyzing chemical concentrations in the lysimeter soil, vegetation, and porewater, downward leaching rates, soil retention capacities, and plant uptake for the chemical of interest may be quantified. Because field lysimetry and porewater sampling are conducted under natural environmental conditions and with minimal soil disturbance, derived results project real-case scenarios and provide valuable information for chemical management. As chemicals are increasingly applied to land worldwide, the described techniques may be utilized to determine whether applied chemicals pose adverse effects to human health or the environment.

Field lysimetry and porewater sampling allow researchers to evaluate the fate of chemicals applied to soils and established vegetation. The goal of this protocol is to demonstrate how to install required instrumentation and collect samples for chemical analysis during integrated field lysimetry and porewater sampling experiments.

Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals ...

Soil Sampling and Isolation of Entomopathogenic Nematodes (Steinernematidae, Heterorhabditidae)

Entomopathogenic nematodes (a.k.a. EPN) represent a group of soil-inhabiting nematodes that parasitize a wide range of insects. These nematodes belong to two families: Steinernematidae and Heterorhabditidae. Until now, more than 70 species have been described in the Steinernematidae and there are about 20 species in the Heterorhabditidae. The nematodes have a mutualistic partnership with Enterobacteriaceae bacteria and together they act as a potent insecticidal complex that kills a wide range of insect species.
Herein, we focus on the most common techniques considered for collecting EPN from soil. The second part of this presentation focuses on the insect-baiting technique, a widely used approach for the isolation of EPN from soil samples, and the modified White trap technique which is used for the recovery of these nematodes from infected insects. These methods and techniques are key steps for the successful establishment of EPN cultures in the laboratory and also form the basis for other bioassays that consider these nematodes as model organisms for research in other biological disciplines. The techniques shown in this presentation correspond to those performed and/or designed by members of S. P. Stock laboratory as well as those described by various authors.

Soil Sampling and Isolation of Entomopathogenic Nematodes Steinernematidae, Heterorhabditidae

Entomopathogenic nematodes are soil-inhabiting roundworms that parasitize a wide range of insects. We demonstrate sampling methods used for the isolation of these nematodes from the soil using two techniques: the insect baiting and the modified White trap, for the recovery of nematodes from soil samples and infected insect cadavers, respectively.

Entomopathogenic nematodes (a.k.a. EPN) represent a group of soil-inhabiting nematodes that parasitize a wide range of insects. These nematodes belong to ...

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% fine dust formation within the EU15. But NH3 emissions also mean a considerable loss of nutrients. Many studies on NH3 emission from organic and mineral fertilizer application have been performed in recent decades. Nevertheless, research related to NH3 emissions after application fertilizers is still limited in particular with respect to relationships to emissions, fertilizer type, site conditions and crop growth. Due to the variable response of crops to treatments, effects can only be validated in experimental designs including field replication for statistical testing. The dominating ammonia loss methods yielding quantitative emissions require large field areas, expensive equipment or current supply, which restricts their application in replicated field trials. This protocol describes a new methodology for the measurement of NH3 emissions on many plots linking a simple semi-quantitative measuring method used in all plots, with a quantitative method by simultaneous measurements using both methods on selected plots. As a semi-quantitative measurement method passive samplers are used. The second method is a dynamic chamber method (Dynamic Tube Method) to obtain a transfer quotient, which converts the semi-quantitative losses of the passive sampler to quantitative losses (kg nitrogen ha-1). The principle underlying this approach is that passive samplers placed in a homogeneous experimental field have the same NH3 absorption behavior under identical environmental conditions. Therefore, a transfer co-efficient obtained from single passive samplers can be used to scale the values of all passive samplers used in the same field trial. The method proved valid under a wide range of experimental conditions and is recommended to be used under conditions with bare soil or small canopies (&#60;0.3 m). Results obtained from experiments with taller plants should be treated more carefully.

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Ammonia emissions are a major threat to the environment by eutrophication, soil acidification and fine particle formation and stem mainly from agricultural sources. This method allows ammonia loss measurements in replicated field trials enabling statistical analysis of emissions and of relationships between crop development and emissions.

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% ...

Administering and Detecting Protein Marks on Arthropods for Dispersal Research

Monitoring arthropod movement is often required to better understand associated population dynamics, dispersal patterns, host plant preferences, and other ecological interactions. Arthropods are usually tracked in nature by tagging them with a unique mark and then re-collecting them over time and space to determine their dispersal capabilities. In addition to actual physical tags, such as colored dust or paint, various types of proteins have proven very effective for marking arthropods for ecological research. Proteins can be administered internally and/or externally. The proteins can then be detected on recaptured arthropods with a protein-specific enzyme-linked immunosorbent assay (ELISA). Here we describe protocols for externally and internally tagging arthropods with protein. Two simple experimental examples are demonstrated: (1) an internal protein mark introduced to an insect by providing a protein-enriched diet and (2) an external protein mark topically applied to an insect using a medical nebulizer. We then relate a step-by-step guide of the sandwich and indirect ELISA methods used to detect protein marks on the insects. In this demonstration, various aspects of the acquisition and detection of protein markers on arthropods for mark-release-recapture, mark-capture, and self-mark-capture types of research are discussed, along with the various ways that the immunomarking procedure has been adapted to suit a wide variety of research objectives.

Proteins are often used to mark arthropods for dispersal research. Methods for administering internal and external protein marks on arthropods are demonstrated. Protein mark detection techniques, either through indirect or sandwich enzyme-linked immunosorbent assays (ELISAs), are also illustrated.

Monitoring arthropod movement is often required to better understand associated population dynamics, dispersal patterns, host plant preferences, and other ...

Clean Sampling and Analysis of River and Estuarine Waters for Trace Metal Studies

Most of the trace metal concentrations in ambient waters obtained a few decades ago have been considered unreliable owing to the lack of contamination control. Developments of some techniques aiming to reduce trace metal contamination in the last couple of decades have resulted in concentrations reported now being orders of magnitude lower than those in the past. These low concentrations often necessitate preconcentration of water samples prior to instrumental analysis of samples. Since contamination can appear in all phases of trace metal analyses, including sample collection (and during preparation of sampling containers), storage and handling, pretreatments, and instrumental analysis, specific care needs to be taken in order to reduce contamination levels at all steps. The effort to develop and utilize "clean techniques" in trace metal studies allows scientists to investigate trace metal distributions and chemical and biological behavior in greater details. This advancement also provides the required accuracy and precision of trace metal data allowing for environmental conditions to be related to trace metal concentrations in aquatic environments.
This protocol that is presented here details needed materials for sample preparation, sample collection, sample pretreatment including preconcentration, and instrumental analysis. By reducing contamination throughout all phases mentioned above for trace metal analysis, much lower detection limits and thus accuracy can be achieved. The effectiveness of "clean techniques" is further demonstrated using low field blanks and good recoveries for standard reference material. The data quality that can be obtained thus enables the assessment of trace metal distributions and their relationships to environmental parameters.

Special care using "clean techniques" is required to properly collect and process water samples for trace metal studies in aquatic environments. A protocol for sampling, processing, and analytical procedures with the aim of obtaining reliable environmental monitoring data and results with high sensitivity for detailed trace metal studies is presented.

Most of the trace metal concentrations in ambient waters obtained a few decades ago have been considered unreliable owing to the lack of contamination ...

Reliable Method for Assessing Seed Germination, Dormancy, and Mortality under Field Conditions

We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester fabric and glue can be folded and glued to construct a strip of compartments that house seeds and identifying information, while allowing contact with soil leachate, water, microorganisms, and ambient temperature. Strips may be constructed with a wide range of compartment numbers and sizes and allow the researcher to house a variety of genotypes within a single species, different species, or seeds that have experienced different treatments. As opposed to individual seed packets, strips are more easily retrieved as a unit. While replicate packets can be included within a strip, different strips can act as blocks or can be retrieved at different times for observation of seed behavior over time. We used a high temperature glue gun to delineate compartments and sealed the strips once the seed and tags identifying block and removal times were inserted. The seed strips were then buried in the field at the desired depth, with the location marked for later removal. Burrowing animal predators were effectively excluded by use of a covering of metal mesh hardware cloth on the soil surface. After the selected time interval for burial, strips were dug up and seeds were assessed for germination, dormancy and mortality. While clearly dead seeds can often be distinguished from ungerminated living ones by eye, dormant seeds were conclusively identified using a standard Tetrazolium chloride colorimetric test for seed viability.

Here we present a protocol for assessing seed survivorship, germination and dormancy under field conditions using buried, labeled seed strips and tetrazolium chloride (TZ) viability testing.

We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester ...

Wastewater Irrigation Impacts on Soil Hydraulic Conductivity: Coupled Field Sampling and Laboratory Determination of Saturated Hydraulic Conductivity

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. Rather than discharging treated wastewater to a stream, and thereby directly impacting the stream quality, the effluent is applied to forested and cropped land managed by the University. Concerns related to reductions in soil hydraulic conductivity occur when considering wastewater reuse. The methodology described in this manuscript, matching soil sample size with the size of the laboratory-based hydraulic conductivity measurement apparatus, provides the benefits of a relatively rapid collection of samples with the benefits of controlled laboratory boundary conditions. The results suggest that there may have been some impact of wastewater reuse on the soil&#39;s ability to transmit water at deeper depths in the depressional areas of the site. Most of the reductions in the soil hydraulic conductivity in the depressions appear to be related to the depth from which the sample was collected, and by inference, associated with the soil structural and textural differences.

Here we present a methodology which matches a soil sample size and a hydraulic conductivity measurement device to prevent the so-called wall flow along the inside of the soil container from being erroneously included in water flow measurements. Its use is demonstrated with samples collected from a wastewater irrigation site.

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. ...

Construction of a Low-cost Mobile Incubator for Field and Laboratory Use

Incubators are essential for a range of culture-based microbial methods, such as membrane filtration followed by cultivation for assessing drinking water quality. However, commercially available incubators are often costly, difficult to transport, not flexible in terms of volume, and/or poorly adapted to local field conditions where access to electricity is unreliable. The purpose of this study was to develop an adaptable, low-cost and transportable incubator that can be constructed using readily available components. The electronic core of the incubator was first developed. These components were then tested under a range of ambient temperature conditions (3.5 &#176;C - 39 &#176;C) using three types of incubator shells (polystyrene foam box, hard cooler box, and cardboard box covered with a survival blanket). The electronic core showed comparable performance to a standard laboratory incubator in terms of the time required to reach the set temperature, inner temperature stability and spatial dispersion, power consumption, and microbial growth. The incubator set-ups were also effective at moderate and low ambient temperatures (between 3.5 &#176;C and 27 &#176;C), and at high temperatures (39 &#176;C) when the incubator set temperature was higher. This incubator prototype is low-cost (&lt; 300 USD) and adaptable to a variety of materials and volumes. Its demountable structure makes it easy to transport. It can be used in both established laboratories with grid power or in remote settings powered by solar energy or a car battery. It is particularly useful as an equipment option for field laboratories in areas with limited access to resources for water quality monitoring.

This paper describes a method for building an adaptable, low-cost and transportable incubator for microbial testing of drinking water. Our design is based on widely available materials and can operate under a range of field conditions, while still offering the advantages of higher-end laboratory-based models.

Incubators are essential for a range of culture-based microbial methods, such as membrane filtration followed by cultivation for assessing drinking water ...

A New Portable In Vitro Exposure Cassette for Aerosol Sampling

This protocol introduces a new in vitro exposure system, capable of being worn, including its characterization and performance. Air-liquid interface (ALI) in vitro exposure systems are often large and bulky, making transport to the field and operation at the source of emission or within the breathing zone difficult. Through miniaturization of these systems, the lab can be brought to the field, expediting processing time and providing a more appropriate exposure method that does not alter the aerosol prior to contacting the cells. The Portable In vitro Exposure Cassette (PIVEC) adapts a 37 mm filter cassette to allow for in vitro toxicity testing outside of a traditional laboratory setting. The PIVEC was characterized using three sizes of copper nanoparticles to determine deposition efficiency based on gravimetric and particle number concentration analysis. Initial cytotoxicity experiments were performed with exposed lung cells to determine the ability of the system to deposit particles while maintaining cell viability. The PIVEC provides a similar or increased deposition efficiency when comparing to available perpendicular flow in vitro exposure devices. Despite the lower sample throughput, the small size gives some advantages to the current in vitro ALI exposure systems. These include the ability to be worn for personal monitoring, mobility from the laboratory to the source of emission, and the option to set-up multiple systems for spatial resolution while maintaining a lower user cost. The PIVEC is a system capable of collecting aerosols in the field and within the breathing zone onto an air-interfaced, in vitro model.

A New Portable In Vitro Exposure Cassette for Aerosol Sampling

Here, we present a protocol to perform portable cellular aerosol exposures and measure cellular response. The method uses cells, grown at the air-liquid interface, mimicking in vivo physiology. Cellular response to copper nanoparticle aerosols was observed as oxidative stress through reactive oxygen species generation and cytotoxicity as lactate dehydrogenase release.

This protocol introduces a new in vitro exposure system, capable of being worn, including its characterization and performance. Air-liquid interface (ALI) ...

Sampling for Estimating Frankliniella Species Flower Thrips and Orius Species Predators in Field Experiments

The western flower thrips, Frankliniella occidentalis (Pergande), is a polyphagous pest that has been spread worldwide. The extensive use of insecticides in attempts to control its populations eliminates natural enemies and competitor flower thrips species, thereby increasing its populations. An unsustainable situation develops with concomitant resistant pest populations, secondary pest outbreaks, and environmental degradation. Integrated pest management utilizes knowledge of pest and natural enemy relationships to implement tactics that are environmentally friendly and sustainable. Minute pirate bugs are the most important worldwide predators of thrips. They can suppress and ultimately control Frankliniella species flower thrips. Flower samples taken at least weekly are needed to understand predator-prey dynamics. Shown here is the sampling of the flowers of fruiting vegetables and companion plants to estimate the densities of individual thrips and minute pirate bug species. Representative data illustrates how the protocol is used to determine the efficacy of management tactics over time and how to evaluate the benefits of predation by minute pirate bugs. The sampling protocol is similarly adaptable to sampling thrips and minute pirate bugs in other plant species hosts.

Sampling for Estimating Frankliniella Species Flower Thrips and Orius Species Predators in Field Experiments

Presented here is a protocol to determine the number of thrips and minute pirate bug predators in crops over multiple dates in field experiments. Also illustrated is how to determine the efficacy of management tactics against thrips and evaluate the benefits of predation by minute pirate bugs.

The western flower thrips, Frankliniella occidentalis (Pergande), is a polyphagous pest that has been spread worldwide. The extensive use of insecticides ...