Non-lethal Monitoring Research Articles

BEE‐quest of the nest: A novel method for eDNA‐based, nonlethal detection of cavity‐nesting hymenopterans and other arthropods

AbstractWild bee populations are facing strong declines due to a variety of stressors, such as habitat loss and pesticide use. Research focused on wild bees has increased over the last three decades, yet species identifications are still relying on lethal sampling approaches, followed by time‐ and labor‐intensive pinning and morphological analysis by experts. The use of DNA metabarcoding for species detection offers a time‐ and cost‐effective complement to traditional approaches and can potentially facilitate nonlethal sampling. We developed a DNA metabarcoding workflow to identify cavity‐nesting Hymenoptera using environmental DNA collected from vacated nest tubes. We compared different nest sizes and sample types and assessed the effect of these parameters on Hymenoptera species detection rates. We also tested whether our method could detect multiple species in mixed‐species nests. The eDNA results were compared to data from morpho‐taxonomical species identifications. Despite limited DNA quantity, we detected Hymenoptera at the species level in 57.4% of our samples. Hymenoptera detection was also possible from single brood cells. In mixed‐species nests, we correctly detected the presence of multiple species. In nests of solitary wasps, we additionally detected other arthropods, which are probably the remains of larval provisions. Morphological and molecular data agreed in large parts. This eDNA approach offers the opportunity for the implementation of large‐scale and nonlethal monitoring of cavity‐nesting Hymenoptera that additionally provides valuable information on trophic interactions.

Metal Contaminants in Fish: Blood as a Potential Non-lethal Monitoring Tool.

The use of fish to monitor metal contamination is well established, but existing studies often focus on internal tissues that require the sacrifice of organisms. Developing non-lethal methods is thus a scientific challenge to enable large scale biomonitoring of wildlife health. We explored blood as a potential non-lethal monitoring tool for metal contamination in brown trout (Salmo trutta fario) as a model species. First, we investigated differences in metal contamination loads (i.e., Cr, Cu, Se, Zn, As, Cd, Pb and Sb) in different blood components (whole blood, red blood cells and plasma). Whole blood was reliable to measure most metals, implying that blood centrifugation is not necessary, thus minimizing sample preparation time. Second, we measured the within individual distribution of metals across tissues (whole blood, muscle, liver, bile, kidney and gonads) to test if blood could be a reliable monitoring tool compared to other tissues. Results show that the whole blood was reliable compared to muscle and bile to measure the levels of metals such as Cr, Cu, Se, Zn, Cd and Pb. This study opens the possibility for future ecotoxicological studies in fish to use blood instead of internal tissues to quantify some metals, thus reducing the negative impacts of biomonitoring on wildlife.

Prospects of fish scale and fin samples usage for nonlethal monitoring of metal contamination: a study on five fish species from the Danube River

The development of nonlethal methods for the monitoring of environmental contamination is essential to minimize the negative effects on studied species and communities. Fish scales and fin clips can be used as nonlethal indicators of water quality given that they are in direct contact with the environment and can accumulate high concentrations of metals and trace elements. Fin clipping causes minimal harm to fish and it does not affect fish growth or survival. In this study, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn concentrations were measured by inductively-coupled plasma mass spectrometry (ICP-MS) in scales, fins, and muscle of common bream (Abramis brama), white bream (Blicca bjoerkna), wels catfish (Silurus glanis), northern pike (Esox lucius), and pikeperch (Sander lucioperca) from the Danube River. The analysis showed a positive correlation for Hg between scales and muscle in pikeperch. Anal fin and muscle were positively correlated in white bream for Hg, in wels catfish for Cu, and in northern pike and pikeperch for As. The results suggest that scales and fins have a potential to be used as indicators of muscle tissue contamination with As, Cu, and Hg, depending on species' ecological traits.

Recommendations for non-lethal monitoring of tree wētā (Hemideina spp.) using artificial galleries

ABSTRACT Wildlife sanctuaries in Aotearoa/New Zealand involve community groups that often prefer using non-lethal monitoring methods for invertebrates. We examined one method for monitoring tree wētā with the aim of improving monitoring design. Pest management at our study site did not vary for 10 years before our study and remained unchanged between sampling, so we assumed that abundance of tree wētā would not vary significantly over the four years of the study. We recorded occupancy and marked every tree wētā (Hemideina spp.) using the same set of 38 artificial tree-hole refuges (galleries) every 1–2 weeks. We tested the prediction that non-lethal monitoring of tree wētā is a suitable proxy for relative wētā abundance by comparing the number of tree wētā using the same galleries four years apart. As expected, no change in numbers of wētā was detected. However, the level of site/gallery fidelity, seasonal fluctuations and movement between artificial galleries suggest that monitoring design needs to incorporate the life history and behaviour of these insects. We recommend comparison of wētā occupancy be restricted to the same season, galleries be placed more than 50 m apart and checked only once or twice a year.

Beeporter: Tools for high-throughput analyses of pollinator-virus infections.

Pollinators are in decline thanks to the combined stresses of disease, pesticides, habitat loss, and climate. Honey bees face numerous pests and pathogens but arguably none are as devastating as Deformed wing virus (DWV). Understanding host-pathogen interactions and virulence of DWV in honey bees is slowed by the lack of cost-effective high-throughput screening methods for viral infection. Currently, analysis of virus infection in bees and their colonies is tedious, requiring a well-equipped molecular biology laboratory and the use of hazardous chemicals. Here we describe virus clones tagged with green fluorescent protein (GFP) or nanoluciferase (nLuc) that provide high-throughput detection and quantification of virus infections. GFP fluorescence is measured noninvasively in living bees via commonly available long-wave UV light sources and a smartphone camera, or a standard ultraviolet transilluminator gel imaging system. Nonlethal monitoring with GFP allows continuous screening of virus growth and serves as a direct breeding tool for identifying honey bee parents with increased antiviral resistance. Expression using the nLuc reporter strongly correlates with virus infection levels and is especially sensitive. Using multiple reporters, it is also possible to visualize competition, differential virulence, and host tissue targeting by co-occuring pathogens. Finally, it is possible to directly assess the risk of cross-species "spillover" from honey bees to other pollinators and vice versa.

A novel trap design for non-lethal monitoring of dung beetles using eDNA metabarcoding

A novel trap design for non-lethal monitoring of dung beetles using eDNA metabarcoding

Energetic Status of Alaskan Chinook Salmon: Interpopulation Comparisons and Predictive Modeling Using Bioelectrical Impedance Analysis

AbstractAdult Pacific salmon Oncorhynchus spp. undertake energetically demanding migrations where they must have adequate energy reserves to survive to reach spawning locations and reproduce. Lethal proximate analysis provides insight into available energy stores (e.g., lipids), but the ability to monitor energetic status nonlethally may be useful for managers. Nonlethal monitoring may be more cost effective, reduce harm to sensitive populations, allow for more fish to be sampled, and assessments can be done relatively quickly. Chinook Salmon Oncorhynchus tshawytscha (N = 129) were sampled for proximate analysis from four populations in Alaska to examine variation in energetic status before and after spawning migration and to create predictive bioelectrical impedance analysis (BIA) models for this species. In addition to proximate analysis we tested the variability between two BIA devices (Q2 and CQR), whether BIA models were generalizable to a congener, Chum Salmon Oncorhynchus keta, and the feasibility of integrating BIA into field studies. The populations that were sampled at prespawning migration had higher %lipid (N = 77; mean = 43%) than those that were collected at postspawning migration (N = 52; mean = 20%). Total %lipid and %water was more accurately predicted based on BIA measurements that were made by using the Q2 device (RMSE = 5.33 and RMSE = 2.43, respectively) than on those that were made by using the CQR device measurements (RMSE = 6.27; RMSE = 2.66). The between‐species (Chinook Salmon to Chum Salmon RMSE = 19.47; Chum to Chinook RMSE = 7.69) models were less accurate than species‐specific models that were created for Chinook Salmon and Chum Salmon, suggesting that single‐species models should be used. We field‐tested the BIA model to predict %lipid and %water for Chinook Salmon on a remote Southeast Alaska river. The range of predicted values of %lipid and %water was similar to the results that are obtained via proximate composition from the other populations. Our results indicate that BIA could be a valuable tool for assessing the spatial and temporal patterns of energetic status for Chinook Salmon populations.

Individual monitoring of immune response in Atlantic salmon Salmo salar following experimental infection with piscine myocarditis virus (PMCV), agent of cardiomyopathy syndrome (CMS)

Piscine myocarditis virus (PCMV) is a double-stranded RNA virus structurally similar to the Totiviridae family. PCMV is the causative agent of cardiomyopathy syndrome (CMS), a severe cardiac disease that affects farmed Atlantic salmon (Salmo salar). A recent study characterized the host immune response in infected salmon through a transcriptome immune profiling, which confirmed a high regulation of immune and anti-viral genes throughout infection with PCMV. Previously we developed a novel model based on repeated non-lethal blood sampling, enabling the individual monitoring of salmonids during an infection. In the present work, we used this model to describe the host immune response in the blood cells of Atlantic salmon after intramuscular infection with PCMV-containing tissue homogenate over a 77-day period. At the final stage heart samples were also collected to verify the PCMV load, the pathological impact of infection and to compare the transcript profiles to blood. The expression level of a range of key immune genes was determined in the blood and heart samples by real-time PCR. Results indicated selected immune genes (mx, cd8α and γip) were up-regulated in the heart tissue of infected animals at the terminal time point, in comparison to the non-infected fish. When analyzing the blood samples over the course of infection, a significant n up-regulation of mx gene was also observed. The time and number of peaks in the kinetics of expression was different between individuals. The PCMV load and CMS pathology was verified by real-time PCR and histopathology, respectively. No pathogen and no pathology could be detected during the course of the experiment except at the terminal stage (viral load by qPCR and pathology by histology). This study emphasizes the value of non-lethal monitoring for evaluating the health status of fish at early stages of infection and in the absence of clinical signs.

In vivo solid-phase microextraction sampling combined with metabolomics and toxicological studies for the non-lethal monitoring of the exposome in fish tissue

Various environmental studies have employed the biomonitoring of fish in their aquatic ecosystems in order to identify potential metabolic responses to the exposome. In this study, we applied in vivo solid-phase microextraction (SPME) to perform non-lethal sampling on the muscle tissue of living fish to extract toxicants and various endogenous metabolites. Sixty white suckers (Catastomus commersonii) were sampled from sites upstream, adjacent, and downstream from the oil sands development region of the Athabasca River (Alberta, Canada) in order to track their biochemical responses to potential contaminants. In vivo SPME sampling facilitated the extraction of a wide range of endogenous metabolites, mainly related to lipid metabolism. The obtained results revealed significant changes in the levels of numerous metabolites, including eicosanoids, linoleic acids, and fat-soluble vitamins, in fish sampled in different areas of the river, thus demonstrating SPME's applicability for the direct monitoring of exposure to different environmental toxicants. In addition, several classes of toxins, including petroleum-related compounds, that can cause serious physiological impairment were tentatively identified in the extracts. In vivo SPME, combined with the analysis of contaminants and endogenous metabolites, provided important information about the exposome; as such, this approach represents a potentially powerful and non-lethal tool for identifying the mechanisms that produce altered metabolic pathways in response to the mixtures of different environmental pollutants.

Non-lethal monitoring of longicorn beetle communities using generic pheromone lures and occupancy models

Longicorn beetles are a diverse group of insects that perform critical ecosystem services and are indicators of forest health. Most longicorn species are data deficient, and many are considered at risk. Longicorn beetle monitoring often relies on lethal methods and are time and cost intensive. In this study we investigated the use of generic pheromones in conjunction with species- and Bayesian community-level hierarchical modeling that accounts for imperfect detection, as a rapid tool for monitoring longicorn beetle diversity. Using 50 flight-intercept traps deployed for one month at two sites in a traditionally-maintained landscape in SW Romania, we implemented non-lethal surveys to evaluate the longicorn species abundance and estimate beetle occupancy. We captured and identified 2370 longicorn beetles of 28 species; two species, Phymatodes testaceus and Plagionotus detritus accounted for more than ½ of the captures, and nine species were only captured once. However the most abundant species estimated in our area was Mesosa nebulosa (36–60 individuals per trap location). Using co-occurrence of high and low detection species, as well as habitat associations, we estimated that 39 species (30–57 95% posterior interval) were present at any given site, suggesting that our survey did not capture the full longicorn diversity. Beetle diversity, occurrence and abundance were associated with higher tree density, volume of dead wood and number of stumps, and lower canopy cover. Our methods allowed to discriminate between common species with low detection, and rare species, and are a promising tool for the rapid assessment of longicorn beetle diversity, as well as the conservation status of listed and non-listed species.

Ecotoxicological Biomarkers in Multiple Tissues of the Neotenic Ambystoma spp. for a Non-lethal Monitoring of Contaminant Exposure in Wildlife and Captive Populations

Amphibians are the most threatened vertebrate group with a third of currently known species endangered with extinction, as a result of climate change, habitat loss, disease-introduced exotic species, and pollution. Because of their vulnerability, they have often been used as environmental quality indicators, as well as laboratory models for toxicological research. Given the sensitivity of amphibians to changes in their surrounding environment, including pollution, it was deemed important to define a non-lethal technique based on the evaluation of a set of biomarkers in different tissues of neotenic individuals of Ambystoma velasci. The levels of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carboxylesterase (CaE), alkaline and acid phosphatases (ALP, ACP), glutathione s-transferase (GST), 7-ethoxyresorufin-O-deethylase (EROD), and superoxide dismutase (SOD) activities, as well as the oxygen radical absorption capacity (ORAC) were measured in tail, gills, liver, plasma, and brain samples. Significant tissue-specific differences were observed for all biomarkers with the exception of ACP. The highest values of specific activity for most biomarkers were detected in the liver. However, the levels measured in gills were very close to those observed in the liver and showed fewer variations than other tissues. These findings suggest that the sampling of gills could be used to evaluate pollution biomarkers in salamanders without apparent harm, as this tissue quickly regenerates.

Can you count on counting? Retrieving reliable data from non-lethal monitoring of micro-snails

Using non-lethal methods is especially important for the monitoring and conservation planning of endangered species and their habitats. The goal of this study is to check whether the current method of monitoring endangered micro-snail populations by soil sampling, which involves killing the snails and altering their microhabitat, could be replaced by a non-lethal method. The invasive and time-consuming soil sampling and analyzing is compared with searching the individuals by eye. Research was conducted in moist sedges meadows and seasonally inundated wetlands in western Poland and focused on two species of micro-snails differing in biology, i.e. Vertigo moulinsiana (a climbing species) and Vertigo angustior (a litter-dwelling species). Both vertiginid species are listed in the Annex II of the EU Habitat Directive and included in the IUCN Red List of Threatened Species. The results showed a significant correlation between the total number of individuals searched by eye and collected from soil samples of V. angustior and V. moulinsiana. Results of this study indicate that monitoring micro-snails by searching individuals by eye is feasible and may reduce further pressure of killing individuals of endangered species. Limitations of this method should however be taken into account – especially its inaccuracy in estimating the absolute abundance of the studied species.

Development of non-lethal monitoring of stable isotopes in asp (Leuciscus aspius): a comparison of muscle, fin and scale tissues

We explored whether fin clips and scales can be used as potential non-lethal alternatives to muscle tissue for examining the isotopic composition of asp Leuciscus aspius, a locally threatened freshwater species. Dorsal fin clips, scales and muscle plugs were collected from two asp populations and subsequently analysed for nitrogen and carbon stable isotopes. Both fins and scales were consistently depleted in 15N and enriched in 13C relative to muscle. A linear regression found that the isotope values in asp fins and scales were significantly related to those in the muscle tissue. These results indicate that fins and scales have the potential to be a substitute for muscle in stable isotope studies of asp, thus providing a non-destructive sampling method for this species. Nevertheless, to determine reliable conversion factors between tissues, a subset of individuals covering a sufficiently wide range of body sizes may need to be sacrificed for any given population.

Non-lethal gill biopsy of juvenile hybrid sturgeon (Acipenser ruthenus♀ × A. schrenckii♂): validity and impact on growth and osmoregulation

Summary The objective of this study was to validate a gill biopsy method for non-lethal monitoring of the osmoregulatory status of young sturgeon in estuary areas. After gill biopsy, hybrid sturgeon (Acipenser ruthenus ♀ 9 A. schrenckii ♂) were transferred from freshwater to brackish water (10 ppt) for 6 weeks. Mortality, serum osmolality, ion concentrations and gill Na + ,K + -ATPase activity of fish exposed to brack

Perfluorinated alkyl substances in water, sediment, plankton and fish from Korean rivers and lakes: A nationwide survey

Water, sediment, plankton, and blood and liver tissues of crucian carp (Carassius auratus) and mandarin fish (Siniperca scherzeri) were collected from six major rivers and lakes in South Korea (including Namhan River, Bukhan River, Nakdong River, Nam River, Yeongsan River and Sangsa Lake) and analyzed for perfluorinated alkyl substances (PFASs). Perfluorooctane sulfonate (PFOS) was consistently detected at the greatest concentrations in all media surveyed with the maximum concentration in water of 15ngL−1 and in biota of 234ngmL−1 (fish blood). A general ascending order of PFAS concentration of water<sediment<plankton<crucian carp tissues<mandarin fish tissues was found. Except for the Nakdong River and Yeongsan River, the sum PFAS concentrations in water samples were below 10ngL−1. The PFOS and perfluorooctanoic acid (PFOA) concentrations in water did not exceed levels for acute and/or chronic effects in aquatic organisms. High concentrations of long chain perfluorocarboxylates (LCPFCAs) were found in sediment samples. PFOS, perfluoroundecanoic acid (PFUnA), perfluorododecanoic acid (PFDoA) and perfluorodecanoic acid (PFDA) accounted for 94–99% of the total PFASs concentration in fish tissues. The mean ratios of PFAS concentration between fish blood and fish liver were above 2 suggesting higher levels in blood than in liver. Significant positive correlations (r>0.80, p<0.001) were observed between PFOS concentration in blood and liver tissues of both crucian carp and mandarin fish. This result suggests that blood can be used for nonlethal monitoring of PFOS in fish. Overall, the rank order of mean bioconcentration factors (BCFs) of PFOS in biota was; phytoplankton (196L/kg)<zooplankton (3233L/kg)<crucian carp liver (4567L/kg)<crucian carp blood (11,167L/kg)<mandarin liver (24,718L/kg)<mandarin blood (73,612L/kg).

On the emerging role of rabbit as human disease model and the instrumental role of novel transgenic tools

The laboratory rabbit (Oryctolagus cuniculus) is widely used as a model for human diseases, because of its size, which permits non-lethal monitoring of physiological changes and similar disease characteristics. Novel transgenic tools such as, the zinc finger nuclease method and the sleeping beauty transposon mediated or BAC transgenesis were recently adapted to the laboratory rabbit and opened new opportunities in precise tissue and developmental stage specific gene expression/silencing, coupled with increased transgenic efficiencies. Many facets of human development and diseases cannot be investigated in rodents. This is especially true for early prenatal development, its long-lasting effects on health and complex disorders, and some economically important diseases such as atherosclerosis or cardiovascular diseases. The first transgenic rabbits models of arrhythmogenesis mimic human cardiac diseases much better than transgenic mice and hereby underline the importance of non-mouse models. Another emerging field is epigenetic reprogramming and pathogenic mechanisms in diabetic pregnancy, where rabbit models are indispensable. Beyond that rabbit is used for decades as major source of polyclonal antibodies and recently in monoclonal antibody production. Alteration of its genome to increase the efficiency and value of the antibodies by humanization of the immunoglobulin genes, or by increasing the expression of a special receptor (Fc receptor) that augments humoral immune response is a current demand.

Sampling-Rate Calibration for Rapid and Nonlethal Monitoring of Organic Contaminants in Fish Muscle by Solid-Phase Microextraction

Solid-phase microextraction (SPME) is a promising technique for determining organic contaminants within biotic systems. Existing in vivo SPME-kinetic calibration (SPME-KC) approaches are unwieldy due to the necessity of predetermining a distribution coefficient for the analyte of interest in the tissue and the preloading of a calibrating compound to the fiber. In this study, a rapid and convenient SPME alternative calibration method for in vivo analysis, termed SPME-sampling rate (SPME-SR) calibration, was developed and validated under both laboratory and field conditions to eliminate such presampling requirements. Briefly, the SPME probe is inserted into tissue, in this study fish dorsal-epaxial muscle, for 20 min allowing the concentrations of target analytes in the fish muscle to be determined by the extracted amount of analyte and the predetermined sampling rates. Atrazine, carbamazepine, and fluoxetine were detected nonlethally in the low ppb levels within fish muscle, with both laboratory and field-derived results obtained by in vivo SPME-KC comparable (within a factor of 1.27) to those obtained by lethal sampling followed by tissue liquid extraction. The technique described in this study represents an important advance which broadens the application of SPME in vivo sampling technology.

Establishing baseline levels of trace elements in blood and skin of bottlenose dolphins in Sarasota Bay, Florida: Implications for non-invasive monitoring

Several major unusual mortality events occurring in recent years have increased the level of concern for the health of bottlenose dolphin populations along the United States Atlantic and Gulf of Mexico coasts. Trace element concentrations were examined in a population of free-ranging dolphins in Sarasota Bay, Florida, in order to develop a benchmark for future comparisons within and between populations. Whole blood ( n = 51) and skin ( n = 40) samples were collected through capture and release health assessment events during 2002–2004. Samples were analyzed for Al, V, Cr, Mn, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, and Pb by inductively coupled plasma mass spectrometry (ICPMS) and Hg via atomic fluorescence spectrometry (AFS). Trace element concentrations (wet mass) in skin were 2 to 45 times greater than blood, except Cu was approximately 1.5 times higher in blood. Statistically strong correlations ( p < 0.05) were found for V, As, Se, Rb, Sr, and Hg between blood and skin demonstrating that these tissues can be used as effective non-lethal monitoring tools. The strongest correlation was established for Hg ( r = 0.9689) and concentrations in both blood and skin were above the threshold at which detrimental effects are observed in other vertebrate species. Female dolphins had significantly greater Hg concentrations in blood and skin and Pb concentrations in skin, relative to males. Calves exhibited significantly lower V, As, and Hg concentrations in blood and V and Hg concentrations in skin, relative to other age classes. Rubidium and Cu concentrations in skin were greatest in subadults and calves, respectively. In blood, V, Zn, and As concentrations were significantly greater in winter, relative to summer, and the opposite trend was observed for Rb and Sr concentrations. In skin, Cu and Zn concentrations were significantly greater in winter, relative to summer, and the opposite trend was observed for Mn, Rb, Cd, and Pb concentrations. The baseline concentrations and trends established in this study will serve as a benchmark for comparison and aid in sampling design for future monitoring of this population and other coastal bottlenose dolphin populations.

THE USE OF TREE-MOUNTED ARTIFICIAL SHELTERS TO INVESTIGATE ARBOREAL SPIDER COMMUNITIES IN NEW ZEALAND NATURE RESERVES

Spiders have been advocated as valuable bio-indicators of forest ecosystem ''health.'' However, the numbers and types of spiders that are recorded at a site will usually be highly dependent on the sampling method employed. The use of lethal, indiscriminate invertebrate sampling techniques is undesirable when investigating rare species, or sampling within areas of high conservation status. There- fore we used non-lethal artificial tree-mounted shelters to monitor arboreal spiders in nature reserves near Christchurch, New Zealand. After three months, over 60% of the shelters had been used by spiders, increasing to 91% after twelve months. There were significant differences in the numbers of spiders found in the shelters at the different sites. However, factors such as the species of tree the shelter was attached to, ground vegetation, and levels of incident light did not affect the likelihood of a shelter being occupied. The species composition of the spider faunas in those sites regarded as high quality forest remnants was dissimilar to the faunas found in the low quality reserves. However, although spiders were more abundant in the high quality sites compared with the poorest stands of woodland, they were not more species rich. The shelters are inexpensive and easy to manufacture and are useful for long-term non-lethal monitoring of spider communities. They also have good potential as a tool for studying spider phenology, population dynamics, behavior, and as a collection/carriage device for live specimens used in conservation translo- cations.

An appraisal of simple tree-mounted shelters for non-lethal monitoring of weta (Orthoptera: Anostostomatidae and Rhaphidophoridae) in New Zealand nature reserves

When monitoring rare insect species, or when surveying faunas within nature reserves, it is desirable not to use indiscriminate lethal sampling techniques. In this investigation we assessed the usefulness of simple tree-mounted wooden shelters to monitor endemic weta (Orthoptera) in nature reserves in Canterbury, New Zealand. Fifty shelters were placed out at six sites and examined at three-monthly intervals for a year. A wide variety of invertebrates were found utilizing the shelters, with Arachnida, Blattodea and Collembola being the most common occupants. After three months over 80% of the shelters exhibited signs of use by invertebrates, increasing to 96% after 12 months. Only seven tree weta (Anostostomatidae) and one (dead) ground weta (Hemiandrus sp.) were observed in the shelters over the full 12 month period. There were 52 observations of cave weta (Rhaphidophoridae) in the shelters, 36 of which occurred at one site, Orton Bradley Park. Occupation of the shelters by cave weta was not affected by soil conditions, light intensity or aspect of the shelter. However, cave weta exhibited a preference for shelters less than 50 cm above the ground and for shelters attached to kanuka and vines. Although weta were found in only a small proportion (9%) of the shelters, this method proved useful in confirming the presence of weta without risk of harming vulnerable populations. These shelters are inexpensive and easy to manufacture and have potential for long-term non-lethal monitoring of weta and as a collection/carriage device for live specimens used in conservation translocations.