Termite tracking agent, its use and method for locating termite nests

Abstract

The present application relates to the technical field of water conservancy safety detection and biological control, and particularly relates to a termite tracer and application thereof and a termite nest positioning method. The termite tracer contains magnetic functional microparticles and a food-attraction matrix; the magnetic functional microparticles contain magnetic microspheres with a saturation magnetization of 50-150 emu / g, and the magnetic microspheres include strontium ferrite and / or iron oxide. The method can realize termite nest positioning based on the combination of tracing marking of termite feeding behavior and nondestructive detection, improve target specificity, break through the application bottleneck of traditional tracers that cannot enter, stay and be detected, overcome the limitations of passive detection mode, and enhance the adaptability to field environment and detection robustness. The method is suitable for precise positioning of termite nests of water conservancy facilities such as reservoir dams, river embankments and canal embankments.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of safety monitoring and biological control in water conservancy projects, and particularly to a magnetic tracer microsphere for active ant nest detection, its preparation method, and its application. Background Technology

[0002] Termites pose a serious potential threat to water conservancy infrastructure such as dikes. Their nesting and foraging behaviors can lead to cavities, seepage channels, and even structural instability within dikes, causing numerous safety accidents in water conservancy projects worldwide. Therefore, there is an urgent need to develop efficient, accurate, and non-destructive monitoring and intervention methods. In addition to traditional visual inspection, non-destructive termite detection technologies that have emerged in recent years mainly include geophysical detection technologies and biosensor technologies.

[0003] In geophysical methods, acoustic emission (AE) technology uses highly sensitive sensor arrays to capture weak transient elastic wave signals generated by termites chewing wood or moving. Combined with advanced spectral analysis and signal denoising algorithms (such as wavelet transform or deep learning denoising), this method can effectively enhance the extraction of characteristic signals in low signal-to-noise ratio environments, thus enabling real-time perception of termite activity. Ground penetrating radar (GPR) identifies medium anomalies caused by termite activity, such as cavities, changes in water content, or areas of soil disturbance, by transmitting high-frequency electromagnetic waves underground and receiving their reflected signals. This technology has high spatial resolution and is suitable for fine imaging of shallow structures, but its penetration ability is limited in highly conductive or highly water-bearing environments. Electrical resistivity tomography (ERT) inverts the internal structure of soil by measuring the spatial distribution of underground resistivity. Termite tunnels are often accompanied by water accumulation or changes in pore structure, leading to a significant decrease in local resistivity. ERT can effectively identify termite tunnel networks and potential seepage paths based on this. This method is particularly suitable for dam projects in high water content environments, and has the advantages of wide coverage and low cost, making it suitable for rapid screening of large-scale potential hazard areas.

[0004] In the field of biosensing, chemical detection techniques focus on specific metabolites of volatile organic compounds (VOCs) released by termites, such as naphthalene and 2-phenoxyethanol. Gas chromatography-mass spectrometry (GC-MS) and electronic nose systems have been used for the qualitative and quantitative analysis of these VOCs. Among them, multi-sensor arrays based on conductive polymers (CPs), metal oxide semiconductors (MOS), and quarter crystal microbalances (QCMs) can form olfactory fingerprints that can distinguish different termite species and their activity levels, providing a new approach for early warning and species identification.

[0005] Current termite hazard detection technologies still have certain limitations: Geophysical methods (such as ground-penetrating radar, resistivity tomography, and acoustic emission) can identify underground anomalies, but they struggle to effectively distinguish termite tunnels from other geological disturbances (such as root holes and construction defects), easily leading to misjudgments. While biosensing technologies (such as VOCs-based electronic noses or GC-MS) are highly sensitive to termite metabolites, their effective range is short, they are easily affected by environmental temperature, humidity, and background gas interference, and they cannot provide spatial location and three-dimensional structural information about termite tunnels. Furthermore, current mainstream technologies are mostly passive detection modes, relying on signals or chemical traces generated by natural termite activity. In complex dam environments, their detection depth is limited, and their target specificity is insufficient, making it difficult to achieve accurate location and efficient identification of hidden nests. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a termite tracer, its application, and a method for locating termite nests. This method combines tracer marking based on termite feeding behavior with non-destructive detection to locate termite nests, improving target specificity and overcoming the limitations of traditional tracers that cannot penetrate, remain, or be detected. It also overcomes the limitations of passive detection methods, enhancing adaptability to the field environment and robustness of detection. It is suitable for the precise location of termite nests in water conservancy facilities such as reservoir dams, river embankments, and canal embankments.

[0007] In a first aspect, the present invention provides a termite tracer, the termite tracer comprising magnetic functional microparticles and a feeding attractant matrix; the magnetic functional microparticles comprising magnetic microspheres with a saturation magnetization of 50-150 emu / g, the magnetic microspheres comprising strontium ferrite and / or iron oxide.

[0008] Preferably, the termite tracer is a powder tracer; the powder tracer is a magnetic tracer microsphere; the feeding attractant matrix modifies or coats the surface of the magnetic functional microspheres; the particle size of the magnetic tracer microspheres is 50-500 μm; the powder tracer may also optionally contain one or more of food-grade flow aids and thickeners; optionally, the termite tracer may also include fluorescent microspheres.

[0009] Preferably, the termite tracer is a liquid tracer; the liquid tracer is an aqueous suspension; the liquid tracer may also optionally contain a suspending agent and an attractant enhancer, wherein the suspending agent is food-grade xanthan gum or carboxymethyl cellulose, and the attractant enhancer is yeast extract and / or cellulose hydrolysate.

[0010] Further preferably, the magnetic functional microparticles include magnetic microspheres with a saturation magnetization of 50-150 emu / g and cellulose bait; the cellulose bait is selected from one or more of microcrystalline cellulose, pure cellulose powder, eucalyptus fiber bait, and pine fiber bait, and the raw material of the cellulose bait preferably includes pine wood or eucalyptus bark.

[0011] Further preferably, the attractant matrix is ​​selected from one or more of microcrystalline cellulose, pure cellulose powder, eucalyptus fiber bait, and pine fiber bait, and the raw material of the cellulose bait preferably includes pine wood or eucalyptus bark.

[0012] Secondly, the present invention provides a method for preparing the termite tracer, comprising the following steps: 1) Synthesis of functional microparticles: Combining cellulose feed with nanoscale magnetic particles to obtain magnetic functional microparticles.

[0013] 2) Surface modification: The feeding-enhancing matrix is ​​adsorbed or coated on the surface of the magnetic functional microparticles.

[0014] 3) Magnetic separation: Using a magnetic field to separate and extract magnetic functional particles.

[0015] 4) Preparation and molding: The separated functional microparticles are post-processed according to the dosage form.

[0016] Preferably, step 4) includes adding deionized water and food-grade suspending agent to prepare a liquid tracer; or using a low-temperature drying method to prepare a powder tracer.

[0017] Thirdly, the present invention provides the application of the termite tracer in the active tracing and detection of termite nests or the detection of termite hazards in dikes.

[0018] Fourthly, the present invention provides a method for locating termite nests, comprising: using the termite tracer; actively releasing the termite tracer based on the social behavior of termites, and locating termite nests by combining magnetic tracer microspheres with surface magnetic surveying.

[0019] Preferably, the termite nest location method includes: 1) Deploy bait stations in areas suspected of termite activity, wherein the bait stations contain the powdered tracer.

[0020] 2) After determining the location of the termite tunnel, remove the bait block and use a micro-injection device to inject the liquid tracer into the tunnel in a pulsed, low-pressure manner.

[0021] 3) After a preset set time, the magnetic functional particles in the liquid tracer are transported and enriched into the deep nest and channel network by the termites’ carrying or feeding behavior.

[0022] 4) High-sensitivity magnetic measurement equipment is used to perform gridded magnetic field anomaly scanning on the ground surface, obtain magnetic field data of the survey area and perform inversion processing, reconstruct the three-dimensional spatial location of the underground magnetic functional particle aggregation area, and realize the accurate location of ant nests and hidden channel networks.

[0023] Fifthly, this invention provides an active termite detection system suitable for dam engineering, comprising a magnetic tracer microsphere delivery device, a high-precision surface magnetic surveying device, and a data acquisition and three-dimensional imaging software module. The magnetic tracer microsphere delivery device is used to inject magnetic tracer microspheres into bait stations, termite tunnels, or adjacent soil. The high-precision surface magnetic surveying device is used to perform gridded magnetic field measurements along the surface to be measured, acquiring magnetic field anomaly signals and coordinate attitude data. The data acquisition and three-dimensional imaging software module is used to correct and invert the acquired magnetic anomaly data, and output a three-dimensional spatial model of the underground magnetic microsphere aggregation area through magnetic gradient tensor inversion or equivalent source imaging algorithms.

[0024] The beneficial effects of this invention are at least as follows: 1) Significantly improve target specificity: To address the problem of misjudgment caused by the difficulty of distinguishing termite tunnels from non-biological geological anomalies (such as root holes and construction gaps) by geophysical methods, this solution actively transports magnetic tracer microspheres into the nest through the social behavior of termites, so that the detection signal originates directly from the core area of ​​termite activity, fundamentally realizing true termite tunnels and true signals, and greatly reducing the misjudgment rate.

[0025] 2) Effectively solves the problems of traditional tracers being unable to penetrate, remain, or be detected; traditional tracers are difficult to penetrate deep into termite nests or are easily lost in complex soil. The magnetic microspheres designed in this solution have feeding attraction, environmental stability, and magnetic response characteristics, which can be efficiently ingested by termites, remain in the nest system for a long time, and continuously generate physical signals that can be stably captured by surface equipment, ensuring that they can penetrate, remain, and be detected.

[0026] 3) Shifting from passive dependence to active guidance, breaking through the bottlenecks of detection depth and coverage; existing technologies mostly rely on acoustic or chemical signals naturally generated by termites, which have short operating distances and low sensitivity in high water content and heterogeneous dams. This solution abandons the passive mode and utilizes the termites themselves to complete internal deployment through biological active transport and physical field enhancement mechanisms, significantly expanding detection depth and spatial coverage capabilities, making it particularly suitable for complex water conservancy engineering scenarios.

[0027] 4) Significantly improved environmental adaptability and detection robustness: Addressing the issue of VOCs and other biosensor signals being susceptible to interference from temperature, humidity, wind speed, and background gases, this solution utilizes magnetic field anomalies as the detection basis. These anomalies possess stable physical properties and strong anti-interference capabilities, enabling reliable, continuous, and high signal-to-noise ratio monitoring under varying field conditions, ensuring the practicality and stability of engineering applications. In summary, this invention innovatively achieves a technological leap from fuzzy recognition to precise imaging, and from passive response to active guidance, providing an efficient, reliable, and engineerable next-generation solution for intelligent termite risk control in water conservancy infrastructure such as dams. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 The preparation process of the magnetic tracer provided in the embodiments of the present invention is as follows.

[0030] Figure 2 A flowchart illustrating the magnetic tracing detection process based on termite behavior response, provided for embodiments of the present invention.

[0031] Figure 3 Ground-based gridded magnetic field signal acquisition is provided for embodiments of the present invention.

[0032] Figure 4 A planar view of magnetic anomalies at depth z=0 provided for an embodiment of the present invention.

[0033] Figure 5 A planar view of magnetic anomalies at a depth of z=1.5m provided for embodiments of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0035] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0036] Unless otherwise specified, the techniques or conditions described in the embodiments of this invention shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Devices, instruments, reagents, etc., without specified manufacturers, are all conventional products that can be purchased through legitimate channels. All experimental reagents and raw materials involved are commercially available products, and all reagents are analytical grade products.

[0037] In a preferred embodiment of the present invention, the termite tracer contains magnetic functional microparticles and a feeding attractant matrix; the magnetic functional microparticles comprise magnetic microspheres with a saturation magnetization ≥50 emu / g, and the magnetic microspheres include strontium ferrite and / or iron oxide. The tracer uses magnetic microspheres as its core functional component. These magnetic tracer microspheres can be carried by termite worker ants and are not easily washed away by the environment. The termite nest location method combines tracer marking based on termite feeding behavior with non-destructive detection, improving target specificity and overcoming the application bottlenecks of traditional tracers that cannot penetrate, remain, or be detected. It overcomes the limitations of passive detection modes and enhances adaptability and robustness in the field environment. It is suitable for the precise location of termite nests in water conservancy facilities such as reservoir dams, river embankments, and canal embankments.

[0038] In a preferred embodiment of the present invention, the termite tracer is a powder tracer; the powder tracer is a magnetic tracer microsphere; in the magnetic tracer microsphere, a feeding-attracting matrix is ​​modified or coated on the surface of the magnetic functional microparticles; the particle size of the magnetic tracer microsphere is 50-500 μm; the magnetic tracer microsphere contains a feeding-attracting matrix (such as cellulose derivatives or termite-preferred food components) and magnetic functional materials (such as strontium ferrite, Fe3O4 nanoparticles), with the particle size controlled within the range of 50-500 μm to ensure that it can be carried by termite worker ants and is not easily washed away by the environment.

[0039] In a preferred embodiment of the present invention, the powder tracer may optionally contain one or more of a food-grade flow aid and a thickener; the termite tracer may optionally include fluorescent microspheres to assist in the identification of termite transport paths.

[0040] In a preferred embodiment of the present invention, the fluorescent microspheres have a smaller particle size than the magnetic powder and are used to adhere to the surface of termites during foraging; the food-grade flow aid or thickener is used to improve the flowability, suspension and dispersibility of the powder.

[0041] In a further preferred embodiment, the feeding-inducing matrix (inducing component) is selected from one or more of yeast extract, starch, plant-derived cellulose microfibers, yeast extract, and cellulose hydrolysate.

[0042] In a preferred embodiment of the present invention, the magnetic powder is a superparamagnetic microsphere, preferably strontium ferrite and / or iron oxide; the saturation magnetization is ≥50 emu / g; the mass of a single microparticle is 1-2 μg, and the particle size is adapted to the size of the mouthparts of termite workers.

[0043] In a preferred embodiment of the present invention, the termite tracer is a liquid tracer; the liquid tracer is an aqueous suspension, the solvent is deionized water, and the pH is adjusted to 6.0-7.5; optionally, the liquid tracer contains a suspending agent and an attractant enhancer, the suspending agent is food-grade xanthan gum or carboxymethyl cellulose, and the attractant enhancer is yeast extract and / or cellulose hydrolysate.

[0044] In a further preferred embodiment, the magnetic functional microparticles include magnetic microspheres and cellulose bait; the cellulose bait is selected from one or more of microcrystalline cellulose, pure cellulose powder, eucalyptus fiber bait, and pine fiber bait prepared from pine wood, eucalyptus bark, etc.

[0045] In a further preferred embodiment, the attractant matrix is ​​selected from one or more of microcrystalline cellulose, pure cellulose powder, eucalyptus fiber bait, and pine fiber bait prepared from pine wood, eucalyptus bark, etc.

[0046] In a further preferred embodiment, the magnetic microspheres have a particle size of 50-500 μm. For example, the liquid magnetic microspheres have a particle size of 50-200 μm, and the powdered magnetic microspheres have a particle size of 100-500 μm.

[0047] To address the core bottlenecks of current termite hazard detection technologies, such as poor target specificity, low positioning accuracy, short operating distance, sensitivity to environmental interference, and passive reliance on natural signals, this invention proposes an active tracer detection method based on the social behavioral characteristics of termites. This invention guides termites to actively transport tracer microspheres with specific physical markers (magnetism) into the nest and tunnel network. Combined with highly sensitive physical field detection methods, it achieves accurate identification and three-dimensional positioning of concealed termite nests. This method effectively improves target specificity and overcomes the application bottlenecks of traditional tracers, which cannot penetrate, remain, or be detected. It overcomes the limitations of passive detection modes and enhances adaptability and robustness in the field environment. By utilizing the termites' own behavior to transport the tracer microspheres deep into the nest, the detection signal originates directly from the core area of ​​termite activity, effectively avoiding misjudgments caused by geophysical methods that cannot distinguish between termite tunnels and root cavities, construction defects, and other non-biological geological anomalies. The tracer microspheres designed in this invention combine attraction, environmental stability, and detectability. They can be efficiently ingested by termites and remain in their nest systems for extended periods, while simultaneously generating physical response signals that can be stably captured by surface devices, thus achieving precise sensing. This invention abandons the passive reliance on natural termite activity signals (such as acoustic emissions or volatile metabolites) and significantly expands the detection depth and coverage through active biological transport and physical field enhancement mechanisms, making it particularly suitable for complex dam engineering scenarios with high water content and strong heterogeneity. This invention uses magnetic field signals as the detection basis, which is less affected by environmental factors such as temperature, humidity, wind speed, and background gases. Compared with VOCs-based biosensing technologies, it has higher stability and reliability, ensuring continuous and effective monitoring capabilities under actual engineering conditions.

[0048] In a preferred embodiment of the present invention, a method for preparing a termite tracer is provided, comprising the following steps: 1) Synthesis of functional microparticles: Combining cellulose feed with nanoscale magnetic particles to obtain magnetic functional microparticles.

[0049] 2) Surface modification: The feeding-enhancing matrix is ​​adsorbed or coated on the surface of the magnetic functional microparticles.

[0050] 3) Magnetic separation: Using a magnetic field to separate and extract magnetic functional particles.

[0051] 4) Preparation and Shaping: The separated functional microparticles are post-processed according to the dosage form. In the examples, step 4) includes preparing a powder tracer by low-temperature drying. Alternatively, step 4) includes adding deionized water and a food-grade suspending agent to prepare a liquid tracer.

[0052] In a preferred embodiment of the present invention, the termite tracer is provided for use in active tracing and detection of termite nests or in the detection of termite hazards in dams. It can be effectively used to induce termite movement, thereby tracing termite foraging behavior, nests, and underground tunnels.

[0053] In a preferred embodiment of the present invention, a method for locating termite nests is provided, comprising: using the aforementioned termite tracer; actively deploying the tracer based on termite social behavior; and combining magnetic tracer microspheres with surface magnetometry to locate termite nests. This method, combining termite feeding behavior-based tracer marking with non-destructive detection, involves throwing a special powder or injecting a liquid tracer into the termite activity area of ​​a dike. The social behavior of termites (including feeding, mate feeding, and nest building activities) is used to diffuse and enrich the tracer in the termite colony and tunnel network, forming a detectable marker signal. This is combined with physical detection methods to non-destructively locate the tracer-rich area (termite nest). This method is applicable to the precise location of termite nests in water conservancy facilities such as reservoir dams, river embankments, and canal embankments.

[0054] In a further preferred embodiment, the termite nest location method includes: 1) Deploy bait stations in areas suspected of termite activity, the bait stations containing termite tracers.

[0055] 2) After determining the location of the termite tunnel, remove the bait block and use a micro-injection device to inject the liquid tracer into the tunnel in a pulsed, low-pressure manner.

[0056] 3) After a preset set time, the magnetic functional particles in the liquid tracer are transported and enriched into the deep nest and channel network by the termites’ carrying or feeding behavior.

[0057] 4) High-sensitivity magnetic measurement equipment is used to perform gridded magnetic field anomaly scanning on the ground surface, obtain magnetic field data of the survey area and perform inversion processing, reconstruct the three-dimensional spatial location of the underground magnetic functional particle aggregation area, and realize the accurate location of ant nests and hidden channel networks.

[0058] In another preferred embodiment of the present invention, the method includes: setting up bait stations in suspected termite activity areas and injecting termite tracers into the bait stations or adjacent soil; utilizing the termite cleaning, carrying, or feeding behaviors to allow them to carry the termite tracers into the nest and tunnel network; after the termite tracers are released and a preset time has elapsed, using a high-sensitivity magnetometer to perform gridded magnetic field measurements along the embankment surface to obtain magnetic anomaly data; and reconstructing the three-dimensional spatial location of the underground magnetic microsphere aggregation area through magnetic gradient tensor inversion or equivalent source imaging algorithms, thereby locating the termite nest and main tunnel.

[0059] In a preferred embodiment, the preset time is 3-7 days, and the high-sensitivity magnetometer includes a cesium optically pumped magnetometer.

[0060] In some embodiments of the present invention, an active termite detection system suitable for dam engineering is provided, comprising a magnetic tracer microsphere delivery device, a high-precision surface magnetic surveying device, and a data acquisition and 3D imaging software module. The magnetic tracer microsphere delivery device is used to inject magnetic tracer microspheres into bait stations, termite tunnels, or adjacent soil. The high-precision surface magnetic surveying device is used to perform gridded magnetic field measurements along the surface to be measured, acquiring magnetic field anomaly signals and coordinate attitude data. The data acquisition and 3D imaging software module is used to correct and invert the acquired magnetic anomaly data, and output a 3D spatial model of the underground magnetic microsphere aggregation area through magnetic gradient tensor inversion or equivalent source imaging algorithms. All components work collaboratively to achieve fully automated or semi-automated operation from attraction and tracing to imaging. This invention relates to an active termite hazard detection system for dike engineering, used to implement the aforementioned termite nest location method. The system includes a magnetic tracer microsphere delivery device comprising a micro-injection device, which is well-suited for in-situ, pulsed, low-pressure injection of the liquid tracer into termite tunnels. A high-precision surface magnetic surveying device includes a high-sensitivity magnetometer and integrated GNSS and IMU modules, which are well-suited for gridded scanning along the surface to acquire magnetic field anomaly signals with precise location and attitude tags. A data acquisition and 3D imaging software module is well-suited for simultaneously acquiring magnetic field, coordinate, and attitude data, and reconstructing the 3D spatial location of underground magnetic particle aggregation areas using a magnetic gradient inversion algorithm.

[0061] Some embodiments of the present invention provide an active tracing and detection method for termite infestations. This method is based on a lure-injection-transportation coordinated strategy and includes the following steps: 1. Use termites' feeding habits to lure them to the pre-set release point.

[0062] 2. Place tracers with magnetic markings at the placement points.

[0063] 3. By utilizing the cleaning, carrying, or feeding behaviors of termites, the tracer is carried and transported to the interior of deep nests and hidden tunnel networks.

[0064] 4. By scanning and inverting the surface magnetic field anomalies using high-sensitivity magnetic measuring equipment (such as cesium optical pump magnetometer), the three-dimensional positioning of underground ant tunnel structures can be achieved.

[0065] The present invention cleverly integrates the inherent biological behavior characteristics of termites with the advantages of physical field detection, transforming the active transport capacity of organisms into a controllable and measurable detection path. This can significantly improve the penetration depth of tracers in complex dam media, the stability of nest retention, and the detectability of the generated physical signals, providing a brand-new technical solution for the accurate identification and intelligent control of hidden termite hazards in water conservancy projects.

[0066] In some embodiments of the present invention, powder tracers and liquid tracers are provided according to the application scenario and environmental adaptability requirements.

[0067] In a specific embodiment of the present invention, the powdered tracer directly acts as an inducer, stimulating termites to transport particles during their foraging behavior. Its components are as follows: 1. Magnetic Powder: The core component of the powder is magnetic microparticles (superparamagnetic microspheres), which can be made of strontium ferrite, iron oxide (Fe3O4, saturation magnetization ≥50 emu / g), etc. The magnetization intensity can be adjusted as needed. The mass of each microparticle is controlled to be sufficient for effective carrying by termites without causing them excessive burden, generally 1-2 micrograms. The specific value can be adjusted according to the habits of different termite species. The particle size of the magnetic microparticles should match the size of the worker termite's mouthparts to facilitate carrying by the termites.

[0068] 2. Attracting Ingredients: To ensure termites are attracted to these particles, the powder surface can be coated with attracting ingredients such as yeast extract, starch, plant-derived cellulose microfibers, and other natural materials to mimic the building materials of termite nests and increase termites' interest. Odor attractants, such as yeast paste and cellulose hydrolysate, can be added appropriately to stimulate termite foraging behavior.

[0069] 3. Powder stability: In order to ensure that the powder can be used stably under different environmental conditions, the powder needs to have good flowability and suspension. The dispersibility can be improved by adding an appropriate amount of food-grade flow aid or thickener.

[0070] 4. Optional auxiliary method: Mix some tiny fluorescent microspheres (with even smaller particle size) into the powder tracer so that termites will attach these tiny particles during their foraging process.

[0071] In some embodiments of the present invention, the liquid tracer provided in this embodiment is an aqueous suspension that does not contain synthetic surfactants, pesticides, or repellent chemicals, and its components are as follows: 1. Functional microparticles: Magnetic microspheres (strontium ferrite, Fe3O4, saturation magnetization Ms≥50 emu / g), with a particle size of 50-500μm (capable of being held by worker ants' mouthparts, common particle size in mud); their surface is modified with natural organic components that termites can recognize, including but not limited to yeast extract, starch or plant-derived cellulose microfibers, so that they mimic the natural mud material used by termites to build nests in terms of physical form, smell and texture, thereby inducing worker ants to mistake them for portable building materials and actively transport them to underground tunnels and nests.

[0072] 2. Solvent: Deionized water, pH adjusted to 6.0-7.5 to match the microenvironment inside the termite nest and avoid irritating reactions.

[0073] 3. Suspension aid: Food-grade xanthan gum or carboxymethyl cellulose (CMC) is used to maintain the suspension stability of microparticles, ensuring that functional microparticles are uniformly dispersed within 24 hours without significant sedimentation, while maintaining the liquid's natural wetting ability on newly built termite tunnels.

[0074] 4. Attractant / Receptivity Enhancer: Yeast extract or cellulose hydrolysate can be added to provide a mild volatile organic signal to help guide termites to the tracer area.

[0075] The general requirements are that the liquid is non-toxic and non-repellent to termites; the viscosity of the liquid should maintain a certain fluidity, the particles should be stably dispersed in the liquid, and they should be transportable by worker ants.

[0076] In some embodiments of the present invention, the preparation process of the tracer is as follows: Figure 1 As shown, the steps are as follows: 1. Synthesis of functional microparticles: magnetic microspheres are generated by combining feed such as cellulose with nanoscale magnetic particles.

[0077] 2. Adsorb the inducing components onto the surface of functional microparticles.

[0078] 3. Use a magnet to separate magnetic functional particles to ensure the purity of the active ingredients in the tracer.

[0079] 4. Prepare tracers according to requirements. For powders, use low-temperature drying. For liquid solvents, add a suspending agent to maintain the stability of the suspended particles.

[0080] In some specific embodiments of the present invention, the implementation process includes the following steps, such as... Figure 2 As shown: 1. Bait induction stage: Place cellulose-containing bait blocks and powdered tracers in suspected termite-infested areas for 7 days to induce termites to establish new feeding tunnels (not yet fully waterproofed by mud lining).

[0081] 2. Liquid injection stage: After determining the location of the termite tunnel, remove the bait and use a micro-injection device to inject the liquid tracer in situ at a pulsed low pressure (pressure 0.01-0.05 MPa, pulse frequency 0.05-0.2 Hz).

[0082] 3. Waiting for Transport Phase: Allow 24-72 hours for the termites to transport the functional microparticles in the liquid to the main nest and various levels of tunnels, forming enrichment zones. This embodiment primarily utilizes the high permeability window during the initial formation of newly formed termite tunnels to inject the tracer. A pulsed, low-pressure injection method effectively avoids disturbing the termite tunnel structure, thereby reducing the risk of triggering active sealing or avoidance behaviors. The liquid tracer's composition is designed to mimic the characteristics of commonly used termite remediation materials to improve termite acceptance of the tracer medium and the probability of secondary transport. Simultaneously, the dosage of the liquid tracer can be dynamically adjusted based on the flood season conditions of the construction area: during flood season, considering the structural integrity of the dike and the safety requirements of seepage, a micro-volume, dispersed injection is preferable; during non-flood season conditions, a larger dose can be injected at specific points above the termite nest or suspected termite tunnels to increase the enrichment of magnetic tracers and the intensity of magnetic anomaly response within the termite tunnels.

[0083] (4) Signal detection and positioning To achieve efficient, accurate, and non-destructive localization of nanoterrestrial (nT) level weak magnetic anomalies generated by magnetic particles transported and accumulated by termites within dams, this invention employs a ground-based cesium optical pump magnetometer (or a more precise fluxgate magnetometer) detection and data processing scheme suitable for complex dam environments. This scheme balances high sensitivity, strong anti-interference capabilities, and engineering operability, and specifically includes the following steps: 1. Detection system configuration Main sensor: A high-sensitivity cesium optically pumped magnetometer (or a higher-precision fluxgate magnetometer) is used, with a typical sensitivity ≤0.01 nT RMS and a sampling rate ≥10 Hz.

[0084] Auxiliary sensors: High-precision GNSS (RTK or PPK mode, positioning accuracy ≤2 cm). Three-axis fiber optic gyroscope IMU (attitude accuracy ≤0.1°).

[0085] Optional: Reference base station magnetometer (for diurnal variation correction).

[0086] Platform type: trolley-type or backpack-type rigid bracket to ensure a constant probe height above the ground (recommended 0.3-0.5 m), and integrate shock absorption and leveling mechanisms.

[0087] 2. Survey network deployment and data acquisition like Figure 3 As shown, a high-density measurement network (grid size adjusted according to accuracy requirements) should be deployed in the suspected termite infestation area. The coverage area should include the bait placement point and its surrounding extended area (it is recommended to have a radius of not less than 10 m centered on the placement point). During measurement, move at a constant speed (≤1 m / s) along the measurement line and simultaneously collect the total magnetic field strength. 3D position coordinates Sensor attitude (including pitch, roll, and yaw angles) and timestamps (used for data synchronization with remote base stations) are required. Before formal data acquisition, the instrument needs to be fully warmed up, and local geomagnetic background field measurements should be conducted near the survey area (it is recommended to observe statically for at least 10 minutes) to ensure stable and reliable data benchmarks.

[0088] 3. Data Processing Diurnal variation correction: Using data from remote base stations, a differential method is employed to eliminate the influence of diurnal variations in the geomagnetic field. (1) In the formula, To eliminate magnetic anomalies caused by diurnal variations in geomagnetism; This is a time series of the actual observed magnetic field; The background or baseline magnetic field that varies over time (e.g., geomagnetic diurnal variation, instrument drift, etc.). The mean over a certain reference period (is a constant and does not depend on time). t ).

[0089] 4. Deep information inversion Total inversion objective function Data fitting difference function and model objective function The former establishes the relationship between observed data and model spatial property parameters through forward modeling formulas, while the latter, as a stabilizing term, can control the distribution characteristics of model spatial properties; the relative weights of the two are determined by parameters. This means that, since the process of adding the model objective function as a stable term in the inversion problem is mathematically called regularization, the parameters... Also known as the regularization parameter. Therefore, the overall inversion objective function is as follows: (2) This is the data fit difference function, mainly used to evaluate the spatial physical parameters of the current model. Forward modeling prediction data With observation data The magnitude of the difference between them.

[0090] (3) It is a diagonal matrix, where each element is a coefficient representing the data fit difference. The default setting is 3%, but it can be adjusted based on the noise level of the observed data. The maximum value of the observed data. This represents the maximum value of the observed data.

[0091] (4) The objective function of the model is added as a constraint term to the overall objective function of the inversion, which can reduce the ambiguity of the inversion problem and improve the instability of its results.

[0092] (5) in, To determine the weight coefficient matrix of the element block in the model space, This is the reference model matrix used for the current inversion problem.

[0093] Finally, the overall inversion objective function is solved using the conjugate gradient method in n iterations. The minimum value corresponds to the magnetic parameter m. (n) This refers to the three-dimensional distribution of underground magnetic bodies.

[0094] Example 1: Preparation of magnetic tracers This embodiment describes in detail the specific preparation methods of powder tracers and liquid tracers for active tracing of termite hazards.

[0095] (1) Synthesis of functional microparticles 10g of nano-Fe3O4 magnetic particles (saturation magnetization of 55 emu / g, average particle size of 200nm) were dispersed in 200 mL of deionized water and ultrasonically vibrated for 30 min to form a homogeneous magnetic colloidal solution. Separately, 15g of microcrystalline cellulose was dissolved in 100 mL of deionized water and heated to 80℃ with stirring to form a gel-like cellulose solution. The magnetic colloidal solution was slowly added dropwise to the cellulose solution while continuously stirring at 800 rpm. After the addition was complete, 2g of yeast extract was added as an inducing agent, and stirring was continued for 1 h. Subsequently, the mixture was treated by spray drying at an inlet air temperature of 180℃ and an outlet air temperature of 80℃ to obtain a crude product of magnetic microspheres with a wide particle size distribution (5-100 μm).

[0096] The crude product obtained by spray drying was processed by an air jet mill and then classified through 200-mesh (75 μm) and 500-mesh (25 μm) sieves to collect microparticles with a particle size range of 25-75 μm as functional microparticles. These microspheres have a core-shell structure with Fe3O4 as the core and cellulose / yeast extract as the shell.

[0097] (2) Surface adsorption of induced components Take 20g of the above-mentioned functional microparticles and disperse them in 300mL of an aqueous solution containing 5% yeast extract and 3% cellulose hydrolysate (including cellobiose, oligocellulose sugars, etc., preferably cellobiose). Stir at room temperature for 2 hours to allow the inducing components to be fully adsorbed onto the surface of the microparticles. After adsorption is complete, centrifuge at 4000 rpm for 10 min, collect the precipitate, and wash it three times with deionized water to remove unadsorbed free components.

[0098] (3) Magnetic separation and purification The washed precipitate was redispersed in 200 mL of deionized water, and magnetic separation was performed using a permanent magnet (magnetic field strength 0.3 T). The magnet was placed on the side wall of the container, and after standing for 5 min, the unadsorbed non-magnetic or weakly magnetic impurities were discarded. The magnetic separation operation was repeated 3 times, and the functional particles adsorbed by the magnet were collected. After magnetic separation, the saturation magnetization of the particles increased to 52 emu / g, and the purity of the magnetic active ingredient was ≥95%.

[0099] (4) Preparation of powder tracer The functional microparticles obtained by magnetic separation were placed in a vacuum freeze dryer and freeze-dried at -50℃ and 10 Pa for 24 h to obtain a dried powder product. 0.5% (mass fraction) of food-grade silica was added to the dried powder as a flow aid, and the mixture was stirred in a three-dimensional mixer for 30 min to ensure uniform dispersion. The powder tracer was then passed through a 100-mesh (150 μm) sieve to obtain the final powder tracer product. Testing showed that the powder tracer had good flowability, an angle of repose of 32°, and a single termite transport capacity of approximately 1-2 μg / termite.

[0100] (5) Preparation of liquid tracers Take 10g of the magnetically separated functional microparticles and disperse them in 1L of deionized water. Adjust the pH to 6.8 with 0.1 mol / L hydrochloric acid or sodium hydroxide solution. Add 0.2% (mass fraction) xanthan gum as a suspending agent to the dispersion and stir at 500 rpm for 1 h to ensure complete dissolution and uniform dispersion of the xanthan gum. Subsequently, add 0.1% (mass fraction) yeast extract and 0.1% cellulose hydrolysate (preferably cellobiose) as attractants and continue stirring for 30 min. Filter the prepared suspension through a 200-mesh (75 μm) sieve to remove large particle agglomerates, obtaining the finished liquid tracer.

[0101] The viscosity of the liquid tracer was measured to be 15-25 mPa·s (at 25°C and a shear rate of 10 s⁻¹). -1 (Measured with a Brookfield DV2T viscometer), the functional microparticles showed a sedimentation rate of ≤10% within 8 hours. It is recommended to shake well before use and inject immediately to ensure uniform particle distribution.

[0102] Example 2: Application of Active Tracing Detection Method for Termite Hazards This embodiment uses a suspected termite-infested area on the back slope of a reservoir's earth-rock dam as an application scenario, and describes in detail the specific implementation process of using the tracer prepared in Example 1 to detect termite nests.

[0103] (1) Bait induction stage A suspected termite-infested area measuring 20 m × 20 m was selected on the back slope of a reservoir dam. After clearing surface weeds, three bait placement points were set up in the center of the area, spaced 5 m apart, in an equilateral triangle pattern. Each placement point contained the following bait combination: a cellulose bait block made of 50 g of pure cellulose powder and 50 g of pine sawdust, and 5 g of the powdered tracer prepared in Example 1 (evenly sprinkled on the surface of the bait block and around it). The bait surface was covered with moist soil to maintain humidity.

[0104] The bait was placed during the non-flood season and continuously for 7 days. According to preliminary experiments, it takes an average of 5-10 days for termites to establish a new foraging tunnel; in this example, the median value of 7 days was used. On the 3rd day, on-site observation showed that termites had begun to establish new foraging tunnels. By the 7th day, obvious signs of termite activity were observed around each placement point. The tunnel diameter was approximately 5-8 mm, and a complete mud lining waterproof layer had not yet formed on the tunnel surface.

[0105] (2) Liquid injection stage After the induction period ended on day 7, the bait blocks were carefully removed, leaving the original tunnel entrance intact. A micro-injection device (equipped with a 0.5 mm inner diameter needle) was used to inject the liquid tracer. The injection parameters were set as follows: injection pressure 0.03-0.05 MPa (dynamically adjusted according to the development of the termite tunnel lining; lower values ​​for new tunnels, higher values ​​for hardened tunnels), pulse frequency 0.1 Hz (i.e., injection once every 10 seconds), single pulse injection volume 1.5 mL, total injection volume 100 mL / placement point. The injection needle was inserted to a depth of approximately 5 cm into the tunnel entrance, and the injection program was initiated, continuing for approximately 17 minutes (100 mL ÷ 1.5 mL / injection ÷ 0.1 Hz = approximately 667 seconds). No termite escape or tunnel entrance blockage was observed during the injection process, indicating that the pulsed low-pressure injection did not induce a repulsive response in the termites.

[0106] This embodiment was implemented during the non-flood season, therefore a larger dose was used for fixed-point injection (100 mL / point). If implemented during the flood season, considering the structural integrity of the dike and the safety requirements of seepage, the injection volume should be controlled at 20-50 mL / point, and a decentralized multi-point injection method should be used.

[0107] (3) Waiting for transport After injecting the liquid tracer, gently cover the injection point with damp turf and restore the original state. Let it stand for 48 hours. The 48-hour transport cycle was determined based on previous indoor termite nest tracing simulation experiments, during which the spatial distribution of magnetic particles tends to stabilize. During this period, termite worker ants mistake the magnetic particles in the tracer for nest building materials and transport them to the main nest, secondary nests, and various levels of the ant tunnel network through transport behavior. According to laboratory simulation experiments, the estimated retention rate of magnetic particles in the main nest during the 48-hour transport cycle is approximately 40%-60%, which can form a stable magnetic anomaly signal.

[0108] (4) Signal detection and positioning stage After the transport phase is completed, immediately conduct magnetic field anomaly detection.

[0109] 1) Detection system configuration A G-859 cesium optically pumped magnetometer (GEM Systems, Canada, sensitivity 0.01 nT RMS, sampling rate 10 Hz) or equivalent device was used as the main sensor, equipped with an RTK-GNSS positioning module (horizontal positioning accuracy 1.5 cm) and a fiber optic gyroscope IMU attitude sensor (attitude accuracy 0.05°). The sensor was mounted on a trolley-type rigid bracket, with the probe height fixed at 0.4 m above the ground. The bracket was equipped with shock-absorbing springs and a leveling bubble.

[0110] 2) Survey network deployment and data acquisition A high-density rectangular survey network of 24 m × 18 m was established with the geometric center of the three deployment points as the center of the survey area. The spacing between survey lines was 0.5 m, and the spacing between survey points was 0.5 m, totaling approximately 37 survey lines × 49 survey points = 1813 survey points. The instrument moved at a constant speed along the survey lines, and at each survey point, total magnetic field strength, three-dimensional coordinates, sensor attitude, and timestamp data were simultaneously collected. Before data collection, the instrument was warmed up for 30 minutes, and a local geomagnetic background field measurement was conducted in an area free of termite activity 500 m outside the survey area, followed by 15 minutes of static observation (complying with the requirements of the "Technical Specification for High-Precision Ground Magnetic Measurement" DZ / T 0071-2016).

[0111] If the direction of termite activity observed during the induction phase indicates that the main direction of the termite tunnels deviates from the center of the survey area, the center of the survey area can be shifted 3-5 meters along the main direction of the termite tunnels to ensure that the anomalies are located within the survey area. For surveys of large areas with unknown termite infestations, the survey network can be expanded to increase the coverage area.

[0112] 3) Data processing After data collection, diurnal variation correction was performed using the differential method. The influence of geomagnetic diurnal variation was eliminated by using the data from the magnetometer of the reference base station located 500 m outside the survey area in a non-magnetic interference area (the deployment of the diurnal variation station should comply with the requirements of DZ / T 0071-2025 "Technical Specification for High-Precision Magnetic Measurement on the Ground").

[0113] Subsequently, a total inversion objective function was constructed, and iterative inversion was performed using the conjugate gradient method. The regularization parameter λ was optimized to 0.1 using the L-curve method, the data fit error coefficient ε was set to 3% (based on the noise level of the observed data), and the number of iterations n was 20 (the convergence threshold was set to a relative change in the objective function between two adjacent iterations of <0.1%). After the inversion converged, the three-dimensional distribution of the underground magnetic anomaly was obtained.

[0114] 4) Detection results The inversion results show that there is a concentrated area of ​​magnetic anomalies approximately (3, -2.8) southeast of the center of the surface survey area. Figure 4 The peak of the magnetic anomaly indicates the presence of a termite nest. As the depth of the cross-section increases, the magnetic anomaly features of some termite tunnels and nests become increasingly significant. Figure 5 Based on the magnitude of its normalized magnetic field strength, the depth of its main nest is estimated to be in the range of 1.5-2m.

[0115] 5) Excavation verification Three days after the initial detection, on-site excavation was conducted to verify the location results. A termite main nest was unearthed at a depth of 1.8 m, containing a queen, king, and numerous worker and soldier termites, highly consistent with the detection findings. This validated the accuracy and reliability of this method for three-dimensional location of termite nests and tunnel networks.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A termite tracer, characterized in that, The termite tracer contains magnetic functional microparticles and a feeding attractant matrix; the magnetic functional microparticles comprise magnetic microspheres with a saturation magnetization of 50-150 emu / g, and the magnetic microspheres include strontium ferrite and / or iron oxide.

2. The termite tracer according to claim 1, characterized in that, The termite tracer is a powder tracer; the powder tracer is a magnetic tracer microsphere; the feeding attractant matrix modifies or coats the surface of the magnetic functional microspheres; the particle size of the magnetic tracer microspheres is 50-500 μm; the powder tracer may also optionally contain one or more of food-grade flow aids and thickeners; the termite tracer may also optionally include fluorescent microspheres.

3. The termite tracer according to claim 1, characterized in that, The termite tracer is a liquid tracer; the liquid tracer is an aqueous suspension; the liquid tracer may also optionally contain a suspending agent and an attractant enhancer, wherein the suspending agent is food-grade xanthan gum or carboxymethyl cellulose, and the attractant enhancer is yeast extract and / or cellulose hydrolysate.

4. The termite tracer according to any one of claims 1-3, characterized in that, The magnetic functional microparticles include magnetic microspheres with a saturation magnetization of 50-150 emu / g and cellulose bait; the cellulose bait is selected from one or more of microcrystalline cellulose, pure cellulose powder, eucalyptus fiber bait, and pine fiber bait, and the raw material of the cellulose bait preferably includes pine wood or eucalyptus bark.

5. The termite tracer according to any one of claims 1-4, characterized in that, The attractant matrix is ​​selected from one or more of microcrystalline cellulose, pure cellulose powder, eucalyptus fiber bait, and pine fiber bait. The raw materials of the cellulose bait preferably include pine wood or eucalyptus bark.

6. A method for preparing the termite tracer according to any one of claims 1-5, characterized in that, Includes the following steps: 1) Synthesis of functional microparticles: Combining cellulose feed with nanoscale magnetic particles to obtain magnetic functional microparticles; 2) Surface modification: Adsorbing or coating the feeding-enhancing matrix onto the surface of the magnetic functional microparticles; 3) Magnetic separation: Using a magnetic field to separate and extract magnetic functional particles; 4) Preparation and molding: The separated functional microparticles are post-processed according to the dosage form.

7. The preparation method according to claim 6, characterized in that, Step 4) includes adding deionized water and food-grade suspending agent to prepare a liquid tracer; or using a low-temperature drying method to prepare a powder tracer.

8. The application of the termite tracer according to any one of claims 1-5 in the active tracing and detection of termite nests or the detection of termite hazards in dikes.

9. A method for locating termite nests, characterized in that, include: The termite tracer described in any one of claims 1-5 is actively deployed based on the social behavior of termites, and termite nests are located by combining magnetic tracer microspheres with surface magnetometry.

10. The termite nest location method according to claim 9, characterized in that, include: 1) Deploy bait stations in areas suspected of termite activity, wherein the bait stations contain the powdered tracer; 2) After determining the location of the termite tunnel, use a micro-injection device to inject the liquid tracer into the tunnel in a pulsed, low-pressure manner. 3) After a preset set time, the magnetic functional particles in the liquid tracer are transported and enriched into the deep nest and channel network by the termites’ carrying or feeding behavior. 4) Use high-sensitivity magnetic measurement equipment to perform gridded magnetic field anomaly scanning on the surface, obtain magnetic field data of the survey area, perform inversion processing, and reconstruct the three-dimensional spatial location of the underground magnetic functional particle aggregation area.

Images