Mecdysone nanoemulsion for improving pupation uniformity of protaetia brevitarsis as well as preparation method and application of ecdysone nanoemulsion

Abstract

The invention discloses an ecdysone nanoemulsion for improving pupation uniformity of protaetia brevitarsis as well as a preparation method and application of the ecdysone nanoemulsion, and relates to the technical field of insect breeding. The ecdysone nanoemulsion is prepared from the following raw materials: ecdysone, ultrapure water, ethanol, sodium bicarbonate, a surfactant, a cosurfactant and edible oil. According to the ecdysone nanoemulsion, 5% of 3-instar larva groups with the average weight of 2.5 g or above, or 80-day larva groups after incubation, or 3-instar larva groups in the same batch are in an aged state, the ecdysone nanoemulsion is continuously used for 7 days by being mixed with feed, meanwhile, the effective content range of ecdysone is within the mixing concentration range of 20-40 mg / kg, the pupation uniformity of the larva groups can be helped to be improved, and the pupation uniformity of the larva groups can be improved. The method is beneficial for improving the population uniformity of the protaetia brevitarsis and expanding the population of the protaetia brevitarsis within a short time, provides technical guarantee for treating agricultural and forestry wastes by applying the protaetia brevitarsis larvae, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of insect breeding technology, specifically to a molting hormone nanoemulsion for improving the uniformity of pupation in the white-spotted flower beetle, its preparation method, and its application. Background Technology

[0002] The white-spotted scarab beetle (Protaetia brevitarsis) belongs to the family Scarabaeidae in the order Coleoptera. Its larvae feed on decaying straw, weeds, and livestock manure, converting the manure into high-quality insect protein, showing great promise in ecological agriculture and resource utilization. However, the pupation start time and cycle of the larvae after the third instar vary greatly, restricting the large-scale breeding of the species and the development of related industries. Current control strategies mainly focus on optimizing the breeding environment and adjusting feed nutrition. While these have improved the situation, there are no reports of using chemicals to improve the uniformity of pupation.

[0003] Utility model patent CN221329902U describes a device for the pupation and emergence of the white-spotted beetle, which improves the pupation rate by constructing breeding facilities and precisely controlling the humidity, temperature, and light of the larval growth environment. However, this process is cumbersome and technically complex. Equipment malfunctions or control errors can easily damage the pupation environment, and adult collection depends on the external environment. Adult activity can easily interfere with larval pupation, making it difficult to improve pupation uniformity simply, efficiently, and economically. Journal article 1, "Study on the Influence of Different Agricultural Organic Wastes on the Biological Characteristics of the White-spotted Beetle," established various single and mixed feed experimental groups and found that the pupation rate was highest in the 75% corn stalk + cow manure mixture group. However, this method still has certain limitations: the supply of corn stalks is affected by the season, and the supply of cow manure is limited by region and farm capacity and is prone to spoilage; this ratio can lead to an imbalance in the adult sex ratio, restricting population reproduction and the expansion of breeding scale; although it can shorten the larval stage, the pupal stage is prolonged, raising doubts about its potential for large-scale application. Journal article 2, "The Influence of Different Edible Fungus Straw on the Growth and Reproduction of White-spotted Flower Beetle," investigated the effects of three different fungus straws as a single feed on pupation rate and other parameters. However, this study only compared the effects of different straw types under single conditions, failing to explore the optimal combination of straw type with moisture content and environmental conditions, and neglecting to investigate differences in the physicochemical indicators of straw, thus hindering standardized control of breeding parameters. Furthermore, the significant differences in straw from different origins and batches made it difficult to reproduce the results in large-scale breeding, limiting its widespread application. Journal article 3, "A Study on Important Conditions for Large-Scale Breeding of White-spotted Flower Beetle," studied the influence of pupation medium and larval density on the pupation process. It found that when loess was used as the pupation medium, the pupation period of 3rd instar larvae was the shortest and the pupation rate was the highest, with a linear relationship between the average pupation period, pupation rate, and larval density. However, the loess in this study was taken from a specific area near the breeding park, making it difficult to replicate the effects in other regions. In large-scale breeding, focusing on pupation rate may reduce the pupation rate, while focusing on pupation rate may increase the pupation period and breeding costs. In conclusion, none of the existing methods can fully meet the needs for a simple, efficient, and economical method to improve the uniformity of pupation in the white-spotted flower beetle.

[0004] Therefore, the present invention aims to provide a molting hormone nanoemulsion that improves the uniformity of pupation of the white-spotted beetle, its preparation method, and its application, in order to solve the above-mentioned problems. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems and provide a molting hormone nanoemulsion for improving the uniformity of pupation of the white-spotted beetle, its preparation method, and its application. It is a nanoemulsion preparation specifically for the pupation stage of the white-spotted beetle, used to improve the uniformity of larval pupation, and is also low in cost and easy to operate.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] This invention provides a molting hormone nanoemulsion that improves the uniformity of pupation in the white-spotted beetle. The molting hormone nanoemulsion is composed of 0.049-0.055% molting hormone, 4.6-5.2% ultrapure water, 1.5-1.8% anhydrous ethanol, 0.05-0.10% sodium bicarbonate, 21.9-31.2% surfactant, 5.1-6.2% co-surfactant, and 55.5-66.8% edible oil.

[0008] The surfactant is one or a mixture of several of Span 83, Span 80, Span 65, Span 60, and Span 40. The co-surfactant is a short-chain alcohol. Edible oils include soybean oil, rapeseed oil, olive oil, rice bran oil, and sesame oil. The zeta potential of the ecdysone nanoemulsion ranges from 2.32±1.85 mV to 7.51±1.41 mV, the particle size ranges from 24.25±6.89 nm to 26.95±5.74 nm, and the polydispersity index ranges from 0.045 to 0.081.

[0009] This invention also provides a method for preparing ecdysone nanoemulsion, the method comprising the following steps:

[0010] S1. Prepare an alcohol solution by dissolving ultrapure water and ethanol in each other. Then dissolve a specified amount of ecdysone in the alcohol solution and add sodium bicarbonate to obtain an ecdysone solution.

[0011] S2. Slowly pour the surfactant and co-surfactant into the ecdysone solution according to the specified amount, mix thoroughly, and obtain the aqueous phase;

[0012] S3. Add the specified amount of edible oil dropwise into the aqueous phase while stirring until all the edible oil is added and stirring is stopped. This yields a water-in-oil nanoemulsion with good transparency and uniform phases, thus obtaining a molting hormone nanoemulsion.

[0013] In this process, ecdysone is dissolved in an alcoholic solution, and then sodium bicarbonate is added to make the final solution slightly alkaline, thus obtaining an aqueous phase.

[0014] Application scope of ecdysone nanoemulsion: The ecdysone nanoemulsion is suitable for 3rd instar larvae with an average weight of 2.5 g or more;

[0015] The molting hormone nanoemulsion is suitable for larval populations that have been cultured for 80 days since hatching;

[0016] The molting hormone nanoemulsion is suitable for a group of 5% of 3rd instar larvae in the same batch that have reached a mature state.

[0017] Method and dosage of ecdysone nanoemulsion: Mix with feed and feed. The effective content of ecdysone is in the range of 20 mg-40 mg / kg. Use for 7 consecutive days.

[0018] The ecdysone nanoemulsion of this invention significantly improves the uniformity of pupation in white-spotted flower beetle colonies, providing a simple and feasible insecticide support for large-scale breeding and improved management efficiency of white-spotted flower beetles. Furthermore, the application of this nanoemulsion provides more scientific and specific pesticide support for insect breeding using agricultural waste, making insect breeding not only more efficient but also more environmentally friendly and sustainable. Through the application of this innovative technology, a positive contribution can be made to the conversion of agricultural waste using carrion insect resources, the optimization of agricultural ecosystems, and environmental protection.

[0019] Compared with existing technologies, the beneficial effects of this solution are:

[0020] 1. The ecdysone nanoemulsion of the present invention shortens the pupation time: Compared with the blank control group of 19.45±7.54 d, the pupation time of the 20 and 40 mg / kg (mixed with feed, calculated as ecdysone) nanoemulsion treatment groups was significantly shortened (P<0.05), to 16.28±5.24 d and 14.65±3.12 d, respectively, demonstrating the positive regulatory effect of ecdysone nanoemulsion on pupation in the time dimension;

[0021] 2. The ecdysone nanoemulsion of the present invention improves the pupation rate: After the pupation cycle, compared with the blank control group of 63.33±1.93%, the pupation rates of the 20 and 40 mg / kg (mixed feed, calculated as ecdysone) nanoemulsion treatment groups were significantly improved (P<0.05) and extremely significantly improved (P<0.01), respectively, to 76.67±3.33% and 83.33±1.93%. The ecdysone nanoemulsion can effectively improve the pupation rate of the white-spotted beetle.

[0022] 3. The ecdysone nanoemulsion of the present invention can reduce pupal mass loss: Compared with the blank control group of 1.69±0.03 g, the average pupal mass of the 20 mg / kg and 40 mg / kg (mixed feed, calculated as ecdysone) nanoemulsion treatment groups increased significantly (P<0.05), to 1.89±0.03 g and 1.79±0.06 g, respectively. The ecdysone nanoemulsion can effectively reduce pupal mass loss.

[0023] 4. The ecdysone nanoemulsion of the present invention improves the eclosion rate: Compared with the blank control group of 58.01±1.73%, the eclosion rates of the 20 and 40 mg / kg (mixed feed, calculated as ecdysone) nanoemulsion treatment groups were significantly improved (P<0.05), at 78.18±1.01% and 74.59±1.86%, respectively. The ecdysone nanoemulsion can effectively promote the improvement of the eclosion rate.

[0024] 5. The ecdysone nanoemulsion of the present invention can improve the quality of adult insects: Compared with the blank control group of 502.77±10.90 mg, the average adult insect weight of the 20 mg / kg and 40 mg / kg (mixed with feed, calculated as ecdysone) nanoemulsion treatment groups was significantly increased (P<0.05), to 585.30±11.72 mg and 547.83±11.10 mg, respectively. The ecdysone nanoemulsion can effectively improve the quality of adult insects. Attached Figure Description

[0025] Figure 1 This is a sample image of the ecdysone nanoemulsion in an embodiment of the present invention;

[0026] Figure 2 This is a graph showing the zeta potential detection results of ecdysone nanoemulsion in an embodiment of the present invention;

[0027] Figure 3 This is a graph showing the particle size detection results of the ecdysone nanoemulsion in an embodiment of the present invention;

[0028] Figure 4 This is a transmission electron microscope image of the ecdysone nanoemulsion in an embodiment of the present invention;

[0029] Figure 5 This is a pupation trend diagram of mature larvae of the white-spotted flower beetle under different ecdysone dosages in the embodiments of the present invention;

[0030] Figure 6 This is a tissue distribution and fluorescence intensity diagram of ecdysone nanoemulsion in an embodiment of the present invention within 2-24 hours. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be described in further detail below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0033] Example 1:

[0034] This embodiment proposes a formulation of ecdysone nanoemulsion to improve the uniformity of pupation in the white-spotted beetle. The mass proportions of each component are as follows: ecdysone powder (Hydroxyecdysone) 0.005 g, ultrapure water 0.47 g, anhydrous ethanol 0.15 g, sodium bicarbonate 0.005 g, surfactant 2.50 g, co-surfactant 0.62 g, and edible oil 6.25 g.

[0035] The surfactant is Span83, the co-surfactant is anhydrous ethanol, and the edible oil is sesame oil.

[0036] Example 2:

[0037] This embodiment proposes a formulation of molting hormone nanoemulsion to improve the uniformity of pupation of the white star flower beetle. The mass proportions of each component are as follows: molting hormone powder (Hydroxyecdysone) 5.53 mg, ultrapure water 0.52 g, sodium bicarbonate 0.010 g, surfactant 2.19 g, co-surfactant 0.52 g, and edible oil 6.57 g.

[0038] The surfactant is Span80, the co-surfactant is 1,2-propanediol, and the edible oil is soybean oil.

[0039] Example 3:

[0040] This embodiment proposes a formulation of ecdysone nanoemulsion to improve the uniformity of pupation in the white-spotted beetle. The total mass is based on 10 g, and the mass proportions of each component are as follows: ecdysone powder 4.43 mg, ultrapure water 0.46 g, anhydrous ethanol 0.15 g, sodium bicarbonate 0.005 g, surfactant 2.68 g, co-surfactant 0.51 g, and edible oil 6.19 g.

[0041] The surfactant is Span 65, the co-surfactant is 1,2-propanediol, and the edible oil is rapeseed oil.

[0042] The embodiments also propose a method for preparing a molting hormone nanoemulsion to improve the uniformity of pupation in the white-spotted beetle, the specific steps of which are as follows:

[0043] S1. Weigh out the following ingredients respectively: ecdysone powder, ultrapure water, sodium bicarbonate, anhydrous ethanol, surfactant, co-surfactant, and edible oil as described in the above examples.

[0044] S2. Prepare an alcohol solution by mixing ultrapure water with a specified amount of ethanol, then dissolve the ecdysone powder in it, add sodium bicarbonate, and oscillate using a vortex oscillator for 50 seconds. After oscillation, set aside for later use.

[0045] S3. Place the above-mentioned ecdysone solution, surfactant, and co-surfactant together in a magnetic stirrer, set the stirring speed to 600 r / min, the temperature to 25 ℃, and the stirring time to 10 min to obtain a uniform and stable aqueous phase.

[0046] S4. Under continuous stirring with a magnetic stirrer, edible oil is added dropwise to the aqueous phase at a constant flow rate of 0.5 ml per second. After the addition is complete, stirring is continued for 10 min to obtain ecdysone nanoemulsion.

[0047] The ecdysone nanoemulsions prepared in Examples 1-3 possess specific physicochemical characteristics, and their samples are illustrated in the figures below. Figure 1 Potential detection was performed using a Zeta potential analyzer, and the results were obtained from... Figure 2 The zeta potentials of the nanoemulsions obtained in Examples 1-3 were 7.51±1.41 mV, 4.25±2.18 mV, and 2.32±1.85 mV, respectively, as shown in the AC analysis. Particle size distribution and polydispersity index were determined using dynamic light scattering (DLS). The results were... Figure 3 According to the AC, the particle sizes of the nanoemulsions in Examples 1-3 were 26.95±5.74 nm, 24.25±6.89 nm, and 26.61±7.13 nm, respectively, and the polydispersity index (PDI) was 0.045, 0.081, and 0.072, respectively.

[0048] The general conditions for achieving the corresponding effects of ecdysone nanoemulsion are as follows: (1) The dosage range of ecdysone nanoemulsion in feed is 20~40 mg / kg (ecdysone powder / dry weight of feed), and it is used for 7 consecutive days; (2) The culture medium (i.e., feed) is oak sawdust, the ambient humidity is 55±5%, the ambient temperature is 27.5±1℃, and the feed thickness is 6 cm; (3) Placed in a plastic feeding box with fine holes at the bottom (25 cm long, 10 cm wide, and 8 cm high); (4) A group of 3rd instar larvae with an average weight ≥2.5 g, or a group of larvae that have been raised for 80 days since hatching, or a group of 3rd instar larvae that have reached maturity in the same batch of 5%.

[0049] Among the above conditions, (4) is a fixed condition. Any one or more of the conditions (1)-(3) can be changed, and within their specified range, the corresponding function of ecdysone nanoemulsion can be achieved.

[0050] Example 4: Effects of different ecdysone dosages on pupation rate and pupation time

[0051] The experiment was conducted using the ecdysone nanoemulsion described in Example 1. The rearing boxes were 25cm × 10cm × 8cm plastic boxes, and the culture medium was oak sawdust. The ambient humidity was controlled at 55±5%, and the temperature was set at 27.5±1℃. 720 third-instar larvae with an average weight ≥2.5 g were randomly selected and randomly divided into 8 groups of 90 larvae each, with 3 replicates (30 larvae / replica). Groups A, B, and C were the ecdysone nanoemulsion experimental groups, with ecdysone content in the feed of 20, 40, and 80 mg / kg, respectively. Groups D, E, and F were the ecdysone solution control groups, with ecdysone content in the feed of 20, 40, and 80 mg / kg, respectively. Group G was the excipient control group (the composition was the same as group B except that it did not contain ecdysone), and group H was the blank control group. Groups A and B received their respective treatments for 7 consecutive days, while group H received the same amount of PBS throughout the experiment. The experimental period was 30 days. At the end of the experiment, SPSS statistical analysis software was used to process the data. One-way ANOVA was used to compare the differences in pupation rate, pupation time, and average pupal weight among groups, and the Waller-Duncan method was used for multiple comparisons. The statistical results of pupation rate and pupation time of mature larvae of the white-spotted flower beetle under different ecdysone dosages are shown in Table 1. The trend graph of pupation of mature larvae of the white-spotted flower beetle under different ecdysone nanoemulsion concentrations is shown in [Figure 1]. Figure 6 As shown.

[0052] Table 1. Effects of effective ecdysone content on pupation rate, pupation time, and average pupal weight of mature larvae of the white-spotted flower beetle.

[0053]

[0054] Note: In Table 1, data are mean ± standard error. Different lowercase letters indicate significant differences between groups at the 0.05 level. Experimental groups A, B, and C used ecdysone nanoemulsions with ecdysone content of 20, 40, and 80 mg / kg, respectively. Groups C, D, and E were ecdysone solution control groups, with ecdysone content corresponding to A, B, and C, respectively. Group G was the excipient control group (effective ecdysone content was 0, otherwise the same as group C). Group H was the blank control group.

[0055] Among them, (1) compared with the blank control group (19.45±7.54 d), the pupation time of the 20 and 40 mg / kg nanoemulsion treatment groups was significantly shortened (P<0.05), to 16.28±5.24 d and 14.65±3.12 d respectively, demonstrating the positive regulatory effect of ecdysone nanoemulsion on pupation in the time dimension. (2) compared with the blank control group (63.33±1.93%), the pupation rate of the 20 and 40 mg / kg nanoemulsion treatment groups was significantly increased (P<0.05) and extremely significantly increased (P<0.01), to 76.67±3.33% and 83.33±1.93% respectively, indicating that the ecdysone nanoemulsion can effectively improve the pupation rate of white star beetle. (3) Compared with the blank control group with an average pupal weight of 1.69±0.03 g, the average pupal weight of the 20 mg / kg and 40 mg / kg (mixed feed, calculated as ecdysone) nanoemulsion treatment groups increased significantly (P<0.05), to 1.89±0.03 g and 1.79±0.06 g, respectively. The ecdysone nanoemulsion can effectively reduce pupal weight loss.

[0056] Example 5: Effect of different ecdysone dosages on average pupal weight

[0057] Experiments were conducted using the ecdysone nanoemulsion described in Example 2. 720 larvae that had been reared for 80 days since hatching were selected. The rearing conditions and grouping were the same as in Case 1. Pupae from each group were collected and placed in a constant-temperature incubator at 28±0.5℃, using sterilized sawdust as the eclosion medium. The ambient humidity was controlled at 55±5%, and the incubation period was 30 days. The adult mass and number of eclosions in each experimental group were recorded. After the experiment, the average adult mass and eclosion rate of each experimental group were calculated. Adult mass was the ratio of the total fresh weight of larvae in each replicate unit to the number of adults, and the eclosion rate was the ratio of the number of eclosions to the actual number of pupae in each replicate unit. Data were processed using SPSS statistical analysis software. One-way ANOVA was used to compare the differences in adult mass and eclosion rate among groups, and the Waller-Duncan method was used for multiple comparisons. The statistical results of the average adult mass and eclosion rate of mature larvae of the white-spotted flower beetle under different ecdysone dosages are shown in Table 2.

[0058] Table 2. Effects of effective ecdysone content on the quality of mature larvae and pupae of the white-spotted flower beetle.

[0059]

[0060] Note: In Table 2, data are mean ± standard error. Different lowercase letters indicate significant differences between groups at the 0.05 level. Experimental groups A, B, and C used ecdysone nanoemulsions with ecdysone content of 20, 40, and 80 mg / kg, respectively. Groups D, E, and F were ecdysone solution control groups, with ecdysone content corresponding to A, B, and C, respectively. Group G was the excipient control group (effective ecdysone content was 0, otherwise the same as group C). Group H was the blank control group (PBS solution).

[0061] Among them, (1) compared with the blank control group (58.01±1.73%), the emergence rates of the 20 and 40 mg / kg nanoemulsion treatment groups were significantly increased (P<0.05), at 78.18±1.01% and 74.59±1.86%, respectively. The ecdysone nanoemulsion can effectively promote the increase of emergence rate. (2) compared with the blank control group (502.77±10.90 mg), the average adult weight of the 20 mg / kg and 40 mg / kg (mixed with feed, calculated as ecdysone) nanoemulsion treatment groups was significantly increased (P<0.05), at 585.30±11.72 mg and 547.83±11.10 mg, respectively. The ecdysone nanoemulsion can effectively improve the adult weight.

[0062] Example 6: Tissue distribution of ecdysone nanoemulsion

[0063] Using the ecdysone nanoemulsion described in Example 3, based on the fact that the ecdysone nanoemulsion formulation is a water-in-oil emulsion system, sodium fluorescein (oil-quenching type) was introduced to label water droplets, and the effective content of ecdysone was 0.1 mg / g.

[0064] Fifteen 3rd instar larvae of the white-spotted flower beetle, all from the same batch and exhibiting similar developmental stages (body length and weight), were selected. Micro-oral administration was performed using a calibrated pipette, with each larva receiving 1 μL. At 2 h, 4 h, 6 h, 12 h, and 24 h post-administration, one larva was randomly selected and fixed to a black background with double-sided tape. Fluorescence images were acquired using a small animal imaging device. The ultraviolet wavelength parameters were set to (510 nm-530 nm) based on the characteristics of the fluorescent dyes. Using specialized analysis software, the fluorescence intensity and spatial distribution of each dye within the larvae at each time point were measured. The experimental results are presented below. Figure 6 The tissue distribution and fluorescence intensity of ecdysone nanoemulsion over 2-24 hours are shown in the figure.

[0065] In summary, Tables 1 and 2, and Figure 5 This indicates that the nanoemulsion exhibits advantages in multiple dimensions, including pupation time, pupation rate, average pupa weight, average adult weight, and emergence rate.

[0066] Ecdysone, a key regulator of insect pupation, plays an indispensable role in initiating the pupation process. The ecdysone nanoemulsion successfully prepared in this study has been shown to effectively improve the uniformity of pupation in mature larvae of the white-spotted flower beetle (shortening pupation time and increasing pupation rate), effectively improving the dispersion of pupation in mature larvae.

[0067] Regarding composition, the nanoemulsions described in this study exhibit adaptability. For the oil phase, in addition to serving as an extra source of fat nutrition, oils with suitable carbon chain lengths, saturation, and polarity parameters were selected based on their dispersion stability under different temperatures and pH conditions. Surfactants were chosen to ensure the emulsion's application stability, selecting surfactants with hydrophilic-lipophilic balance (HLB) values ​​that synergistically match the carbon chain length of the oil phase.

[0068] Regarding biosafety, the nanoemulsion system used in this study consists of natural oils (such as sesame oil and soybean oil), biodegradable surfactants (such as Span 80 and Span 65), and co-surfactants (such as ethanol and propylene glycol). These components can be degraded through metabolic pathways such as β-oxidation and glycolysis in larvae, preventing their accumulation in the insect's body and greatly reducing the risk of potential harm to the organism.

[0069] In addition to the methods used in this study, high-pressure homogenization, microfluidization, and ultrasonic emulsification are also applicable to the preparation of ecdysone nanoemulsions.

[0070] The above specific embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A molting hormone nanoemulsion for improving the uniformity of pupation in the white-spotted flower beetle, characterized by: The ecdysone nanoemulsion is composed of 0.049-0.055% ecdysone, 4.6-5.2% ultrapure water, 1.5-1.8% anhydrous ethanol, 0.05-0.10% sodium bicarbonate, 21.9-31.2% surfactant, 5.1-6.2% co-surfactant, and 55.5-66.8% edible oil.

2. The molting hormone nanoemulsion for improving the uniformity of pupation in the white-spotted flower beetle as described in claim 1, characterized in that: The surfactant is one or a mixture of several of Span 83, Span 80, Span 65, Span 60 and Span 40.

3. The molting hormone nanoemulsion for improving the uniformity of pupation in the white-spotted flower beetle as described in claim 1, characterized in that: The co-surfactant is a short-chain alcohol.

4. The molting hormone nanoemulsion for improving the uniformity of pupation in the white-spotted flower beetle as described in claim 1, characterized in that: The edible oils include soybean oil, rapeseed oil, olive oil, rice bran oil, and sesame oil.

5. The molting hormone nanoemulsion for improving the uniformity of pupation in the white-spotted flower beetle as described in claim 1, characterized in that: The ecdysone nanoemulsion has a zeta potential distribution range of 2.32±1.85 mV to 7.51±1.41 mV, a particle size distribution range of 24.25±6.89 nm to 26.95±5.74 nm, and a polydispersity index distribution range of 0.045 to 0.

081.

6. The method for preparing a ecdysone nanoemulsion as described in claim 1, characterized in that: The method includes the following steps: S1. Prepare an alcohol solution by dissolving ultrapure water and ethanol in each other. Then dissolve a specified amount of ecdysone in the alcohol solution and add sodium bicarbonate to obtain an ecdysone solution. S2. Slowly pour the surfactant and co-surfactant into the ecdysone solution according to the specified amount, mix thoroughly, and obtain the aqueous phase; S3. Add the specified amount of edible oil dropwise into the aqueous phase while stirring until all the edible oil is added and stirring is stopped. This yields a water-in-oil nanoemulsion with good transparency and uniform phases, thus obtaining a molting hormone nanoemulsion.

7. The method for preparing a ecdysone nanoemulsion as described in claim 6, characterized in that: Ecdysone was dissolved in an alcohol solution, and then sodium bicarbonate was added to make the final solution slightly alkaline, thus obtaining an aqueous phase.

8. The application of the ecdysone nanoemulsion as described in claim 1, characterized in that: The molting hormone nanoemulsion is suitable for 3rd instar white-spotted flower beetle larvae with an average weight of 2.5 g or more. The molting hormone nanoemulsion is suitable for populations of white-spotted flower beetle larvae that have been cultured for 80 days since hatching. The molting hormone nanoemulsion is suitable for a group of 5% of 3rd instar larvae in the same batch that have reached a mature state. The method of using the ecdysone nanoemulsion is as follows: Mix 20 mg-40 mg / kg of the ecdysone nanoemulsion with feed and feed it to the white-spotted flower beetle larvae population for 7 consecutive days.

Images