Methods for preparing frozen silkworms and methods for feeding forked-horned bugs with frozen silkworms

Abstract

This invention discloses a method for preparing frozen silkworms and a method for feeding forked-horned bugs with frozen silkworms. The method for preparing frozen silkworms is as follows: S1, select 3rd, 4th and / or 5th instar silkworms 1-3 days old; S2, evenly spray a mixed aqueous solution A containing ascorbic acid and trehalose on mulberry leaves, and feed the silkworms after the mulberry leaves are dried; S3, immerse the silkworms fed with the above-mentioned mulberry leaves in hot water for 10-30 seconds, quickly place them in a mixed aqueous solution B containing magnesium ascorbate phosphate and trehalose, soak for 10-15 minutes, remove and drain the water, and freeze at -20℃ for later use to obtain frozen silkworms. Frozen silkworms are used to feed fortified bugs, which eliminates the limitations of the silkworm rearing season, facilitates preservation, allows bugs of all ages to feed easily, and eliminates the need for additional water supply devices, reducing the rearing process. This method has many advantages, including significantly improving the survival rate of nymphs and adults of fortified bugs, extending the egg-laying period, increasing egg production, and facilitating winter preservation of fortified bugs.

Description

Technical Field

[0001] This invention belongs to the technical field of forked-horn bug rearing technology. Specifically, it relates to a method for preparing frozen silkworms and a method for rearing forked-horn bugs using frozen silkworms. Background Technology

[0002] Forked-horned bug Eocanthecona furcellata It belongs to the genus *Asopinae* of the family Pentatomidae in the order Heteroptera. Eocanthecona This insect is highly mobile, has high predation efficiency, and a wide range of prey. It can prey on the larvae, pupae, and adults of more than 40 kinds of pests, including Lepidoptera, Coleoptera, Hemiptera, and Hymenoptera. It has a strong preference for the larvae of Lepidoptera pests and has a strong pest control ability. It is an important predatory natural enemy insect in agricultural and forestry production and is widely used.

[0003] Currently, research on artificial feed for the large-scale breeding of the Forked-horned bug is insufficient. Live feed is mainly provided by mealworms, fall armyworms, and beet armyworms. When using mealworms to breed Forked-horned bugs, improper management leads to high mortality rates among young nymphs, a short oviposition period, and low egg production. Furthermore, mealworms consume the egg masses, causing egg loss. When lepidopteran pests breed Forked-horned bugs, a large number of pests need to be bred to feed on them, inevitably increasing the risk of pest migration and spread around the breeding base, causing potential ecological damage. In contrast, silkworms are oligophagous, primarily feeding on mulberry leaves, which are high in water content and rich in nutrients. Using silkworms as feed for Forked-horned bugs eliminates the need for additional watering devices, reducing the need for manual feeding and offering significant advantages such as improved survival rates of nymphs and adults, extended oviposition period, and increased egg production. However, silkworm rearing is limited by the growth period of mulberry leaves. In autumn and winter, there are no mulberry leaves left to continue raising silkworms. Moreover, it is difficult for young 3-5 instar silkworms to obtain nutritious food. Therefore, this invention freezes and preserves silkworms to serve as feed for 3-5 instar silkworms. This provides key technical support for the industrialized, large-scale, and year-round breeding of high-quality 3-5 instar silkworms, improves breeding efficiency, reduces breeding procedures, and lowers breeding costs. Summary of the Invention

[0004] When silkworms are frozen directly, they oxidize and turn black within 1-2 hours after thawing and are then fed to forked bugs, significantly reducing the bugs' willingness to feed on them. Therefore, treating silkworms as follows before freezing can effectively prevent oxidation and blackening after thawing, without adversely affecting the feeding and growth of forked bugs.

[0005] In order to overcome the problems existing in the prior art, the present invention proposes a method for preparing frozen silkworms and a method for feeding forked-horned bugs using frozen silkworms.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for preparing frozen silkworms, characterized by comprising the following steps: S1, select silkworms in the 3rd, 4th and / or 5th instar 1 to 3 days; S2, spray a mixed aqueous solution A containing ascorbic acid and trehalose evenly on mulberry leaves, and feed the dried mulberry leaves to silkworms; S3. Soak the silkworms that have been fed the above mulberry leaves in hot water for 10-30 seconds, then quickly place them in a mixed aqueous solution B containing magnesium ascorbate phosphate and trehalose for 10-15 minutes. Remove them, drain the water, and freeze them at -20℃ for later use to obtain frozen silkworms.

[0007] Further, in step S2, the mixed aqueous solution A contains the following components in parts by mass: 0.02-2 parts ascorbic acid, 0.1-1 parts trehalose, and 100 parts water.

[0008] Furthermore, in step S2, the mulberry leaves are dried and then fed to the silkworms twice.

[0009] Furthermore, in step S3, the hot water temperature used for scalding the silkworms is 65°C.

[0010] Further, in step S3, the mixed aqueous solution B contains the following components in parts by mass: 0.1 to 1 part magnesium ascorbate phosphate, 1 to 7.5 parts trehalose, and 100 parts ice water at 4°C.

[0011] The second aspect of the present invention provides frozen silkworms prepared by the method described in the first aspect.

[0012] The third aspect of the present invention provides the application of frozen silkworms of the second aspect in feeding forked bugs.

[0013] Furthermore, the method of feeding forked bugs with frozen silkworms includes the following steps: For A1, feed 10-20 frozen 3rd instar silkworms per 100 2nd instar for 100 larvae daily; feed 25-35 frozen 3rd instar silkworms per 100 larvae daily, or 5-10 frozen 4th instar silkworms, or 2-6 frozen 5th instar silkworms per 100 larvae daily; feed 15-20 frozen 4th instar silkworms per 100 larvae daily, or 10-15 frozen 5th instar silkworms per 100 larvae daily; feed 20-30 frozen 4th instar silkworms per 100 larvae daily, or 10-20 frozen 5th instar silkworms per 100 larvae daily. A2. Adult Forked-horn bugs are paired in a female-to-male ratio of 1:1 or 1:2, and 5 pairs are raised in one oviposition box. 2-3 frozen silkworms of the 4th or 5th instar are fed daily.

[0014] Through the above technical solution, the present invention can achieve at least the following beneficial effects: Silkworms are oligophagous resource insects, rich in nutrients. Approximately 60% of their dry weight is protein, containing 17 amino acids, as well as various vitamins, minerals, lipids, and other nutrients, making them a complete and high-quality protein source. Freezing silkworms for use as feed for *Triplophysa cristatus* (a type of bug) eliminates the seasonal limitations of silkworm rearing, facilitates preservation, allows for easy feeding by bugs of all instars, and eliminates the need for additional watering devices, reducing the rearing process. This significantly improves the survival rate of *Triplophysa cristatus* nymphs and adults, extends the egg-laying period, increases egg production, and facilitates winter stockpiling. Therefore, this invention utilizes frozen silkworms as feed for *Triplophysa cristatus*, providing key technical support for the industrialized, large-scale, year-round breeding of high-quality *Triplophysa cristatus*, improving breeding efficiency, reducing breeding procedures, and lowering breeding costs. Attached Figure Description

[0015] Figure 1 This is a photograph of a frozen silkworm from Embodiment 1 of the present invention; Figure 2 This is a photograph of the actual silkworms (AE and CK) thawed for 20 minutes in Example 2 of this invention. Figure 3 This is a photograph of the actual products of frozen silkworms AE and CK after thawing for 2 hours in Example 2 of this invention; Figure 4 This is a photograph of the frozen silkworms AE and CK processed in Example 2 of this invention after thawing for 4 hours; Figure 5 This is a photograph of the actual silkworms (AE and CK) thawed for 8 hours in Example 2 of this invention. Figure 6 This is a photograph of the actual silkworms (AE and CK) thawed for 24 hours in Example 2 of this invention. Detailed Implementation

[0016] Unless otherwise stated, all materials and reagents used in this invention are commercially available.

[0017] Example 1 Fourth-instar silkworms were fed ordinary mulberry leaves without any antioxidant treatment and directly frozen at -20℃. After one month of storage, they were taken out and thawed at 25℃. Within two hours of thawing, the silkworms showed signs of dehydration and oxidation, turning black. As the thawing time increased, the dehydration, shrinkage, and blackening intensified. After six hours, the silkworms were shriveled and wrinkled; after 24 hours, significant dehydration, shriveling, and wrinkling were clearly visible. (See attached image.) Figure 1 As shown, it was observed that when the silkworm body turned black and lost a lot of water, the feeding intention of the forked-horned bug decreased significantly, and it even stopped feeding altogether.

[0018] Example 2 ck: After feeding silkworms with ordinary mulberry leaves from the 4th instar, perform anti-oxidation treatment on the surface of the silkworms: Immerse the silkworms fed with the above-mentioned mulberry leaves in 65℃ hot water for 20 seconds, then quickly place them in a mixed aqueous solution B containing magnesium ascorbate phosphate and trehalose, soak for 12 minutes, remove and drain the water, and freeze at -20℃ for later use to obtain frozen silkworms; the mixed aqueous solution B contains the following components in parts by mass: 0.5 parts magnesium ascorbate phosphate, 5 parts trehalose and 100 parts ice water at 4℃.

[0019] AE: Fourth instar silkworms were fed a mixed aqueous solution A containing ascorbic acid and trehalose. After the mulberry leaves were dried, the silkworms were fed two meals. Then, the surface of the silkworms was treated with antioxidants: the silkworms were soaked in 65℃ hot water for 10-30 seconds, then quickly placed in a mixed aqueous solution B containing magnesium ascorbate phosphate and trehalose for 10-15 minutes. After soaking, the silkworms were drained and stored at -20℃.

[0020] The weight proportions of each component in the mixed aqueous solutions A and B used to treat AE are shown in Table 1 below: Table 1. Statistical table of the weight ratio of each component in the mixed aqueous solution A and B used to treat AE. After freezing for one month, remove and thaw at 25°C. See below for the observation of silkworm oxidation and blackening 20 minutes to 24 hours after thawing. Figures 2-6 After surface anti-oxidation treatment, silkworms treated with CK turned black after thawing for 24 hours, but did not show obvious dehydration, shrinkage, or shriveling. Silkworms treated with a combination of C and D concentrations and then frozen could effectively delay oxidation and blackening after thawing, and the silkworms did not show obvious dehydration, shrinkage, or shriveling. In particular, even after 24 hours of thawing, there was still no obvious blackening, and the silkworms did not lose water, shrink, or shrivele, and still maintained elasticity. It was observed that the forked bugs showed a positive willingness to feed on it, and actively fed on it 5 minutes after feeding.

[0021] Compared with the above-mentioned Example 1 and Example 2, Example 2, by feeding treated mulberry leaves and anti-oxidation treatment of silkworms and then freezing them, can effectively prevent the silkworms from oxidizing and turning black after thawing, and can effectively prevent the silkworms from losing water, wrinkling and drying out, basically maintaining their original state. Moreover, the forked-horned bugs are willing to feed on it, and it has no impact on its growth and development.

[0022] Experiment Example 3 Comparison of growth, development, and reproductive capacity of *Bombyx mori* fed with live silkworms and those fed with frozen silkworms.

[0023] Select egg masses with plump, uniformly colored eggs and more than 80 eggs each, and place them in an incubation box. Incubate them at 25℃, 60% humidity, and L:D=14:10. After hatching, place leaf dishes made of mulberry leaves in the box to facilitate the transfer of first-instar nymphs to the leaf dishes to feed on the sap. Two days later, the first-instar nymphs molt into second-instar nymphs. Place the second-instar nymphs into plastic rearing boxes with dimensions of 8 cm long, 8 cm wide, and 5 cm high, one nymph per box. 50 nymphs are fed live silkworms daily (control group), and 50 nymphs are fed frozen silkworms prepared in treatment C of Example 2 daily (treatment group). Observe and record the growth, development, and reproductive capacity of molting, emergence, death time, egg production, etc. at 9:00 AM every day.

[0024] Table 2 compares the effects of the two types of silkworm feed on the survival rate of the forked bug.

[0025] Table 2 shows that the survival rate of 1st and 2nd instar nymphs in both the treatment and control groups was 100%, with no deaths. Only one nymph died in the 3rd instar, resulting in a survival rate of 98%. In the 4th instar, three nymphs died, resulting in a survival rate of 95.91%, while in the control group, two nymphs died, resulting in a survival rate of 97.96%. In the 5th instar, one nymph died in both the treatment and control groups, with survival rates of 97.87% and 97.92%, respectively. The emergence rate of adults was 100% in both the treatment and control groups. This indicates that both types of feed resulted in high survival rates for the *Scylla spicata*, and there was no significant difference in survival between frozen and live silkworm feeding.

[0026] Table 3 compares the effects of the two types of silkworm feed on the growth, development, and reproduction of the forked-horn bug.

[0027] Note: The treatment group consisted of *Triplophysa cristatus* feeding frozen silkworms prepared according to treatment C of Example 2, while the control group consisted of *Triplophysa cristatus* feeding live silkworms. The developmental duration of the egg stage and the first instar was the same in both the treatment and control groups, at 7.00 days and 2.00 days, respectively. Although the developmental duration of the second, third, fourth, and fifth instar nymphs in the experimental group was slightly slower than that in the control group, there was no difference. The lifespan of the adults in the experimental group was 28.46 days, which was significantly longer than that in the control group (21.58 days). The total lifespan in the experimental group was 54.43 days, which was significantly longer than that in the control group (46.10 days). The lifespans of the female and male adults in the experimental group were 22.21 days and 34.71 days, respectively, which were significantly longer than those in the control group (18.92 days and 24.23 days, respectively). The pre-spawning period was 7.54 days in the experimental group and 6.00 days in the control group, with the pre-spawning period in the experimental group being significantly longer. The average number of eggs laid per female in the experimental group was 352.69, while that in the control group was 370.78. The average hatching rate of eggs in the experimental group was 87.36%, while that in the control group was 88.34%. The highest number of eggs laid per female in the experimental group was 643, while that in the control group was 663. Although the above indicators in the experimental group were lower than those in the control group, there was no significant difference.

[0028] In summary, the data showed no significant differences between treated and frozen silkworms fed on *Triplophysa fasciata* in nymphal development duration, egg hatching rate, single female egg production, and maximum single female egg production compared to those fed live silkworms. This indicates that treated and frozen silkworms can completely replace live silkworms in feeding *Triplophysa fasciata*, without adversely affecting its growth, development, and reproduction. On the other hand, the lifespan, total lifespan, and pre-oviposition period of adult females and males fed with frozen silkworms were significantly longer than those fed with live silkworms. This provides great convenience for factory-scale rearing of *Triplophysa fasciata*. In winter, mulberry leaves age and fall, failing to meet the conditions for silkworm rearing, resulting in a lack of high-quality live silkworm feed for *Triplophysa fasciata* populations requiring breeding stock. However, pre-freezing silkworms can overcome seasonal limitations, providing a stable and high-quality silkworm feed for *Triplophysa fasciata* breeding stock during winter. Furthermore, feeding frozen silkworms significantly extends the lifespan of both male and female adults of the Forked-horn bug and delays the egg-laying time of each generation. This means that frequent generation replacements are unnecessary to maintain the population during winter conservation rearing, reducing the operational complexity of winter conservation management and the space and labor costs associated with rearing. Moreover, the egg-laying capacity and hatching rate of the retained adults remain unaffected, ensuring the potential for population recovery and production in the spring. Therefore, using frozen silkworms as feed reduces winter management costs while maintaining population reproductive efficiency. This provides crucial technical support for the industrialized, large-scale, and year-round rearing of the Forked-horn bug.

[0029] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing frozen silkworms fed with forked-horned bugs, characterized in that: It includes the following steps: S1, select silkworms in their 3rd, 4th and / or 5th instar 1-3 days; S2, spray a mixed aqueous solution A containing ascorbic acid and trehalose evenly on mulberry leaves, and feed the silkworms twice after the mulberry leaves are dried; the mixed aqueous solution A contains the following components in parts by mass: 0.02~2 parts ascorbic acid, 0.1~1 parts trehalose, and 100 parts water; S3. The silkworms fed with the above-mentioned mulberry leaves are soaked in hot water at 65°C for 10-30 seconds, then quickly placed in a mixed aqueous solution B containing magnesium ascorbate phosphate and trehalose, soaked for 10-15 minutes, removed and drained, and frozen at -20°C for later use to obtain frozen silkworms; the mixed aqueous solution B contains the following components in parts by mass: 0.1-1 parts magnesium ascorbate phosphate, 1-7.5 parts trehalose and 100 parts ice water at 4°C.

2. Frozen silkworms prepared using the method for preparing frozen silkworms as described in claim 1.

3. The application of frozen silkworms as described in claim 2 in feeding forked bugs.

4. The application according to claim 3, characterized in that: The method of feeding forked bugs with frozen silkworms includes the following steps: For A1, feed 10-20 frozen 3rd instar silkworms per 100 2nd instar for 100 larvae daily; feed 25-35 frozen 3rd instar silkworms per 100 larvae daily, or 5-10 frozen 4th instar silkworms, or 2-6 frozen 5th instar silkworms per 100 larvae daily; feed 15-20 frozen 4th instar silkworms per 100 larvae daily, or 10-15 frozen 5th instar silkworms per 100 larvae daily; feed 20-30 frozen 4th instar silkworms per 100 larvae daily, or 10-20 frozen 5th instar silkworms per 100 larvae daily. A2. Adult Forked-horn bugs are paired in a female-to-male ratio of 1:1 or 1:2, and 5 pairs are raised in one oviposition box. 2-3 frozen silkworms of the 4th or 5th instar are fed daily.

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