Bag worm nest material

Abstract

A nest material, which can be stably supplied, is hygienic, and has a high nest-building efficiency, has been developed and is provided in the breeding of bag worms.　Provided is a bag worm nest material including pieces of bark having specific shapes and sizes according to the growth stage of bag worms.

Description

Bagworm nesting material

[0001] The present invention relates to a bagworm nesting material and a method for assisting bagworm nesting using the same.

[0002] Bagworms are the general term for the larvae of moths belonging to the family Psychidae in the order Lepidoptera. Bagworm silk, which they spin, has superior physical properties to silk produced by silkworms, and has therefore attracted attention in recent years as a promising new animal-derived natural fiber (Patent Document 1 and Non-Patent Document 1).

[0003] The bagworm silk industry is just beginning, and breeding techniques are still under development. As a result, bagworms are obtained solely through wild collection. However, mass breeding and successive breeding of bagworms is essential for industrialization, and therefore the establishment of breeding techniques for bagworms is an urgent task.

[0004] Bagworm rearing techniques that have been established in the sericulture industry for silkworms, which are also in the Lepidoptera order, can be applied to bagworm rearing. However, due to differences in their ecology, there are many aspects to silkworm rearing techniques that cannot be used. One of these is nest building. Silkworms do not build nests, but bagworms do. Furthermore, since bagworms spend their entire larval stage living with their nests, nests are essential for their survival and are also an important factor in efficient bagworm rearing.

[0005] Bagworms begin building nests immediately after hatching to protect themselves, keep warm, and retain moisture. Generally, when hatching, they build nests by scraping off the surface of bark or leaves, etc., and entangling them with the silk they spin. As a rule, once a nest is built, it is not replaced, and is used throughout the entire larval stage, with repeated renovations and expansions made as the bagworms grow. Therefore, when raising bagworms in large numbers, it is essential to provide them with appropriate nesting material according to their growth stage. However, the optimal nesting material for raising bagworms has not yet been developed.

[0006] Bagworms can use the branches and leaves provided for feeding as nesting material. However, when raising bagworms in large numbers, they are fed artificial diets to ensure a stable supply of food of consistent quality, and branches and leaves are not fed. When suitable nesting material is not available when reared on artificial diets, bagworms will use the artificial food as nesting material. However, when fresh artificial food is used as nesting material, the nest becomes humid due to the moisture in the artificial food, and under normal rearing conditions, hygiene problems arise due to mold growth and decay. On the other hand, artificial food dries out after a few days. If such dried artificial food is used as nesting material, the problem of the nest collapsing due to the powdered artificial food arises.

[0007] When artificially removed from their nests and left completely naked, bagworms quickly begin nesting. They use small pieces of material found around them as nesting material, replacing leaves and branches. Taking advantage of this property, children have long played a game of feeding naked bagworms small pieces of colored paper or scraps of wool as nesting material, encouraging them to build colorful nests. Therefore, in addition to leaves and branches, bagworms can also use artificial materials such as small pieces of paper, scraps of wool, and pieces of plastic as nesting material. However, these are merely temporary nesting materials for bagworms. In reality, these nesting materials pose various problems and are hardly ideal for breeding. For example, small pieces of paper become flexible when wet, significantly reducing the rigidity of the nest. Furthermore, the high hygroscopicity of scraps of wool increases humidity within the nest, leading to stuffiness and the development of disease. On the other hand, experiments by the inventors have confirmed that when plastic film or small pieces are given as nesting material, as the bagworm bites or scrapes them off with its mouthparts, the small pieces are taken into the body through the mouthparts and accumulate in the intestines, causing death.

[0008] WO2019 / 003364

[0009] Shigeyoshi Osaki, 2002, Journal of the Society of Fiber Science and Technology (Fibers and Industry), 58: 74-78

[0010] The objective of the present invention is to develop nesting material for raising bagworms that can be supplied stably, is hygienic, and has high nesting efficiency.

[0011] To solve the above problems, the inventors provided bagworms with various types of candidate nesting materials to search for nesting materials that bagworms could use efficiently for nesting. They found that bark, especially cork, is the most suitable nesting material for bagworms. They also found that even the same bark varies in size and shape depending on the growth stage of the bagworm. They also found that providing suitable nesting material according to the growth stage significantly affects not only the survival rate but also the growth rate of bagworms, demonstrating that the nesting material promotes the growth of bagworms. Based on these novel findings, the present invention provides the following: (1) Bagworm nesting material that contains bark and whose shape varies depending on the growth stage of the bagworm, wherein the nesting material for early-stage bagworms is of any shape, the nesting material for mid-stage bagworms is granular with a major axis of 0.3 mm to 5.0 mm, and the nesting material for late-stage bagworms is plate-shaped. (2) Bagworm nesting material according to (1), further comprising plate-shaped nesting material as nesting material for the mid-stage bagworms and block-shaped nesting material as nesting material for the late-stage bagworms. (3) Bagworm nesting material for all growth stages, including granular nesting material and plate-shaped nesting material with a major diameter of 0.3 mm to 5.0 mm, including bark. (4) Bagworm nesting material according to any of (1) to (3), wherein the bark is made of cork. (5) Bagworm nesting material according to any of (1) to (4), wherein the bagworm nesting material is disinfected or sterilized. (6) A method for assisting bagworm nesting, comprising providing bagworms with the bagworm nesting material according to (1) or (2) depending on their growth stage. (7) A method for assisting bagworm nesting, comprising providing bagworm nesting material according to (3) at all growth stages of the bagworms. (8) The method for assisting bagworm nesting according to (6) or (7), wherein the bark is cork. (9) The method for assisting bagworm nesting according to any one of (6) to (8), wherein the nesting material is disinfected or sterilized. (10) A bagworm nest comprising granular nesting material made of cork and having a major axis of 0.3 mm to 5.0 mm. This specification includes the disclosure of Japanese Patent Application No. 2021-101905, from which the present application claims priority.

[0012] According to the bagworm nesting material of the present invention, when raising bagworms, nesting material in which bagworms can efficiently build nests according to their growth stage can be provided stably and in hygienic conditions.

[0013] According to the method for assisting bagworm nesting of the present invention, it is possible to increase the nesting efficiency and survival rate of bagworms when they are raised, and to promote the growth of the bagworms.

[0014] 1 shows the nesting material preference of early-stage bagworms (Giant Sackworm) after hatching. Preference was determined by the nesting rate 3 and 24 hours after providing the bagworms with nesting material. This figure shows the state of nests at each growth stage of bagworms (Giant Sackworm) when using cork nesting material. A shows a nest built by an early-stage bagworm. It can be seen that the provided granular nesting material (cork) (arrow) is further ground into powder and used as nesting material. B shows a nest built by a middle-stage third-instar bagworm. It can be seen that the provided granular nesting material is used either as is or after finely processing. C shows a nest built by a late-stage bagworm. It can be seen that the provided cork sheet (arrow) is roughly scraped into small pieces and used as nesting material. This figure shows the nesting rate in Example 3. The figure shows the nesting rate after (day 0) when the first test area (a) was provided with cork granules and cork sheets, the second test area (b) with cork granules and Kimtowel, and the third test area (c) with cork sheets only. This figure shows the growth rate in Example 3. The figure shows the nest length (long axis length) 21 days after the first test area (a) was provided with cork granules and cork sheets, the second test area (b) with cork granules and Kimtowel, and the third test area (c) with cork sheets only. This figure shows the survival rate in Example 3. The figure shows the survival rate over time from the first test area (a) with cork granules and cork sheets, the second test area (b) with cork granules and Kimtowel, and the third test area (c) with cork sheets only. 1 shows the relationship between the particle size of cork particles and growth rate. FIG. 1A is a graph showing the nest length (long axis length) at the start of the experiment in each test plot. FIG. 1B is a graph showing the growth rate, showing the nest length on the 7th day after nesting as a relative value when the nest length at the start of the experiment is set to 1. In both A and B, (a) shows the first test plot, (b) the second test plot, (c) the third test plot, (d) the fourth test plot, and (e) the fifth test plot. FIG. 1B is a graph showing the nesting rate results in Example 5.In the figure, the first test area (a) uses cork pellets approximately 3 mm in diameter, the second test area (b) uses 3 mm pieces of filter paper, and the third test area (c) uses 3 mm diameter plastic beads as nesting material. A shows the nest length at the start of the experiment in Example 5. The first test area (a) uses cork pellets approximately 3 mm in diameter, the second test area (b) uses 3 mm pieces of filter paper, and the third test area (c) uses 3 mm diameter plastic beads as nesting material. B shows the growth rate, expressed as a relative value of the nest length on the 9th day of nesting, with the nest length at the start of the experiment set at 1. (a) to (c) are the same as A.

[0015] 1. Bagworm Nesting Material 1-1. Overview The first aspect of the present invention is bagworm nesting material. The bagworm nesting material of this aspect has a shape optimized for efficient use by bagworms according to their growth stage, and is composed of a material containing bark suitable for raising bagworms. The bagworm nesting material of the present invention can provide nesting material for raising bagworms that is hygienic, can be supplied in a stable supply, and can be used efficiently by bagworms.

[0016] 1-2. Definitions The following terms frequently used in this specification are defined as follows: "Baguworm" refers to the larvae of moths belonging to the family Psychidae in the order Lepidoptera, as mentioned above. Moths of the family Psychidae are distributed throughout the world, but the bagworms covered by this specification may be any species. For example, but not limited to, species belonging to Acanthopsyche, Anatolopsyche, Bacotia, Bambalina, Canephora, Chalioides, Dahlica, Diplodoma, Eumeta, Eumasia, Kozhantshikovia, Mahasena, Nipponopsyche, Paranarychia, Proutia, Psyche, Pteroma, Siederia, Striglocyrbasia, Taleporia, Theriodopteryx, and Trigonodoma are included. Bagworms covered by this specification may be male or female, and may be of any age.

[0017] As used herein, "growth stage" refers to a standard for classifying bagworms according to their growth. In this specification, they are classified into three stages: early stage, middle stage, and late stage, and bagworms in each stage are referred to as early stage bagworms, middle stage bagworms, and late stage bagworms.

[0018] As used herein, "early bagworms" refers to bagworms in the early stages of growth. Although not limited to, this refers to bagworms that build nests with a long diameter of 1 mm or more and less than 10 mm, and generally refers to first- to second-instar bagworms immediately after hatching. As used herein, "early bagworm group" refers to a group consisting of multiple early bagworms. The growth stages of the individuals that make up the group may be the same or different. An example of a group of early bagworms at different growth stages is a group of early bagworms consisting of late first-instar and second-instar individuals.

[0019] As used herein, "mid-stage bagworms" refers to bagworms in the middle stage of growth. This includes, but is not limited to, bagworms that build nests with a long diameter of 10 mm or more but less than 20 mm, generally in the third or fourth instar. As used herein, "mid-stage bagworm group" refers to a group consisting of multiple mid-stage bagworms. The growth stages of the individuals in the group may be the same or different.

[0020] As used herein, "late-stage bagworms" refers to bagworms in the later stages of growth. This includes, but is not limited to, bagworms that build nests with a major axis of 20 mm or more, generally bagworms of the fifth instar or later. As used herein, "late-stage bagworm group" refers to a group consisting of multiple late-stage bagworms. The growth stages of the individuals in the group may be the same or different.

[0021] As used herein, "(bagworm) nest" refers to a bag-like, mobile dwelling that can be spindle-shaped, cylindrical, conical, or other shapes and encases the entire body of the bagworm. The nest is composed of silk threads spun by the bagworm itself and materials such as leaf fragments and branch fragments bound together with the silk threads. Bagworms essentially hide within the nest throughout their entire larval stage and never leave it. Even when feeding or moving, they only expose part of their body through the opening of the nest, and always carry the nest with them. Furthermore, from the first to last instar, they do not usually replace their nests, but continue to use the nests they made in the first instar, repeatedly renovating and expanding them as they grow. Furthermore, they do not make cocoons, and pupation occurs within the nest. As described above, the bagworm and the nest are inseparably linked.

[0022] As used herein, "nesting" refers to the act of bagworms constructing a nest. As mentioned above, bagworms do not replace the nests they construct immediately after hatching, but use them throughout their entire larval stage, repeatedly repairing and expanding them as they grow. Therefore, in this specification, nesting refers to nesting in a broad sense, including not only the creation of a nest from scratch, but also the repair or expansion of an existing nest to maintain the nest in optimal condition. "Repairing or expanding a nest" refers to expanding the nest or repairing damaged parts in accordance with the condition of the nest and the growth of the bagworm. Repairing or expanding a nest is usually done by adding new nesting material or reinforcing it with bagworm silk.

[0023] As used herein, "silk thread" refers to thread derived from insects, which is a protein thread spun by insect larvae and adults for the purposes of nesting, moving, anchoring, spinning cocoons, capturing food, etc. Furthermore, as used herein, "bagworm silk thread" refers to silk thread spun by bagworms.

[0024] As used herein, "nesting material" refers to a component of a bagworm nest, a substance that the bagworm takes in from the outside when building a nest. Typically, bagworms cover the surface of their nest with pieces of plant leaves and twigs for purposes such as camouflage and reinforcement. In nature, these leaves and twigs constitute nesting material. As used herein, the term includes any material that is artificially supplied in a breeding environment and used by bagworms as nesting material. Examples include bark, wood, paper, resin, fiber, and hair. Of these, bark is an essential component (material) of the nesting material of this embodiment.

[0025] "Bark" refers to cork tissue consisting of a cork layer located closer to the environment than the cork cambium in the trunks, branches, and roots of woody plants. "Woody plants" refer to perennial plants that have a cambium that becomes lignified. This includes so-called trees. The cork layer is composed of dead cork cells. The tree species from which bark is derived is not limited, but dicotyledonous plants or gymnosperms are preferred. There are no limitations on the type of these. Dicotyledonous plants include, for example, plants belonging to the orders Fagales, Juglandales, Hamamelidales, Laurales, Ebenales, Salicales, Ericales, Rosales, and Sapindales. Furthermore, examples of gymnosperms include plants belonging to the orders Coniferales, Taxales, and Cycadales, as well as ginkgo biloba. The bark of plants from the Fagaceae family and the Pinaceae family, which have a thick cork layer, is suitable. Among these, the bark of plants from the Quercus genus and the Pinus genus is more preferred as the bark used in this specification. The bark of cork oak (Q. suber) and Quercus variabilis is particularly preferred. So-called "cork" refers to raw or processed bark of cork oak.

[0026] In this specification, bark includes both processed and unprocessed bark. "Processed bark" refers to bark that has been harvested, crushed, hollowed out, or sliced, and then molded as necessary. Examples include cork made from cork oak bark, which is crushed into granules to produce cork powder; cork chips, which are crushed into small pieces; cork sheets or cork mats, which are compressed and molded into plates from cork powder or cork chips; hollowed-out cork stoppers; and bark chips, which are crushed into chunks.

[0027] 1-3. Structure The bagworm nesting material of this embodiment contains bark as the main component (main material). Bark derived from dicotyledonous plants or angiosperms is preferred. The bark may be from a single tree species or a mixture of multiple species. While not limited to, cork is suitable as bark for nesting material because it is easily available, has relatively consistent quality, and is inexpensive. The bagworm nesting material of the present invention may be composed solely of bark, but can also contain other materials as auxiliary components (auxiliary materials). Examples include fiber, hair, paper, and resin. When the nesting material of this embodiment is composed of multiple materials, by providing it to the bagworm, the bagworm will use the material it prefers to build its nest.

[0028] The bagworm nesting material of this embodiment may be disinfected or sterilized. As used herein, "disinfection" refers to a process aimed at reducing the number of surviving bacteria or viruses present in an object and deactivating or neutralizing their infectivity. Furthermore, as used herein, "sterilization" refers to a process that reduces the survival probability of bacteria or viruses present in an object to one in a million or less, preferably zero. Disinfected or sterilized bagworm nesting material is suitable because it also helps prevent bagworm infection. It is particularly preferred for use on newly hatched bagworms, which have low resistance. Methods for disinfecting or sterilizing bagworm nesting material may be performed using methods known in the art. Examples of disinfection methods include hot water disinfection, which involves exposing the material to hot water at 60°C to 100°C for a predetermined period of time; cleaning disinfection using a surfactant; and disinfection, which involves exposing the material to a disinfectant such as alcohol or sodium hypochlorite. Examples of sterilization methods include high-pressure steam sterilization (autoclave method), boiling sterilization, ethylene oxide gas sterilization, and gamma ray sterilization.

[0029] The bagworm nesting material of this embodiment is characterized by the shape and size of the bark, which is the main component, varying depending on the growth stage of the bagworm. Bagworm nesting materials are classified into nesting materials for early-stage bagworms, nesting materials for mid-stage bagworms, and nesting materials for late-stage bagworms depending on the growth stage. Furthermore, by combining nesting materials for each growth stage, it is possible to use them for all growth stages. Each nesting material will be explained in detail below.

[0030] (1) Nesting material for early stage bagworms In this specification, "nesting material for early stage bagworms" refers to nesting material suitable for early stage bagworms.

[0031] Our research has revealed that early-stage bagworms have the highest nesting rate when provided with bark as nesting material. We have also found that at this stage, they can effectively use any type of nesting material, including granular, planar, and lumpy materials. This is because, regardless of the shape of the nesting material, early-stage bagworms do not simply use the material as is, but instead use their mouthparts to scrape off the surface of the material into a size and shape that they prefer, and then use this material as nesting material.

[0032] Therefore, the shape and size of the individual nesting materials that make up the nesting material for early-stage bagworms are not limited, and they can be the same or different sizes and shapes as long as they contain bark. On the other hand, in the early stages, the mouthparts are small and the biting force is weak, so it is difficult to use hard wood or tough fibers as nesting material. Therefore, bark that is relatively soft and easy to scrape off, such as the corky part of the bark of dicotyledonous or gymnospermous plants, is suitable.

[0033] (2) Nesting material for mid-stage bagworms In this specification, "nesting material for mid-stage bagworms" refers to nesting material suitable for mid-stage bagworms.

[0034] Our research has revealed that mid-stage bagworms also prefer bark as nesting material. However, unlike early-stage bagworms, they also have preferences for shape and size. The most suitable shape for mid-stage bagworms is granular nesting material with a specific size.

[0035] "Granular nesting material" refers to nesting material in particle form. The particle shape is not particularly limited and includes all shapes, such as spherical, approximately spherical, rectangular, approximately rectangular, and irregular. The shape and size of each particle may be uniform or may vary. A specific example is bark crushed into powder or granules. With such granular nesting material, mid-stage bagworms use the provided nesting material as is, or with only minor processing, such as scraping off a portion. This significantly reduces the labor required for nesting by bagworms and significantly increases the nesting rate.

[0036] For these reasons, nesting material for mid-stage bagworms preferably contains bark as its primary component and is granular in shape. The size of the granular nesting material should be within the range of 0.3 mm to 5.0 mm, 0.5 mm to 4.5 mm, 0.8 mm to 4.0 mm, 1.0 mm to 3.5 mm, or 1.5 mm to 3.0 mm in length. Granular nesting material with a length of approximately 3.0 mm, i.e., 2.0 mm to 4.0 mm or 2.5 mm to 3.5 mm, is particularly preferred as nesting material for mid-stage bagworms, as it not only increases nesting rates but also significantly increases bagworm growth rates. Meanwhile, fine particles with a length of less than 0.3 mm can also be used as nesting material, but the growth rate of bagworms is reduced compared to granular nesting material of the aforementioned specific sizes. Note that, in this specification, "longest length" refers to the width across the longest end of the nesting material. For example, if the nesting material is nearly spherical, its diameter is the appropriate value. Granular nesting material includes bark particles crushed to a specified size, such as cork particles. When mid-stage bagworms are given granular nesting material with a major axis of 0.3 mm to 5.0 mm, such as cork particles, the granular nesting material adheres to the surface of the nest either as is or with only slight processing that leaves the shape almost unchanged, resulting in a nest with a characteristic shape.

[0037] In addition to granular nesting material, mid-stage bagworms can also utilize plate-shaped nesting material. "Plate-shaped nesting material" refers to a relatively thin, sheet-like nesting material. While there are no limitations on the sheet area, it is preferable that both the length and width be equal to or greater than the bagworm's body length. As described below, bagworms will shred the nesting material to the optimal shape, so the shape of the sheet provided is not important. It can be square, approximately square, circular, approximately circular, polygonal, approximately polygonal, or irregular. There are also no limitations on the thickness, but it can be 0.2mm to 10mm, 0.5mm to 8mm, 0.8mm to 8mm, 1mm to 6mm, 2mm to 5mm, or 3mm to 4mm. Examples of plate-shaped nesting material include a thin bark layer made by slicing bark or cork sheets made by compressing crushed bark particles into sheets.

[0038] Plate-shaped nesting material is too large to be used as nesting material as is, so bagworms cut it into pieces of the size and shape they prefer. Compared to the granular nesting material, the nesting rate is lower because it requires more labor to build the nest. Therefore, when providing plate-shaped nesting material to mid-stage bagworms as nesting material, it is preferable to provide it in combination with the granular nesting material.

[0039] (3) Nesting material for late-stage bagworms In this specification, "nesting material for late-stage bagworms" refers to nesting material suitable for late-stage bagworms.

[0040] Our research has revealed that, like early- and mid-stage bagworms, late-stage bagworms also have the highest nesting rate when provided with bark as nesting material. However, it was found that planar nesting material is preferable to granular nesting material. Late-stage bagworms have larger mouthparts and stronger biting force. Therefore, even if they are provided with planar nesting material, they can scrape it off and reprocess it into a size appropriate for their own growth stage and use it as nesting material. On the other hand, granular nesting material, which was suitable for mid-stage bagworms, can be used as nesting material by late-stage bagworms, but the problem is that it is too small and not suitable.

[0041] Based on the above, it is preferable that nesting material for later-stage bagworms contains bark as its main component and is in the form of a plate.

[0042] In addition to plate-shaped nesting material, late-stage bagworms can also use block-shaped nesting material. "Bulk-shaped nesting material" refers to block-shaped nesting material that can be either regular or irregular. There are no restrictions on the size or volume of the block-shaped nesting material, but its length, width, and height should all be within the ranges of 1cm to 15cm, 2cm to 12cm, 4cm to 10cm, or 5cm to 5cm. Specific examples of block-shaped nesting material include cork stoppers and bark chips.

[0043] (4) Bagworm nesting material for all growth stages In this specification, "bagworm nesting material for all growth stages" refers to nesting material suitable for all growth stages of bagworms.

[0044] As mentioned above, the ideal nesting material shape for bagworms varies depending on their growth stage. Because bagworm nests are renovated and expanded throughout the larval stage, nesting material must be provided continuously throughout the bagworm breeding period. Therefore, nesting material must be replaced as the bagworms grow. However, when raising a large number of bagworms, individual differences in growth rate can occur. For example, when raising multiple bagworms, if mid-stage bagworms grow and some of them become late-stage bagworms, a mixture of late-stage and mid-stage bagworms will result, making it difficult to determine when to replace the nesting material. Furthermore, replacing the nesting material itself is time-consuming.

[0045] The all-growth-stage bagworm nesting material can accommodate all growth stages, from early to late bagworms, and provides optimal nesting material for each growth stage, eliminating the need to replace the nesting material. Therefore, the above-mentioned problems do not occur.

[0046] Bagworm nesting materials for all growth stages include granular nesting material of a specific size for mid-stage bagworms and plate-shaped nesting material for late-stage bagworms. As mentioned above, the nesting materials for each stage are common in that they all contain bark. Furthermore, early-stage bagworms do not care about the shape of the nesting material. Therefore, the nesting material composition should be suitable for both mid-stage and late-stage bagworms. Mid-stage bagworms can use plate-shaped nesting material, which is suitable for late-stage bagworms. However, this is not the optimal nesting material, as it can reduce nesting rates and growth rates. On the other hand, if the nesting material is a mixture of granular and plate-shaped nesting material with a major axis of 0.3 mm to 5.0 mm, which is suitable for mid-stage bagworms, mid-stage bagworms will actively use the granular nesting material, which has better nesting efficiency, while late-stage bagworms will use the plate-shaped nesting material. When mid-stage bagworms grow into late-stage bagworms, the mature late-stage bagworms switch to using flat nesting material. In other words, the all-stage bagworm nesting material provides all the nesting materials with optimal shapes for each growth stage, allowing the bagworms to select the nesting material that is most appropriate for their own growth.

[0047] The ratio of granular nesting material to plate-shaped nesting material in bagworm nesting material for all growth stages is not limited. It can be determined appropriately depending on the number of individuals being raised and the ratio of individuals at each growth stage when the nesting material is provided. For example, the ratio of granular nesting material to plate-shaped nesting material can be 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, or 9:1 by weight or volume. Generally, since later-stage bagworms require large amounts of nesting material, a higher ratio of plate-shaped nesting material is preferable. Note that bagworm nesting material for all growth stages may also contain block nesting material if necessary.

[0048] 2. Method for assisting bagworm nesting 2-1. Overview A second aspect of the present invention is a method for assisting bagworm nesting. This method is characterized by providing bagworms with nesting material suitable for their growth stage, as described in the first aspect, when they nest. This method allows bagworms to nest efficiently and in a short time, thereby reducing the labor required for nesting and increasing the survival rate and growth rate of bagworms when kept in captivity.

[0049] 2-2. Method The nest-building assistance method of the present invention is characterized by providing different nesting materials to the bagworms being raised according to their growth stage.

[0050] In this specification, "nesting assistance" refers to reducing the labor required for nesting by bagworms and assisting them in nesting efficiently and in a short time. The nesting assistance method of the present invention uses the bagworm nest material described in the first aspect.

[0051] Specifically, when raising early stage bagworms, any form of nesting material, including bark, can be used, so such nesting material can be placed in the rearing container, from nesting material for first-instar bagworms immediately after hatching to nesting material for renovations or additions.

[0052] When raising mid-stage bagworms, granular or plate-shaped nesting material with a long diameter of 0.3 mm to 5.0 mm can be placed inside the rearing container as nesting material for renovation or expansion.

[0053] When raising late-stage bagworms, plate-shaped and / or block-shaped nesting material can be placed in the rearing container as nesting material for renovation or expansion.

[0054] If bagworms of different growth stages are mixed in a rearing container, nesting material of shapes and sizes suitable for each growth stage can be provided. In this case, bagworms will use nesting material of the size and shape they prefer depending on their growth stage. Alternatively, nesting material of a common shape can be provided for each growth stage. For example, nesting material containing bark can be used for early-stage bagworms, regardless of shape, while nesting material containing bark and in the form of particles or plates with a major axis of 0.3 mm to 5.0 mm can be used for mid-stage bagworms. Therefore, by placing nesting material in the rearing container in the form of particles or plates with a major axis of 0.3 mm to 5.0 mm, both early-stage and mid-stage bagworms can be reared.

[0055] In addition, if all stages of bagworm development are mixed, or if nesting material is not changed from the early to the late stage of bagworm development, the above-mentioned nesting material for all stages of bagworm development can be placed in the rearing container. In this case, nesting material can be added as needed.

[0056] It is also preferable to disinfect or sterilize nesting materials, including bark, before providing them as nesting material, as this makes the nesting material hygienic and reduces the mortality rate of first-instar larvae immediately after hatching, which have low resistance to bacteria and other pathogens.

[0057] In this method, there is no particular limit to the time for which nesting material is provided, and since the nesting material will continue to be needed for repairing or expanding the nest even after nesting, it is sufficient to leave it in place.

[0058] (Effects) The bagworm nest-building assistance method of the present invention allows bagworms to build nests efficiently and in a short time. Furthermore, the bagworm nest-building assistance method of the present invention not only reduces the labor required for nest-building and increases the survival rate of bagworms when reared, but also promotes the growth rate of bagworms. This can also lead to a shortened rearing period for bagworms and reduced rearing costs.

[0059] Example 1: Nesting material preference of bagworms (Objective) To identify the nesting material preferred for raising bagworms, the nesting material preference of bagworms is examined.

[0060] (Method) The following six types of materials were used as candidate nesting materials for bagworms: (1) cherry bark (bark scraped off outdoor-planted cherry branches with a utility knife: 1 teaspoon) (2) cork granules (commercially available cork particles, approximately 2-3 mm in diameter: 1 teaspoon) (3) cork sheet (commercially available cork sheet, 40 mm long x 40 mm wide x 2 mm thick) (4) cherry smoking chips (commercially available, 3-5 mm granules: 1 teaspoon) (5) Japanese cypress (Chamaecyparis obtusa) square timber (commercially available, 5 mm long x 70 mm wide x 3 mm thick: 3 pieces) (6) palm rope (commercially available, 4 mm diameter x 70 mm long: 3 pieces) The cork granules and cork sheet are derived from the bark of the cork oak, a dicotyledonous plant. Cherry chips are small pieces of the wood (lumber) of the dicotyledonous cherry tree. Hinoki lumber is made by drying the wood of the gymnosperm cypress and then processing it into square lumber. Palm rope is made by processing the fibrous part obtained from the palm bark of the monocotyledonous Trachycarpus plant into rope-like material. "Palm bark" is the fibrous part that covers the trunk of the palm tree and comes from the leaf sheath at the base of the palm leaf. It is not bark, but is made when old palm leaves die and only the fiber of the leaf sheath remains.

[0061] One type of each candidate nesting material and a small amount of artificial diet were placed in a 9 cm diameter plastic petri dish lined with filter paper.

[0062] The bagworms used were early stage larvae of the giant bagworm moth that had not yet built a nest within 24 hours of hatching. Ten individuals were placed in each petri dish and allowed to build nests at 24°C. Three and 24 hours after placing the bagworms, the number of individuals that had completed building nests in each dish was counted and the nesting rate per number of individuals placed was calculated. The shorter the nesting time required from providing the nesting material to completing nesting, and the higher the nesting rate within a certain time, the more suitable the nesting material for bagworms is. The tests were conducted three times independently.

[0063] (Results) The results are shown in Figure 1. Cherry bark, cork granules, and cork sheets, which are made of bark, all showed a nesting rate of over 60% three hours after bagworm placement, and a high nesting rate of over 90% was confirmed 24 hours later. Furthermore, it became clear that any bark material, whether in granular or sheet form, can be used. On the other hand, with cherry chips and cypress wood, which are woody parts, the nesting rate did not reach 40% three hours after bagworm placement, and even 24 hours later, the cypress lumber only exceeded 60%. Furthermore, with fibrous palm rope, no nests were found three hours after bagworm placement, and even 24 hours later, the cypress lumber had a nesting rate of less than 40%.

[0064] These results revealed that early-stage bagworms prefer bark as nesting material. Cork is particularly suitable as nesting material, with a nesting rate of over 90% in just three hours after the bagworms were placed. On the other hand, although wood can be used as nesting material over a long nesting period, it is not as efficient a material as bark. Furthermore, palm rope is less suitable as nesting material for bagworms than bark.

[0065] Example 2: Nest material shape preferences at each growth stage of bagworms (Objective) To examine the nest material preferences at each growth stage of bagworms.

[0066] (Method) The bagworms used were larvae of the giant bagworm moth. The growth stages of the bagworms used were first and second instar larvae as early bagworms, third instar larvae as mid-stage bagworms, and fifth instar larvae as late bagworms.

[0067] Cork, which gave good results in Example 1, was used as nesting material. For the early-stage and mid-stage bagworms, commercially available cork particles with a major axis of approximately 2 to 3 mm, as in Example 1, were used. One type of nesting material and a small amount of artificial diet were placed in a 9 cm diameter plastic petri dish lined with filter paper. For the late-stage bagworms, the same commercially available cork sheet as in Example 1 was used. An acrylic cage measuring 210 mm long x 210 mm wide x 120 mm high was prepared, and a 10 mm thick layer of artificial diet was placed so that it covered the entire ceiling surface. Strips of cork sheet were installed so that they hung from the area where the artificial diet was placed to the floor.

[0068] Ten to 40 bagworms of each growth stage were placed in each of the petri dishes and cages and allowed to build nests. The condition of the nests was observed 24 to 48 hours later.

[0069] (Results) The results are shown in Figure 2. The early-stage bagworms shown in A did not use the cork grains (arrows) they were given as is, but instead scraped off their surface to process them into fine particles and use them as nesting material. Unlike the early-stage bagworms, the mid-stage bagworms shown in B used the cork grains as nesting material either as is, or after fine processing that still left the cork grains intact. The late-stage bagworms shown in C scraped off the surface of a cork sheet (arrow) hanging from the ceiling inside the cage into small, plate-shaped pieces and used them as nesting material.

[0070] Example 3: Relationship between nesting material and nesting rate, growth rate and survival rate (Objective) To examine the influence of the type and shape of nesting material on nesting rate, growth rate and survival rate.

[0071] (Method) The bagworms used were mid-stage bagworms (third instar larvae) of the giant bagworm moth. The bagworms were reared on fresh leaves until the early stages, and then switched to artificial diet from the mid-stage.

[0072] The nesting materials used in the three test plots were as follows: (a) Test plot 1: Cork granules + cork sheet (the cork granules were the same as those used in Example 1, and the cork sheet was a commercially available cork sheet measuring 125 mm long x 5 mm wide x 0.5 mm thick); (b) Test plot 2: Cork granules + Kimtowel (the cork granules were the same as those used in Example 1, and the Kimtowel [Nippon Paper Industries] was 125 mm long x 5 mm wide x 0.5 mm thick); (c) Test plot 3: Cork sheet only (the same as that used in Example 1).

[0073] For each test area, an acrylic cage measuring 210mm long x 210mm wide x 120mm high was prepared, and a 10mm thick layer of artificial feed was placed over the entire ceiling. Strips of mino material (cork sheet or Kimtowel) were placed so that they hung from the artificial feed area to the floor. In the second and third test areas, 35cc of cork pellets were placed on the floor.

[0074] Thirty to forty bagworms of approximately the same size at the third instar were placed on the floor of each cage. They were kept at 24°C for 14 days. After the start of the experiment, the percentage of individuals that had attached new nesting material to their nests was calculated daily, and the condition of the attached nesting material was observed. In addition, 23 days after the bagworms were placed, the length (long axis length) of the nests in each test area was measured. Furthermore, the number of surviving individuals in each test area was counted on days 7, 15, 23, 32, 40, 48, and 55 from the time of placement of the bagworms (day 0), and the survival rate was calculated.

[0075] (Results) Figure 3 shows the nesting rate (in this example, the rate of individuals that newly added nesting material to existing nests), Figure 4 shows the growth rate, and Figure 5 shows the survival rate.

[0076] The results in Figure 3 show that in the first test area (a), which was provided with cork granules and cork sheets, and the second test area (b), which was provided with cork granules and Kimtowel, the nesting rate was over 80% after 14 days. In contrast, in the third test area, which was provided with cork sheets only, the nesting rate was less than 30% even after 14 days. These results demonstrate that mid-stage bagworms can use both cork granules and cork sheets as nesting material, but that nesting rate is significantly lower when cork sheets are used alone. Furthermore, it was found that providing mid-stage bagworms with granular nesting material containing bark, such as cork, can increase nesting rate.

[0077] The results in Figure 4 show that nest length was longer in the first test area (a) than in the second and third test areas (b) and (c). Specifically, the nest length after 21 days in the third test area was 13 mm, while in the first test area it was more than double that at 30 mm. Nest length is proportional to the size of the bagworms inside. In other words, these results suggest that the bagworms in the first test area were more than twice as long as those in the third test area. The second test area also had a higher growth rate than the cork sheet alone in the third test area, demonstrating that granular nesting material containing cork is optimal for mid-stage bagworms and that granular nesting material has a growth-promoting effect.

[0078] The results in Figure 5 show that in Test Area 1 (a) and Test Area 3 (c), almost all individuals survived throughout the 55-day test period. On the other hand, in Test Area 2 (b), deaths gradually began to appear from the 15th, and by the 55th day, the survival rate had dropped to 68%. In Test Area 2, cork particles and Kimtowel were used as nesting material. Kimtowel, being a paper material, absorbs and retains moisture, resulting in the nests being constantly over-humid, which is thought to be the cause of the low survival rate.

[0079] These results indicate that cork grains are the best nesting material for mid-stage bagworms in terms of nesting rate, growth rate, and survival rate.

[0080] Example 4: Relationship between cork particle size and growth rate (Objective) Mid-stage bagworms use the cork particles they are given as nesting material either through micro-processing that barely changes their shape, or as is. If the reduction in nesting labor required by nesting material affects growth rate, it is likely that the cork particle size with the highest utilization efficiency will result in a higher growth rate. Therefore, we investigated the relationship between particle size (long diameter) and growth rate when cork particles are used as nesting material.

[0081] (Method) The bagworms used were mid-stage bagworms (3rd to 4th instar larvae) of the giant bagworm moth. Five test plots with different cork particle sizes were prepared: (a) Test plot 1: 0.53 ± 0.12 mm; (b) Test plot 2: 1.28 ± 0.20 mm; (c) Test plot 3: 3.28 ± 0.53 mm; (d) Test plot 4: 5.77 ± 0.58 mm; (e) Test plot 5: 10.63 ± 0.73 mm. For each test plot, a 10 cm diameter, 4 cm high plastic petri dish lined with filter paper was prepared, and the nesting material and a small amount of artificial diet were placed inside.

[0082] Bagworms that had been raised to the third or fourth instar without cork pellets were placed in a petri dish, 10 individuals per dish, and reared at 24°C for 24 hours. The number of individuals that had attached new cork pellets to existing nests after the start of the experiment, i.e., individuals that had used cork pellets as nesting material, was counted, and the length of the nests (long axis length) was measured. The bags were then reared for another six days, and the nest length was measured again on the seventh day after the bagworms were placed. The growth rate was converted into the rate of elongation of the nest length, and the nest length on the seventh day after nesting was expressed as a relative value, with the nest length on the first day of nesting set as 1.

[0083] (Results) The results are shown in Figure 6. A shows the nest length in each test area before the start of the test. B shows the growth rate on the seventh day after nesting. The nesting rate on the first day after nesting (as in Example 3, the percentage of individuals that added new nesting material to existing nests) was 100% in test areas 1 to 3, 50% in test area 4, and 20% in test area 5 (not shown). These results show that although cork pellets are suitable as nesting material for mid-stage bagworms, there are clear differences in nesting rate depending on particle size, with the highest nesting rate achieved when cork pellets between 0.3 mm and 5 mm were provided.

[0084] Furthermore, there was no significant difference in the length of the nests between the test areas before the start of the test, but by the seventh day, the length was significantly longer in test area 3.

[0085] From the above results, it became clear that the nesting rate of mid-stage bagworms was high when bark grains with a long diameter of 0.3 mm to 5 mm were used as nesting material, and that the growth rate also improved, especially when bark grains with a long diameter of 2.5 mm to 4.0 mm were used.

[0086] Example 5: Relationship between the optimal long diameter of particle nesting material and the type of nesting material (Objective) Examples 2 to 4 revealed that cork particles are suitable as nesting material for mid-stage bagworms, and Example 4 identified the range of long diameter (particle size) that results in the highest nesting rate. However, it remains possible that the type of nesting material is irrelevant as long as the long diameter is optimal. Therefore, we examined the nesting rate and growth rate for different types of granular nesting material when their long diameter values ​​were set as optimal.

[0087] (Method) The bagworms used were mid-stage bagworms (3rd to 4th instar larvae) of the giant bagworm moth. The following three test plots were prepared, each with roughly the same long diameter but different nesting materials: (a) Test plot 1: Cork granules (particle size 3.28 mm) (b) Test plot 2: Filter paper (ADVANTEC No. 2: 3 mm x 3 mm x 0.26 mm) (c) Test plot 3: Plastic beads (φ3 mm) For each test plot, a plastic petri dish 10 cm in diameter and 4 cm high lined with filter paper was prepared, and each nesting material and a small amount of artificial diet were placed inside.

[0088] Bagworms were raised to the third or fourth instar without being fed cork grains, and ten individuals were placed in each petri dish and reared at 24°C for 24 hours. After the start of the experiment, the number of individuals that had attached nesting material was counted and the length of the nest (long axis length) was measured. The bags were then reared for another eight days, and the length of the nest was measured again on the ninth day after the bagworms were placed.

[0089] (Results) Figure 7 shows the nesting rate (the percentage of individuals that added new nesting material to existing nests, as in Example 3), Figure 8A shows the length (longest diameter) of the nests in each test area before the start of the test, and Figure 8B shows the growth rate on the 9th day after nesting.

[0090] The nesting rate was 100% in test area 1 (a), 80% in test area 2 (b), and 20% in test area 3 (c). These results reaffirm that cork, i.e., bark, is the preferred nesting material, as revealed in Example 1, even when the major axis of the granular nesting material is the optimal value.

[0091] Furthermore, no significant difference in nest length was observed among the test sections on the first day of nesting. However, on the ninth day, the longest nest was again observed in test section 1, which used cork as nesting material. On the other hand, even when filter paper was used as nesting material, favorable results were obtained in terms of nesting rate and nest length by optimizing the long diameter. However, when paper is used as nesting material, as in the results of Example 3, there is a possibility that the survival rate will decrease over long-term rearing, so it is difficult to say that it is an appropriate nesting material.

[0092] From the above results, it became clear that in the case of granular nesting material, even if the long diameter is the optimum value, bark is the most suitable nesting material. All publications, patents, and patent applications cited in this specification are incorporated herein by reference in their entirety.

Claims

1. A bagworm nesting material that includes cork bark and changes shape depending on the growth stage of the bagworm, The nesting material for the early stage bagworms can be of any shape. The nesting material for mid-stage bagworms is granular with a long diameter of 0.3 mm to 5.0 mm, and The nesting material for the later stage bagworms is plate-shaped. The bagworm nesting material.

2. The bagworm nesting material described in claim 1, further comprising a plate-shaped nesting material as nesting material for the mid-stage bagworms and a block-shaped nesting material as nesting material for the late-stage bagworms.

3. Bagworm nesting material for all growth stages, including granular nesting material and plate-shaped nesting material with a long diameter of 0.3 mm to 5.0 mm, including bark made of cork.

4. The bagworm nesting material according to claim 1 or 3, wherein the bagworm nesting material is disinfected or sterilized.

5. A method for assisting bagworm nesting, comprising: The nesting assistance method comprises providing bagworms with the bagworm nesting material described in claim 1 according to their growth stage.

6. A method for assisting bagworm nesting, comprising: The method for assisting nesting, comprising providing the bagworm nesting material described in claim 3 to all stages of the bagworm's life.

7. A method for assisting bagworm nesting as described in claim 5 or 6, wherein the nesting material is disinfected or sterilized.

8. A bagworm nest containing granular nesting material made of cork with a long diameter of 0.3 mm to 5.0 mm.