Larva collection device for insects belonging to the order Diptera

Abstract

To provide a device for recovering a larva of an insect that belongs to diptera which can surely separate an organic waste from a larva and recover the larva by performing uniform processing of the organic waste.SOLUTION: A device for recovering a larva of an insect that belongs to diptera comprises: a processing tank in which a culture medium for rearing a larva of an insect that belongs to diptera is provided; a recovery tank which is arranged under the processing tank and recovers the larva reared in the culture medium. The processing tank comprises: a bottom surface; a wall surface which surrounds the bottom surface; and a through hole which leads to the recovery tank. An opening of the through hole is provided at a position in front of the wall surface and higher than the bottom surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to an apparatus for rearing and collecting larvae of insects belonging to the order Diptera. [Background technology]

[0002] Housefly larvae have a habit of preferring to live in an environment with moderate humidity during their development stage and moving to a relatively dry environment when they pupate. Taking advantage of this habit, devices have been disclosed that feed housefly larvae on organic waste and collect the grown larvae (see, for example, Patent Documents 1 and 2).

[0003] The device disclosed in Patent Document 1 uses a rearing container that contains organic waste as food for housefly larvae and rears the larvae. The rearing container has a storage section that stores the organic waste and a crawl-out opening through which housefly larvae crawl out before pupating, and the crawl-out opening is formed by a sloping wall with an angle of 5 to 15 degrees. The device disclosed in Patent Document 2 also has a structure in which a sloping wall is provided to guide the housefly larvae that pupate into the rearing container. These devices have a mechanism in which the housefly larvae that climb up the sloping wall fall from the outer end of the sloping wall into a collection container provided at the bottom and are collected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-020190 [Patent Document 2] Japanese Patent Publication No. 2020-110751 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional devices for collecting housefly larvae are unable to collect all larvae from the rearing container, and some larvae may remain in the organic waste or its residue that they are fed. Housefly larvae have a habit of trying to move out of the rearing container in search of a dry environment just before pupation. However, for some reason, they may pupate inside the rearing container.

[0006] In addition, conventional rearing containers have inclined walls, which means that the thickness of the organic waste provided as food is uneven, and the organic waste is not treated evenly by the larvae as they eat it, resulting in some of the waste being collected untreated.

[0007] One embodiment of the present invention has been developed in consideration of such problems, and aims to provide a device for collecting larvae of Diptera insects that can uniformly process organic waste and reliably separate and collect the organic waste and larvae. [Means for solving the problem]

[0008] One embodiment of the present invention utilizes the tendency of larvae of insects classified as Diptera to move to dry environments when they pupate, and involves providing holes or grooves in front of the wall of a treatment tank in which the larvae are reared, thereby separating and recovering organic waste from the larvae in the treatment tank.

[0009] An apparatus for collecting larvae of insects belonging to the order Diptera according to one embodiment of the present invention comprises a treatment tank in which a culture medium for raising larvae of insects belonging to the order Diptera is provided, and a collection tank placed on top of the treatment tank for collecting the larvae raised in the culture medium, the treatment tank having a bottom surface, a wall surface surrounding the bottom surface, and a through hole leading to the collection tank, the opening of the through hole being located in front of the wall surface and at a position higher than the bottom surface.

[0010] In one embodiment of the present invention, the treatment tank may have a convex portion protruding upward from the bottom surface, and the through-hole may be provided in the convex portion. The convex portion may be provided along the wall surface, or may be provided at a position separated from the wall surface.

[0011] In one embodiment of the present invention, the through-hole may have an opening provided on the upper surface of the convex portion, and the opening may have an elongated shape extending along one side of the convex portion in a plan view.

[0012] In one embodiment of the present invention, a protrusion may be provided on the upper surface of the convex portion.

[0013] In one embodiment of the present invention, a plurality of convex portions may be arranged in the treatment tank. The convex portions may have a square or rectangular shape in plan view. [Effects of the Invention]

[0014] According to one embodiment of the present invention, a treatment tank for raising larvae of insects belonging to the order Diptera has a through-hole that leads to a collection tank, and the opening of the through-hole is located on the front side of the wall and at a position higher than the bottom, thereby ensuring separation of organic waste or treatment residue from the larvae and preventing falling objects (foreign matter) other than the larvae from entering the collection tank. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B show a device for collecting larvae of insects belonging to the order Diptera according to one embodiment of the present invention, in which (A) is a plan view, (B) is a cross-sectional view corresponding to the section A1-B1 shown in the plan view, and (C) is a partial plan view. [Figure 2] 1A to 1C show a larvae collection device according to one embodiment of the present invention, and are diagrams illustrating how to use the device. [Figure 3] 1A and 1B show an apparatus for collecting larvae of insects belonging to the order Diptera according to one embodiment of the present invention, in which (A) is a plan view and (B) is a cross-sectional view corresponding to the line A2-B2 shown in the plan view. [Figure 4] 1A and 1B show an apparatus for collecting larvae of insects belonging to the order Diptera according to one embodiment of the present invention, in which (A) is a plan view and (B) is a cross-sectional view corresponding to the line A2-B2 shown in the plan view. [Figure 5]1A and 1B show a device for collecting larvae of insects belonging to the order Diptera according to one embodiment of the present invention, in which (A) and (B) are cross-sectional views. [Figure 6] 1A and 1B show an apparatus for collecting larvae of insects belonging to the order Diptera according to one embodiment of the present invention, in which (A) is a plan view and (B) is a cross-sectional view corresponding to the line A4-B4 shown in the plan view. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. For clarity of explanation, the drawings may show the length, width, height, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings may be designated by the same reference numerals (or reference numerals with A, B, a, b, etc. suffixed thereto), and detailed description thereof may be omitted as appropriate. Furthermore, the letters "first" and "second" attached to each element are convenient labels used to distinguish each element and have no further meaning unless otherwise specified.

[0017] The larvae collection device in one embodiment of the present invention is a device that raises larvae of insects belonging to the order Diptera by feeding them organic waste, and separates and collects the larvae of the insects belonging to the order Diptera from the organic waste, larvae carcasses, pupae, and other remains (hereinafter also referred to as "processed material residue") left behind by the larvae after feeding, unless otherwise specified. In the following description, larvae of insects belonging to the order Diptera will be simply referred to as "larvae." Furthermore, depending on the growth stage of the larvae, they may also be referred to as "1-day-old larvae," "2-day-old larvae," "3-day-old larvae," "4-day-old larvae," "5-day-old larvae," "6-day-old larvae," "7-day-old larvae," or "8-day-old larvae."

[0018] In this specification, "processed residue" refers to the remains of organic waste, as described above, and includes larval excrement (low-concentration organic decomposition products), excrement of microorganisms that were originally contained in the organic waste or that were mixed in during the process of subjecting the organic waste to some kind of processing, and dried organic waste (organic waste that remains without being eaten by insects).

[0019] In this specification, "separation" when referring to separating larvae from the treated residue refers to separating the treated residue from the larvae, and includes the larvae moving out (escape) from the treated residue through the through-holes, as described in the following embodiments. Note that the removal of larvae carcasses, pupae, etc. remaining in the treated residue by sieving or the like is also included in the scope of separation.

[0020] In this specification, collecting larvae means collecting the separated larvae in a predetermined area or container, etc. As described in the following embodiments, collecting larvae means dropping them through through-holes from a medium in which organic waste has been accumulated (hereinafter referred to as "medium") and collecting them in a container.

[0021] [First embodiment] Details of an apparatus for collecting larvae of insects belonging to the order Diptera (hereinafter also simply referred to as a "larva collection apparatus") according to one embodiment of the present invention will be described with reference to Fig. 1. In the following description, house fly larvae will be used as an example of the insect larvae, but in addition to house fly larvae, flesh flies, black soldier flies, and other larvae of insects belonging to the order Diptera can also be used.

[0022] 1(A) and (B) show the configuration of a larvae collection device 100 according to this embodiment. In FIG. 1, (A) shows a plan view of the larvae collection device 100, and (B) shows a cross-sectional view corresponding to the line A1-B1 shown in the plan view. As shown in FIGS. 1(A) and (B), the larvae collection device 100 includes a treatment tank 102 and a collection tank 104. The treatment tank 102 is a container in which a culture medium is provided on which organic waste 201 for rearing larvae is accumulated, and the collection tank 104 is a container for collecting the larvae reared in the treatment tank 102. The larvae collection device 100 has a structure in which the collection tank 104 is disposed below the treatment tank 102.

[0023] The treatment tank 102 has a bottom surface 1021 and wall surfaces 1022 surrounding the bottom surface 1021, and is box-shaped with an open ceiling. Organic waste 201 is spread in the treatment tank 102 so that it covers the entire bottom surface 1021, forming a culture medium for rearing larvae. The treatment tank 102 has a depth (height of the wall surfaces 1022) that allows the organic waste 201 to be spread to a predetermined thickness and prevents the larvae from easily crawling out. Larvae prefer a humid environment and feed by peristalsing through the culture medium, but if the culture medium is too moist and thick, breathing becomes difficult, reducing the survival rate of the larvae. For this reason, the organic waste 201 introduced into the treatment tank 102 is spread to an appropriate thickness with an appropriate moisture content. The culture medium formed in the treatment tank 102 by the organic waste 201 can be made suitable for the growth of larvae by making the moisture content 60 to 80% and the thickness 30 to 80 mm, preferably 40 to 50 mm, depending on the type of organic waste 201.

[0024] The organic waste 201 used to form the culture medium includes, for example, at least one of livestock manure, food waste, and agricultural waste. Livestock manure is the excrement and urine discharged from livestock such as cow manure, pig manure, and chicken manure. Food waste is processing residues and leftover food generated during the food manufacturing and cooking process, specifically vegetable scraps, tofu scraps, soybean pulp, sake lees, shochu lees, beer lees, etc., as well as food waste discarded from households, etc. Agricultural waste is the remains of crops that are not used for food, such as crop stems, leaves, peels, bean husks, bran, and wheat bran.

[0025] The medium formed from the organic waste 201 described above is inoculated with eggs of insects belonging to the order Diptera (hereinafter simply referred to as "eggs" or "insect eggs"). For example, housefly eggs hatch in about one day. The larvae (one-day-old larvae) that hatch from the eggs feed on the organic waste 201 and grow into larvae (three-day-old larvae) that have reached the pupal metamorphosis stage in about four to seven days.

[0026] Larvae (three-day-old larvae) undergoing pupal metamorphosis in the organic waste 201 try to move from the moisture (humidity) containing medium of the organic waste 201 to a dry area by peristaltic dispersal. In order to utilize this behavior to guide the larvae to the collection tank 104, the treatment tank 102 is provided with a structure to attract the larvae.

[0027] Specifically, the treatment tank 102 is provided with a through-hole 1024 having an opening at a position higher than the bottom surface 1021. The through-hole 1024 is provided in a convex portion 1026 that protrudes upward from the bottom surface 1021. The vertical length (height) of the convex portion 1026 is greater than the thickness of the culture medium formed from the organic waste 201, and the opening at the upper end of the through-hole 1024 is exposed from the organic waste 201. The through-hole 1024 passes through the convex portion 1026 and out the bottom surface 1021, forming a passage for the larvae to escape to the outside of the treatment tank 102.

[0028] 1(A) and 1(B) show a structure in which a convex portion 1026 is provided along a wall surface 1022. In the case of such a shape, the convex portion 1026 may be integrally formed with the side wall of the processing tank 102.

[0029] The larvae in the treatment tank 102 not only move to a dry environment when they reach the pupal metamorphosis stage, but also have the habit of climbing up the wall surface 1022 when they bump into it. The convex portion 1026 is a structure that blocks the path of the larvae (three-day-old larvae). However, the larvae (three-day-old larvae) have the habit of climbing up the convex portion 1026 just like the wall surface 1022, and as a result, the larvae (third instar larvae) can be guided to the through-hole 1024. Because the collection tank 104 is arranged below the through-hole 1024, the larvae (third instar larvae) that fall from the through-hole 1024 can be collected in the collection tank 104 without leakage.

[0030] The convex portion 1026 may be provided on at least a part of the wall surface 1022, but is preferably provided so as to circle the inner surface of the treatment tank 102 as shown in Fig. 1(A). Since the larvae (third instar larvae) move in any direction, providing the convex portion 1026 and the through-holes 1024 along the inner surface of the treatment tank 102 ensures the collection of the larvae (third instar larvae).

[0031] The through-holes 1024 are large enough for larvae (three-day-old larvae) undergoing pupal metamorphosis to pass through. FIG. 1(A) shows that the through-holes 1024 have an elongated shape along the wall surface 1022 so that larvae (third-instar larvae) climbing up the convex portion 1026 can drop into the holes from any position. In this case, the width (length in the short direction) of the through-holes 1024 is preferably about 1 mm to 3 mm. As shown in FIG. 1(C), the through-holes 1024 may be provided discretely on the upper surface of the convex portion 1026. In this case, the size (diameter) of the through-holes 1024 is appropriately set depending on the type of insect. For example, in the case of houseflies, the size (diameter) of the through-holes 1024 is preferably about 1.0 mm to 3 mm. The interval between the first through-holes 1024 is preferably about 5 mm to 10 mm.

[0032] If the width or diameter of the through-holes 1024 is smaller than this range, it will be difficult to pass the larvae (3-day-old larvae) through and separate them from the organic waste 201, whereas if it is too large, the effective area for forming a culture medium in the treatment tank 102 will be reduced and the strength will be reduced, which is undesirable. There is no limitation on the shape of the through-holes 1024 in a plan view, and various shapes such as a circle, oval, square, rectangle, diamond, and hexagon can be used.

[0033] There are no limitations on the material of the treatment tank 102, but a material having the rigidity to maintain the shape of the container is used. The treatment tank 102 is formed of, for example, metal, plastic, or wood. The bottom surface 1021, wall surface 1022, and convex portion 1026 of the treatment tank 102 may be integrated, or part or all of the bottom surface 1021, wall surface 1022, and convex portion 1026 may each have a disassembly structure.

[0034] The collection tank 104 has a bottom surface 1041 and wall surfaces 1042 surrounding the bottom surface 1041, and has a box-like shape with an open ceiling. The collection tank 104 is a container for collecting larvae that have fallen from through-holes 1024 provided in the bottom surface 1021 of the treatment tank 102. The collection tank 104 is used to temporarily store larvae (3-day-old larvae) that have fallen from the treatment tank 102 through the through-holes 1024. The collection tank 104 preferably has a volume that can store the larvae (3-day-old larvae). Since the larvae (3-day-old larvae) that have fallen from the treatment tank 102 can move around, it is preferable that the collection tank 104 has a certain depth to prevent them from climbing up the wall surfaces 1042 and escaping to the outside.

[0035] The collection tank 104 is disposed directly below the treatment tank 102. The open top of the collection tank 104 is large enough that the open ceiling surface covers at least the portion of the bottom surface 1021 of the treatment tank 102 where the through-hole 1024 is formed. For example, as shown in FIG. 1(B), the treatment tank 102 and the collection tank 104 preferably have the same outer diameter and are stacked. To prevent misalignment when the treatment tank 102 and the collection tank 104 are stacked, protrusions, guide grooves, or the like may be provided so that the lower part of the treatment tank 102 and the upper part of the collection tank 104 fit together. Furthermore, the treatment tank 102 and the collection tank 104 may be configured to be fastened together with screws, clamps, or the like. In either case, the treatment tank 102 and the collection tank 104 are disposed so that they can be easily attached and detached, facilitating the introduction of organic waste 201, inoculation with insect eggs, collection of larvae, and cleaning of each tank.

[0036] By stacking treatment tank 102 on top of collection tank 104, treatment tank 102 acts as a lid to prevent larvae collected from collection tank 104 from escaping. Collection tank 104 has a space filled with air to the extent that the larvae do not suffocate, and even if the top of collection tank 104 is covered with treatment tank 102, an air inflow path is secured by through-hole 1024, so that the stored larvae can be prevented from suffocating.

[0037] The processed residue 202 remaining in the processing tank 102 is collected and subjected to a predetermined treatment (for example, heat treatment) so that it can be used as a feed material or a fertilizer material. The larvae collected in the collection tank 104 can be subjected to a predetermined treatment so that they can be used as livestock feed, or can be provided as a food ingredient containing clean animal protein, or can be processed into food.

[0038] Next, an example of a method of using the larvae collecting device 100 according to this embodiment will be described with reference to FIGS. 2(A) to 2(C).

[0039] 2(A) shows the stage of inoculating insect eggs 203. Organic waste 201 is placed in the treatment tank 102 and spread evenly on the bottom surface 1021 to a uniform thickness. As mentioned above, livestock manure, food waste, agricultural waste, etc. are used as the organic waste 201. For example, soybean pulp, which is generated in large quantities during the tofu manufacturing process, is used as the organic waste 201.

[0040] Okara is a by-product produced in the process of manufacturing tofu and soy milk, but it is said that less than 1% of it is used for food, and the rest is used as feed and fertilizer, but is discarded as industrial waste. Therefore, by using okara as organic waste 201 and processing it in the larva collection device 100, it is possible to make effective use of resources.

[0041] The organic waste 201 introduced into the treatment tank 102 is spread over the entire surface so as not to block the through-holes 1024 provided in the convex portion 1026. Then, insect eggs 203 are inoculated into the organic waste 201. The larvae collection device 100 is installed in an environment suitable for the inoculated insect eggs 203 to hatch and for the larvae to grow. For example, the larvae collection device 100 is placed in a building where the temperature is adjusted to 20 to 50°C (preferably 25 to 40°C) and the humidity is adjusted to 40 to 100% (preferably 50 to 80%). The ceiling of the treatment tank 102 is open, so the inside can be observed and the moisture content and temperature of the organic waste 201 can be monitored to easily control the growth environment.

[0042] FIG. 2(B) shows the developmental stages of larvae 204 hatched from insect eggs 203. The larvae 204 grow by feeding on the organic waste 201 while moving through a medium formed by the organic waste 201. The moisture content of the organic waste 201 is adjusted to suit the growth of the larvae 204. The larvae 204 need an appropriate amount of void space to move through the organic waste 201. Therefore, the moisture content is adjusted to create an appropriate amount of void space within the organic waste 201. For example, when soybean pulp is used as the organic waste 201, the moisture content is preferably set to a range of 60 to 80%. If the moisture content of the medium on which the organic waste 201 is piled is appropriate, the larvae 204 can feed on the organic waste 201 and move around, creating an appropriate amount of void space. If the moisture content of the organic waste 201 is too low, the medium becomes hard, restricting the peristalsis of the larvae 204 and adversely affecting their growth. On the other hand, if the moisture content of the organic waste 201 is too high, it is not preferable because it reduces the feeding preference of the larvae 204. By adjusting the moisture content of the organic waste 201 used in the larvae collection device 100 to an appropriate range, it is possible to optimize the growth environment for the eggs 203 and larvae 204, prevent the death of the eggs 203 and larvae 204 due to environmental deterioration, and improve the hatching rate and survival rate.

[0043] The organic waste 201 ingested by the larvae 204 is enzymatically decomposed within the bodies of the larvae 204 and excreted as low-concentration organic decomposition products. One-day-old larvae hatch from the eggs 203 and grow into three-day-old larvae before pupation in about four to seven days. Treatment residue 202, which is the remains of the organic waste 201, is left in the treatment tank 102.

[0044] FIG. 2(C) shows the stage of separating the treatment residue 202 and the larvae 204. Larvae 204 (3-day-old larvae) that have grown in the treatment tank 102 and reached the final stage attempt to move to a dry environment by dispersal (peristaltic dispersal). At this time, the larvae 204 (3-day-old larvae) move by peristalsis toward the convex portion 1026, which is relatively dry compared to the medium. The convex portion 1026 protrudes from the medium along the wall surface 1022. The larvae 204 (3-day-old larvae) that reach the convex portion 1026 climb up its side wall and reach the top surface. A through-hole 1024 is opened on the top surface, and the larvae 204 (3-day-old larvae) are dropped into it. Since the recovery tank 104 is placed below the treatment tank 102, the larvae 204 (three-day-old larvae) that enter the through-holes 1024 fall directly into the recovery tank 104 and are contained therein.

[0045] The opening of the through-hole 1024 provided in the treatment tank 102 is located higher than the organic waste 201 or the treated residue 202, so the larvae 204 do not fall through the through-hole 1024 but remain in the treatment tank 102. In this way, the larvae 204 can be separated from the organic waste 201 or the treated residue 202, and the larvae 204 can be collected in the collection tank 104. In other words, it is possible to prevent the organic waste 201 or the treated residue 202 left after the larvae have eaten from spilling out of the through-hole 1024 and becoming mixed into the collection tank 104. The treated residue 202 remains in the treatment tank 102, so it can be collected.

[0046] As described above, the larvae collection device 100 according to this embodiment allows the larvae 204 to be reared on the organic waste 201, and the larvae 204 (three-day-old larvae) that have reached the pupation stage fall through the through-holes 1024 into the collection tank 104, so that the larvae 204 before pupation and the treatment residue 202 can be separated and collected safely and inexpensively without requiring human labor. Because the bottom surface 1021 of the treatment tank 102 is horizontal, the thickness of the organic waste 201 that forms the culture medium can be made uniform. Therefore, the organic waste 201 can be spread at a uniform thickness, and treatment (production of the treatment residue 202) by feeding by the larvae 204 can be made uniform.

[0047] The larvae collection apparatus 100 according to this embodiment does not require a sloped structure in the treatment tank 102 in which the larvae 204 are reared, and the collection tank 104 can be placed directly below the treatment tank 102 in a stacked manner, thereby reducing the area required for installation and improving space efficiency. The larvae collection apparatus 100 can be stored in multiple stages using shelves or the like, which allows for an improved yield of the treatment residue 202 and the larvae 204 per unit area.

[0048] [Second embodiment] This embodiment shows a larvae collection device having a different configuration of the collection tank from that of the larvae collection device shown in Embodiment 1. In the following, only the parts that differ from the first embodiment will be described, and common configurations will be omitted as appropriate.

[0049] 3(A) and (B) show the configuration of a larvae collection device 100 according to this embodiment. In FIG. 3, (A) shows a plan view of the larvae collection device 100, and (B) shows a cross-sectional view corresponding to the line A2-B2 shown in the plan view. As shown in FIGS. 3(A) and (B), the treatment tank 102 has a first wall surface 1022A forming the outer edge, a second wall surface 1022B on the inside thereof, and a third wall surface 1022C on the inside thereof. Accompanying these walls, the treatment tank 102 is provided with a plurality of convex portions (a first convex portion 1026A, a second convex portion 1026B, and a third convex portion 1026C).

[0050] First convex portion 1026A is provided along the inner side of first wall surface 1022A, second convex portion 1026B is provided along the inner side of second wall surface 1022B, and third convex portion 1026C is provided along third wall surface 1022C. Also, similar to the first embodiment, first through-hole 1024A is provided in first convex portion 1026A, second through-hole 1024B is provided in second convex portion 1026B, and third through-hole 1024C is provided in third convex portion 1026C.

[0051] 3(A) and 3(B), the inside of the treatment tank 102 is divided into three regions by a first wall surface 1022A, a second wall surface 1022B, and a third wall surface 1022C. That is, the treatment tank 102 has a first region 1020A between the first wall surface 1022A and the second wall surface 1022B, a second region 1020B between the second wall surface 1022B and the third wall surface 1022C, and a third region 1020C surrounded by the third wall surface 1022C. Organic waste 201 can be placed in the first region 1020A, the second region 1020B, and the third region 1020C, respectively, and a culture medium capable of rearing larvae is formed.

[0052] 3(A) and 3(B), by providing a wall surface and an associated convex portion inside the treatment tank 102, the distance from the culture medium provided in each region to the convex portion can be shortened. With this configuration, the distance that the larvae travel from each culture medium to the through-hole (first through-hole 1024A, second through-hole 1024B, third through-hole 1024C) can be shortened, the time required to collect the larvae can be shortened, and the larvae can be reliably dropped into the collection tank 104.

[0053] The larva collection device 100 of this embodiment is the same as that of the first embodiment except that the sets of wall surfaces and convex portions (and through holes) are arranged in multiple stages in the treatment tank 102, and the same effects can be obtained.

[0054] [Third embodiment] This embodiment shows a larvae collection device having a different configuration of the collection tank from that of the larvae collection device shown in Embodiment 1. In the following, only the parts that differ from the first embodiment will be described, and common configurations will be omitted as appropriate.

[0055] 4(A) and (B) show the configuration of a larva collection device 100 according to this embodiment. In FIG. 4, (A) shows a plan view of the larva collection device 100, and (B) shows a cross-sectional view corresponding to the line A3-B3 in the plan view. As shown in FIGS. 3(A) and (B), the treatment tank 102 has a bottom surface 1021 and a wall surface 1022A. A first convex portion 1026A having a first through-hole 1024A is provided along the wall surface 1022A. The bottom surface 1021 is provided with island-shaped first convex portions 1023A, second convex portions 1023B, and third convex portions 1023C in an inner region away from the first convex portion 1026A. The island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C are provided with second through-holes 1024B. The second through-holes 1024B have openings on the upper surfaces of the island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C, respectively, and are provided so as to penetrate the bottom surface 1021.

[0056] The island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C have heights such that their upper surfaces are exposed above the organic waste 201 introduced into the treatment tank 102. As shown in FIG. 4(A), the opening of the first through-hole 1024A has an elongated shape extending along the wall surface 1022 in a plan view, and the opening of the second through-hole 1024B has an elongated shape extending along one side of the island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C in a plan view. Although not shown, the first through-hole 1024A, second through-hole 1024B, and third through-hole 1024C may be discretely formed with circular openings as shown in FIG. 1(C).

[0057] 4(A) and (B), in addition to the first convex portion 1026A, island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C are provided inside the treatment tank 102, and by providing through-holes (first through-hole 1024A, second through-hole 1024B) in each convex portion, the linear distance from any point on the medium to any of the through-holes in the convex portions can be made shorter than that in the first embodiment. With this configuration, the distance required for larvae to reach the through-holes (first through-hole 1024A, second through-hole 1024B) from any point on the medium can be shortened, the time required to collect larvae can be shortened, and the larvae can be reliably dropped into the collection tank 104.

[0058] 4(A) and 4(B), by providing multiple (two) second through-holes 1024B in the island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C, larvae crawling up the convex portions from any direction can be guided to the through-holes in as short a distance as possible. Larvae (third instar larvae) do not move in a straight line to take the shortest distance until they reach the through-holes, but move by peristalsis in any direction. Therefore, by providing island-shaped convex portions that protrude into the medium and providing through-hole openings on their upper surfaces, the time it takes for the larvae (third instar larvae) to reach the through-holes can be shortened, thereby shortening the distance they travel.

[0059] 5(A), the number of second through-holes 1024B provided in the island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C may be one. Also, the first through-holes 1024A and second through-holes 1024B may be discretely formed with circular openings as shown in FIG. 1(C).

[0060] 5(B), the island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C may have upwardly projecting protrusions 1029 provided along second through-hole 1024B. Protrusions 1029 can restrict the movement of larvae that have crawled up onto the upper surfaces of island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C, making it easier for them to fall into second through-hole 1024B.

[0061] 4(A) shows the case where the island-shaped first convex portion 1023A, second convex portion 1023B, and third convex portion 1023C have a rectangular shape in plan view, but the island-shaped convex portions are not limited to this shape and can have any shape. Furthermore, the number of island-shaped convex portions is not limited to three, as long as there is at least one on the bottom surface 1021.

[0062] For example, as shown in the plan view of FIG. 6(A) and the cross-sectional view of FIG. 6(B) (corresponding to the section A4-B4 in FIG. 6(A)), island-shaped convex portions (first convex portion 1023A, second convex portion 1023B, third convex portion 1023C, and fourth convex portion 1023D) may be provided at four locations on the bottom surface 1021, and these convex portions may have a square shape in plan view. Furthermore, protrusions 1029 may be provided on the upper surfaces of the convex portions (first convex portion 1023A, second convex portion 1023B, third convex portion 1023C, and fourth convex portion 1023D). Second through-holes 1024B may be provided to surround the protrusions 1029.

[0063] The shape and arrangement of the convex portions allow particles creeping up the convex portions from any direction to be guided to the through-holes in as short a distance as possible. Note that, even in the configurations shown in Figures 6(A) and 6(B), the number of island-shaped convex portions is arbitrary, as long as there are one or more convex portions and associated through-holes in plan view.

[0064] According to the larvae collection device 100 of this embodiment, by providing island-shaped convex portions (first convex portion 1023A, second convex portion 1023B, third convex portion 1023C, and fourth convex portion 1023D) in the culture medium, the distance from any point on the culture medium to the convex portions can be shortened. As a result, the distance that the larvae take to reach the through-holes (first through-hole 1024A, second through-hole 1024B) from any point on the culture medium can be shortened, the time required to collect the larvae can be shortened, and the larvae can be reliably dropped into the collection tank 104.

[0065] The larvae collection device 100 of this embodiment is similar to that of the first embodiment except that the convex portion (and the through-hole) is provided inside the treatment tank 102, and similar effects can be obtained. [Industrial Applicability]

[0066] The larvae collection devices shown in the first to third embodiments allow organic waste such as food waste and agricultural waste to be fed to larvae of insects belonging to the order Diptera, and the treated residue can be used as a raw material for compost or fertilizer. In addition, the larvae separated and collected from the treated residue before pupation or the pupae after pupation can be used as feed for livestock and farmed fish, or as food for pets, or as an insect-derived food raw material.

[0067] The larvae collection devices shown in the first to third embodiments have a simple configuration and do not require a large installation area, so that by arranging them in multiple stages in a building, it is possible to process large amounts of organic waste and collect large amounts of larvae accordingly.Insects belonging to the order Diptera, such as houseflies, have an egg period of about one day and a larval period of about four to seven days, so the period from egg inoculation to larval collection is short.Therefore, a series of processes, such as egg inoculation, larval rearing (organic waste treatment), and separation and collection of treated residue and larvae, can be carried out in a short period of time, thereby increasing productivity. [Explanation of symbols]

[0068] 100: larvae collection device, 102: treatment tank, 1020A: first area, 1020B: second area, 1020C: third area, 1021: bottom surface, 1022: wall surface, 1022A: first wall surface, 1022B: second wall surface, 1022C: third wall surface, 1024: through-hole, 1024A: first through-hole, 1024B : second through-hole, 1024C: third through-hole, 1026: convex portion, 1026A: first convex portion, 1026B: second convex portion, 1026C: third convex portion, 1029: protrusion, 104: collection tank, 1041: bottom surface, 1042: wall surface, 201: organic waste, 202: treatment residue, 203: eggs, 204: larvae

Claims

1. a treatment tank provided with a culture medium for rearing larvae of insects belonging to the order Diptera; a recovery tank disposed under the treatment tank and configured to recover the larvae reared in the culture medium; The treatment tank has a bottom surface, a wall surface surrounding the bottom surface, a convex portion protruding vertically upward from the bottom surface along the wall surface, and a through hole having a width of 1 mm to 3 mm that is provided in the convex portion and leads to the recovery tank, an upper surface of the convex portion is connected to the wall surface so as to be continuous with the wall surface, and is provided at a position higher than the bottom surface of the treatment tank; An apparatus for collecting larvae of insects belonging to the order Diptera, wherein the opening of the through hole is provided on the upper surface of the convex portion in front of the wall surface and at a position higher than the bottom surface.

2. The larvae collection device according to claim 1 , wherein the through-hole has an opening on an upper surface of the convex portion, and the opening has an elongated shape extending along one side of the convex portion in a plan view.

3. The device for collecting larvae of insects belonging to the order Diptera according to claim 1 , wherein a protrusion is provided on an upper surface of the convex portion.

4. The device for collecting Diptera larvae according to claim 1 , wherein a plurality of the convex portions are arranged in the treatment tank.

5. The device for collecting Diptera larvae according to claim 1 , wherein the convex portion has a square or rectangular shape in plan view.

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