自由論題［投稿論文：研究論文］

An Evaluation of Optimal Space ofa 3D-Printed Scaffold for a CricketBreeding Module

3D プリンターによるコオロギ飼育空間最適化の評価
Takuya Onishi

Doctoral Program, Graduate School of Media and Governance, Keio University

オオニシ タクヤ
慶應義塾大学大学院政策・メディア研究科後期博士課程
Correspondence to: takkun@sfc.keio.ac.jp

Giovanni Innella

Assistant Professor, Department of Master of Fine Arts in Design Studies, VCUarts Qatar, Doha,
Qatar

ジョヴァンニ イネラ
VCUarts カタール Master of Fine Arts in Design Studies 学部講師

Hiroto Kobayashi

Professor, Graduate School of Media and Governance, Keio University

小林 博人
慶應義塾大学大学院政策・メディア研究科教授

Fumitoshi Kato

Professor, Department of Environment and Information Studies, Keio University

加藤 文俊
慶應義塾大学環境情報学部教授

Abstract:

Crickets will gain importance as a future animal protein source. Optimizing thedesign of their living space is vital to further their mass production. To obtain datathat can be used as a reference for realizing it, four types of truncated octahedron
frame shelters (scaffold modules) with sides measuring 9, 11, 13, and 15 mm werecreated with a 3D printer. Shelters occupied most of the crickets’ living space, andtheir preference for these frames was examined. Results found crickets tend to prefer
the 9 mm scaffold module. Considering the industrial benefits of low weight, thelighter 11 mm scaffold module, with the second-highest cricket preference, is optimal
for large-scale cricket farming.

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An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module
コオロギは未来の動物性タンパク質源として期待されている。今後コオロ
ギの大量生産を実現する際、コオロギの好む最適居住空間の確立が求められる。その参考となる情報を得るため、一辺が 9，11，13，そして 15mm の 4 種
類の切頂八面体充填フレームを 3D プリンターを用いて制作し、それらに対するコオロギの選好性を検証した。その結果、最多となるコオロギの入居数は、
最も細かい一辺 9mm の飼育モジュールにおいて記録された。しかし、軽量化
による産業上の利点を考慮すると、次点の一辺 11mm の飼育モジュールがコオ
ロギ養殖産業における至適条件であることも示唆された。

Keywords: Acheta domesticus, the optimal size of habitable space, truncated octahedron frame
scaffold, 3D printer, large-scale cricket farms

ヨーロッパイエコオロギ、最適居住空間、切頂八面体充填フレーム構造、3D
プリンター、コオロギ養殖産業

1

INTRODUCTION
The global demand for food in 2050 will be 1.6 to 2.0 times higher than that oftoday (Maarten et al., 2016), due to the growth of the worldʼs population and theconsequent increase in global food consumption. Therefore, the discussion on foodsecurity and production increase is urgent (Gahukar, 2011). In particular, protein
nutrients are crucial for a healthy and balanced diet. Unfortunately, proteins are also
the most expensive nutrient to produce in terms of the resources required (van Zanten
et al., 2016). The Food and Agriculture Organization (FAO) introduced insect-based
food as a possible solution to the food crisis in a published document titled Edible
Insects: Future Prospects for Food and Feed Security in 2013 (van Huis et al., 2013).
Our current livestock industry relies on the use of large land areas, heavy
consumption of energy and water, and generates considerable amounts of greenhousegases, e.g., CO2, CH4, and N2O (Smith, 1996). To respond to those issues, edible
insects were introduced as an environmentally friendly animal protein option. The
impact of the FAOʼs paper has garnered interest from the food and agricultureindustry, and it has engaged with various disciplines, ranging from social science tofood science, and of course design (Aguirre et al., 2011). This research is concernedwith the design of a cricket breeding system that will help the safe, efficient
production of animal proteins with minimum environmental impact. According to
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previous studies included in this research, cricket farming proved beneficial inenvironmental, energetical, ethical, social, and possibly economic ways. Therefore, it
is legitimate to assume that cricket meat will be one of the solutions forundernourished societies and to tackle the global food crisis. The overarching goal ofthis project is to facilitate the making of a healthy nutritious global society byproviding a considerable amount of alternative animal proteins through cricket massproduction. In this study, the researchers investigate the possibilities for the design ofan optimal breeding space for future large-scale cricket farming.
From the approximately 1,500 species of edible insects (Mlcek et al., 2014), thehouse cricket (Acheta domesticus) was chosen for this design development projectfor several reasons. Crickets are already established as a food ingredient in temperate,
tropical, and savannah regions, and the availability of crickets is nearly global. In
addition to being an edible insect for humans, crickets are a popular feed for pets,
such as reptiles, fish, birds, and livestock (Straub et al., 2019). Therefore, there is alarge body of research on crickets in biology, nutritional science, entomology, etc., aswell as the breeding techniques used. Crickets rapidly reproduce in large numbers;
the time needed to breed a batch of crickets from birth to harvest is only 4 to 6 weeks(Clifford et al., 1977). The cricket is an animal characterized by incomplete
metamorphosis, therefore, the cricket farming environment requires a single condition
to be maintained for the whole duration of their breeding. As crickets require only a
dry environment, the maintenance of the farming facilities is simple, and can easily
avoid odor problems and environmental pollution. Since cricket farming does not
require any expensive facility or infrastructure, small-scale cricket enterprises, inparticular, can deliver significant profit as an alternative to the regular income for
local farmers (Fuah et al., 2015), while women or the elderly could easily be involvedin farming operations. Domestic waste can be used as feed for the crickets, therefore,
local organic waste can turn into a resource of the cricket farming industry (Bawa etal., 2020). Lastly, cricketʼs feed conversion eﬃciency is 8 times higher than that ofbeef, for example, and cricket proteins are characterized by high-quality nutrients.
Cricket proteins achieve a good score in terms of containing essential amino acids,

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An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module

exceeding the standards set by the World Health Organization (Collavo et al., 2005).
The field trips for this study took place in Thailand in 2018 and 2019. In August
2018, Dr. Yupa Hanboonsong introduced the research group to the Noppadon Cricket
Farm in Lopburi Province, Central Thailand. The second trip occurred in November
2019, to one of the largest cricket farms in Thailand, run by Smile Bull Marketing
Co. Ltd., a company known for its famous fried cricket snacks available in many
convenience stores and supermarkets in Thailand.
Generally, both the visited farms had adopted a similar method for farming,
especially in cricket housing. The conventional cricket housing is built by layers of
paper egg trays in a breeding box, which create hiding spaces for crickets (Fig. 1A).
The layers of egg trays create numerous vertical narrow gaps that can host many
crickets inside. The paper egg trays are light and cheap, making them easy to handle

Fig. 1 A Conventional Cricket Farm and Prototypes of Breeding Modules
A) Paper egg tray for cricket housing, with holes bitten by crickets. B) The sun-drying processof current cricket housing, allowing tray reuse 2–3 times. C) In the earlier prototype of thebreeding module with a square grid scaffold, the test cricket displayed discomfort in movement.
D) The prototype with a truncated octahedron structure provided a smooth landscape for cricket
movement. (Image source: the author).
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and dispose of when dirty or damaged. This system is economically reasonable as itfeatures good eﬃciency. However, the paper egg trays easily accumulate waste, suchas droppings, feces, molted skin, and food leftovers on the surface. Since the layersof egg trays are not replaced until harvest, the accumulated dirt remains on thesurface for a long time. Furthermore, some holes were spotted on the surface of theegg tray, because the humidity or dripping of water onto the egg trays makes thematerial soft and easily bitten by crickets (Fig. 1A). Normally, egg trays are reused
two or three times, as farmers dry them under the sun after each harvest. The current
sun drying treatment requires large areas in the farms to lay out the egg trays on the
ground (Fig. 1B). In practice, there is no strict guideline to inform the rightprocedures for discarding the egg trays, not even in GAP1). Findings from a series ofobservations suggest that it is essential to develop a novel cricket housing system foreasier and safer hygiene control.
A 3D-printed scaffold has been developed to replace the current paper egg trays
and give shape to space-filling geometry for vertical cricket housing. This study
started from the result of a previous simple test, consisting of an ethologicalobservation of the cricketsʼ behavior. In the previous test, we compared the behaviorof crickets in a space divided by a regular square grid and in a space divided by units
shaped as truncated octahedrons. The movie from the previous ethologicalobservation recorded the cricketʼs struggle to move in the square grid (Fig. 1C), andsmooth movement in a truncated octahedron scaffold (Fig. 1D). The truncatedoctahedron scaffold was found to be beneficial in the distribution of the crickets
within the three-dimensional space, and in facilitating their smooth movement.
From the previous ethological observations derived from the tests, the length of
one side of the module determines the volume of the cell, and this directly affects thecricketʼs behavior. Our previous ethological observations led the researchers to noticethat to provide both comfortable occupancy and movement across truncatedoctahedron modules, the length of each side of the cells needs to be 50–70% of thecricketsʼ body length. This study aims to evaluate the optimal breeding space of thetruncated octahedron structure in greater detail.

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An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module

2

METHODS
Four different cell sizes of breeding modules were prepared for this comparative

experiment. The series of breeding modules measured 162 mm in diameter and 100
mm in height, with a spatial volume of 2,060,154 cubic millimeters (Fig. 2). There
were four different lengths, i.e. 9, 11, 13, and 15 mm, for the side of the breeding
module's cells for the test crickets (Fig. 3), which covered the ideal range of sizes
since the body size of the test crickets was an average of 20 mm. This comparative
experiment with four types of breeding modules was carried out in a round-robin
tournament fashion, between two modules with 100 test crickets. This comparative
experiment relied on the recording of the number of test crickets inhabiting eachdifferently sized module.

Fig. 2 Drawing of the Breeding Module in Comparison with Cricket’s Body Size
There were four different lengths, i.e. 9, 11, 13, and 15 mm, for the side of the breeding module's
cells for the test crickets. (Image source: the author).

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Fig. 3 Four Types of 3D-Printed Breeding Modules for Comparative Experiment
Each module was named Module_09, Module_11, Module_13, and Module_15, indicating thatthe length of each side of the cell was 9, 11, 13, and 15 mm, respectively. (Image source: theauthor).

2.1

The Flow of the Comparative Experiment
We used nearly 500 healthy adult European house crickets, with a body size

averaging 20 mm long. Four types of 3D-printed breeding modules formed as
truncated octahedron scaffolds were used, with a size of 162 mm diameter and 100
mm height. Each module was named as ʻModule_09ʼ, ʻModule_11ʼ, ʻModule_13ʼ andʻModule_15ʼ, indicating that the length of each side of the cell was 9, 11, 13, and 15mm, respectively. Three plastic containers with dimensions of 335 mm for the inner
width, 490 mm in length, and 285 mm in height were used, with a spatial volume of46,782,750 cubic millimeters. An A3 plastic sheet was used as a space divider foreasier cricket count. Additionally, a fixed-point observation camera, electric heater,
air circulator, etc., were used.
As a priority, the test crickets needed to be kept healthy during the experiment.
One of the plastic containers contained a resting colony that was filled with soil and36

An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module

layers of egg trays that created a comfortable hiding space for the test crickets. The
roomʼs environmental conditions were kept stable and comfortable for the test
crickets, with the temperature kept at 30–33 ˚C using an air conditioner, electricheater, air circulator, and constant lighting conditions. One hundred healthy test
crickets were then released into the plastic container. The plastic container was gently
tilted to bring the test crickets to the edge, then positioned back to horizontal, andcarefully located between two test breeding modules in the plastic container
immediately. This action ensured the test crickets were not accidentally crushed underthe breeding module. Both breeding modules needed to be evenly distanced fromboth sides of the walls (Fig. 4). The crickets were then left quietly for 20 minutes
until they hid and settled into the breeding modules. After a further 20 minutes, theinterior space of the plastic container was carefully and quietly divided in half byplastic sheets. A photograph of both sides of the space was taken and the number ofʻnon-resident cricketsʼ was counted and categorized as ʻAʼ, which were outside of theFig. 4 The Breeding Modules in Position
Both modules were located evenly distanced from the wall of the plastic container. (Image
source: the author).
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test breeding modules. Each test breeding module was then gently shaken toencourage all inhabitants out into each divided space. Another photograph of both
spaces was taken and the total number of all crickets was counted, and this number
was referred to as ʻBʼ. The actual number of inhabitants of the breeding module wascalculated by subtracting the number of ʻAʼ crickets from the number of ʻBʼ crickets.
After repeating the comparative experiments three times without changing test
crickets, except as a replacement in cases of death, then all crickets were broughtback to the resting colony. At this point, another hundred healthy test crickets werechosen for further experiment. To avoid potential environmental bias brought about
by smell or dirt from the previous crickets, the floor of the plastic container wascleaned before another hundred test crickets were introduced. All the 12 combinationsof round-robin comparative experiments were repeated 10 times, to obtain reliableaverageable data. This required 120 sessions in total.
2.2

Evaluation
For defining a winning evaluation level, the margin of victory was quantified inTable 1. This evaluation score was the calculation of the loserʼs number of inhabitants
divided by the winnerʼs number of inhabitants. A victory with a large margin was
rated as five stars (*****), while a victory with a small margin was rated with one
star (*) and scored zero (0) for a draw. Margin definitions are defined in Table 1.
Table 1 Definition of Winning Evaluation
The winning evaluation was defined across five levels.
Loss/Win

Winnerʼs Mark

Loserʼs Mark

Evaluation

L/W ≦ 0.5

*****

-----

5 Star Winning

0.5 ＜ L/W ≦ 0.6

****

----

4 Star Winning

0.6 ＜ L/W ≦ 0.7

***

---

3 Star Winning

0.7 ＜ L/W ≦ 0.8**--

2 Star Winning

0.8 ＜ L/W ≦ 0.9*-

1 Star Winning

0.9 ＜ L/W ≦ 1

o

o

Draw

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An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module

3

RESULTS

3.1

Comparative Pre-Experiments
Before starting the main comparative experiment, a comparative pre-experiment

was carried out to find the environmental bias of the left and right sides of the plastic
container. The comparative pre-experiments used the same breeding modules tocompare the results between modules in the left and right sided positions. The processof the comparative pre-experiments was the same as discussed in in the methodology
section. The results (Fig. 5) were rather random and demonstrated there weredifferent environmental conditions between the left and right sides of the plastic
container. As such, for reliable results, the main comparative experiment was tested
in both left and right positions, to obtain reliable averageable data.

Fig. 5 The Result of Comparative Pre-Experiments
In a comparative pre-experiment, the popularity of each modules on the left and right sides of
the container were examined. A represents the result of Module_09, B for Module_11, C for
Module_13, and D for Module_15. Standard deviation is indicated in each result. Results wererandom, therefore the environmental conditions on the left and right sides of the plastic
container were not even.
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3.2

Evaluation by Crickets’ Behavior
The results of the main comparison experiment presented clear rules, orders, andtendencies. The total average inhabitation rate of the test breeding modules reached76.9 %. The test crickets had a very low mortality rate of 0.09 %, with 11 deaths outof a total of 12,000 test crickets during a total of 120 sessions.
The results of all round-robin tournaments in the comparative experiments areshown in Table 2. The numbers in this table refer to the average number of
inhabitants in the breeding module, out of 10 sessions. The numbers in the dark greybox indicate the modules that are positioned to the right inside the plastic container,
while the numbers in the white box represent the left position, during the comparative
experiments.
The results were well ordered, for example, the modules with smaller cells
prevailed against the larger sizes, except in only one case in session #6. However,regardless of whether they were positioned on the left or right, the results indicatedthe modules with smaller cells were preferred by the test crickets. One of the great
noticeable results was the overwhelming victory of Module_09 (right) against
Module_15 (left) in session #4. Module_09, which contained the smallest cells, had
Table 2 The Result of the Comparative Experiments
The numbers in this table refer to the average number of inhabitants in the breeding module, outof 10 sessions. The numbers in the dark grey box indicate the modules that are positioned to theright inside the plastic container, while the numbers in the white box represent the left position.
Results clearly demonstrate that smaller cell modules prevailed against their larger-celled
opponents in all sessions, except session #6, which was more even.
Right
Left

Module_09

Module_09
Module_11
Module_13
Module_15

Module_11

Module_13

Module_15

session #7

session #8

session #9

42

50

50

41

36

28

session #1

session #10

session #11

34

46

45

46

33

24

session #2

session #3

session #12

23

26

39

54

48

session #4

session #5

session #6

21

26

39

55

50

40

38

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An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module

over 2.5 times more inhabitants on average than Module_15 which contained thebiggest cells. In session #7, Module_09 also narrowly outperformed Module_11
which contained the second smallest cells. Results, therefore, indicate that the gap of
the cell size affected the level of scores.
Table 3 shows the compiled data; results show that modules with smaller cells
prevailed against their opponents in the round-robin testing. The strongest andsmallest cell size, Module_09, won three times against all other modules. The second
smallest cells, Module_11, won twice; Module_13 won once, and Module_15, whichcontained the biggest cells, lost all of its comparative matches. The winningevaluation level was high when the gap of cell size was large, for example,
Module_09 scored five stars (*****) against Module_15 (Table 3). Furthermore, thewinning evaluation level was low while the gap of cell size was narrow, for example,
Module_09 scored a single star (*) by winning against Module_11, as did Module_13
which scored (*) against Module_15. Interestingly, Module_11 scored three stars(***) against Module_13, which was not as narrow as other results in close size gap
combinations. Many cricket inhabitants found an individual space for themselves,

Table 3 The Final Result of Comparative Experiments
Combined final data from Table 2. Results show Module_09 to be the clear winner against allother module sizes.
Module_09
Module_09

Module_11

Module_13

Module_15

Number ofWins

44 (vs 38)
0.86*

52 (vs 30)
0.58
****

53 (vs 25)
0.47
*****

3

47 (vs 30)
0.64
***

48 (vs 25)
0.52
****

2

39 (vs 34)
0.87
*

1

Module_11

38 (vs 44)-

Module_13

30 (vs 52)----

30 (vs 47)---

Module_1525 (vs 53)-----

25 (vs 48)----

34 (vs 39)-

0

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claimed their own territory in a single cell, and remained there for a long time,
especially in Module_09 and Module_11. On the other hand, the bigger cells in
Module_13 and Module_15 contained multiple crickets in a single cell and allowed
trespassers to cross the space already occupied by other crickets. Therefore,
Module_09 and Module_11 provided high livability, while Module_13 andModule_15 provided livability and high mobility at the same time.

4

DISCUSSION

4.1

Discussion in Entomological AspectFirstly, the comparative experiment presented clear, definitive quantitative

results. It is very rare to find studies that combine cricket behavioral research withbreeding space design. The behavior of crickets has been scientifically investigatedthrough neurobiological studies (Mallory et al., 2016). However, such studies donʼt
usually investigate the relationship between the cricketsʼ preferences and the qualityof space. In 1976, a simple cricket behavioral experiment was carried out thatfeatured both qualitative and quantitative aspects in the study; its approach was
similar to ours. The 1976 study examined cricket ethology in a terrarium with tubes
and a resting colony. The results of this study demonstrated that crickets preferrednarrower and darker tubes and places for resting since crickets are mostly photophobic and shelter in humid, dark places (Kieruzel, 1976). This characteristic of thecrickets is clearly reﬂected in the results of our comparative experiments. The mostpopular breeding module was the densest one, Module_09, which offers narrower anddarker spaces inside, which in turn attracted many test crickets during theexperiments. In contrast, our experimental room was bright because of the intentionof keeping clear visibility for monitoring purposes. This bright environment
persuaded the test crickets to choose one of the breeding modules to hide. Thereseems to have environmental bias between two positions in the plastic container, as
Table 1 shows; however, the characteristic of photophobicity forced the crickets tochoose the right breeding modules to hide during the comparative experiments. The
accuracy of the cricketsʼ selection was successfully observed through the comparative42

An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module

experiments.
There exists an interesting behavioral study tracking cricket movement in two
dimensions using sensors, video analysis, and identifying tracking (Kaláb et al.,2021). The technology for tracking cricket movements is well developed in this study,
however, the space used for such tracking studies only operates across the horizontal
dimension, to favor scientific rigor. However, the real potential in this study is thatthe same methodology and technology can be applied in our 3-dimensional study
featuring truncated octahedron scaffolds in the future.
It is also said that crickets like to climb, so it is important to vertically maximize
the available housing surface for better industrialization (van Huis and Tomberlin,2017). Since the relationship between cricket behavioral analysis and space design
has rarely been examined since 1976, our methodology of conducting comparative
experiments using truncated octahedron scaffolds has a great value in this field today.
4.2 Space Design Aspect
Since there were dense numbers of inhabitants in the breeding modules during
the comparative experiments, what we are studying is a design of the housing
complex for the crickets; simply put, spaces that can accommodate a density of
inhabitants to shelter them eﬃciently. In architectural history, the modernization ofbuilding design and urban planning was developed when the human population rose
greatly after the industrial revolution. The Swiss-French architect Le Corbusier, whomodernized and standardized building design to meet the emerging needs of a
growing population, displayed the Modulor, which shows a relationship between thearchitectonic space and the human body (Le Corbusier, 1967). Most importantly, theachievement of the Modulor is that the standard can be applied in any city, any
region, and for any religious background, globally. As with the Modulor, themethodology for building a cricket breeding module is repeatable geometry andspace-filling cells, that create constant regular 3-dimensional patterns that waste nospace. Our investigation started with specific species of cricket, the European housecricket (Acheta domesticus), which is smaller than other popular edible crickets in the
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world. One of the most important achievements through this study is the evaluationof the habitable space in comparison to the cricketʼs body size. It has discovered astrong relationship between body length and volume of space. If the Modulor of thecricket-breeding world proves successful, then it can be applied in any type of cricket
in any region of the world.
Our study is focused on the adult European house cricket with an average bodylength of 20 mm. There are many species of edible cricket in the world with varied
average body sizes; as such, the breeding modules need to be modified locally for theworldwide industrialization of cricket farming. Three-dimensional data of thetruncated octahedron scaffold can be easily modified by local farmers, designers, orengineers, and affordably 3D printed at local institutes in any region. Further
optimization for different species of cricket can be done locally, remotely, andwithout geographical limitations. Our 3D data of the breeding module will be an
open-source resource, so engineers, designers, and farmers can access it from any
region, aiding more accurate locally-adapted optimization of cricket housing in the
future (Singh et al., 2011).
4.3

Industrial Aspect
The conventional large-scale livestock industry, such as the one for cattle, pigs,

and poultry, is accurately defined by a scale ratio between the breeding space/volume
and the amount of harvest (Hlavarty and Krejci, 2020). Also, the scale of initialinvestment, equipment, facility, maintenance, labor cost, energy consumption,
feeding, and handling are optimized through the process of industrialization.
However, the cricket farming industry has not yet reached such a level. The results ofthis experiment need to be considered in terms of industry, as well as cricket
preference. The weight of the product is one of the most important factors in industry(Beukers and Hinte, 2001), for example, heavy modules consume more material,time, and energy during production and transportation, and can impose handlingdiﬃculties during the production process as well as on the farm.
The data about the build statistics of the breeding modules are extracted from44

An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module

the program ʻSimplify3Dʼ for 3D printer (Table 4), with data being digitally
calculated and highly reliable. As the size of the cells decreases, the density ofinternal space becomes higher and the breeding moduleʼs weight also increases. For
example, while Module_09 features the best score in Table 3, it is the heaviest
module (Table 4), and costs 2.6 times the price of Module_15, the lightest one, while
being 2.6 times the weight.
To effectively balance the ratio between the cricket preference and the industrial
requirements, Fig. 6 represents the weight of each module per cricket capita. The
lighter module is considered more eﬃcient than its opponents, according to the aspectof industrial advantage; its reevaluation in terms of industrial preferences has resulted
in an interesting development. The bars highlighted in pale gray score lighter, whichis considered better in terms of the industrial approach. As seen in Fig. 6, the modulewith the best industrial results is Module_11, with three scores, which is lighter thanseveral opponents. Surprisingly, Module_09 which gained the best score in Table 3
scored the worse in terms of industrial aspects (Fig. 6). Finally, Module_11 performed
excellently in the comparative experiment, being successful both in terms of its
industrial benefits and cricket preference. Apart from having the lower number of
inhabitants, Module_15 scored 3.79 g, the best total average of weight per cricket
capita (Fig. 6). Module_09, the most preferred module according to cricket choice,but the worst by industrial merit, still presents the chance to perform a greaternumber of harvests. This is because this study did not explore habit observation, suchas territory claim and cannibalism, in higher densities over a longer period.
Table 4 The Data of Build Statistics of Each Breeding Module for 3D Printing
Data were extracted from Simplify3D and showed the densest module, Module_09, was theheaviest and the most expensive to produce.
ModuleBuild time(minutes)

Plastic weight(g)

Filament length(mm)

Material cost
(USD)

Module_09

1,228

Module_11

838

272

90,41713

183

60,705Module_13

8

610

128

42,5796

Module_15

503

104

34,446

5

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Fig. 6 The Result of Module Weight per Cricket Capita
A represents the result of Module_09, B for Module_11, C for Module_13, and D forModule_15. Module_11, which is second place in Table 3, achieved an excellent result after the
analysis of the relationship between its weight and its cricket population. ‘g’ represents theweight per cricket capita. ‘n’ represents the number of crickets in the population. Pale graycolumns represent a module that is lighter than its opponent in the comparative experiments.
Lighter models are considered a better fit for industrial application.

Endnotes
1)

As the cricket industry has grown rapidly in Thailand in recent years, the GAP (Good
Agricultural Practices for Cricket Farm, November 2017) has been enforced (National46

An Evaluation of Optimal Space of a 3D-Printed Scaffold for a Cricket-Breeding Module
Bureau of Agricultural Commodity and Food Standards, 2017). The GAP is a protocol
aiming at standardizing the cricket farming know-how that was developed independently
through the local farmersʼ own past experiences. Since the GAP was made public, thecricket industry has gradually solidified for further growth in Thailand. More recently, an
English version has been made available (Hanboonsong and Durst, 2020).

Acknowledgement
I would like to thank Dr. Yupa Hanboonsong and Shinjiro Saeki for supporting
entomological strength in this study. This study was supported by Keio University Academic
Development Funds and Showa Womenʼs University Grant-in-Aid for Research Projects.

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