The a renewable resource that would otherwise go

The Black Soldier Fly (BSF) can develop from egg to adult in
approximately 40 to 43 days, eggs hatching in 4-6 days, spending at least 22 to
24 days as larvae, and 14 days or more as pupae depending on temperature
(Tomberlin et al., 2009), humidity (Holmes et al., 2012),
bacterial community present (Yu et al. 2011), pupation substrate (Holmes et al.
2013), and location of origin (Tomberlin et al., 2009, Yu et al.,
2011, Holmes et al., 2012, 2013, Zhou et al., 2013). Bacteria, light
intensity, temperature, and humidity have also been shown to influence
oviposition preference and clutch size (Tomberlin and Sheppard 2002, Zheng et
al., 2013). The BSF has also been shown to be useful in the process of
converting manure to biofuel (Li et al. 2011), reduce Escherichia coli in dairy
manure (Liu et al. 2008), and have an antibacterial effect against
gram-negative bacteria (Choi et al. 2012). Not only has the BSF been shown to
reduce dangerous bacteria associated with various types of manure, it also
provides a hygienic method for disposal of human waste (Banks et al.,
2014). House fly oviposition is inhibited by the presence of BSF larvae
(Bradley and Sheppard 1984, Tomberlin and Sheppard 2002). This is important
because, unlike the house fly, the BSF reduces pathogenic bacteria in
substrates (Erickson et al., 2004). BSF larvae primarily consume
decaying plant matter, but are also known to consume decaying animal flesh such
as outdoor carrion (Tomberlin et al., 2005). BSF, and other insects that
are capable of utilizing waste food, open the door to utilizing food supply
chain waste as a renewable resource that would otherwise go to waste
(Pfaltzgraff et al., 2013). While BSF adults do not require food, they
do have somewhat complex mating behavior, requiring sunlight and space to fly
(Tomberlin and Sheppard 2001, Zhang et al., 2010). BSF pre-pupae can be
self-harvested under the correct conditions with little extra effort (Tomberlin
and Sheppard 2001). A successful self-harvesting system was built by (Sheppard et
al., 1994) using strategically placed openings and 40 degree inclined ramps
to allow dispersing BSF pre-pupae to exit the area underneath layer hen cages
where manure accumulated and was eaten by BSF larvae. According to (Booth and
Sheppard 1984), using strips of corrugated cardboard and oviposition substrate,
a single worker could conceivably collect one million eggs per day, making the
BSF a very efficient system for potential waste reduction and alternative food
production. The BSF has been explored as a possible partial substitute for
fishmeal in aquaculture (Kroeckel et al., 2012). It has nutritional
value similar to that of soybean, meat, and bone meal in that all have high
protein content (Zhang et al., 2010). (Barroso et al., 2014)
indicate that insects in general contain adequate nutritional components for
inclusion in fish diets. In fact, Bell et al. (1994) analyzed the nutritional
content of invertebrates (mainly insects) that are consumed by Atlantic salmon
(Salmo salar) (L), finding that the insects studied were better sources of
required fatty acids than commercially produced fish food. Other insects, such
as silkworm pupae, have also been explored as part of carp (Cyprinidae) diet,
and light-trapped insects used to supplement diets for bluegill sunfish
Leopomis macrochirus (Rafinesque) production (Bondari and Sheppard 1981).
Kroeckel et al., (2012) found that BSF can be a partial substitute as a
protein source for aquaculture fish. BSF meal can replace approximately 33% of
the fish meal and fish oil diet of turbot, Psetta maxima, (L.) with minimal
adverse effect (Kroeckel et al., 2012). Another trial showed that BSF
prepupae could replace 25% of the fish meal and 38% of the fish oil in the diet
of the rainbow trout, Oncorhynchus mykiss (Walbaum) (St-Hilaire et al.,
2007a). Similar studies have shown that BSF can also partially substitute for
fish meal and fish oil in blue tilapia, Oreochromis aureus (Steindachner), and
channel catfish, Ictalurus puncatus (Rafinesque) without significant growth or
flavor differences (Bondari and Sheppard 1987). In addition, BSF can be used to
recycle fish offal (organ meat), which is a waste product generated from the
aquaculture industry and currently has limited uses. Some studies have shown
that such recycling of fish offal can enrich BSF, increasing content of long
chain-polyunsaturated fatty acids, which fish need in their diets (Sealey et
al., 2011). The prepupal stage of BSF can be used as a partial replacement
of the fish meal and fish oil in the diets of carnivorous fish which cannot be
fed plant-based protein (St-Hilaire et al., 2007). The amino acid
content of BSF as compared to house flies is known: a total of 38.85% in BSF
and 47.06% in house flies (St-Hilaire et al., 2007b). In developing
where protein malnutrition is a serious struggle, efficient alternate protein
production methods are a high priority (Anyango et al., 2011). BSF are
ideal for this application because no specialized equipment is necessary for
production (Sheppard et al., 1994), this species is widely distributed around
the world (Tomberlin et al., 2002), and it can subsist on a variety of
wastes (Nguyen et al., 2015).  The
goal of my research on the BSF is to determine if this insect could be improved
for use as a source of alternate protein for use as food for humans or feed for
aquaculture, livestock, or poultry. The global distribution of the BSF and ease
with which it can be mass-produced suggests that the BSF could be ideal for use
as an alternate protein source.

Rearing:

          The black
soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), is a good
candidate for treating organic wastesor livestock manure. It can feed on a wide
variety of organic matter, from fruits and vegetables to animal remains and
manure (James 1935; May 1961), and can reduce manure accumulation by up to 56 %
(Sheppard 1983). At the same time, the larvae and pupae can provide valuable
feed for a variety of animals, including chickens (Hale 1973), swine (Newton et
al., 1977), fish (Bondari and Sheppard 1981, 1987; St-Hilaire et al.,
2007), and even predatory mites (Nguyen et al. 2015). Pre-pupae contain 44 %
dry matter and are composed of 42 % protein and 35 % fat, including essential
amino acids and fatty acids (Hale 1973). The major obstacles associated with
the production of larvae to treat organic wastes or to feed animals involve
scaling up the production capacity and insufficient knowledge of the fly’s
biology necessary to produce large amounts of eggs (Cic Kova et al.,
2015). Although there are some reports on rearing black soldier fly adults to
obtain fertilized eggs (Sheppard et al., 2002; Tomberlin and Sheppard
2002; Tingle et al., 1975; Zhang et al., 2010), all of those
studies used large cages (>1 m on all sides) holding 750–1000 flies in a
greenhouse or outdoors. Such methods can make it costly to maintain suitable
temperatures throughout the year (Sheppard et al., 2002), and the large
scale makes it inconvenient to conduct precise experiments. As there is little
information on the biology of the black soldier fly, a small-scale method of
rearing in the laboratory is needed. Here, we obtained fertilized eggs in small
cages in the laboratory and compared ovipositional and survival curves of adults
between methods using supplemental artificial lighting or sunlight, since light
sources are reportedly a key factor for fertilizing eggs (Tingle et al. 1975;
Tomberlin and Sheppard 2002; Zhang et al. 2010). We also compared adult
longevities among feeding conditions. Black soldier
flies are an ideal candidate for mass production.  Adults are not pests and larvae tolerate and
thrive at densities up to almost 3lb per sq. ft. (14kg/m2).  Prepupae are self-collected as they leave the
larval mass to pupate, then processed before developing into flies.  With larvae maturing to crawl-off in four
weeks or less, high rates of production are possible in an intensive
system.  This will require scaleing up
and refinement of already proven systems. 
These systems were developed during 30 years of university research
trials and more recent commercial production of Phoenix Worm larvae.  This is the specially reared black soldier
fly larvae produced as a live food for captive reptiles, fish and birds.  A proprietary system is being developed to
support very intensive automated production in a controlled environment.  Waste food or fresh swine manure will be fed
at up to 2lb per sq. ft. per day.  Feed
conversion rates of up to 25% (dry matter basis) are expected.  Conservative projections indicate that a
400,000 square foot production plant would produce 3,750 tons of dry whole
prepupae meal per year.  However, we
expect the prepupae to be processed into protein, fat (especially lauric acid),
chitin and other products for best utilization.

 

Waste Material:

Food waste represents a significant source of food production
inefficiency. (Cuellar and Webber 2010) study suggesting that 27% of all edible
food is wasted, but point out several discrepancies that might drive that
percentage even higher. In fact, Parfitt et al., (2010) claim that the
most common estimate is that as much as half of all food grown is lost or
wasted, but this claim is tempered with clearer definitions of what constitutes
food waste in three parts. First, it is defined as waste from simply discarded edible
material. Second, it is defined adding waste which is intentionally fed to
animals or is lost through processing. Finally, it is defined to include the
food that makes up the gap between energy consumed and energy needed per capita
(Parfitt et al., 2010). A more recent study by (Martinez et al., 2014),
estimates that 35% of all food is wasted. Furthermore, (Levis et al., 2010)
estimate that over 97% of wasted food in the United States is buried in
landfills. While Levis et al., (2010) suggest a composting approach;
this food waste could also be used as feed, providing a source of alternate
protein production that does not remove food upstream of humans in the food
chain, but rather recovers nutrients through conversion of waste by certain
decomposer insects Diener et al., (2009). Other studies suggest using
food waste directly for fish food (Cheng et al., 2014), or using food
waste to feed algae (Lau et al., 2014).

Protein:

In Africa, protein malnutrition is a serious problem (Anyango et
al., 2011). Participants in a survey conducted in Niger consider sorghum
(Sorghum bicolor L. Moench) or millet (Pennisetum glaucum) porridge to
be a staple food (Towns et al. 2013). (Anyango et al.,2011) advocate an
increase of cowpea (Vigna ungiculata L. Walp), (AKA black-eyed pea)
consumption to increase the amount of protein in sorghum-based diets, because
cowpea grows well in the region and is more protein rich than sorghum,
averaging about 23.5% protein where sorghum averages only about 8.4 11%
protein. Additionally, black-eyed peas are known to be a common food source in
Nigeria in the form of baked bean puddings, fried bean cakes, bean porridge,
and boiled beans (Sanusi and Adebiyi 2009). Influenced by the above-described
concerns regarding food security, many alternative sources of food and feed are
being explored. For example, algae have been examined as a possible feed for
fish as a partial substitute for fishmeal (Patterson and Gatlin III 2013).
Insects are also viable sources of protein that could potentially be cultured
for protein production, just as insects have been farmed for at least 7,000
years to produce human-valued goods such as silk, shellac, and honey (Rumpold
and Schlüter 2013).

Insects could serve as a viable option for protein production. Van
Huis (2013) gives a broad account of the benefits of insects as food and feed.
Such an approach for alternate protein production could reduce the production
of organic waste, produce feed ingredients for animal feed, and reduce
dependency on international fisheries for fishmeal to supply the aquaculture
industry (Van Huis 2013). Several insect species produce as little as half as
much CO2 emissions as beef cattle in g/kg mass gain (Oonincx et al.,
2010). Measured by comparing the edible weight to dietary intake, crickets
Acheta domesticus (Orthoptera: Gryllidae) are twice as efficient as chickens,
four times as efficient as pigs, and twelve times as efficient as cattle at
converting feed to meat (van Huis 2013). Insects do not carry livestock
pathogens among themselves like traditional livestock can, such as swine flu or
bovine spongiform encephalopathy (which could spread to humans by proximity to,
or by eating traditional livestock), because insects are very taxonomically
distant from humans and other mammals (van Huis 2013). Some studies have even
indicated that certain insects such as black soldier flies and house flies
demonstrate innate antibacterial qualities (Choi et al. 2012). Insects are also
hypothesized to use less water than traditional livestock because many edible
insects are drought tolerant, although studies confirming this have not yet
been completed (van Huis 2013). Certain insects can reduce dry mass of organic
waste by up to 58% (Van Huis 2013). Diener et al., (2009) demonstrate a
capacity of certain insects to reduce chicken feed up to 43.2% at an optimal
feeding rate of 50 mg per day per larvae. This ability makes insects ideal for
use in recycling waste food into a food or feed source, and allows the
production of a nutritious soil amendment with increased ammonia content
compared to that of the waste food alone (Diener et al., 2009, Green and
Popa 2012). This process, combined with the antibacterial properties of certain
insects, could revolutionize composting culture by further reducing the
possibility of pathogenic microbes present in waste reaching the consumer
(Jones and Martin 2003, Erickson et al. 2004).

 

 

Conclusion:

          Laboratory rearing of
the black soldier fly is difficult (Cic Kova et al., 2015), since the
flies have a complex mating behavior (Tomberlin and Sheppard 2001). All
previous studies that obtained fertilized eggs used a large cage (ranging in
size from 1.8 × 1.2 × 1.5 m to 2 × 2 × 4 m) holding 750–1000 adult in the field
or in a greenhouse (Sheppard et al. 2002; Tomberlin and Sheppard 2002; Tingle
et al. 1975; Zhang et al. 2010). Tingle et al. (1975) could not achieve mating
or egg collection in two small cages (53 × 91 × 53 cm and 38 × 46 × 38 cm) in a
greenhouse with an unstated number of adults. Here, we achieved fertilized eggs
in a 27 × 27 × 27 cm cage, which was only 1/800 of the volume of the cage used
by Sheppard et al. (2002) and 1/165 that of Zhang et al., (2010).
However, the adult density in our experiment was approximately 108 times that
of Sheppard et al. (2002) and 25 times that of Zhang et al. (2010). We thus
speculate that high density is an important factor in achieving mating and
fertilized eggs in a limited volume. Sunlight is an important factor in
achieving mating: higher light intensity promoted mating (Tomberlin and
Sheppard 2002) and shade or cloud inhibited it (Tingle et al. 1975). No mating
occurred when the light intensity was <63 µmol m?2 s?1, and the mating rate was 75 % when it was >200 µmol m?2 s?1 (Tomberlin and Sheppard 2002).
Nevertheless, we obtained fertilized eggs without sunlight, using fluorescent
lighting supplemented with only a 20-W LED lamp with a light intensity range of
47–790 µmol m?2 s?1. Zhang et al. (2010) achieved mating and fertilized eggs of
black soldier flies in a 1.8 × 1.2 × 1.5 m cage under a 500-W quartz-iodine
lamp with an intensity of 135 µmol m?2 s?1 at 50 cm below the bulb, but not
under a 450-W rare-earth lamp with a light intensity of 160 µmol m?2 s?1. The
quartz-iodine lamp had a spectrum between 350 and 2500 nm, and the rare-earth
lamp had a spectrum between 350 and 450 nm. They concluded that wavelengths
between 450 and 700 nm were crucial, since insects typically cannot see
wavelengths longer than 700 nm (Briscoe and Chittka 2001). As the LED lamp has
a wavelength range of 400–800 nm, our results support the suggestion of Zhang et
al., (2010) that wavelengths between 450 and 700 nm influence the mating
behavior of the black soldier fly. Although the LED lamps promoted
fertilization, sunlight promoted greater fertility and hatchability. There was
no significant difference in the total numbers of egg clutches per female or
oviposition periods. Therefore, additional research on the characteristics of
light sources, such as light intensity, spectral range, and duration of
exposure, is needed to understand mating behavior better. Adult longevity did
not differ significantly between sexes in the water-only and unfed treatments.
However, males lived significantly longer than females on sugar and water and
in the group oviposition experiment, although we dont know why. Tomberlin et
al., (2002) found that females dissected 3 days after oviposition contained
no visible fat or developing ovaries, and speculated that females mate once and
oviposit once in their lifetime on account of their short adult lifespan and
reliance on fat reserves acquired during the larval stage. However, they did
not examine ovaries and oviposition when females were provided with sugar, as
would be available in the wild. In our experiment, adult longevity increased
greatly with sugar supply. Thus, it will be necessary to study how many times
the flies mate and oviposit in their lifetime when adequately nourished in
order to understand their biology and to enhance their mass production.
Although we successfully obtained fertilized eggs in a small cage and have
maintained a black soldier fly colony for more than 22 months in the
laboratory, only 11.2 % of clutches were fertilized under LED, and only 39.5 %
under sunlight. Therefore, we need to examine how to increase the rate of
fertilization for more efficient rearing in the laboratory.