Black Fly Larvae Research Articles

Comparing Selected Life-History Traits of Black Soldier Fly (Diptera: Stratiomyidae) Larvae Produced in Industrial and Bench-Top-Sized Containers

As global food demand is increasing along with human population growth, there is a greater need for alternative protein sources. Insect protein, especially the larvae of the black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), has become a key approach for solving this issue in part due to its ability to convert organic waste into insect biomass with minimal resource (e.g., land, water) requirements. However, most information utilized to develop industrial production of this species is reliant on data generated from laboratory-scaled studies. Unfortunately, scaling these data to an industrial level potentially is not linear resulting in over, or under, estimating production. In this study, we compared selected life-history traits of larval black soldier fly produced at benchtop (e.g., 1 liter container with 614 larvae) and industrial scales (e.g., 29.5 liter container inoculated with 10,000 larvae). Larvae were provided a single feeding (2 g/larva) in each treatment. Significant differences in the mean larval weight (24.7%), survivorship (−28.2%), and biomass conversion (−2.7%) were determined between benchtop and industrial treatments. These results indicate larval number and the associated container size are important factors to consider when designing a black soldier fly factory. Furthermore, caution should be taken when applying data from laboratory studies to industrial scale production systems as the values potentially are not linear.

Chromosomal Relationships of Black Flies (Diptera: Simuliidae) in the Simulium aureum Fries Species Group on the Greek Island of Rhodes

Larval black flies in the Simulium (Eusimulium) aureum Fries species group from the Greek island of Rhodes were chromosomally analyzed to clarify species limits and relationships with mainland taxa. Three species were identified, corresponding with earlier morphological identifications: S. flexibranchium Crosskey, S. petricolum (Rivosecchi), and S. rubzovianum (Sherban). The morphologically established endemic species S. flexibranchium shows chromosomal banding equivalency with S. angustipes Edwards, a widespread Palearctic species; the pair, therefore, are homosequential species, the ninth such example in the Simuliidae. The species status of S. flexibranchium is maintained on the basis of structural characters that allow diagnosis across the four islands from which it is known in the Aegean Sea. The chromosomal banding sequences of Rhodian populations of S. petricolum and S. rubzovianum, as well as a population of the latter that we examined from Cyprus, conform to the classic sequences of these species across their ranges, but tend toward the monomorphic condition typical of island black flies. The first definitive hybrid in the S. aureum group, a larva of S. flexibranchium × S. petricolum, was discovered chromosomally, and suggests an overall hybridization rate in the S. aureum group, with hybrid survival to the late larval stage, of less than 0.1%.

Contrasting responses of black fly species (Diptera: Simuliidae) to experimental whole‐stream warming

Abstract As global temperatures continue to rise, assessment of how species within ecological communities respond to shifts in temperature has become increasingly important. However, such assessments require detailed long‐term observations or ecosystem‐level manipulations that allow for interactions among species and the potential for species dispersal and exchange with the regional species pool. We examined the effects of experimental whole‐stream warming on a larval black fly assemblage in southwest Iceland. We used a paired‐catchment design, in which we studied the warmed stream and a nearby reference stream for 1 year prior to warming and 2 years during warming and estimated population abundance, biomass, secondary production, and growth rates for larvae of three black fly species. Experimental warming by 3.8°C had contrasting effects on the three black fly species in the assemblage. The abundance, biomass, growth, and production of Prosimulium ursinum decreased in the experimental stream during the warming manipulation. Despite increasing in the reference stream, the abundance, biomass, and production of another species, Simulium vernum, decreased in the experimental stream during warming. In contrast, warming had an overall positive effect on Simulium vittatum. While warming had little effect on the growth of overwintering cohorts of S. vittatum, warming led to an additional cohort during the summer months and increased its abundance, biomass, and production. Overall, family‐level production was enhanced by warming, despite variation in species‐level responses. Our study illustrates that the effects of climate warming are likely to differ even among closely related species. Moreover, our study highlights the need for further investigation into the uneven effects of warming on individual species and how those variable effects influence food web dynamics and ecosystem function.

Blackfly Larvae (Simulium spp.) Can Intensify Methylmercury Biomagnification in Boreal Food Webs

Global pollution of mercury (Hg) threatens ecosystem and human health. We measured total Hg (THg) and monomethylmercury (MMHg) concentrations in filter-feeding blackfly (Simulium spp.) larvae in the inflows and the outflows of six boreal lakes with no Hg point source pollution. THg in the larvae ranged from 0.03 to 0.31 mg kg−1 dw and MMHg between 0.02 and 0.25 mg kg−1 dw. The proportion of MMHg in the larvae was 74 ± 0.16% and ranged from 43 to 98% of THg, the highest proportions being comparable to those typically found in aquatic predatory insects and fish. We compared the larvae MMHg concentrations to river water quality, catchment land-use, and to size-adjusted lake pike THg data. Two of the investigated catchments have been affected by a multimetal biomine since 2008 and were characterized by higher conductivity and higher urban land-use activity. Larvae THg and MMHg concentrations were higher in the lake inflows than in outflows and associated with water conductivity and catchment land-use activity. Lake pike THg concentrations were highly correlated to lake outflow blackfly larvae MMHg concentrations. Our data illustrate that blackfly larvae take up high percentage of THg that is MMHg, which in turn is available for higher consumers in aquatic and terrestrial food webs.

Use of dietary frass from black soldier fly larvae, Hermetia illucens, in hybrid tilapia (Nile x Mozambique, Oreocromis niloticus x O. mozambique) diets improves growth and resistance to bacterial diseases

Frass, a by-product of the larval meal industry, is heterogeneous and includes larval excrement, exoskeleton sheds and residual feed ingredients along with abundant nutrients, chitin and beneficial microbes. The present study was performed to evaluate the changes in growth, feed utilization, body composition, hematology, serum chemistry, immune responses and disease resistance of hybrid tilapia, Nile x Mozambique (Oreocromis niloticus x O. mozambique) fed diets containing frass from black soldier fly larvae, Hermetia illucens. Five diets containing frass at levels of 0, 5, 10, 20, and 30% as partial replacements of a combination of soybean meal, wheat short and corn meal on an equal protein basis were fed to juvenile hybrid tilapia (2.6 ± 0.035 g) in quadruplicate aquaria to apparent satiation twice a day for the first two weeks and once daily for rest of the feeding trail. Final weight gain was significantly increased in fish fed the diet including the highest level of frass (30%). Fish fed diets containing frass (5% to 30%) had significantly higher protein efficiency than the group fed diet without frass (control diet). Feed intake and feed utilization efficiency were not significantly affected by dietary treatments. Survival during the feeding trail, whole-body composition, hematological parameters, and serum biochemistry were not affected by dietary treatment. Serum complement activity of fish fed 30% dietary frass was significantly higher than that of fish fed other treatments. Fish fed the diets containing frass showed significant dose-dependent trends in survival against both Flavobacterium columnare and Streptococcus iniae challenges. Frass from the larvae of black solder flies fed Distillers’ dried grains with solubles has potential for use as feed ingredient for improving growth of hybrid tilapia. Use of frass in tilapia diets may prove beneficial by improving innate immune components and the resistance of hybrid tilapia against bacterial infection.

РАЗРАБОТКА ЛАБОРАТОРНОЙ УСТАНОВКИ ДЛЯ СУШКИ ЛИЧИНОК МУХИ HERMETIA ILLUCENS В ВИБРООЖИЖЕННОМ СЛОЕ

One of the modern and promising areas for the disposal of food waste and agricultural waste from plant and animal origin is the use of larvae of Black stratiomys flies (Hermetia illucens) with the subsequent receipt of them high-quality natural protein feed for livestock, poultry, aquaculture, etc. Use larvae in live frozen and dried state. Drying allows you to increase the shelf life and get a more concentrated feed. However, most drying methods are characterized by high energy intensity of the process with varying degrees of preservation of the properties of the feedstock. One of the methods for drying larvae is drying in a vibro-fluidized bed in an infrared field generated by a gas mixture. To implement this method, a laboratory setup has been developed. A closed perforated container with larvae, which performs vertical vibrations, is installed in the working chamber. The oscillation frequency is selected depending on the degree of drying. At the bottom of the chamber is a gas infrared generator fed by a propane-butane mixture from a cylinder. To create a steady flow, an exhaust fan is installed in the upper part of the working chamber. Temperature control in the upper and lower parts of the working area is carried out by thermocouples. During the experiments, the drying regimes and the rate of moisture evaporation were clarified. The moisture content of the dried material was measured over the entire drying period. The energy consumption for moisture evaporation was controlled. As a result, the energy intensity and productivity of the heat and moisture transfer process are determined. The larvae of Black stratiomys flies dried by this method have a dense texture, a homogeneous structure, and a tan color.

Nutritional value of frass from black soldier fly larvae, Hermetia illucens, in a channel catfish, Ictalurus punctatus, diet

Frass is the by-product of the larval meal industry and includes larval waste, exoskeleton sheds and residual feed ingredients. Experimental frass was derived from the larvae of black solder flies fed distillers' dried grains with solubles and had a protein and fat content of 216 and 60 g/kg, respectively. A 10-week study was conducted to evaluate the effect of dietary levels of frass on growth, feed utilization, and body proximate and mineral composition of channel catfish, Ictalurus punctatus. Five diets containing 0, 50, 100, 200 and 300 g frass per kg diet were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. Final weight gain was significantly increased in fish fed diets containing frass at levels from 100 to 300 g/kg. Fish fed diets without frass, and with 300 g/kg frass, showed the lowest and highest feed intake, respectively. Feed and protein efficiencies, however, were significantly lower in fish fed frass at levels of 200 g/kg and higher compared to the control diet. Survival, whole-body composition and mineral content were not affected by frass. In summary, black soldier fly larval frass has potential as a protein source or just an ingredient for enhancing palatability of catfish diets.

Preliminary observations on the patterns of co-occurrence of Black fly (Diptera: Simuliidae) larvae and some of their potential macroinvertebrate predators

ABSTRACT Biotic factors such as predation, although important drivers of the black fly community, are rarely investigated in the literature. This study aimed to test the hypothesis that the patterns of co-occurrence of black fly larvae and its potential predators is not random and that there is a correlation between its frequencies and Simuliidae larvae abundances. Larvae were sampled from two localities in the Pedra Branca State Park, Rio de Janeiro, Brazil, during the dry season in june 2018. We collected Simulium pertinax Kollar, 1832, Simulium subpallidum Lutz, 1910, Simulium (Inaequalium) sp., Simulium (Psaroniocompsa) sp. and Simulium (Trichodagmia) sp. The predators families present were Perlidae, Hydropsychidae, Leptoceridae, Libellulidae and Chironomidae. The null models showed that species co-occurred significantly more than expected by chance. The canonical correlation analyses for the Vargem Grande and Pau da Fome areas area showed a significant relationship between black fly abundances and predator abundances. In Vargem Grande the abundance of Chironomidae showed a highly significant positive correlation to S. (Psaroniocompsa) sp., while Hydropsychidae was significantly correlated to Simulium sp. On the other hand, in Pau da Fome Libellulidae was significantly correlated to S. (Psaroniocompsa) sp. and Simulium sp. and Chironomidae correlated significantly to Simulium sp. The result is consistent with what would be expected of organisms that exercise mutual population regulation, although other factors than biotic interactions may be causing these patterns. However the lack of mechanistic evidences on the effect of biotic interactions on black fly populations pose a challenge on the understanding of these patterns.

Evaluation of Larval Medium in the Controlled Current Toxicity Test.

The Controlled Current Toxicity Test (CCTT) is a protocol used by the University of Georgia Black Fly Rearing and Bioassay Laboratory to evaluate the efficacy of larvicides based on Bacillus thuringiensis subsp. israelensis (Bti) against Simulium vittatum larvae. A standard CCTT provides a larval medium with suspended organic nutrients, a sustained current, and a clean surface for black fly larval attachment in each exposure vessel. In an effort to streamline the CCTT and eliminate a potential source of variability, 3 types of larval medium were evaluated: deionized water, distilled water, and moderately hard water, which were compared to the currently used protocol. A statistical significance in mean lethal concentration (LC50) rates was observed between the CCTT (deionized water with suspended organic nutrients) medium and the other 3 experimental media. The presence of suspended organic nutrients in the CCTT significantly improved the efficacy of the Bti-based larvicide. The interaction of the suspended organic nutrient particles and the Bti-based particles in the larvicide appears to produce a mixture that is more efficiently captured and ingested by the black fly larvae than the larvicide formulation particles alone.

Harpellales (Kickxellomycotina: Zygomycetes) fungi associated with the digestive tract of larval black flies (Diptera: Simuliidae) in Korea

AbstractHarpellales fungi associated with larval black flies were studied for the first time in Korea. They are a common, widespread group of filamentous fungi that, as obligate symbionts, inhabit the digestive tracts of many terrestrial and aquatic arthropods. Total of 842 ultimate/penultimate instar larvae of black flies from 53 stream were dissected to detect trichomycetes colonization. As a result of the study, seven species of Harpellales including single undetermined Pennella species was found from eight species of black fly hosts: Harpella melusinae, Pennella angustispora, Pennella hovassi, Pennella KNU‐1, Simuliomyces microsporus, Smittium simulii, and Smittium megazygosporum. Descriptions for general features including size and shape of trichospore and zygospores (if available) of each species and their host larval black flies were provided. A key to all known Harpellales fungi found in larval black flies from Korea was also provided.

Characterization and Whole Genome Sequencing of AR23, a Highly Toxic Bacillus thuringiensis Strain Isolated from Lebanese Soil

The demand for sustainable and eco-friendly control methods of pests and insects is increasing worldwide. From this came the interest in Bacillus thuringiensis, an entomopathogenic bacterium capable of replacing chemical pesticides. However, the possibility of pests developing resistance to a particular strain may impair its use, and there is a need to identify novel strains of this species as potential commercial biopesticides. B. thuringiensis sv. israelensis is one of the most successful serovars, widely commercialized for its activity against black fly and mosquito larvae. In this study, we isolated, characterized, and sequenced a new Lebanese B. thuringiensis sv. israelensis isolate, strain AR23. Compared to the commercialized reference strain AM65-52 (Vectobac®, Sumitomo), AR23 showed an increased activity against several mosquito species. The genomic analysis revealed that this strain, compared to AM65-52, possesses a simplified plasmid content and an additional functional cry4Ba coding gene that most likely accounts for the increased effectiveness of this strain in mosquito larvae killing.

PERFORMANS BURUNG PUYUH (Coturnix-Coturnix Japonica) FASE GROWER YANG DIBERIKAN TEPUNG MANURE HASIL DEGRADASI LARVA LALAT HITAM (H. illucensL.) MENGGANTIKAN TEPUNG IKAN DALAM RANSUM

QUAIL (Coturnix-Coturnix Japonica) GROWER PERFORMANCE SUPPLIED WITH MANURE FLOUR DEGRADED BY BLACK FLY LARVAE (H.ILLUCENS L.) TO REPLACE FISH MEAL. This study aims to determine the manure yield of black fly larvae replacing fish meal in the quail feed of the grower phase. The materials used in this study were 100 unsexed quails, 3 weeks old; the dimension of cage was 40 x 40 x 20 cm. The quails were arranged randomly in each unit. The study was realized by using a completely randomized design (CRD) with 4 treatments and 5 replications. The treatments were R0 = 0% degraded manure flour (MHD); R1 = 4% MHD flour; R2 = 8% MHD flour; R3 = 12% MHD flour. The research variables consisted of ration consumption, body weight gain and feed efficiency. The results obtained showed that treatments provide a very significant influence (P <0.01) on ration consumption. Body weight gain and feed efficiency were not significant different (P> 0.05). The conclusion of this study is that MHD flour up to the 12% level can be used in quail rations replacing fish meal. Keywords: Quail, MHD, Fish meal.

Industrial and natural compounds in filter-feeding black fly larvae and water in 3 tundra streams.

We report concentrations of polychlorinated biphenyls, polybrominated diphenyl ethers, novel flame retardants, and naturally occurring bromoanisoles in water and filter-feeding black fly (Simuliidae) larvae in 3 tundra streams in northern Sweden. The results demonstrate that black fly larvae accumulate a wide range of organic contaminants and can be used as bioindicators of water pollution in Arctic streams. Environ Toxicol Chem 2018;37:3011-3017. © 2018 SETAC.

A comparison of gut fluorescence methods using black fly larvae

A comparison of gut fluorescence methods using black fly larvae

Community-directed vector control to supplement mass drug distribution for onchocerciasis elimination in the Madi mid-North focus of Northern Uganda.

BackgroundOnchocerciasis a neglected tropical disease that historically has been a major cause of morbidity and an obstacle to economic development in the developing world. It is caused by infection with Onchocerca volvulus, which is transmitted by black flies of the genus Simulium. The discovery of the potent effect of Mectizan (ivermectin) on O. volvulus microfilariae and the decision by its manufacturer to donate the drug for onchocerciasis spurred the implementation of international programs to control and, more recently, eliminate this scourge. These programs rely primarily on mass distribution of ivermectin (MDA) to the afflicted populations. However, MDA alone will not be sufficient to eliminate onchocerciasis where transmission is intense and where ivermectin MDA is precluded by co-endemicity with Loa loa. Vector control will likely be required as a supplemental intervention in these situations.Methodology/Principal findingsBecause biting by the black fly vectors is often a major nuisance in onchocerciasis afflicted communities, we hypothesized that community members might be mobilized to clear the breeding sites of the vegetation that represents the primary black fly larvae attachment point. We evaluated the effect of such a community based "slash and clear" intervention in multiple communities in Northern Uganda. Slash and Clear resulted in 89–99% declines in vector biting rates. The effect lasted up to 120 days post intervention.Conclusions/SignificanceSlash and clear might represent an effective, inexpensive, community- based tool to supplement ivermectin distribution as a contributory method to eliminate onchocerciasis and prevent recrudescence.

Abundance and diversity of black flies (Diptera: Simuliidae) in rivers of the Andean Eastern Hills of Bogotá (Colombia),

Black flies are abundant benthic organisms in well-oxygenated running water and are considered effective bioindicators of water quality. Information on the ecology of these organisms at the species level is important, since up to now information has mainly been available on a family level. The aim of this study was to evaluate the composition of black flies and their relationships to a group of physical and chemical factors in four small rivers of the Eastern Hills around Bogotá, Colombia. These headwaters are protected by the Empresa de Acueducto y Alcantarillado de Bogotá. Black fly larvae and pupae were collected during four sampling periods during the dry season to the early rainy season of 2012. Multivariate methods were used to determine the presence of each species in relation to dissolved oxygen, nitrates, pH, temperature, and water velocity. PCA ordination revealed a physicochemical environment with a tendency towards a certain homogeneity in the fourrivers studied. The DCA ordination confirmed that in La Vieja River the G. ortizi complex dominated while S. muiscorum was dominant in the other three rivers. Similarly, according to the NMDS, the composition of black flies in Arzobispo and Chorro de Padilla rivers was similar, while that of El Delirio and La Vieja rivers were different, especially in this last river. The rivers hadlow species richness (four species and one species complex). Simulium muiscorum was negatively correlated with dissolved oxygen, temperature and current velocity while S. ignescens was associated with slightly more oxygenated waters and S. furcilatum with fastercurrents.The low species diversity and richness for the four rivers is consistent with previous report sof low Neotropical diversity of black flies. Results showed that simuliid species could possibly be good indicators of the environmental conditions of Eastern Hills rivers around Bogotá.

Precipitation and ectoparasitism reduce reproductive success in an arctic-nesting top-predator

Indirect impacts of climate change, mediated by new species interactions (including pathogens or parasites) will likely be key drivers of biodiversity reorganization. In addition, direct effects of extreme weather events remain understudied. Simultaneous investigation of the significance of ectoparasites on host populations and extreme weather events is lacking, especially in the Arctic. Here we document the consequences of recent black fly outbreaks and extreme precipitation events on the reproductive output of an arctic top predator, the peregrine falcon (Falco peregrinus tundrius) nesting at the northern range limit of ornithophilic black flies in Nunavut, Canada. Overall, black fly outbreaks and heavy rain reduced annual nestling survival by up to 30% and 50% respectively. High mortality caused by ectoparasites followed record-breaking spring snow precipitation, which likely increased stream discharge and nutrient runoff, two key parameters involved in growth and survival of black fly larvae. Using the RCP4.5 intermediate climate scenario run under the Canadian Global Climate Model, we anticipate a northward expansion of black fly distribution in Arctic regions. Our case study demonstrates that, in the context of climate change, extreme weather events can have substantial direct and indirect effects on reproductive output of an arctic top-predator population.

Anaerobic digestion of black solider fly larvae (BSFL) biomass as part of an integrated biorefinery

Abstract Black soldier fly larvae (BSFL) (Hermetia illucens) have been used in a variety of applications including composting, animal feed and biodiesel production. This paper presents the results of bio-methane potential (BMP) assays for BSFL biomass according to several hypothetical biorefinery pathways. The mean biomethane potential (BMP) of BSFL was 671 mL CH4/g VS, while mean BMP of lipid extracted BSFL (LE-BSFL) was 334 mL CH4/g VS. Mean BMP of adult flies and chitinous cuticle were 570 and 343 mL CH4/g VS, respectively. The impact of BSFL diet on bio-methane potential and the biomethane potential of BSFL residue was also investigated. This study suggests that anaerobic digestion of BSFL has potential as part of an integrated energy and waste management solution.

Changes in feeding selectivity of freshwater invertebrates across a natural thermal gradient.

Environmental warming places physiological constraints on organisms, which may be mitigated by their feeding behavior. Theory predicts that consumers should increase their feeding selectivity for more energetically valuable resources in warmer environments to offset the disproportionate increase in metabolic demand relative to ingestion rate. This may also result in a change in feeding strategy or a shift towards a more specialist diet. This study used a natural warming experiment to investigate temperature effects on the feeding selectivity of three freshwater invertebrate grazers: the snail Radix balthica, the blackfly larva Simulium aureum, and the midgefly larva Eukiefferiella minor. Chesson’s Selectivity Index was used to compare the proportional abundance of diatom species in the guts of each invertebrate species with corresponding rock biofilms sampled from streams of different temperature. The snails became more selective in warmer streams, choosing high profile epilithic diatoms over other guilds and feeding on a lower diversity of diatom species. The blackfly larvae appeared to switch from active collector gathering of sessile high profile diatoms to more passive filter feeding of motile diatoms in warmer streams. No changes in selectivity were observed for the midgefly larvae, whose diet was representative of resource availability in the environment. These results suggest that key primary consumers in freshwater streams, which constitute a major portion of invertebrate biomass, can change their feeding behavior in warmer waters in a range of different ways. These patterns could potentially lead to fundamental changes in the flow of energy through freshwater food webs.

Effects of dietary black soldier fly larvae on performance of broilers mediated or not through changes in microbiota

A total of 40 one-day-old male Ross chickens were individually fed a commercial feed with either 0 or 8% of de-frosted larvae of black soldier flies (BSF; wet weight). We recorded daily body weights and feed intake of each chicken for a period of 13 days. After euthanasia, we visually scored masses of abdominal fat tissues, and lesions and quantity of fat in intestinal villi. We measured percentages of tibia ash. Larvae, their growing substrate, and the caecal content of the chickens were collected for further microbiota characterisation. Statistical analyses included analyses of variance, chi-square tests, partial least square regressions and mediation analyses. We did not observe any significant differences in the overall means of zootechnical measures and in the relative abundances of most bacterial families in the caeca of birds fed insect larvae or not. On the other hand, relative abundances of bothRhodobacteraceae andBacillaceae were lowest in birds receiving larvae. We identified new, and confirmed previously published, modifications in the chicken phenotypes as gut microbiota composition varied. For example, we observed indirect changes in the average daily gain, feed conversion ratio, tibia ash percentage and abdominal fat score in relation with the introduction of larvae in the diet, changes mediated by the influence of the diet on the relative abundance ofBacillaceae. We suggested presence ofDysgonomonas in larvae and in the growing substrate (after the passage of BSF larvae) may be one of the mechanisms used by the larvae to transform manure because these bacteria have a fermentative metabolism producing acids and no gas.