Insect Larvae Research Articles

Automated Dual-Side Leather Defect Detection and Classification Using YOLOv11: A Case Study in the Finished Leather Industry

This study explores the optimization of leather defect detection through the advanced YOLOv11 model, addressing long-standing challenges in quality control within the leather industry. Traditional inspection methods, reliant on human accuracy ranging between 70% and 85%, have limited leather utilization rates and contributed to substantial material waste. To overcome these limitations, we developed an automated solution leveraging controlled environmental conditions within a custom-designed light chamber. This research specifically targets common defects in leather, such as insect larvae damage and removal cuts, by analyzing both the grain and flesh sides of the material. The results reveal a notable improvement in detection accuracy on the flesh side, achieving 93.5% for grubs and 91.8% for suckout, compared to 85.8% and 87.1% on the grain side. Classification accuracy further demonstrates the advantage of dual-side analysis, with the flesh side reaching 98.2% for grubs and 97.6% for suckout, significantly outperforming the grain side. The dual-side methodology, combined with YOLOv11’s enhanced capabilities, enables the precise identification of subtle defects and offers a transformative approach to leather defect detection. By integrating cutting-edge AI models with standardized digitization environments, this research presents a scalable, highly efficient solution that reduces human error, optimizes leather utilization, and supports industrial sustainability.

Exploring the potential of black soldier fly live larvae as a sustainable protein source for laying hens: A comprehensive study on egg quality

Live insect larvae were recently proposed for use in laying hens in intensive chicken farming as an innovative form of environmental enrichment. This study aimed to evaluate the effect of laying hen age and feeding with live Black Soldier Fly larvae (BSFL) on egg quality attributes, i.e., chemical composition, fatty acid (FA) profile, and metabolic profile using nuclear magnetic resonance (NMR) spectroscopy. To this aim, 108 Lohman Brown hens were housed in 27 cages (9 replicates per treatment, 4 birds per pen) and monitored between 16 and 34 weeks of age. The hens were split into three experimental groups: a control group fed a commercial diet, and two experimental groups fed the same commercial diet plus 15% or 30% of live BSFL, as fed basis on the expected daily feed intake (DFI). The experimental treatments did not affect the egg and eggshell quality attributes. The supplementation with live BSFL did not influence the chemical composition in terms of macronutrients or the main NMR profiles of egg yolk and albumen. The FA profile of the egg yolk significantly changed as the eggs from hens fed BSFL presented higher rates of SFA and PUFA (P<0.05), lower rate of MUFA (P<0.001), and higher rates of C18:2n 6 (P<0.05) and C18:3 n3 compared to the control eggs (P<0.001). There were no significant differences in the ratio of n-6 to n-3 PUFA. The age of the hens strongly affected egg quality traits (P<0.001), mainly the egg weight, shell weight, shell thickness, eggshell-breaking strength, and eggshell redness (a*) and yellowness (b*), besides the metabolic profile of both egg yolk and albumen. Considering the interaction diet * age of hens, only a few significant effects occurred on egg quality attributes and FA profile. In conclusion, a supplementation with live BSFL up to 30% of DFI may be safely used in laying hen feeding without impairing egg quality.

Use of a Novel Feeding System to Assess the Survival of a Very Stable Mammalian Virus, Porcine Parvovirus, Within Black Soldier Fly (Hermetia illucens) Larvae: A Comparison with Mealworm (Tenebrio molitor) Larvae

Insect larvae production offers the potential for large-scale synthesis of high-quality protein that can be used as feed or food. However, currently, there are limitations on the source of substrates for the insect larvae to use. One concern is the potential survival of animal pathogens within insect larvae if their feed is contaminated. In this study, the survival of a very stable virus, porcine parvovirus (PPV), within mealworm (Tenebrio molitor) and black soldier fly (BSF) (Hermetia illucens) larvae has been analyzed after oral ingestion of the virus. PPV genomic DNA could be readily detected by PCR in both species of larvae up until 9 days post ingestion (DPI), the end of the study period. Furthermore, infection of susceptible PK15 cells by PPV from homogenized mealworm larvae could be detected until at least 3 DPI, using an immunoperoxidase staining method and, up until 9 DPI, with a more sensitive real time PCR assay. Thus, PPV can remain infectious within mealworm larvae during their main growth phase through to their harvesting. However, it may be considered that PPV is exceptional in this respect since it displays unusual stability, e.g., to heat.

Small intestine structural and functional responses to environmental heavy metal stress in tree sparrow Passer montanus nestlings.

Tree sparrow nestlings predominantly consume protein-rich insect larvae, making them vulnerable to environmental heavy metal contamination through the food web, potentially affecting their growth. Understanding the effects of heavy metals on the structure and function of the small intestine, the principal organ responsible for protein digestion and absorption, is therefore crucial. This study investigated tree sparrow nestlings at three developmental stages (3, 6, and 12days old) in Liujiaxia (LJX), a comparatively unpolluted area, and Baiyin (BY), a heavy metal polluted area, to elucidate the factors and mechanisms by which heavy metals affect nutrient absorption. We compared heavy metal accumulation levels, structural integrity, and protein digestion and absorption functions of the duodenum, jejunum, and ileum. The increase of fluctuating asymmetry and decrease in body condition in tree sparrow nestlings were found to be associated with environmental heavy metal accumulation in the small intestine. Structural impairments of villi and crypts were observed in the duodenum and jejunum of tree sparrow nestlings at 3-, 6-, and 12-day-old in the polluted site BY. Conversely, structures related to the ileum were elevated, and the small intestine of nestlings at all stages exhibited abnormally elevated protein digestibility but diminished absorption of amino acids. However, there was no significant difference in small peptide absorption. These findings indicate that environmental heavy metal pollution impacts the structure of the small intestine in tree sparrow nestlings through the food chain and further affects their digestion and absorption function of proteins.

Development of mixed linear models to analyze and describe the impact of malathion on the larval growth of Megaselia scalaris (Diptera: Phoridae) under various feeding media and environmental conditions.

Forensic entomology plays a crucial role in estimating the minimum postmortem interval through the study of insect larvae found at crime scenes. The precision of this estimation relies on various biotic and abiotic elements that simultaneously influence insect growth and development, encompassing factors such as temperature, humidity, photoperiod, diet, and the existence of xenobiotics in decomposing tissues. Despite numerous studies on the influence of these factors, including the impact of xenobiotics, there are currently no robust tools available for making corrections to this estimation considering concurrently all variables. In an attempt to propose an exploratory and descriptive statistical model to analyze the simultaneous effect and interaction of different variables on larval growth, this study aimed to compare the effect of malathion on the growth of Megaselia scalaris (Loew, 1866) (Diptera: Phoridae) raised in malathion-spiked porcine muscle, under controlled and uncontrolled temperature and humidity conditions (environmental conditions). Larvae were also reared using various growth media. A split-plot design that combined crossed and nested factors was employed; 2 linear mixed models were developed to assess the relationships between the variables. The model provides valuable insights into the complex interactions among xenobiotics, growth media, and environmental conditions in the size and development of M. scalaris.

Swill and Pig Manure Substrates Differentially Affected Transcriptome and Metabolome of the Black Soldier Fly Larvae.

Black soldier fly larvae (Hermetia illucens) (BSFL) are insect larvae with significant ecological and economic value. This study aims to investigate whether swill and manure had any effects on the transcriptome and metabolome of BSFL. Through high-throughput transcriptome sequencing, we found that larvae fed with swill exhibited higher levels of gene expression, especially with the upregulation of genes related to energy metabolism, amino acid metabolism, and redox reactions. Metabolomics analysis showed a significant increase in energy metabolism-related metabolites, such as organic acids and amino acids, in the swill-fed larvae. In contrast, gene expression and metabolic characteristics in the pig manure-fed group indicated a higher stress response, with relevant genes and metabolites (such as short-chain fatty acids and antioxidants) showing significant upregulation. GO and KEGG enrichment analyses further supported these results, suggesting that swill promotes larval growth and metabolism, whereas pig manure induces the activation of stress response mechanisms. These findings offer clear molecular and physiological insights into the optimization of substrate selection for enhancing the performance of BSFL in waste management.

Pig manure characteristics and decomposition ability of Protaetia brevitarsis seulensis larval instar stages

AbstractMany types of livestock waste can be treated with insect larvae; however, in‐depth research on the decomposition ability of Protaetia brevitarsis seulensis (PBS) larvae and the characteristics of manure after treatment with PBS is extremely limited. Therefore, this study examined the decomposition ability and survival rates of different instars of PBS larvae and their effects on the characteristics and pathogen counts of pig manure. Two treatments were designed: 1 kg of second instar or third instar PBS larvae per 10 kg of pig manure. Pig manure did not affect the decomposing capacity and survival rates of the two PBS larval instar groups (P &gt; 0.05). However, the decomposition abilities of the different PBS larval instar groups on days 2, 7 and 8 significantly differed (P &lt; 0.05). Over time, the changes observed in pH, moisture, total nitrogen, acid detergent fiber (ADF), neutral detergent fiber (NDF) and hemicelluloses did not significantly differ (P &gt; 0.05) between treatments using second or third instar PBS larvae. On day 15, both total nitrogen and NDF significantly differed (P &lt; 0.05) between the two treatment groups. During the experimental period, no significant (P &gt; 0.05) change in Escherichia coli or Salmonella counts was observed in pig manure treated with different PBS larval instars. Our findings suggest that the decomposition abilities and survival rates of larvae and pig manure characteristics and pathogen counts do not differ for different PBS larval instar stages.

Bacillus thuringiensis strains with high insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera

Abstract The concept of sustainable agricultural development is aimed at reducing the use of chemical pest control agents. Since the use of chemical pesticides poses a significant environmental threat, one of the possible solutions to overcome this problem is the study of biological approaches, in particular, the use of entomopathogenic microorganisms as biological pest control agents. Insecticidal activity of over 220 strains of Bacillus thuringiensis (Bt) and Lysinibacillus sphaericus from the collection of the Laboratory of Spore-Forming Microorganisms of the Microbial Depository Center of the Scientific and Production Center “Armbiotechnology” and 15 strains isolated from samples of dead insects (imago) of representatives of various genera of the Coleoptera order was studied. The pathogenic effect of the strains was assessed in relation to the insect species Tenebrio molitor, Zophobas morio, Leptinotarsa decemlineata Say and Pieris brassicae, belonging to the Coleoptera and Lepidoptera orders. Among the test objects, the representative of Lepidoptera Pieris brassicae demonstrated the highest degree of sensitivity to B. thuringiensis strains up to 100%, with some Bt strains causing 60–100% mortality of Tenebrio molitor and Zophobas morio larvae of different ages. The larvae of the beetle Leptinotarsa decemlineata Say were also partially susceptible, presenting mortality levels of between 31 and 60%. The article is devoted to the study of Bt bacterial strains that have pronounced insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera.

An Investigation on the Food and Feeding Habit of &amp;lt;i&amp;gt;Sarotherodon Galilaeus &amp;lt;/i&amp;gt;(Cichlidae) in Egbe Reservoir, Ekiti State, Nigeria

A study on the food and feeding ecology of &amp;lt;i&amp;gt;Sarotherodon galilaeus&amp;lt;/i&amp;gt;, a species of cichlid found in Nigeria&amp;apos;s Egbe Reservoir. For the investigation, 305 fish specimens were used. The stomach contents were analyzed using diet indices such as stomach fullness, numerical approach, and frequency of occurrence method. Additionally, the Geometric Index of value (GII) was used to determine the relative value of these food products. The findings showed that both adult and juvenile &amp;lt;i&amp;gt;Sarotherodon galilaeus&amp;lt;/i&amp;gt; fed on nine various food sources. The variety of food items included rotifers, algae, desmids, diatoms, protozoa, detritus, aquatic insects, aquatic plants, and insect larvae. The inclusion of detritus in the food items suggests that the fish species graze on both surface water and bottom sediments. Algae had the highest frequency of occurrence (46.39%) in both sizes and seasons, whereas rotifer had the lowest value (1.55%). Since it is possible to create the artificial diet required for this species&amp;apos; mass production in Nigeria, the findings of this study are very significant for the culture of that species&amp;lt;i&amp;gt;. Sarotherodon galilaeus&amp;lt;/i&amp;gt; can be classified as an omnivore because it consumed a variety of foods. Since feeding accounts for 60–65% of the aquaculture industry for any species being raised, research on fish diet and feeding habits is essential to developing an effective aquaculture management system. As a result, the fish species may be raised in our garden.

Evaluating Black Soldier Fly and Bloodworm Larvae Meals as Sustainable Protein Sources for Growth and Survival of Red Hybrid Tilapia (Oreochromis spp.) in the Nursery Phase

Aims: This study aimed to assess the effects of using insect larvae meals, such as BSF and BW larvae, as alternative feeds to commercial pellets on the growth performance and survival of Oreochromis spp. at the nursery stage. Study Design: This study followed the randomized control treatment with three different diet. Place and Duration of Study: This study was carried out at the Fisheries Research Institute Glami Lemi (FRIGL) in Negeri Sembilan, Malaysia, within 35 days from July to August 2023. Methodology: A total of 360 red hybrid tilapia (Oreochromis spp.) fingerlings weighing 0.62 ± 0.06 g were randomly distributed into 12 rectangular aquarium tanks (250mm) at a stocking density of 30 fish per tank. They were fed with commercial pellets (CP), Black Soldier Fly (BSF) larvae, and Bloodworm (BW). The feed amount was calculated at 10% of the total body weight per tank, with feeding conducted three times daily. The experimental setup was performed in triplicate. For the analysis of growth performances and fish survival, sampling was conducted weekly. Results: BSF larvae meal had high lipid and protein content, measuring 35.35 ± 0.21% and 29.67 ± 0.98%, respectively. BW larvae meal also showed high lipid and protein content, with 28.23 ± 1.33% and 27.94 ± 0.52%, respectively. Fish fed with BSF and BW larvae exhibited significantly higher survival rates, 93.3 ± 3.3% and 86.7 ± 14.5%, respectively, compared to the control group. Meanwhile, the group fed with the commercial pellet showed the lowest survival rate, just 74.4 ± 12.6%. Fish fed with the BW larvae recorded the highest weight gain, 1.07 ± 0.16 g, followed by fish fed with BSF larvae, 0.66 ± 0.11 g, and then fish fed with commercial pellets, 0.41 ± 0.09 g. Conclusion: Both BSF and BW larvae exhibited significant growth response properties to tilapia fingerings compared to commercial pellets. The findings from this study are promising and should be further verified at the farm scale.

Processing of Larvae of Alphitobius diaperinus and Tenebrio molitor in Cooked Sausages: Effects on Physicochemical, Microbiological, and Sensory Parameters.

Proteins from insect production represent an interesting (environmentally friendly) option or supplement to commercial livestock farming. At present, however, the larval stages of T. molitor (mealworm) and A. diaperinus (buffalo worm) have been authorized as food for human consumption EU-wide, as have the nymph and adult stages of Locusta (L.) migratoria (Locusta migratoria, Linnaeus, 1758) and Acheta (A.) domesticus (house cricket, Acheta domesticus, Linnaeus, 1758). However, there is the problem that insects that are recognizable as a whole tend to be avoided by consumers, especially in the European region, as they are reminiscent of living things and can cause aversion and disgust in consumers. Against this background, in the present study, five batches of two types of cooked sausages were produced: on the one hand, with turkey, and on the other hand, with pork lean meat as a base. In different formulations, 10% and 20% of the meat contents (turkey or pork) in these meat products were replaced by deep-frozen, pulverized T. molitor and A. diaperinus larvae. The effects of the addition of these insects in the products on the microbiological and physicochemical parameters of these cooked sausages, compared to a product without insect content, directly after heating, were investigated. After production, a storage trial was also carried out to determine whether possible insect ingredients could influence the growth of inoculated bacterial species (Bacillus (B.) cereus, Escherichia (E.) coli, Listeria (L.) monocytogenes, and Campylobacter (C.) jejuni) and how the addition of insect larvae affectsthe sensory and physicochemical properties during storage. The study showed that the products with insects had reduced lightness (turkey p C = 0.025), increased yellowness (pork p S = 0.0009, p C < 0.0001 and turkey p C = 0.0027) and a reduced red color (pork p S < 0.0001, p C = 0.0001) after heating when compared to the cooked sausages without insects. However, no significant differences between the various cooked sausages with or without insects in terms of cooking loss, firmness, and protein, ash, and fat or water contents were found. The microbiological tests showed, on the one hand, that the prior microbial reduction (e.g., in the form of blanching) of the insect larvae was essential in order to guarantee the flawless microbiological quality of the cooked sausages and, on the other hand, that the addition of insects to the cooked sausages did not significantly affect the growth of the inoculated bacterial species and that no sensory differences could be detected during storage. Despite the significant color effects on the product, A. diaperinus and T. molitor larvae would be suitable as protein or meat alternatives in cooked sausages, but they would have to undergo pre-treatment, primarily with regard to microbiological safety. The extent to which a complete replacement of meat is possible has to be investigated in further studies.

Age, Growth, Sex Composition, and Diet of the Burbot, Lota lota, the Only Freshwater Species of the Family Lotidae in the Amur (Heilongjiang) River, Northeast China

Information about the population structure, including the age and sex composition, growth characteristics, and diet of fish, is essential for the conservation and sustainable exploitation of fish stock. The burbot, Lota lota, is the only freshwater species of the family Lotidae in the Amur (Heilongjiang) River catchment located in northeastern China. Information on the biological characteristics and data on the population structure of this fish from the Amur River are scarce. To study these factors in burbot, Lota lota, in the Amur River of China, 749 specimens from four sampling areas were taken and analyzed in October 2022, January 2023, and May 2023. The ages of the sampled fish ranged from 1+ to 7+ years. The female/male ratio was 1.04:1, and body length and mass varied from 175 to 595 mm and 73.5 to 1958.7 g, respectively. The length–weight regression parameter b value was estimated as 2.80. The parameters of the von Bertalanffy growth model were L∞ = 596, K = 0.221, and t0 = −0.771 for all sampled fish; L∞ = 625, K = 0.208, and t0 = −0.756 for females; and L∞ = 584, K = 0.219, and t0 = −0.980 for males. The analysis of the stomach contents showed fish to be the major source of nutrition across all areas and sampling periods. In January, the secondary prey of burbots in the Huma reach of the upper Amur River was aquatic insect larvae, while, in the Tongjiang and Fuyuan reaches of the middle Amur River, the secondary prey was shrimp. The mean stomach fullness index and rate of empty stomachs differed with the sampling area, with the greatest proportion of empty stomachs observed in the Luobei reach of the middle Amur River, and the lowest in the Tongjiang and Fuyuan reaches. The mean stomach fullness index showed the opposite trend. In the Huma reach, the contributions of fish to the diet and the mean stomach fullness index were significantly higher in May than in October and January. The study provides the first detailed information on the population age and sex structure, growth patterns, and feeding ecology of burbots from the Amur River, China. The results will aid in formulating management strategies and regulations for local populations of burbots in the Amur River, China.

Insect Meal as a Dietary Protein Source for Pheasant Quails: Performance, Carcass Traits, Amino Acid Profile and Mineral Contents in Muscles.

The aim of the study was to determine the effects of replacing soybean meal with insect meal on the body weight and the chemical composition of selected muscle groups of common pheasant females and males, including the mineral composition and the amino acid profile of the thigh and breast muscles. The study was conducted on three feeding groups, namely one control and two experimental groups. In the control group, plant feed components were used, which are commonly used to feed pheasants in confined breeding facilities. In the experimental groups, 100 g (group II) and 200 g (group III) portions of insect meal were introduced instead of the plant-protein components. The experiment used a preparation of insect larvae (Hermetia illucens) containing approximately 52% crude protein. The pheasant diet supplementation applied contributed to an increase in the proportion of muscles in the carcasses, with the highest effectiveness obtained for a 20% addition of insect meal. Lower and significant differences were noted in the feed conversion by birds from the experimental groups, as compared to the control group. The chemical composition of the birds' muscles also changed. The experimental groups exhibited higher protein and fat contents and a lower water content. No significant changes in the amino acid profile or the mineral composition of the muscles were noted. The few exceptions concerned the methionine levels in both muscle groups and the isoleucine levels in the breast muscles. In most cases, the mineral composition did not vary significantly (p < 0.05). When supplementing the diet of breeding pheasants for improving meatiness, a 20% addition of insect meal is recommended, which affects the production effect of this trait while reducing feed consumption and maintaining the fatty acid profile.

Death, flies and environments: Towards a qualitative assessment of insect (Diptera) colonization of human cadavers retrieved from sites of death in Brazil

Empirical data on decomposition ecology have long established blowflies (Calliphoridae) and flesh flies (Sarcophagidae) (Diptera) as the most frequent colonizers of carrion, especially at early stages of decomposition. However, the scarcity of studies based on human cadavers has hindered inferences about colonization of homicide victims in real case scenarios. We describe here a survey of insects associated with cadavers retrieved from the site of death in Northeastern Brazil, with emphasis on the association between species diversity and the surrounding environment. We examined 81 cadavers, most of which were of men and resulting from violent death. Twelve cadavers (14.8 %) contained insect larvae, which were reared in the laboratory until adult emergence and identification. Ten species of Diptera effectively colonized the cadavers; seven of Family Calliphoridae – Chrysomya albiceps (Wiedemann, 1819), Chrysomya megacephala (Fabricius, 1794), Chrysomya putoria (Wiedemann, 1830), Cochliomyia macellaria (Fabricius, 1775), Hemilucilia segmentaria (Fabricius, 1805), Lucilia cuprina (Wiedemann, 1830), Lucilia eximia (Wiedemann, 1819) and three of Family Sarcophagidae, Blaesoxipha (Gigantotheca) stallengi (Lahille, 1907), Microcerella halli (Engel, 1931) and Peckia (Sarcodexia) lambens (Wiedemann, 1830). The species C. albiceps and C. macellaria were the most frequent colonizers, while Sarcophagidae was reported in only four cases. Insects were present on cadavers found in urban (n = 8) and rural (n = 4) sites, outdoors (n = 6) and inside (n = 6) residences. Presence of larvae was more frequent in the natural orifices in the head (n = 11). Clothing did not prevent from ovi/larviposition for most species. We present the first register of B. stallengi colonizing human corpses and expand the knowledge on the geographical distribution of necrophagous insects. Our protocol may contribute to forensic entomology in areas exposed to fast decomposition, such as the Neotropical Region.

A new species of the genus Notodoma Lacordaire, 1854 (Coleoptera, Histeridae, Exosternini) from Korea, with a revised key to species of the genus.

A new species of the genus Notodoma Lacordaire, 1854 (Coleoptera, Histeridae, Exosternini), Notodoma koreanum sp. nov., is described from Korea. Most of them recognized from various fungi colonies, feeding on small insect eggs or larvae, as well as fungi. We present the descriptions and images of diagnostic characters for Korean Notodoma species, including Notodoma fungorum Lewis, 1884. Additionally, a revised key to all seven species of the genus Notodoma worldwide, including the newly described species, is provided.

Carbon‐to‐nitrogen stoichiometry of organic amendments regulates microbial biomass growth and nitrogen mineralization in soil

AbstractThe carbon‐to‐nitrogen (C:N) ratio of organic amendments regulates nutrient cycling in soil through its influence on microbial activity. Where an organic amendment has a C:N ratio sparingly higher than that of soil microbes (C:N ratio 6.7—8.7), meeting microbial requirements of carbon and nitrogen may promote microbial biomass growth and nitrogen mineralization. Here we sought to understand the microbial response to the addition of organic amendments with varying C:N ratios and subsequent changes in nitrogen mineralization and plant nitrogen uptake. Dried insect larvae, beef feedlot manure and mixtures of beef feedlot manure with insect larvae or sugarcane residue were used as soil amendments to create a gradient of molar C:N ratios (Cm:Nm) ranging from 6 to 28. An untreated control treatment with a C:N ratio of 17 was also included. Sorghum (Sorghum bicolor L.) was grown in control and organic matter amended soils for 20 days after germination. The mixture of beef feedlot manure and insect larvae treatment (Cm:Nm = 9.7) had on average 68% higher microbial biomass compared with the other treatments. Beef feedlot manure with Cm:Nm ratio of 11 did not influence microbial biomass growth. The concentration of mineral nitrogen was highest in the insect larvae (Cm:Nm = 6) treatment, where 23% of the plant nitrogen was derived from the insect larvae as indicated by the δ15N of plant dry matter. We observed both carbon and nitrogen contents in the organic amendment determine microbial biomass growth and nitrogen mineralization in soil. The results presented here demonstrate that microbial response to organic amendments determines the availability of mineral nitrogen in soil.

Seasonal Feeding Activity and Ontogenetic Dietary Shifts of the Common Carp (Cyprinus carpio) in Lake Arekit, a Small, Eutrophic Lake in Ethiopia

ABSTRACTSeasonal feeding activity and ontogenetic dietary shifts of Cyprinus carpio (Linnaeus, 1758) were examined using 209 fish samples from Lake Arekit, Ethiopia. Among the 209 specimens, 174 (83.3%) displayed a range of dietary items in their stomachs. The species’ feeding patterns were determined through numerical indexes (frequency of occurrence and volumetric contribution) and composite indexes (index of preponderance [IOP] and Geometric Index of Importance [GIIi]). Detritus emerged as the primary food source for C. carpio, followed by macrophytes, insects and zooplankton. A lesser amount of phytoplankton, nematodes and ostracods were also consumed. On the basis of the findings, C. carpio can be classified as a detri‐omnivore, as it consumes benthic species like nematodes, ostracods and insect larvae. Seasonal fluctuations in food item consumption were noted (p &lt; 0.05), with higher intake during the rainy season and reduced consumption in the dry season. There was a distinct ontogenetic shift in the relative importance of food items and showed significant variations in food preferences among size groups (p &lt; 0.05). The contributions of animal‐origin food categories (ostracods, zooplankton and insects) were important in the diet of the smaller size class, whereas food of plant origin (macrophytes) and detritus were more important in the diet of adults. Understanding the seasonal feeding patterns and ontogenetic dietary shifts of C. carpio in Lake Arekit provides crucial insights into their ecological role within the lake's ecosystem and highlights their adaptability to eutrophic conditions.

Cultivating Flesh Fly Larvae as a Sustainable Feed Source for the Ornamental Fish (Carassius auratus)

Background: Providing ornamental fish (Carassius auratus), with nutritious and sustainable food sources is an increasingly important part of that process. Flesh flies (Sarcophaga spp.) have a high content of nutrient in their larval stage, which make their bodies grow quickly during their larval phase. Methods: The nutrient composition of Sarcophaga larvae and their effect as a feeding source on C. auratus growth during the process were studied. In a laboratory, Sarcophaga larvae were cultured on shrimp shells and C. auratus fed on Sarcophaga larvae were compared to C. auratus fed on commercial food. Result: Crude protein content of 52.5% was remarkably high, followed by crude lipid (30.2%), crude fibers (9.8%) and finally crude ash (7.5%). Our results showed also a significant improvement in growth performance of C. auratus fed on Sarcophaga larvae, with a median weight of 25.3 g compared with the control group (17.3 g) by the fourth week, indicating significant advantages for C. auratus fed on Sarcophaga larvae. In this study, Sarcophaga larvae are examined as a sustainable and nutritious source of food for C. auratus fish. Using insect larvae for aquaculture should be further refined and evaluated for long-term benefits and safety.

Live black soldier fly larvae as environmental enrichment for native chickens: implications for bird performance, welfare, and excreta microbiota

Dietary live insect larvae were recently proposed for use in laying hens and broiler−intensive chicken farming as an innovative form of environmental enrichment, but their use in native dual-purpose chickens has never been investigated. This study aims to evaluate the effects of live black soldier fly (BSF) larvae as environmental enrichment in two autochthonous dual-purpose chicken breeds, namely Bionda Piemontese (BP) and Bianca di Saluzzo (BS), in terms of bird performance, behaviour, integument status, excreta corticosterone metabolites (ECMs), and microbiota analyses. A total of 90 BP and 90 BS hens aged 308 days old were randomly distributed between two treatment groups (three replicates/group/breed, 15 hens/replicate). For the following 90 days, the control group (C) was fed a commercial feed only, whereas the BSF group was fed the commercial diet plus BSF live larvae calculated at 6% of the expected daily feed intake (DFI). Larva ingestion time, bird performance, integument scores, and behavioural observations were assessed at regular intervals, and excreta samples were collected to evaluate ECM and microbiota. The larva ingestion time became faster over the course of the experimental trial (P < 0.001). The DFI of BSF-fed hens was lower than that of C hens independently of breed (P < 0.001), whereas only in the BS hens, the live weight of the BSF-fed group was greater than that of the C group (P < 0.01). The BSF-fed BP hens showed a higher laying rate and feed conversion ratio compared with BSF-BS (P < 0.05). Better total integument scores were observed in BSF-fed BP hens compared with C-birds (P < 0.05). The BSF-fed hens displayed higher frequencies of preening, trotting, and wing flapping than C, as well as a lower incidence of severe feather pecking (P < 0.05). An increase in allopreening was only identified in BSF-fed BS hens with respect to the C hens (P < 0.001). No differences in ECM and faecal microbiota were observed between treatment groups. In conclusion, the administration of BSF live larvae as environmental enrichment has the potential to positively influence the welfare of both BP and BS chickens, by enhancing the frequency of positive behaviours whilst reducing severe feather pecking, without affecting their excreta microbiota. BSF larva administration also has the potential to improve the productive performance and the plumage status of the BP breed.

Goal-directed behavior in Tenebrio molitor larvae

Can signs of intentional behavior be traced in an insect larva, traditionally thought to be driven only by mere reflexes? We trained Tenebrio molitor coleoptera larvae in a uniform Y-maze to prefer one target branch to get access to food, observing their ability to learn and retain access to the reward-associated side for up to 24 h. During reward devaluation, the reward food (experimental group) and a different food (control group) were paired with an aversive stimulus in a new environment. When tested again in the Y-maze, mealworms of the experimental group significantly reduced their visits to the target branch, whereas mealworms of the control group did not. Importantly, we found that the larvae did not have to experience the unpleasant consequences directly in the target branch to halt their behavior, as the exposure to the aversive taste occurred in a separate unfamiliar context. This is evidence that the mealworms formed a mental representation of action-consequence relationships, demonstrating flexible control of their actions to achieve desired outcomes at an early stage of their development.